123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574575576577578579580581582583584585586587588589590591592593594595596597598599600601602603604605606607608609610611612613614615616617618619620621622623624625626627628629630631632633634635636637638639640641642643644645646647648649650651652653654655656657658659660661662663664665666667668669670671672673674675676677678679680681682683684685686687688689690691692693694695696697698699700701702703704705706707708709710711712713714715716717718719720721722723724725726727728729730731732733734735736737738739740741742743744745746747748749750751752753754755756757758759760761762763764765766767768769770771772773774775776777778779780781782783784785786787788789790791792793794795796797798799800801802803804805806807808809810811812813814815816817818819820821822823824825826827828829830831832833834835836837838839840841842843844845846847848849850851852853854855856857858859860861862863864865866867868869870871872873874875876877878879880881882883884885886887888889890891892893894895896897898899900901902903904905906907908909910911912913914915916917918919920921922923924925926927928929930931932933934935936937938939940941942943944945946947948949950951952953954955956957958959960961962963964965966967968969970971972973974975976977978979980981982983984985986987988989990991992993994995996997998999100010011002100310041005100610071008100910101011101210131014101510161017101810191020102110221023102410251026102710281029103010311032103310341035103610371038103910401041104210431044104510461047104810491050105110521053105410551056105710581059106010611062106310641065106610671068106910701071107210731074107510761077107810791080108110821083108410851086108710881089109010911092109310941095109610971098109911001101110211031104110511061107110811091110111111121113111411151116111711181119112011211122112311241125112611271128112911301131113211331134113511361137113811391140114111421143114411451146114711481149115011511152115311541155115611571158115911601161116211631164116511661167116811691170117111721173117411751176117711781179118011811182118311841185118611871188118911901191119211931194119511961197119811991200120112021203120412051206120712081209121012111212121312141215121612171218121912201221122212231224122512261227122812291230123112321233123412351236123712381239124012411242124312441245124612471248124912501251125212531254125512561257125812591260126112621263126412651266126712681269127012711272127312741275127612771278127912801281128212831284128512861287128812891290129112921293129412951296129712981299130013011302130313041305130613071308130913101311131213131314131513161317131813191320132113221323132413251326132713281329133013311332133313341335133613371338133913401341134213431344134513461347134813491350135113521353135413551356135713581359136013611362136313641365136613671368136913701371137213731374137513761377137813791380138113821383138413851386138713881389139013911392139313941395139613971398139914001401140214031404140514061407140814091410141114121413141414151416141714181419142014211422142314241425142614271428142914301431143214331434143514361437143814391440144114421443144414451446144714481449145014511452145314541455145614571458145914601461146214631464146514661467146814691470147114721473147414751476147714781479148014811482148314841485148614871488148914901491149214931494149514961497149814991500150115021503150415051506150715081509151015111512151315141515151615171518151915201521152215231524152515261527152815291530153115321533153415351536153715381539154015411542154315441545154615471548154915501551155215531554155515561557155815591560156115621563156415651566156715681569157015711572157315741575157615771578157915801581158215831584158515861587158815891590159115921593159415951596159715981599160016011602160316041605160616071608160916101611161216131614161516161617161816191620162116221623162416251626162716281629163016311632163316341635163616371638163916401641164216431644164516461647164816491650165116521653165416551656165716581659166016611662166316641665166616671668166916701671167216731674167516761677167816791680168116821683168416851686168716881689169016911692169316941695169616971698169917001701170217031704170517061707170817091710171117121713171417151716171717181719172017211722172317241725172617271728172917301731173217331734173517361737173817391740174117421743174417451746174717481749175017511752175317541755175617571758175917601761176217631764176517661767176817691770177117721773177417751776177717781779178017811782178317841785178617871788178917901791179217931794179517961797179817991800180118021803180418051806180718081809181018111812181318141815181618171818181918201821182218231824182518261827182818291830183118321833183418351836183718381839184018411842184318441845184618471848184918501851185218531854185518561857185818591860186118621863186418651866186718681869187018711872187318741875187618771878187918801881188218831884188518861887188818891890189118921893189418951896189718981899190019011902190319041905190619071908190919101911191219131914191519161917191819191920192119221923192419251926192719281929193019311932193319341935193619371938193919401941194219431944194519461947194819491950195119521953195419551956195719581959196019611962196319641965196619671968196919701971197219731974197519761977197819791980198119821983198419851986198719881989199019911992199319941995199619971998199920002001200220032004200520062007200820092010201120122013201420152016201720182019202020212022202320242025202620272028202920302031203220332034203520362037203820392040204120422043204420452046204720482049205020512052205320542055205620572058205920602061206220632064206520662067206820692070207120722073207420752076207720782079208020812082208320842085208620872088208920902091209220932094209520962097209820992100210121022103210421052106210721082109211021112112211321142115211621172118211921202121212221232124212521262127212821292130213121322133213421352136213721382139214021412142214321442145214621472148214921502151215221532154215521562157215821592160216121622163216421652166216721682169217021712172217321742175217621772178217921802181218221832184218521862187218821892190219121922193219421952196219721982199220022012202220322042205220622072208220922102211221222132214221522162217221822192220222122222223222422252226222722282229223022312232223322342235223622372238223922402241224222432244224522462247224822492250225122522253225422552256225722582259226022612262226322642265226622672268226922702271227222732274227522762277227822792280228122822283228422852286228722882289229022912292229322942295229622972298229923002301230223032304230523062307230823092310231123122313231423152316231723182319232023212322232323242325232623272328232923302331233223332334233523362337233823392340234123422343234423452346234723482349235023512352235323542355235623572358235923602361236223632364236523662367236823692370237123722373237423752376237723782379238023812382238323842385238623872388238923902391239223932394239523962397239823992400240124022403240424052406240724082409241024112412241324142415241624172418241924202421242224232424242524262427242824292430243124322433243424352436243724382439244024412442244324442445244624472448244924502451245224532454245524562457245824592460246124622463246424652466246724682469247024712472247324742475247624772478247924802481248224832484248524862487248824892490249124922493249424952496249724982499250025012502250325042505250625072508250925102511251225132514251525162517251825192520252125222523252425252526252725282529253025312532253325342535253625372538253925402541254225432544254525462547254825492550255125522553255425552556255725582559256025612562256325642565256625672568256925702571257225732574257525762577257825792580258125822583258425852586258725882589259025912592259325942595259625972598259926002601260226032604260526062607260826092610261126122613261426152616261726182619262026212622262326242625262626272628262926302631263226332634263526362637263826392640264126422643264426452646264726482649265026512652265326542655265626572658265926602661266226632664266526662667266826692670267126722673267426752676267726782679268026812682268326842685268626872688268926902691269226932694269526962697269826992700270127022703270427052706270727082709271027112712271327142715271627172718271927202721272227232724272527262727272827292730273127322733273427352736273727382739274027412742274327442745274627472748274927502751275227532754275527562757275827592760276127622763276427652766276727682769277027712772277327742775277627772778277927802781278227832784278527862787278827892790279127922793279427952796279727982799280028012802280328042805280628072808280928102811281228132814281528162817281828192820282128222823282428252826282728282829283028312832283328342835283628372838283928402841284228432844284528462847284828492850285128522853285428552856285728582859286028612862286328642865286628672868286928702871287228732874287528762877287828792880288128822883288428852886288728882889289028912892289328942895289628972898289929002901290229032904290529062907290829092910291129122913291429152916291729182919292029212922292329242925292629272928292929302931293229332934293529362937293829392940294129422943294429452946294729482949295029512952295329542955295629572958295929602961296229632964296529662967296829692970297129722973297429752976297729782979298029812982298329842985298629872988298929902991299229932994299529962997299829993000300130023003300430053006300730083009301030113012301330143015301630173018301930203021302230233024302530263027302830293030303130323033303430353036303730383039304030413042304330443045304630473048304930503051305230533054305530563057305830593060306130623063306430653066306730683069307030713072307330743075307630773078307930803081308230833084308530863087308830893090309130923093309430953096309730983099310031013102310331043105310631073108310931103111311231133114311531163117311831193120312131223123312431253126312731283129313031313132313331343135313631373138313931403141314231433144314531463147314831493150315131523153315431553156315731583159316031613162316331643165316631673168316931703171317231733174317531763177317831793180318131823183318431853186318731883189319031913192319331943195319631973198319932003201320232033204320532063207320832093210321132123213321432153216321732183219322032213222322332243225322632273228322932303231323232333234323532363237323832393240324132423243324432453246324732483249325032513252325332543255325632573258325932603261326232633264326532663267326832693270327132723273327432753276327732783279328032813282328332843285328632873288328932903291329232933294329532963297329832993300330133023303330433053306330733083309331033113312331333143315331633173318331933203321332233233324332533263327332833293330333133323333333433353336333733383339334033413342334333443345334633473348334933503351335233533354335533563357335833593360336133623363336433653366336733683369337033713372337333743375337633773378337933803381338233833384338533863387338833893390339133923393339433953396339733983399340034013402340334043405340634073408340934103411341234133414341534163417341834193420342134223423342434253426342734283429343034313432343334343435343634373438343934403441344234433444344534463447344834493450345134523453345434553456345734583459346034613462346334643465346634673468346934703471347234733474347534763477347834793480348134823483348434853486348734883489349034913492349334943495349634973498349935003501350235033504350535063507350835093510351135123513351435153516351735183519352035213522352335243525352635273528352935303531353235333534353535363537353835393540354135423543354435453546354735483549355035513552355335543555355635573558355935603561356235633564356535663567356835693570357135723573357435753576357735783579358035813582358335843585358635873588358935903591359235933594359535963597359835993600360136023603360436053606360736083609361036113612361336143615361636173618361936203621362236233624362536263627362836293630363136323633363436353636363736383639364036413642364336443645364636473648364936503651365236533654365536563657365836593660366136623663366436653666366736683669367036713672367336743675367636773678367936803681368236833684368536863687368836893690369136923693369436953696369736983699370037013702370337043705370637073708370937103711371237133714371537163717371837193720372137223723372437253726372737283729373037313732373337343735373637373738373937403741374237433744374537463747374837493750375137523753375437553756375737583759376037613762376337643765376637673768376937703771377237733774377537763777377837793780378137823783378437853786378737883789379037913792379337943795379637973798379938003801380238033804380538063807380838093810381138123813381438153816381738183819382038213822382338243825382638273828382938303831383238333834383538363837383838393840384138423843384438453846384738483849385038513852385338543855385638573858385938603861386238633864386538663867386838693870387138723873387438753876387738783879388038813882388338843885388638873888388938903891389238933894389538963897389838993900390139023903390439053906390739083909391039113912391339143915391639173918391939203921392239233924392539263927392839293930393139323933393439353936393739383939394039413942394339443945394639473948394939503951395239533954395539563957395839593960396139623963396439653966396739683969397039713972397339743975397639773978397939803981398239833984398539863987398839893990399139923993399439953996399739983999400040014002400340044005400640074008400940104011401240134014401540164017401840194020402140224023402440254026402740284029403040314032403340344035403640374038403940404041404240434044404540464047404840494050405140524053405440554056405740584059406040614062406340644065406640674068406940704071407240734074407540764077407840794080408140824083408440854086408740884089409040914092409340944095409640974098409941004101410241034104410541064107410841094110411141124113411441154116411741184119412041214122412341244125412641274128412941304131413241334134413541364137413841394140414141424143414441454146414741484149415041514152415341544155415641574158415941604161416241634164416541664167416841694170417141724173417441754176417741784179418041814182418341844185418641874188418941904191419241934194419541964197419841994200420142024203420442054206420742084209421042114212421342144215421642174218421942204221422242234224422542264227422842294230423142324233423442354236423742384239424042414242424342444245424642474248424942504251425242534254425542564257425842594260426142624263426442654266426742684269427042714272427342744275427642774278427942804281428242834284428542864287428842894290429142924293429442954296429742984299430043014302430343044305430643074308430943104311431243134314431543164317431843194320432143224323432443254326432743284329433043314332433343344335433643374338433943404341434243434344434543464347434843494350435143524353435443554356435743584359436043614362436343644365436643674368436943704371437243734374437543764377437843794380438143824383438443854386438743884389439043914392439343944395439643974398439944004401440244034404440544064407440844094410441144124413441444154416441744184419442044214422442344244425442644274428442944304431443244334434443544364437443844394440444144424443444444454446444744484449445044514452445344544455445644574458445944604461446244634464446544664467446844694470447144724473447444754476447744784479448044814482448344844485448644874488448944904491449244934494449544964497449844994500450145024503450445054506450745084509451045114512451345144515451645174518451945204521452245234524452545264527452845294530453145324533453445354536453745384539454045414542454345444545454645474548454945504551455245534554455545564557455845594560456145624563456445654566456745684569457045714572457345744575457645774578457945804581458245834584458545864587458845894590459145924593459445954596459745984599460046014602460346044605460646074608460946104611461246134614461546164617461846194620462146224623462446254626462746284629463046314632463346344635463646374638463946404641464246434644464546464647464846494650465146524653465446554656465746584659466046614662466346644665466646674668466946704671467246734674467546764677467846794680468146824683468446854686468746884689469046914692469346944695469646974698469947004701470247034704470547064707470847094710471147124713471447154716471747184719472047214722472347244725472647274728472947304731473247334734473547364737473847394740474147424743474447454746474747484749475047514752475347544755475647574758475947604761476247634764476547664767476847694770477147724773477447754776477747784779478047814782478347844785478647874788478947904791479247934794479547964797479847994800480148024803480448054806480748084809481048114812481348144815481648174818481948204821482248234824482548264827482848294830483148324833483448354836483748384839484048414842484348444845484648474848484948504851485248534854485548564857485848594860486148624863486448654866486748684869487048714872487348744875487648774878487948804881488248834884488548864887488848894890489148924893489448954896489748984899490049014902490349044905490649074908490949104911491249134914491549164917491849194920492149224923492449254926492749284929493049314932493349344935493649374938493949404941494249434944494549464947494849494950495149524953495449554956495749584959496049614962496349644965496649674968496949704971497249734974497549764977497849794980498149824983498449854986498749884989499049914992499349944995499649974998499950005001500250035004500550065007500850095010501150125013501450155016501750185019502050215022502350245025502650275028502950305031503250335034503550365037503850395040504150425043504450455046504750485049505050515052505350545055505650575058505950605061506250635064506550665067506850695070507150725073507450755076507750785079508050815082508350845085508650875088508950905091509250935094509550965097509850995100510151025103510451055106510751085109511051115112511351145115511651175118511951205121512251235124512551265127512851295130513151325133513451355136513751385139514051415142514351445145514651475148514951505151515251535154515551565157515851595160516151625163516451655166516751685169517051715172517351745175517651775178517951805181518251835184518551865187518851895190519151925193519451955196519751985199520052015202520352045205520652075208520952105211521252135214521552165217521852195220522152225223522452255226522752285229523052315232523352345235523652375238523952405241524252435244524552465247524852495250525152525253525452555256525752585259526052615262526352645265526652675268526952705271527252735274527552765277527852795280528152825283528452855286528752885289529052915292529352945295529652975298529953005301530253035304530553065307530853095310531153125313531453155316531753185319532053215322532353245325532653275328532953305331533253335334533553365337533853395340534153425343534453455346534753485349535053515352535353545355535653575358535953605361536253635364536553665367536853695370537153725373537453755376537753785379538053815382538353845385538653875388538953905391539253935394539553965397539853995400540154025403540454055406540754085409541054115412541354145415541654175418541954205421542254235424542554265427542854295430543154325433543454355436543754385439544054415442544354445445544654475448544954505451545254535454545554565457545854595460546154625463546454655466546754685469547054715472547354745475547654775478547954805481548254835484548554865487548854895490549154925493549454955496549754985499550055015502550355045505550655075508550955105511551255135514551555165517551855195520552155225523552455255526552755285529553055315532553355345535553655375538553955405541554255435544554555465547554855495550555155525553555455555556555755585559556055615562556355645565556655675568556955705571557255735574557555765577557855795580558155825583558455855586558755885589559055915592559355945595559655975598559956005601560256035604560556065607560856095610561156125613561456155616561756185619562056215622562356245625562656275628562956305631563256335634563556365637563856395640564156425643564456455646564756485649565056515652565356545655565656575658565956605661566256635664566556665667566856695670567156725673567456755676567756785679568056815682568356845685568656875688568956905691569256935694569556965697569856995700570157025703570457055706570757085709571057115712571357145715571657175718571957205721572257235724572557265727572857295730573157325733573457355736573757385739574057415742574357445745574657475748574957505751575257535754575557565757575857595760576157625763576457655766576757685769577057715772577357745775577657775778577957805781578257835784578557865787578857895790579157925793579457955796579757985799580058015802580358045805580658075808580958105811581258135814581558165817581858195820582158225823582458255826582758285829583058315832583358345835583658375838583958405841584258435844584558465847584858495850585158525853585458555856585758585859586058615862586358645865586658675868586958705871587258735874587558765877 |
- // SPDX-License-Identifier: GPL-2.0-only
- /*
- * Generic hugetlb support.
- * (C) Nadia Yvette Chambers, April 2004
- */
- #include <linux/list.h>
- #include <linux/init.h>
- #include <linux/mm.h>
- #include <linux/seq_file.h>
- #include <linux/sysctl.h>
- #include <linux/highmem.h>
- #include <linux/mmu_notifier.h>
- #include <linux/nodemask.h>
- #include <linux/pagemap.h>
- #include <linux/mempolicy.h>
- #include <linux/compiler.h>
- #include <linux/cpuset.h>
- #include <linux/mutex.h>
- #include <linux/memblock.h>
- #include <linux/sysfs.h>
- #include <linux/slab.h>
- #include <linux/sched/mm.h>
- #include <linux/mmdebug.h>
- #include <linux/sched/signal.h>
- #include <linux/rmap.h>
- #include <linux/string_helpers.h>
- #include <linux/swap.h>
- #include <linux/swapops.h>
- #include <linux/jhash.h>
- #include <linux/numa.h>
- #include <linux/llist.h>
- #include <linux/cma.h>
- #include <asm/page.h>
- #include <asm/pgalloc.h>
- #include <asm/tlb.h>
- #include <linux/io.h>
- #include <linux/hugetlb.h>
- #include <linux/hugetlb_cgroup.h>
- #include <linux/node.h>
- #include <linux/page_owner.h>
- #include "internal.h"
- int hugetlb_max_hstate __read_mostly;
- unsigned int default_hstate_idx;
- struct hstate hstates[HUGE_MAX_HSTATE];
- #ifdef CONFIG_CMA
- static struct cma *hugetlb_cma[MAX_NUMNODES];
- #endif
- static unsigned long hugetlb_cma_size __initdata;
- /*
- * Minimum page order among possible hugepage sizes, set to a proper value
- * at boot time.
- */
- static unsigned int minimum_order __read_mostly = UINT_MAX;
- __initdata LIST_HEAD(huge_boot_pages);
- /* for command line parsing */
- static struct hstate * __initdata parsed_hstate;
- static unsigned long __initdata default_hstate_max_huge_pages;
- static bool __initdata parsed_valid_hugepagesz = true;
- static bool __initdata parsed_default_hugepagesz;
- /*
- * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages,
- * free_huge_pages, and surplus_huge_pages.
- */
- DEFINE_SPINLOCK(hugetlb_lock);
- /*
- * Serializes faults on the same logical page. This is used to
- * prevent spurious OOMs when the hugepage pool is fully utilized.
- */
- static int num_fault_mutexes;
- struct mutex *hugetlb_fault_mutex_table ____cacheline_aligned_in_smp;
- static inline bool PageHugeFreed(struct page *head)
- {
- return page_private(head + 4) == -1UL;
- }
- static inline void SetPageHugeFreed(struct page *head)
- {
- set_page_private(head + 4, -1UL);
- }
- static inline void ClearPageHugeFreed(struct page *head)
- {
- set_page_private(head + 4, 0);
- }
- /* Forward declaration */
- static int hugetlb_acct_memory(struct hstate *h, long delta);
- static inline void unlock_or_release_subpool(struct hugepage_subpool *spool)
- {
- bool free = (spool->count == 0) && (spool->used_hpages == 0);
- spin_unlock(&spool->lock);
- /* If no pages are used, and no other handles to the subpool
- * remain, give up any reservations based on minimum size and
- * free the subpool */
- if (free) {
- if (spool->min_hpages != -1)
- hugetlb_acct_memory(spool->hstate,
- -spool->min_hpages);
- kfree(spool);
- }
- }
- struct hugepage_subpool *hugepage_new_subpool(struct hstate *h, long max_hpages,
- long min_hpages)
- {
- struct hugepage_subpool *spool;
- spool = kzalloc(sizeof(*spool), GFP_KERNEL);
- if (!spool)
- return NULL;
- spin_lock_init(&spool->lock);
- spool->count = 1;
- spool->max_hpages = max_hpages;
- spool->hstate = h;
- spool->min_hpages = min_hpages;
- if (min_hpages != -1 && hugetlb_acct_memory(h, min_hpages)) {
- kfree(spool);
- return NULL;
- }
- spool->rsv_hpages = min_hpages;
- return spool;
- }
- void hugepage_put_subpool(struct hugepage_subpool *spool)
- {
- spin_lock(&spool->lock);
- BUG_ON(!spool->count);
- spool->count--;
- unlock_or_release_subpool(spool);
- }
- /*
- * Subpool accounting for allocating and reserving pages.
- * Return -ENOMEM if there are not enough resources to satisfy the
- * request. Otherwise, return the number of pages by which the
- * global pools must be adjusted (upward). The returned value may
- * only be different than the passed value (delta) in the case where
- * a subpool minimum size must be maintained.
- */
- static long hugepage_subpool_get_pages(struct hugepage_subpool *spool,
- long delta)
- {
- long ret = delta;
- if (!spool)
- return ret;
- spin_lock(&spool->lock);
- if (spool->max_hpages != -1) { /* maximum size accounting */
- if ((spool->used_hpages + delta) <= spool->max_hpages)
- spool->used_hpages += delta;
- else {
- ret = -ENOMEM;
- goto unlock_ret;
- }
- }
- /* minimum size accounting */
- if (spool->min_hpages != -1 && spool->rsv_hpages) {
- if (delta > spool->rsv_hpages) {
- /*
- * Asking for more reserves than those already taken on
- * behalf of subpool. Return difference.
- */
- ret = delta - spool->rsv_hpages;
- spool->rsv_hpages = 0;
- } else {
- ret = 0; /* reserves already accounted for */
- spool->rsv_hpages -= delta;
- }
- }
- unlock_ret:
- spin_unlock(&spool->lock);
- return ret;
- }
- /*
- * Subpool accounting for freeing and unreserving pages.
- * Return the number of global page reservations that must be dropped.
- * The return value may only be different than the passed value (delta)
- * in the case where a subpool minimum size must be maintained.
- */
- static long hugepage_subpool_put_pages(struct hugepage_subpool *spool,
- long delta)
- {
- long ret = delta;
- if (!spool)
- return delta;
- spin_lock(&spool->lock);
- if (spool->max_hpages != -1) /* maximum size accounting */
- spool->used_hpages -= delta;
- /* minimum size accounting */
- if (spool->min_hpages != -1 && spool->used_hpages < spool->min_hpages) {
- if (spool->rsv_hpages + delta <= spool->min_hpages)
- ret = 0;
- else
- ret = spool->rsv_hpages + delta - spool->min_hpages;
- spool->rsv_hpages += delta;
- if (spool->rsv_hpages > spool->min_hpages)
- spool->rsv_hpages = spool->min_hpages;
- }
- /*
- * If hugetlbfs_put_super couldn't free spool due to an outstanding
- * quota reference, free it now.
- */
- unlock_or_release_subpool(spool);
- return ret;
- }
- static inline struct hugepage_subpool *subpool_inode(struct inode *inode)
- {
- return HUGETLBFS_SB(inode->i_sb)->spool;
- }
- static inline struct hugepage_subpool *subpool_vma(struct vm_area_struct *vma)
- {
- return subpool_inode(file_inode(vma->vm_file));
- }
- /* Helper that removes a struct file_region from the resv_map cache and returns
- * it for use.
- */
- static struct file_region *
- get_file_region_entry_from_cache(struct resv_map *resv, long from, long to)
- {
- struct file_region *nrg = NULL;
- VM_BUG_ON(resv->region_cache_count <= 0);
- resv->region_cache_count--;
- nrg = list_first_entry(&resv->region_cache, struct file_region, link);
- list_del(&nrg->link);
- nrg->from = from;
- nrg->to = to;
- return nrg;
- }
- static void copy_hugetlb_cgroup_uncharge_info(struct file_region *nrg,
- struct file_region *rg)
- {
- #ifdef CONFIG_CGROUP_HUGETLB
- nrg->reservation_counter = rg->reservation_counter;
- nrg->css = rg->css;
- if (rg->css)
- css_get(rg->css);
- #endif
- }
- /* Helper that records hugetlb_cgroup uncharge info. */
- static void record_hugetlb_cgroup_uncharge_info(struct hugetlb_cgroup *h_cg,
- struct hstate *h,
- struct resv_map *resv,
- struct file_region *nrg)
- {
- #ifdef CONFIG_CGROUP_HUGETLB
- if (h_cg) {
- nrg->reservation_counter =
- &h_cg->rsvd_hugepage[hstate_index(h)];
- nrg->css = &h_cg->css;
- /*
- * The caller will hold exactly one h_cg->css reference for the
- * whole contiguous reservation region. But this area might be
- * scattered when there are already some file_regions reside in
- * it. As a result, many file_regions may share only one css
- * reference. In order to ensure that one file_region must hold
- * exactly one h_cg->css reference, we should do css_get for
- * each file_region and leave the reference held by caller
- * untouched.
- */
- css_get(&h_cg->css);
- if (!resv->pages_per_hpage)
- resv->pages_per_hpage = pages_per_huge_page(h);
- /* pages_per_hpage should be the same for all entries in
- * a resv_map.
- */
- VM_BUG_ON(resv->pages_per_hpage != pages_per_huge_page(h));
- } else {
- nrg->reservation_counter = NULL;
- nrg->css = NULL;
- }
- #endif
- }
- static void put_uncharge_info(struct file_region *rg)
- {
- #ifdef CONFIG_CGROUP_HUGETLB
- if (rg->css)
- css_put(rg->css);
- #endif
- }
- static bool has_same_uncharge_info(struct file_region *rg,
- struct file_region *org)
- {
- #ifdef CONFIG_CGROUP_HUGETLB
- return rg && org &&
- rg->reservation_counter == org->reservation_counter &&
- rg->css == org->css;
- #else
- return true;
- #endif
- }
- static void coalesce_file_region(struct resv_map *resv, struct file_region *rg)
- {
- struct file_region *nrg = NULL, *prg = NULL;
- prg = list_prev_entry(rg, link);
- if (&prg->link != &resv->regions && prg->to == rg->from &&
- has_same_uncharge_info(prg, rg)) {
- prg->to = rg->to;
- list_del(&rg->link);
- put_uncharge_info(rg);
- kfree(rg);
- rg = prg;
- }
- nrg = list_next_entry(rg, link);
- if (&nrg->link != &resv->regions && nrg->from == rg->to &&
- has_same_uncharge_info(nrg, rg)) {
- nrg->from = rg->from;
- list_del(&rg->link);
- put_uncharge_info(rg);
- kfree(rg);
- }
- }
- /*
- * Must be called with resv->lock held.
- *
- * Calling this with regions_needed != NULL will count the number of pages
- * to be added but will not modify the linked list. And regions_needed will
- * indicate the number of file_regions needed in the cache to carry out to add
- * the regions for this range.
- */
- static long add_reservation_in_range(struct resv_map *resv, long f, long t,
- struct hugetlb_cgroup *h_cg,
- struct hstate *h, long *regions_needed)
- {
- long add = 0;
- struct list_head *head = &resv->regions;
- long last_accounted_offset = f;
- struct file_region *rg = NULL, *trg = NULL, *nrg = NULL;
- if (regions_needed)
- *regions_needed = 0;
- /* In this loop, we essentially handle an entry for the range
- * [last_accounted_offset, rg->from), at every iteration, with some
- * bounds checking.
- */
- list_for_each_entry_safe(rg, trg, head, link) {
- /* Skip irrelevant regions that start before our range. */
- if (rg->from < f) {
- /* If this region ends after the last accounted offset,
- * then we need to update last_accounted_offset.
- */
- if (rg->to > last_accounted_offset)
- last_accounted_offset = rg->to;
- continue;
- }
- /* When we find a region that starts beyond our range, we've
- * finished.
- */
- if (rg->from > t)
- break;
- /* Add an entry for last_accounted_offset -> rg->from, and
- * update last_accounted_offset.
- */
- if (rg->from > last_accounted_offset) {
- add += rg->from - last_accounted_offset;
- if (!regions_needed) {
- nrg = get_file_region_entry_from_cache(
- resv, last_accounted_offset, rg->from);
- record_hugetlb_cgroup_uncharge_info(h_cg, h,
- resv, nrg);
- list_add(&nrg->link, rg->link.prev);
- coalesce_file_region(resv, nrg);
- } else
- *regions_needed += 1;
- }
- last_accounted_offset = rg->to;
- }
- /* Handle the case where our range extends beyond
- * last_accounted_offset.
- */
- if (last_accounted_offset < t) {
- add += t - last_accounted_offset;
- if (!regions_needed) {
- nrg = get_file_region_entry_from_cache(
- resv, last_accounted_offset, t);
- record_hugetlb_cgroup_uncharge_info(h_cg, h, resv, nrg);
- list_add(&nrg->link, rg->link.prev);
- coalesce_file_region(resv, nrg);
- } else
- *regions_needed += 1;
- }
- VM_BUG_ON(add < 0);
- return add;
- }
- /* Must be called with resv->lock acquired. Will drop lock to allocate entries.
- */
- static int allocate_file_region_entries(struct resv_map *resv,
- int regions_needed)
- __must_hold(&resv->lock)
- {
- struct list_head allocated_regions;
- int to_allocate = 0, i = 0;
- struct file_region *trg = NULL, *rg = NULL;
- VM_BUG_ON(regions_needed < 0);
- INIT_LIST_HEAD(&allocated_regions);
- /*
- * Check for sufficient descriptors in the cache to accommodate
- * the number of in progress add operations plus regions_needed.
- *
- * This is a while loop because when we drop the lock, some other call
- * to region_add or region_del may have consumed some region_entries,
- * so we keep looping here until we finally have enough entries for
- * (adds_in_progress + regions_needed).
- */
- while (resv->region_cache_count <
- (resv->adds_in_progress + regions_needed)) {
- to_allocate = resv->adds_in_progress + regions_needed -
- resv->region_cache_count;
- /* At this point, we should have enough entries in the cache
- * for all the existings adds_in_progress. We should only be
- * needing to allocate for regions_needed.
- */
- VM_BUG_ON(resv->region_cache_count < resv->adds_in_progress);
- spin_unlock(&resv->lock);
- for (i = 0; i < to_allocate; i++) {
- trg = kmalloc(sizeof(*trg), GFP_KERNEL);
- if (!trg)
- goto out_of_memory;
- list_add(&trg->link, &allocated_regions);
- }
- spin_lock(&resv->lock);
- list_splice(&allocated_regions, &resv->region_cache);
- resv->region_cache_count += to_allocate;
- }
- return 0;
- out_of_memory:
- list_for_each_entry_safe(rg, trg, &allocated_regions, link) {
- list_del(&rg->link);
- kfree(rg);
- }
- return -ENOMEM;
- }
- /*
- * Add the huge page range represented by [f, t) to the reserve
- * map. Regions will be taken from the cache to fill in this range.
- * Sufficient regions should exist in the cache due to the previous
- * call to region_chg with the same range, but in some cases the cache will not
- * have sufficient entries due to races with other code doing region_add or
- * region_del. The extra needed entries will be allocated.
- *
- * regions_needed is the out value provided by a previous call to region_chg.
- *
- * Return the number of new huge pages added to the map. This number is greater
- * than or equal to zero. If file_region entries needed to be allocated for
- * this operation and we were not able to allocate, it returns -ENOMEM.
- * region_add of regions of length 1 never allocate file_regions and cannot
- * fail; region_chg will always allocate at least 1 entry and a region_add for
- * 1 page will only require at most 1 entry.
- */
- static long region_add(struct resv_map *resv, long f, long t,
- long in_regions_needed, struct hstate *h,
- struct hugetlb_cgroup *h_cg)
- {
- long add = 0, actual_regions_needed = 0;
- spin_lock(&resv->lock);
- retry:
- /* Count how many regions are actually needed to execute this add. */
- add_reservation_in_range(resv, f, t, NULL, NULL,
- &actual_regions_needed);
- /*
- * Check for sufficient descriptors in the cache to accommodate
- * this add operation. Note that actual_regions_needed may be greater
- * than in_regions_needed, as the resv_map may have been modified since
- * the region_chg call. In this case, we need to make sure that we
- * allocate extra entries, such that we have enough for all the
- * existing adds_in_progress, plus the excess needed for this
- * operation.
- */
- if (actual_regions_needed > in_regions_needed &&
- resv->region_cache_count <
- resv->adds_in_progress +
- (actual_regions_needed - in_regions_needed)) {
- /* region_add operation of range 1 should never need to
- * allocate file_region entries.
- */
- VM_BUG_ON(t - f <= 1);
- if (allocate_file_region_entries(
- resv, actual_regions_needed - in_regions_needed)) {
- return -ENOMEM;
- }
- goto retry;
- }
- add = add_reservation_in_range(resv, f, t, h_cg, h, NULL);
- resv->adds_in_progress -= in_regions_needed;
- spin_unlock(&resv->lock);
- VM_BUG_ON(add < 0);
- return add;
- }
- /*
- * Examine the existing reserve map and determine how many
- * huge pages in the specified range [f, t) are NOT currently
- * represented. This routine is called before a subsequent
- * call to region_add that will actually modify the reserve
- * map to add the specified range [f, t). region_chg does
- * not change the number of huge pages represented by the
- * map. A number of new file_region structures is added to the cache as a
- * placeholder, for the subsequent region_add call to use. At least 1
- * file_region structure is added.
- *
- * out_regions_needed is the number of regions added to the
- * resv->adds_in_progress. This value needs to be provided to a follow up call
- * to region_add or region_abort for proper accounting.
- *
- * Returns the number of huge pages that need to be added to the existing
- * reservation map for the range [f, t). This number is greater or equal to
- * zero. -ENOMEM is returned if a new file_region structure or cache entry
- * is needed and can not be allocated.
- */
- static long region_chg(struct resv_map *resv, long f, long t,
- long *out_regions_needed)
- {
- long chg = 0;
- spin_lock(&resv->lock);
- /* Count how many hugepages in this range are NOT represented. */
- chg = add_reservation_in_range(resv, f, t, NULL, NULL,
- out_regions_needed);
- if (*out_regions_needed == 0)
- *out_regions_needed = 1;
- if (allocate_file_region_entries(resv, *out_regions_needed))
- return -ENOMEM;
- resv->adds_in_progress += *out_regions_needed;
- spin_unlock(&resv->lock);
- return chg;
- }
- /*
- * Abort the in progress add operation. The adds_in_progress field
- * of the resv_map keeps track of the operations in progress between
- * calls to region_chg and region_add. Operations are sometimes
- * aborted after the call to region_chg. In such cases, region_abort
- * is called to decrement the adds_in_progress counter. regions_needed
- * is the value returned by the region_chg call, it is used to decrement
- * the adds_in_progress counter.
- *
- * NOTE: The range arguments [f, t) are not needed or used in this
- * routine. They are kept to make reading the calling code easier as
- * arguments will match the associated region_chg call.
- */
- static void region_abort(struct resv_map *resv, long f, long t,
- long regions_needed)
- {
- spin_lock(&resv->lock);
- VM_BUG_ON(!resv->region_cache_count);
- resv->adds_in_progress -= regions_needed;
- spin_unlock(&resv->lock);
- }
- /*
- * Delete the specified range [f, t) from the reserve map. If the
- * t parameter is LONG_MAX, this indicates that ALL regions after f
- * should be deleted. Locate the regions which intersect [f, t)
- * and either trim, delete or split the existing regions.
- *
- * Returns the number of huge pages deleted from the reserve map.
- * In the normal case, the return value is zero or more. In the
- * case where a region must be split, a new region descriptor must
- * be allocated. If the allocation fails, -ENOMEM will be returned.
- * NOTE: If the parameter t == LONG_MAX, then we will never split
- * a region and possibly return -ENOMEM. Callers specifying
- * t == LONG_MAX do not need to check for -ENOMEM error.
- */
- static long region_del(struct resv_map *resv, long f, long t)
- {
- struct list_head *head = &resv->regions;
- struct file_region *rg, *trg;
- struct file_region *nrg = NULL;
- long del = 0;
- retry:
- spin_lock(&resv->lock);
- list_for_each_entry_safe(rg, trg, head, link) {
- /*
- * Skip regions before the range to be deleted. file_region
- * ranges are normally of the form [from, to). However, there
- * may be a "placeholder" entry in the map which is of the form
- * (from, to) with from == to. Check for placeholder entries
- * at the beginning of the range to be deleted.
- */
- if (rg->to <= f && (rg->to != rg->from || rg->to != f))
- continue;
- if (rg->from >= t)
- break;
- if (f > rg->from && t < rg->to) { /* Must split region */
- /*
- * Check for an entry in the cache before dropping
- * lock and attempting allocation.
- */
- if (!nrg &&
- resv->region_cache_count > resv->adds_in_progress) {
- nrg = list_first_entry(&resv->region_cache,
- struct file_region,
- link);
- list_del(&nrg->link);
- resv->region_cache_count--;
- }
- if (!nrg) {
- spin_unlock(&resv->lock);
- nrg = kmalloc(sizeof(*nrg), GFP_KERNEL);
- if (!nrg)
- return -ENOMEM;
- goto retry;
- }
- del += t - f;
- hugetlb_cgroup_uncharge_file_region(
- resv, rg, t - f, false);
- /* New entry for end of split region */
- nrg->from = t;
- nrg->to = rg->to;
- copy_hugetlb_cgroup_uncharge_info(nrg, rg);
- INIT_LIST_HEAD(&nrg->link);
- /* Original entry is trimmed */
- rg->to = f;
- list_add(&nrg->link, &rg->link);
- nrg = NULL;
- break;
- }
- if (f <= rg->from && t >= rg->to) { /* Remove entire region */
- del += rg->to - rg->from;
- hugetlb_cgroup_uncharge_file_region(resv, rg,
- rg->to - rg->from, true);
- list_del(&rg->link);
- kfree(rg);
- continue;
- }
- if (f <= rg->from) { /* Trim beginning of region */
- hugetlb_cgroup_uncharge_file_region(resv, rg,
- t - rg->from, false);
- del += t - rg->from;
- rg->from = t;
- } else { /* Trim end of region */
- hugetlb_cgroup_uncharge_file_region(resv, rg,
- rg->to - f, false);
- del += rg->to - f;
- rg->to = f;
- }
- }
- spin_unlock(&resv->lock);
- kfree(nrg);
- return del;
- }
- /*
- * A rare out of memory error was encountered which prevented removal of
- * the reserve map region for a page. The huge page itself was free'ed
- * and removed from the page cache. This routine will adjust the subpool
- * usage count, and the global reserve count if needed. By incrementing
- * these counts, the reserve map entry which could not be deleted will
- * appear as a "reserved" entry instead of simply dangling with incorrect
- * counts.
- */
- void hugetlb_fix_reserve_counts(struct inode *inode)
- {
- struct hugepage_subpool *spool = subpool_inode(inode);
- long rsv_adjust;
- bool reserved = false;
- rsv_adjust = hugepage_subpool_get_pages(spool, 1);
- if (rsv_adjust > 0) {
- struct hstate *h = hstate_inode(inode);
- if (!hugetlb_acct_memory(h, 1))
- reserved = true;
- } else if (!rsv_adjust) {
- reserved = true;
- }
- if (!reserved)
- pr_warn("hugetlb: Huge Page Reserved count may go negative.\n");
- }
- /*
- * Count and return the number of huge pages in the reserve map
- * that intersect with the range [f, t).
- */
- static long region_count(struct resv_map *resv, long f, long t)
- {
- struct list_head *head = &resv->regions;
- struct file_region *rg;
- long chg = 0;
- spin_lock(&resv->lock);
- /* Locate each segment we overlap with, and count that overlap. */
- list_for_each_entry(rg, head, link) {
- long seg_from;
- long seg_to;
- if (rg->to <= f)
- continue;
- if (rg->from >= t)
- break;
- seg_from = max(rg->from, f);
- seg_to = min(rg->to, t);
- chg += seg_to - seg_from;
- }
- spin_unlock(&resv->lock);
- return chg;
- }
- /*
- * Convert the address within this vma to the page offset within
- * the mapping, in pagecache page units; huge pages here.
- */
- static pgoff_t vma_hugecache_offset(struct hstate *h,
- struct vm_area_struct *vma, unsigned long address)
- {
- return ((address - vma->vm_start) >> huge_page_shift(h)) +
- (vma->vm_pgoff >> huge_page_order(h));
- }
- pgoff_t linear_hugepage_index(struct vm_area_struct *vma,
- unsigned long address)
- {
- return vma_hugecache_offset(hstate_vma(vma), vma, address);
- }
- EXPORT_SYMBOL_GPL(linear_hugepage_index);
- /*
- * Return the size of the pages allocated when backing a VMA. In the majority
- * cases this will be same size as used by the page table entries.
- */
- unsigned long vma_kernel_pagesize(struct vm_area_struct *vma)
- {
- if (vma->vm_ops && vma->vm_ops->pagesize)
- return vma->vm_ops->pagesize(vma);
- return PAGE_SIZE;
- }
- EXPORT_SYMBOL_GPL(vma_kernel_pagesize);
- /*
- * Return the page size being used by the MMU to back a VMA. In the majority
- * of cases, the page size used by the kernel matches the MMU size. On
- * architectures where it differs, an architecture-specific 'strong'
- * version of this symbol is required.
- */
- __weak unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
- {
- return vma_kernel_pagesize(vma);
- }
- /*
- * Flags for MAP_PRIVATE reservations. These are stored in the bottom
- * bits of the reservation map pointer, which are always clear due to
- * alignment.
- */
- #define HPAGE_RESV_OWNER (1UL << 0)
- #define HPAGE_RESV_UNMAPPED (1UL << 1)
- #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED)
- /*
- * These helpers are used to track how many pages are reserved for
- * faults in a MAP_PRIVATE mapping. Only the process that called mmap()
- * is guaranteed to have their future faults succeed.
- *
- * With the exception of reset_vma_resv_huge_pages() which is called at fork(),
- * the reserve counters are updated with the hugetlb_lock held. It is safe
- * to reset the VMA at fork() time as it is not in use yet and there is no
- * chance of the global counters getting corrupted as a result of the values.
- *
- * The private mapping reservation is represented in a subtly different
- * manner to a shared mapping. A shared mapping has a region map associated
- * with the underlying file, this region map represents the backing file
- * pages which have ever had a reservation assigned which this persists even
- * after the page is instantiated. A private mapping has a region map
- * associated with the original mmap which is attached to all VMAs which
- * reference it, this region map represents those offsets which have consumed
- * reservation ie. where pages have been instantiated.
- */
- static unsigned long get_vma_private_data(struct vm_area_struct *vma)
- {
- return (unsigned long)vma->vm_private_data;
- }
- static void set_vma_private_data(struct vm_area_struct *vma,
- unsigned long value)
- {
- vma->vm_private_data = (void *)value;
- }
- static void
- resv_map_set_hugetlb_cgroup_uncharge_info(struct resv_map *resv_map,
- struct hugetlb_cgroup *h_cg,
- struct hstate *h)
- {
- #ifdef CONFIG_CGROUP_HUGETLB
- if (!h_cg || !h) {
- resv_map->reservation_counter = NULL;
- resv_map->pages_per_hpage = 0;
- resv_map->css = NULL;
- } else {
- resv_map->reservation_counter =
- &h_cg->rsvd_hugepage[hstate_index(h)];
- resv_map->pages_per_hpage = pages_per_huge_page(h);
- resv_map->css = &h_cg->css;
- }
- #endif
- }
- struct resv_map *resv_map_alloc(void)
- {
- struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL);
- struct file_region *rg = kmalloc(sizeof(*rg), GFP_KERNEL);
- if (!resv_map || !rg) {
- kfree(resv_map);
- kfree(rg);
- return NULL;
- }
- kref_init(&resv_map->refs);
- spin_lock_init(&resv_map->lock);
- INIT_LIST_HEAD(&resv_map->regions);
- resv_map->adds_in_progress = 0;
- /*
- * Initialize these to 0. On shared mappings, 0's here indicate these
- * fields don't do cgroup accounting. On private mappings, these will be
- * re-initialized to the proper values, to indicate that hugetlb cgroup
- * reservations are to be un-charged from here.
- */
- resv_map_set_hugetlb_cgroup_uncharge_info(resv_map, NULL, NULL);
- INIT_LIST_HEAD(&resv_map->region_cache);
- list_add(&rg->link, &resv_map->region_cache);
- resv_map->region_cache_count = 1;
- return resv_map;
- }
- void resv_map_release(struct kref *ref)
- {
- struct resv_map *resv_map = container_of(ref, struct resv_map, refs);
- struct list_head *head = &resv_map->region_cache;
- struct file_region *rg, *trg;
- /* Clear out any active regions before we release the map. */
- region_del(resv_map, 0, LONG_MAX);
- /* ... and any entries left in the cache */
- list_for_each_entry_safe(rg, trg, head, link) {
- list_del(&rg->link);
- kfree(rg);
- }
- VM_BUG_ON(resv_map->adds_in_progress);
- kfree(resv_map);
- }
- static inline struct resv_map *inode_resv_map(struct inode *inode)
- {
- /*
- * At inode evict time, i_mapping may not point to the original
- * address space within the inode. This original address space
- * contains the pointer to the resv_map. So, always use the
- * address space embedded within the inode.
- * The VERY common case is inode->mapping == &inode->i_data but,
- * this may not be true for device special inodes.
- */
- return (struct resv_map *)(&inode->i_data)->private_data;
- }
- static struct resv_map *vma_resv_map(struct vm_area_struct *vma)
- {
- VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
- if (vma->vm_flags & VM_MAYSHARE) {
- struct address_space *mapping = vma->vm_file->f_mapping;
- struct inode *inode = mapping->host;
- return inode_resv_map(inode);
- } else {
- return (struct resv_map *)(get_vma_private_data(vma) &
- ~HPAGE_RESV_MASK);
- }
- }
- static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map)
- {
- VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
- VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
- set_vma_private_data(vma, (get_vma_private_data(vma) &
- HPAGE_RESV_MASK) | (unsigned long)map);
- }
- static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags)
- {
- VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
- VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma);
- set_vma_private_data(vma, get_vma_private_data(vma) | flags);
- }
- static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag)
- {
- VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
- return (get_vma_private_data(vma) & flag) != 0;
- }
- /* Reset counters to 0 and clear all HPAGE_RESV_* flags */
- void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
- {
- VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
- if (!(vma->vm_flags & VM_MAYSHARE))
- vma->vm_private_data = (void *)0;
- }
- /* Returns true if the VMA has associated reserve pages */
- static bool vma_has_reserves(struct vm_area_struct *vma, long chg)
- {
- if (vma->vm_flags & VM_NORESERVE) {
- /*
- * This address is already reserved by other process(chg == 0),
- * so, we should decrement reserved count. Without decrementing,
- * reserve count remains after releasing inode, because this
- * allocated page will go into page cache and is regarded as
- * coming from reserved pool in releasing step. Currently, we
- * don't have any other solution to deal with this situation
- * properly, so add work-around here.
- */
- if (vma->vm_flags & VM_MAYSHARE && chg == 0)
- return true;
- else
- return false;
- }
- /* Shared mappings always use reserves */
- if (vma->vm_flags & VM_MAYSHARE) {
- /*
- * We know VM_NORESERVE is not set. Therefore, there SHOULD
- * be a region map for all pages. The only situation where
- * there is no region map is if a hole was punched via
- * fallocate. In this case, there really are no reserves to
- * use. This situation is indicated if chg != 0.
- */
- if (chg)
- return false;
- else
- return true;
- }
- /*
- * Only the process that called mmap() has reserves for
- * private mappings.
- */
- if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
- /*
- * Like the shared case above, a hole punch or truncate
- * could have been performed on the private mapping.
- * Examine the value of chg to determine if reserves
- * actually exist or were previously consumed.
- * Very Subtle - The value of chg comes from a previous
- * call to vma_needs_reserves(). The reserve map for
- * private mappings has different (opposite) semantics
- * than that of shared mappings. vma_needs_reserves()
- * has already taken this difference in semantics into
- * account. Therefore, the meaning of chg is the same
- * as in the shared case above. Code could easily be
- * combined, but keeping it separate draws attention to
- * subtle differences.
- */
- if (chg)
- return false;
- else
- return true;
- }
- return false;
- }
- static void enqueue_huge_page(struct hstate *h, struct page *page)
- {
- int nid = page_to_nid(page);
- list_move(&page->lru, &h->hugepage_freelists[nid]);
- h->free_huge_pages++;
- h->free_huge_pages_node[nid]++;
- SetPageHugeFreed(page);
- }
- static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid)
- {
- struct page *page;
- bool nocma = !!(current->flags & PF_MEMALLOC_NOCMA);
- list_for_each_entry(page, &h->hugepage_freelists[nid], lru) {
- if (nocma && is_migrate_cma_page(page))
- continue;
- if (PageHWPoison(page))
- continue;
- list_move(&page->lru, &h->hugepage_activelist);
- set_page_refcounted(page);
- ClearPageHugeFreed(page);
- h->free_huge_pages--;
- h->free_huge_pages_node[nid]--;
- return page;
- }
- return NULL;
- }
- static struct page *dequeue_huge_page_nodemask(struct hstate *h, gfp_t gfp_mask, int nid,
- nodemask_t *nmask)
- {
- unsigned int cpuset_mems_cookie;
- struct zonelist *zonelist;
- struct zone *zone;
- struct zoneref *z;
- int node = NUMA_NO_NODE;
- zonelist = node_zonelist(nid, gfp_mask);
- retry_cpuset:
- cpuset_mems_cookie = read_mems_allowed_begin();
- for_each_zone_zonelist_nodemask(zone, z, zonelist, gfp_zone(gfp_mask), nmask) {
- struct page *page;
- if (!cpuset_zone_allowed(zone, gfp_mask))
- continue;
- /*
- * no need to ask again on the same node. Pool is node rather than
- * zone aware
- */
- if (zone_to_nid(zone) == node)
- continue;
- node = zone_to_nid(zone);
- page = dequeue_huge_page_node_exact(h, node);
- if (page)
- return page;
- }
- if (unlikely(read_mems_allowed_retry(cpuset_mems_cookie)))
- goto retry_cpuset;
- return NULL;
- }
- static struct page *dequeue_huge_page_vma(struct hstate *h,
- struct vm_area_struct *vma,
- unsigned long address, int avoid_reserve,
- long chg)
- {
- struct page *page;
- struct mempolicy *mpol;
- gfp_t gfp_mask;
- nodemask_t *nodemask;
- int nid;
- /*
- * A child process with MAP_PRIVATE mappings created by their parent
- * have no page reserves. This check ensures that reservations are
- * not "stolen". The child may still get SIGKILLed
- */
- if (!vma_has_reserves(vma, chg) &&
- h->free_huge_pages - h->resv_huge_pages == 0)
- goto err;
- /* If reserves cannot be used, ensure enough pages are in the pool */
- if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0)
- goto err;
- gfp_mask = htlb_alloc_mask(h);
- nid = huge_node(vma, address, gfp_mask, &mpol, &nodemask);
- page = dequeue_huge_page_nodemask(h, gfp_mask, nid, nodemask);
- if (page && !avoid_reserve && vma_has_reserves(vma, chg)) {
- SetPagePrivate(page);
- h->resv_huge_pages--;
- }
- mpol_cond_put(mpol);
- return page;
- err:
- return NULL;
- }
- /*
- * common helper functions for hstate_next_node_to_{alloc|free}.
- * We may have allocated or freed a huge page based on a different
- * nodes_allowed previously, so h->next_node_to_{alloc|free} might
- * be outside of *nodes_allowed. Ensure that we use an allowed
- * node for alloc or free.
- */
- static int next_node_allowed(int nid, nodemask_t *nodes_allowed)
- {
- nid = next_node_in(nid, *nodes_allowed);
- VM_BUG_ON(nid >= MAX_NUMNODES);
- return nid;
- }
- static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed)
- {
- if (!node_isset(nid, *nodes_allowed))
- nid = next_node_allowed(nid, nodes_allowed);
- return nid;
- }
- /*
- * returns the previously saved node ["this node"] from which to
- * allocate a persistent huge page for the pool and advance the
- * next node from which to allocate, handling wrap at end of node
- * mask.
- */
- static int hstate_next_node_to_alloc(struct hstate *h,
- nodemask_t *nodes_allowed)
- {
- int nid;
- VM_BUG_ON(!nodes_allowed);
- nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed);
- h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed);
- return nid;
- }
- /*
- * helper for free_pool_huge_page() - return the previously saved
- * node ["this node"] from which to free a huge page. Advance the
- * next node id whether or not we find a free huge page to free so
- * that the next attempt to free addresses the next node.
- */
- static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
- {
- int nid;
- VM_BUG_ON(!nodes_allowed);
- nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed);
- h->next_nid_to_free = next_node_allowed(nid, nodes_allowed);
- return nid;
- }
- #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \
- for (nr_nodes = nodes_weight(*mask); \
- nr_nodes > 0 && \
- ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \
- nr_nodes--)
- #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \
- for (nr_nodes = nodes_weight(*mask); \
- nr_nodes > 0 && \
- ((node = hstate_next_node_to_free(hs, mask)) || 1); \
- nr_nodes--)
- #ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE
- static void destroy_compound_gigantic_page(struct page *page,
- unsigned int order)
- {
- int i;
- int nr_pages = 1 << order;
- struct page *p = page + 1;
- atomic_set(compound_mapcount_ptr(page), 0);
- atomic_set(compound_pincount_ptr(page), 0);
- for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
- clear_compound_head(p);
- set_page_refcounted(p);
- }
- set_compound_order(page, 0);
- page[1].compound_nr = 0;
- __ClearPageHead(page);
- }
- static void free_gigantic_page(struct page *page, unsigned int order)
- {
- /*
- * If the page isn't allocated using the cma allocator,
- * cma_release() returns false.
- */
- #ifdef CONFIG_CMA
- if (cma_release(hugetlb_cma[page_to_nid(page)], page, 1 << order))
- return;
- #endif
- free_contig_range(page_to_pfn(page), 1 << order);
- }
- #ifdef CONFIG_CONTIG_ALLOC
- static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
- int nid, nodemask_t *nodemask)
- {
- unsigned long nr_pages = 1UL << huge_page_order(h);
- if (nid == NUMA_NO_NODE)
- nid = numa_mem_id();
- #ifdef CONFIG_CMA
- {
- struct page *page;
- int node;
- if (hugetlb_cma[nid]) {
- page = cma_alloc(hugetlb_cma[nid], nr_pages,
- huge_page_order(h),
- GFP_KERNEL | __GFP_NOWARN);
- if (page)
- return page;
- }
- if (!(gfp_mask & __GFP_THISNODE)) {
- for_each_node_mask(node, *nodemask) {
- if (node == nid || !hugetlb_cma[node])
- continue;
- page = cma_alloc(hugetlb_cma[node], nr_pages,
- huge_page_order(h),
- GFP_KERNEL | __GFP_NOWARN);
- if (page)
- return page;
- }
- }
- }
- #endif
- return alloc_contig_pages(nr_pages, gfp_mask, nid, nodemask);
- }
- #else /* !CONFIG_CONTIG_ALLOC */
- static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
- int nid, nodemask_t *nodemask)
- {
- return NULL;
- }
- #endif /* CONFIG_CONTIG_ALLOC */
- #else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */
- static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
- int nid, nodemask_t *nodemask)
- {
- return NULL;
- }
- static inline void free_gigantic_page(struct page *page, unsigned int order) { }
- static inline void destroy_compound_gigantic_page(struct page *page,
- unsigned int order) { }
- #endif
- static void update_and_free_page(struct hstate *h, struct page *page)
- {
- int i;
- struct page *subpage = page;
- if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
- return;
- h->nr_huge_pages--;
- h->nr_huge_pages_node[page_to_nid(page)]--;
- for (i = 0; i < pages_per_huge_page(h);
- i++, subpage = mem_map_next(subpage, page, i)) {
- subpage->flags &= ~(1 << PG_locked | 1 << PG_error |
- 1 << PG_referenced | 1 << PG_dirty |
- 1 << PG_active | 1 << PG_private |
- 1 << PG_writeback);
- }
- VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page);
- VM_BUG_ON_PAGE(hugetlb_cgroup_from_page_rsvd(page), page);
- set_compound_page_dtor(page, NULL_COMPOUND_DTOR);
- set_page_refcounted(page);
- if (hstate_is_gigantic(h)) {
- /*
- * Temporarily drop the hugetlb_lock, because
- * we might block in free_gigantic_page().
- */
- spin_unlock(&hugetlb_lock);
- destroy_compound_gigantic_page(page, huge_page_order(h));
- free_gigantic_page(page, huge_page_order(h));
- spin_lock(&hugetlb_lock);
- } else {
- __free_pages(page, huge_page_order(h));
- }
- }
- struct hstate *size_to_hstate(unsigned long size)
- {
- struct hstate *h;
- for_each_hstate(h) {
- if (huge_page_size(h) == size)
- return h;
- }
- return NULL;
- }
- /*
- * Test to determine whether the hugepage is "active/in-use" (i.e. being linked
- * to hstate->hugepage_activelist.)
- *
- * This function can be called for tail pages, but never returns true for them.
- */
- bool page_huge_active(struct page *page)
- {
- return PageHeadHuge(page) && PagePrivate(&page[1]);
- }
- /* never called for tail page */
- void set_page_huge_active(struct page *page)
- {
- VM_BUG_ON_PAGE(!PageHeadHuge(page), page);
- SetPagePrivate(&page[1]);
- }
- static void clear_page_huge_active(struct page *page)
- {
- VM_BUG_ON_PAGE(!PageHeadHuge(page), page);
- ClearPagePrivate(&page[1]);
- }
- /*
- * Internal hugetlb specific page flag. Do not use outside of the hugetlb
- * code
- */
- static inline bool PageHugeTemporary(struct page *page)
- {
- if (!PageHuge(page))
- return false;
- return (unsigned long)page[2].mapping == -1U;
- }
- static inline void SetPageHugeTemporary(struct page *page)
- {
- page[2].mapping = (void *)-1U;
- }
- static inline void ClearPageHugeTemporary(struct page *page)
- {
- page[2].mapping = NULL;
- }
- static void __free_huge_page(struct page *page)
- {
- /*
- * Can't pass hstate in here because it is called from the
- * compound page destructor.
- */
- struct hstate *h = page_hstate(page);
- int nid = page_to_nid(page);
- struct hugepage_subpool *spool =
- (struct hugepage_subpool *)page_private(page);
- bool restore_reserve;
- VM_BUG_ON_PAGE(page_count(page), page);
- VM_BUG_ON_PAGE(page_mapcount(page), page);
- set_page_private(page, 0);
- page->mapping = NULL;
- restore_reserve = PagePrivate(page);
- ClearPagePrivate(page);
- /*
- * If PagePrivate() was set on page, page allocation consumed a
- * reservation. If the page was associated with a subpool, there
- * would have been a page reserved in the subpool before allocation
- * via hugepage_subpool_get_pages(). Since we are 'restoring' the
- * reservtion, do not call hugepage_subpool_put_pages() as this will
- * remove the reserved page from the subpool.
- */
- if (!restore_reserve) {
- /*
- * A return code of zero implies that the subpool will be
- * under its minimum size if the reservation is not restored
- * after page is free. Therefore, force restore_reserve
- * operation.
- */
- if (hugepage_subpool_put_pages(spool, 1) == 0)
- restore_reserve = true;
- }
- spin_lock(&hugetlb_lock);
- clear_page_huge_active(page);
- hugetlb_cgroup_uncharge_page(hstate_index(h),
- pages_per_huge_page(h), page);
- hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h),
- pages_per_huge_page(h), page);
- if (restore_reserve)
- h->resv_huge_pages++;
- if (PageHugeTemporary(page)) {
- list_del(&page->lru);
- ClearPageHugeTemporary(page);
- update_and_free_page(h, page);
- } else if (h->surplus_huge_pages_node[nid]) {
- /* remove the page from active list */
- list_del(&page->lru);
- update_and_free_page(h, page);
- h->surplus_huge_pages--;
- h->surplus_huge_pages_node[nid]--;
- } else {
- arch_clear_hugepage_flags(page);
- enqueue_huge_page(h, page);
- }
- spin_unlock(&hugetlb_lock);
- }
- /*
- * As free_huge_page() can be called from a non-task context, we have
- * to defer the actual freeing in a workqueue to prevent potential
- * hugetlb_lock deadlock.
- *
- * free_hpage_workfn() locklessly retrieves the linked list of pages to
- * be freed and frees them one-by-one. As the page->mapping pointer is
- * going to be cleared in __free_huge_page() anyway, it is reused as the
- * llist_node structure of a lockless linked list of huge pages to be freed.
- */
- static LLIST_HEAD(hpage_freelist);
- static void free_hpage_workfn(struct work_struct *work)
- {
- struct llist_node *node;
- struct page *page;
- node = llist_del_all(&hpage_freelist);
- while (node) {
- page = container_of((struct address_space **)node,
- struct page, mapping);
- node = node->next;
- __free_huge_page(page);
- }
- }
- static DECLARE_WORK(free_hpage_work, free_hpage_workfn);
- void free_huge_page(struct page *page)
- {
- /*
- * Defer freeing if in non-task context to avoid hugetlb_lock deadlock.
- */
- if (!in_task()) {
- /*
- * Only call schedule_work() if hpage_freelist is previously
- * empty. Otherwise, schedule_work() had been called but the
- * workfn hasn't retrieved the list yet.
- */
- if (llist_add((struct llist_node *)&page->mapping,
- &hpage_freelist))
- schedule_work(&free_hpage_work);
- return;
- }
- __free_huge_page(page);
- }
- static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
- {
- INIT_LIST_HEAD(&page->lru);
- set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
- set_hugetlb_cgroup(page, NULL);
- set_hugetlb_cgroup_rsvd(page, NULL);
- spin_lock(&hugetlb_lock);
- h->nr_huge_pages++;
- h->nr_huge_pages_node[nid]++;
- ClearPageHugeFreed(page);
- spin_unlock(&hugetlb_lock);
- }
- static void prep_compound_gigantic_page(struct page *page, unsigned int order)
- {
- int i;
- int nr_pages = 1 << order;
- struct page *p = page + 1;
- /* we rely on prep_new_huge_page to set the destructor */
- set_compound_order(page, order);
- __ClearPageReserved(page);
- __SetPageHead(page);
- for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) {
- /*
- * For gigantic hugepages allocated through bootmem at
- * boot, it's safer to be consistent with the not-gigantic
- * hugepages and clear the PG_reserved bit from all tail pages
- * too. Otherwise drivers using get_user_pages() to access tail
- * pages may get the reference counting wrong if they see
- * PG_reserved set on a tail page (despite the head page not
- * having PG_reserved set). Enforcing this consistency between
- * head and tail pages allows drivers to optimize away a check
- * on the head page when they need know if put_page() is needed
- * after get_user_pages().
- */
- __ClearPageReserved(p);
- set_page_count(p, 0);
- set_compound_head(p, page);
- }
- atomic_set(compound_mapcount_ptr(page), -1);
- atomic_set(compound_pincount_ptr(page), 0);
- }
- /*
- * PageHuge() only returns true for hugetlbfs pages, but not for normal or
- * transparent huge pages. See the PageTransHuge() documentation for more
- * details.
- */
- int PageHuge(struct page *page)
- {
- if (!PageCompound(page))
- return 0;
- page = compound_head(page);
- return page[1].compound_dtor == HUGETLB_PAGE_DTOR;
- }
- EXPORT_SYMBOL_GPL(PageHuge);
- /*
- * PageHeadHuge() only returns true for hugetlbfs head page, but not for
- * normal or transparent huge pages.
- */
- int PageHeadHuge(struct page *page_head)
- {
- if (!PageHead(page_head))
- return 0;
- return page_head[1].compound_dtor == HUGETLB_PAGE_DTOR;
- }
- /*
- * Find and lock address space (mapping) in write mode.
- *
- * Upon entry, the page is locked which means that page_mapping() is
- * stable. Due to locking order, we can only trylock_write. If we can
- * not get the lock, simply return NULL to caller.
- */
- struct address_space *hugetlb_page_mapping_lock_write(struct page *hpage)
- {
- struct address_space *mapping = page_mapping(hpage);
- if (!mapping)
- return mapping;
- if (i_mmap_trylock_write(mapping))
- return mapping;
- return NULL;
- }
- pgoff_t hugetlb_basepage_index(struct page *page)
- {
- struct page *page_head = compound_head(page);
- pgoff_t index = page_index(page_head);
- unsigned long compound_idx;
- if (compound_order(page_head) >= MAX_ORDER)
- compound_idx = page_to_pfn(page) - page_to_pfn(page_head);
- else
- compound_idx = page - page_head;
- return (index << compound_order(page_head)) + compound_idx;
- }
- static struct page *alloc_buddy_huge_page(struct hstate *h,
- gfp_t gfp_mask, int nid, nodemask_t *nmask,
- nodemask_t *node_alloc_noretry)
- {
- int order = huge_page_order(h);
- struct page *page;
- bool alloc_try_hard = true;
- /*
- * By default we always try hard to allocate the page with
- * __GFP_RETRY_MAYFAIL flag. However, if we are allocating pages in
- * a loop (to adjust global huge page counts) and previous allocation
- * failed, do not continue to try hard on the same node. Use the
- * node_alloc_noretry bitmap to manage this state information.
- */
- if (node_alloc_noretry && node_isset(nid, *node_alloc_noretry))
- alloc_try_hard = false;
- gfp_mask |= __GFP_COMP|__GFP_NOWARN;
- if (alloc_try_hard)
- gfp_mask |= __GFP_RETRY_MAYFAIL;
- if (nid == NUMA_NO_NODE)
- nid = numa_mem_id();
- page = __alloc_pages_nodemask(gfp_mask, order, nid, nmask);
- if (page)
- __count_vm_event(HTLB_BUDDY_PGALLOC);
- else
- __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL);
- /*
- * If we did not specify __GFP_RETRY_MAYFAIL, but still got a page this
- * indicates an overall state change. Clear bit so that we resume
- * normal 'try hard' allocations.
- */
- if (node_alloc_noretry && page && !alloc_try_hard)
- node_clear(nid, *node_alloc_noretry);
- /*
- * If we tried hard to get a page but failed, set bit so that
- * subsequent attempts will not try as hard until there is an
- * overall state change.
- */
- if (node_alloc_noretry && !page && alloc_try_hard)
- node_set(nid, *node_alloc_noretry);
- return page;
- }
- /*
- * Common helper to allocate a fresh hugetlb page. All specific allocators
- * should use this function to get new hugetlb pages
- */
- static struct page *alloc_fresh_huge_page(struct hstate *h,
- gfp_t gfp_mask, int nid, nodemask_t *nmask,
- nodemask_t *node_alloc_noretry)
- {
- struct page *page;
- if (hstate_is_gigantic(h))
- page = alloc_gigantic_page(h, gfp_mask, nid, nmask);
- else
- page = alloc_buddy_huge_page(h, gfp_mask,
- nid, nmask, node_alloc_noretry);
- if (!page)
- return NULL;
- if (hstate_is_gigantic(h))
- prep_compound_gigantic_page(page, huge_page_order(h));
- prep_new_huge_page(h, page, page_to_nid(page));
- return page;
- }
- /*
- * Allocates a fresh page to the hugetlb allocator pool in the node interleaved
- * manner.
- */
- static int alloc_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
- nodemask_t *node_alloc_noretry)
- {
- struct page *page;
- int nr_nodes, node;
- gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE;
- for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
- page = alloc_fresh_huge_page(h, gfp_mask, node, nodes_allowed,
- node_alloc_noretry);
- if (page)
- break;
- }
- if (!page)
- return 0;
- put_page(page); /* free it into the hugepage allocator */
- return 1;
- }
- /*
- * Free huge page from pool from next node to free.
- * Attempt to keep persistent huge pages more or less
- * balanced over allowed nodes.
- * Called with hugetlb_lock locked.
- */
- static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
- bool acct_surplus)
- {
- int nr_nodes, node;
- int ret = 0;
- for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
- /*
- * If we're returning unused surplus pages, only examine
- * nodes with surplus pages.
- */
- if ((!acct_surplus || h->surplus_huge_pages_node[node]) &&
- !list_empty(&h->hugepage_freelists[node])) {
- struct page *page =
- list_entry(h->hugepage_freelists[node].next,
- struct page, lru);
- list_del(&page->lru);
- h->free_huge_pages--;
- h->free_huge_pages_node[node]--;
- if (acct_surplus) {
- h->surplus_huge_pages--;
- h->surplus_huge_pages_node[node]--;
- }
- update_and_free_page(h, page);
- ret = 1;
- break;
- }
- }
- return ret;
- }
- /*
- * Dissolve a given free hugepage into free buddy pages. This function does
- * nothing for in-use hugepages and non-hugepages.
- * This function returns values like below:
- *
- * -EBUSY: failed to dissolved free hugepages or the hugepage is in-use
- * (allocated or reserved.)
- * 0: successfully dissolved free hugepages or the page is not a
- * hugepage (considered as already dissolved)
- */
- int dissolve_free_huge_page(struct page *page)
- {
- int rc = -EBUSY;
- retry:
- /* Not to disrupt normal path by vainly holding hugetlb_lock */
- if (!PageHuge(page))
- return 0;
- spin_lock(&hugetlb_lock);
- if (!PageHuge(page)) {
- rc = 0;
- goto out;
- }
- if (!page_count(page)) {
- struct page *head = compound_head(page);
- struct hstate *h = page_hstate(head);
- int nid = page_to_nid(head);
- if (h->free_huge_pages - h->resv_huge_pages == 0)
- goto out;
- /*
- * We should make sure that the page is already on the free list
- * when it is dissolved.
- */
- if (unlikely(!PageHugeFreed(head))) {
- spin_unlock(&hugetlb_lock);
- cond_resched();
- /*
- * Theoretically, we should return -EBUSY when we
- * encounter this race. In fact, we have a chance
- * to successfully dissolve the page if we do a
- * retry. Because the race window is quite small.
- * If we seize this opportunity, it is an optimization
- * for increasing the success rate of dissolving page.
- */
- goto retry;
- }
- /*
- * Move PageHWPoison flag from head page to the raw error page,
- * which makes any subpages rather than the error page reusable.
- */
- if (PageHWPoison(head) && page != head) {
- SetPageHWPoison(page);
- ClearPageHWPoison(head);
- }
- list_del(&head->lru);
- h->free_huge_pages--;
- h->free_huge_pages_node[nid]--;
- h->max_huge_pages--;
- update_and_free_page(h, head);
- rc = 0;
- }
- out:
- spin_unlock(&hugetlb_lock);
- return rc;
- }
- /*
- * Dissolve free hugepages in a given pfn range. Used by memory hotplug to
- * make specified memory blocks removable from the system.
- * Note that this will dissolve a free gigantic hugepage completely, if any
- * part of it lies within the given range.
- * Also note that if dissolve_free_huge_page() returns with an error, all
- * free hugepages that were dissolved before that error are lost.
- */
- int dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
- {
- unsigned long pfn;
- struct page *page;
- int rc = 0;
- if (!hugepages_supported())
- return rc;
- for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << minimum_order) {
- page = pfn_to_page(pfn);
- rc = dissolve_free_huge_page(page);
- if (rc)
- break;
- }
- return rc;
- }
- /*
- * Allocates a fresh surplus page from the page allocator.
- */
- static struct page *alloc_surplus_huge_page(struct hstate *h, gfp_t gfp_mask,
- int nid, nodemask_t *nmask)
- {
- struct page *page = NULL;
- if (hstate_is_gigantic(h))
- return NULL;
- spin_lock(&hugetlb_lock);
- if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages)
- goto out_unlock;
- spin_unlock(&hugetlb_lock);
- page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask, NULL);
- if (!page)
- return NULL;
- spin_lock(&hugetlb_lock);
- /*
- * We could have raced with the pool size change.
- * Double check that and simply deallocate the new page
- * if we would end up overcommiting the surpluses. Abuse
- * temporary page to workaround the nasty free_huge_page
- * codeflow
- */
- if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) {
- SetPageHugeTemporary(page);
- spin_unlock(&hugetlb_lock);
- put_page(page);
- return NULL;
- } else {
- h->surplus_huge_pages++;
- h->surplus_huge_pages_node[page_to_nid(page)]++;
- }
- out_unlock:
- spin_unlock(&hugetlb_lock);
- return page;
- }
- static struct page *alloc_migrate_huge_page(struct hstate *h, gfp_t gfp_mask,
- int nid, nodemask_t *nmask)
- {
- struct page *page;
- if (hstate_is_gigantic(h))
- return NULL;
- page = alloc_fresh_huge_page(h, gfp_mask, nid, nmask, NULL);
- if (!page)
- return NULL;
- /*
- * We do not account these pages as surplus because they are only
- * temporary and will be released properly on the last reference
- */
- SetPageHugeTemporary(page);
- return page;
- }
- /*
- * Use the VMA's mpolicy to allocate a huge page from the buddy.
- */
- static
- struct page *alloc_buddy_huge_page_with_mpol(struct hstate *h,
- struct vm_area_struct *vma, unsigned long addr)
- {
- struct page *page;
- struct mempolicy *mpol;
- gfp_t gfp_mask = htlb_alloc_mask(h);
- int nid;
- nodemask_t *nodemask;
- nid = huge_node(vma, addr, gfp_mask, &mpol, &nodemask);
- page = alloc_surplus_huge_page(h, gfp_mask, nid, nodemask);
- mpol_cond_put(mpol);
- return page;
- }
- /* page migration callback function */
- struct page *alloc_huge_page_nodemask(struct hstate *h, int preferred_nid,
- nodemask_t *nmask, gfp_t gfp_mask)
- {
- spin_lock(&hugetlb_lock);
- if (h->free_huge_pages - h->resv_huge_pages > 0) {
- struct page *page;
- page = dequeue_huge_page_nodemask(h, gfp_mask, preferred_nid, nmask);
- if (page) {
- spin_unlock(&hugetlb_lock);
- return page;
- }
- }
- spin_unlock(&hugetlb_lock);
- return alloc_migrate_huge_page(h, gfp_mask, preferred_nid, nmask);
- }
- /* mempolicy aware migration callback */
- struct page *alloc_huge_page_vma(struct hstate *h, struct vm_area_struct *vma,
- unsigned long address)
- {
- struct mempolicy *mpol;
- nodemask_t *nodemask;
- struct page *page;
- gfp_t gfp_mask;
- int node;
- gfp_mask = htlb_alloc_mask(h);
- node = huge_node(vma, address, gfp_mask, &mpol, &nodemask);
- page = alloc_huge_page_nodemask(h, node, nodemask, gfp_mask);
- mpol_cond_put(mpol);
- return page;
- }
- /*
- * Increase the hugetlb pool such that it can accommodate a reservation
- * of size 'delta'.
- */
- static int gather_surplus_pages(struct hstate *h, int delta)
- __must_hold(&hugetlb_lock)
- {
- struct list_head surplus_list;
- struct page *page, *tmp;
- int ret, i;
- int needed, allocated;
- bool alloc_ok = true;
- needed = (h->resv_huge_pages + delta) - h->free_huge_pages;
- if (needed <= 0) {
- h->resv_huge_pages += delta;
- return 0;
- }
- allocated = 0;
- INIT_LIST_HEAD(&surplus_list);
- ret = -ENOMEM;
- retry:
- spin_unlock(&hugetlb_lock);
- for (i = 0; i < needed; i++) {
- page = alloc_surplus_huge_page(h, htlb_alloc_mask(h),
- NUMA_NO_NODE, NULL);
- if (!page) {
- alloc_ok = false;
- break;
- }
- list_add(&page->lru, &surplus_list);
- cond_resched();
- }
- allocated += i;
- /*
- * After retaking hugetlb_lock, we need to recalculate 'needed'
- * because either resv_huge_pages or free_huge_pages may have changed.
- */
- spin_lock(&hugetlb_lock);
- needed = (h->resv_huge_pages + delta) -
- (h->free_huge_pages + allocated);
- if (needed > 0) {
- if (alloc_ok)
- goto retry;
- /*
- * We were not able to allocate enough pages to
- * satisfy the entire reservation so we free what
- * we've allocated so far.
- */
- goto free;
- }
- /*
- * The surplus_list now contains _at_least_ the number of extra pages
- * needed to accommodate the reservation. Add the appropriate number
- * of pages to the hugetlb pool and free the extras back to the buddy
- * allocator. Commit the entire reservation here to prevent another
- * process from stealing the pages as they are added to the pool but
- * before they are reserved.
- */
- needed += allocated;
- h->resv_huge_pages += delta;
- ret = 0;
- /* Free the needed pages to the hugetlb pool */
- list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
- if ((--needed) < 0)
- break;
- /*
- * This page is now managed by the hugetlb allocator and has
- * no users -- drop the buddy allocator's reference.
- */
- put_page_testzero(page);
- VM_BUG_ON_PAGE(page_count(page), page);
- enqueue_huge_page(h, page);
- }
- free:
- spin_unlock(&hugetlb_lock);
- /* Free unnecessary surplus pages to the buddy allocator */
- list_for_each_entry_safe(page, tmp, &surplus_list, lru)
- put_page(page);
- spin_lock(&hugetlb_lock);
- return ret;
- }
- /*
- * This routine has two main purposes:
- * 1) Decrement the reservation count (resv_huge_pages) by the value passed
- * in unused_resv_pages. This corresponds to the prior adjustments made
- * to the associated reservation map.
- * 2) Free any unused surplus pages that may have been allocated to satisfy
- * the reservation. As many as unused_resv_pages may be freed.
- *
- * Called with hugetlb_lock held. However, the lock could be dropped (and
- * reacquired) during calls to cond_resched_lock. Whenever dropping the lock,
- * we must make sure nobody else can claim pages we are in the process of
- * freeing. Do this by ensuring resv_huge_page always is greater than the
- * number of huge pages we plan to free when dropping the lock.
- */
- static void return_unused_surplus_pages(struct hstate *h,
- unsigned long unused_resv_pages)
- {
- unsigned long nr_pages;
- /* Cannot return gigantic pages currently */
- if (hstate_is_gigantic(h))
- goto out;
- /*
- * Part (or even all) of the reservation could have been backed
- * by pre-allocated pages. Only free surplus pages.
- */
- nr_pages = min(unused_resv_pages, h->surplus_huge_pages);
- /*
- * We want to release as many surplus pages as possible, spread
- * evenly across all nodes with memory. Iterate across these nodes
- * until we can no longer free unreserved surplus pages. This occurs
- * when the nodes with surplus pages have no free pages.
- * free_pool_huge_page() will balance the freed pages across the
- * on-line nodes with memory and will handle the hstate accounting.
- *
- * Note that we decrement resv_huge_pages as we free the pages. If
- * we drop the lock, resv_huge_pages will still be sufficiently large
- * to cover subsequent pages we may free.
- */
- while (nr_pages--) {
- h->resv_huge_pages--;
- unused_resv_pages--;
- if (!free_pool_huge_page(h, &node_states[N_MEMORY], 1))
- goto out;
- cond_resched_lock(&hugetlb_lock);
- }
- out:
- /* Fully uncommit the reservation */
- h->resv_huge_pages -= unused_resv_pages;
- }
- /*
- * vma_needs_reservation, vma_commit_reservation and vma_end_reservation
- * are used by the huge page allocation routines to manage reservations.
- *
- * vma_needs_reservation is called to determine if the huge page at addr
- * within the vma has an associated reservation. If a reservation is
- * needed, the value 1 is returned. The caller is then responsible for
- * managing the global reservation and subpool usage counts. After
- * the huge page has been allocated, vma_commit_reservation is called
- * to add the page to the reservation map. If the page allocation fails,
- * the reservation must be ended instead of committed. vma_end_reservation
- * is called in such cases.
- *
- * In the normal case, vma_commit_reservation returns the same value
- * as the preceding vma_needs_reservation call. The only time this
- * is not the case is if a reserve map was changed between calls. It
- * is the responsibility of the caller to notice the difference and
- * take appropriate action.
- *
- * vma_add_reservation is used in error paths where a reservation must
- * be restored when a newly allocated huge page must be freed. It is
- * to be called after calling vma_needs_reservation to determine if a
- * reservation exists.
- */
- enum vma_resv_mode {
- VMA_NEEDS_RESV,
- VMA_COMMIT_RESV,
- VMA_END_RESV,
- VMA_ADD_RESV,
- };
- static long __vma_reservation_common(struct hstate *h,
- struct vm_area_struct *vma, unsigned long addr,
- enum vma_resv_mode mode)
- {
- struct resv_map *resv;
- pgoff_t idx;
- long ret;
- long dummy_out_regions_needed;
- resv = vma_resv_map(vma);
- if (!resv)
- return 1;
- idx = vma_hugecache_offset(h, vma, addr);
- switch (mode) {
- case VMA_NEEDS_RESV:
- ret = region_chg(resv, idx, idx + 1, &dummy_out_regions_needed);
- /* We assume that vma_reservation_* routines always operate on
- * 1 page, and that adding to resv map a 1 page entry can only
- * ever require 1 region.
- */
- VM_BUG_ON(dummy_out_regions_needed != 1);
- break;
- case VMA_COMMIT_RESV:
- ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
- /* region_add calls of range 1 should never fail. */
- VM_BUG_ON(ret < 0);
- break;
- case VMA_END_RESV:
- region_abort(resv, idx, idx + 1, 1);
- ret = 0;
- break;
- case VMA_ADD_RESV:
- if (vma->vm_flags & VM_MAYSHARE) {
- ret = region_add(resv, idx, idx + 1, 1, NULL, NULL);
- /* region_add calls of range 1 should never fail. */
- VM_BUG_ON(ret < 0);
- } else {
- region_abort(resv, idx, idx + 1, 1);
- ret = region_del(resv, idx, idx + 1);
- }
- break;
- default:
- BUG();
- }
- if (vma->vm_flags & VM_MAYSHARE)
- return ret;
- else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) && ret >= 0) {
- /*
- * In most cases, reserves always exist for private mappings.
- * However, a file associated with mapping could have been
- * hole punched or truncated after reserves were consumed.
- * As subsequent fault on such a range will not use reserves.
- * Subtle - The reserve map for private mappings has the
- * opposite meaning than that of shared mappings. If NO
- * entry is in the reserve map, it means a reservation exists.
- * If an entry exists in the reserve map, it means the
- * reservation has already been consumed. As a result, the
- * return value of this routine is the opposite of the
- * value returned from reserve map manipulation routines above.
- */
- if (ret)
- return 0;
- else
- return 1;
- }
- else
- return ret < 0 ? ret : 0;
- }
- static long vma_needs_reservation(struct hstate *h,
- struct vm_area_struct *vma, unsigned long addr)
- {
- return __vma_reservation_common(h, vma, addr, VMA_NEEDS_RESV);
- }
- static long vma_commit_reservation(struct hstate *h,
- struct vm_area_struct *vma, unsigned long addr)
- {
- return __vma_reservation_common(h, vma, addr, VMA_COMMIT_RESV);
- }
- static void vma_end_reservation(struct hstate *h,
- struct vm_area_struct *vma, unsigned long addr)
- {
- (void)__vma_reservation_common(h, vma, addr, VMA_END_RESV);
- }
- static long vma_add_reservation(struct hstate *h,
- struct vm_area_struct *vma, unsigned long addr)
- {
- return __vma_reservation_common(h, vma, addr, VMA_ADD_RESV);
- }
- /*
- * This routine is called to restore a reservation on error paths. In the
- * specific error paths, a huge page was allocated (via alloc_huge_page)
- * and is about to be freed. If a reservation for the page existed,
- * alloc_huge_page would have consumed the reservation and set PagePrivate
- * in the newly allocated page. When the page is freed via free_huge_page,
- * the global reservation count will be incremented if PagePrivate is set.
- * However, free_huge_page can not adjust the reserve map. Adjust the
- * reserve map here to be consistent with global reserve count adjustments
- * to be made by free_huge_page.
- */
- static void restore_reserve_on_error(struct hstate *h,
- struct vm_area_struct *vma, unsigned long address,
- struct page *page)
- {
- if (unlikely(PagePrivate(page))) {
- long rc = vma_needs_reservation(h, vma, address);
- if (unlikely(rc < 0)) {
- /*
- * Rare out of memory condition in reserve map
- * manipulation. Clear PagePrivate so that
- * global reserve count will not be incremented
- * by free_huge_page. This will make it appear
- * as though the reservation for this page was
- * consumed. This may prevent the task from
- * faulting in the page at a later time. This
- * is better than inconsistent global huge page
- * accounting of reserve counts.
- */
- ClearPagePrivate(page);
- } else if (rc) {
- rc = vma_add_reservation(h, vma, address);
- if (unlikely(rc < 0))
- /*
- * See above comment about rare out of
- * memory condition.
- */
- ClearPagePrivate(page);
- } else
- vma_end_reservation(h, vma, address);
- }
- }
- struct page *alloc_huge_page(struct vm_area_struct *vma,
- unsigned long addr, int avoid_reserve)
- {
- struct hugepage_subpool *spool = subpool_vma(vma);
- struct hstate *h = hstate_vma(vma);
- struct page *page;
- long map_chg, map_commit;
- long gbl_chg;
- int ret, idx;
- struct hugetlb_cgroup *h_cg;
- bool deferred_reserve;
- idx = hstate_index(h);
- /*
- * Examine the region/reserve map to determine if the process
- * has a reservation for the page to be allocated. A return
- * code of zero indicates a reservation exists (no change).
- */
- map_chg = gbl_chg = vma_needs_reservation(h, vma, addr);
- if (map_chg < 0)
- return ERR_PTR(-ENOMEM);
- /*
- * Processes that did not create the mapping will have no
- * reserves as indicated by the region/reserve map. Check
- * that the allocation will not exceed the subpool limit.
- * Allocations for MAP_NORESERVE mappings also need to be
- * checked against any subpool limit.
- */
- if (map_chg || avoid_reserve) {
- gbl_chg = hugepage_subpool_get_pages(spool, 1);
- if (gbl_chg < 0) {
- vma_end_reservation(h, vma, addr);
- return ERR_PTR(-ENOSPC);
- }
- /*
- * Even though there was no reservation in the region/reserve
- * map, there could be reservations associated with the
- * subpool that can be used. This would be indicated if the
- * return value of hugepage_subpool_get_pages() is zero.
- * However, if avoid_reserve is specified we still avoid even
- * the subpool reservations.
- */
- if (avoid_reserve)
- gbl_chg = 1;
- }
- /* If this allocation is not consuming a reservation, charge it now.
- */
- deferred_reserve = map_chg || avoid_reserve || !vma_resv_map(vma);
- if (deferred_reserve) {
- ret = hugetlb_cgroup_charge_cgroup_rsvd(
- idx, pages_per_huge_page(h), &h_cg);
- if (ret)
- goto out_subpool_put;
- }
- ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg);
- if (ret)
- goto out_uncharge_cgroup_reservation;
- spin_lock(&hugetlb_lock);
- /*
- * glb_chg is passed to indicate whether or not a page must be taken
- * from the global free pool (global change). gbl_chg == 0 indicates
- * a reservation exists for the allocation.
- */
- page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, gbl_chg);
- if (!page) {
- spin_unlock(&hugetlb_lock);
- page = alloc_buddy_huge_page_with_mpol(h, vma, addr);
- if (!page)
- goto out_uncharge_cgroup;
- if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) {
- SetPagePrivate(page);
- h->resv_huge_pages--;
- }
- spin_lock(&hugetlb_lock);
- list_add(&page->lru, &h->hugepage_activelist);
- /* Fall through */
- }
- hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page);
- /* If allocation is not consuming a reservation, also store the
- * hugetlb_cgroup pointer on the page.
- */
- if (deferred_reserve) {
- hugetlb_cgroup_commit_charge_rsvd(idx, pages_per_huge_page(h),
- h_cg, page);
- }
- spin_unlock(&hugetlb_lock);
- set_page_private(page, (unsigned long)spool);
- map_commit = vma_commit_reservation(h, vma, addr);
- if (unlikely(map_chg > map_commit)) {
- /*
- * The page was added to the reservation map between
- * vma_needs_reservation and vma_commit_reservation.
- * This indicates a race with hugetlb_reserve_pages.
- * Adjust for the subpool count incremented above AND
- * in hugetlb_reserve_pages for the same page. Also,
- * the reservation count added in hugetlb_reserve_pages
- * no longer applies.
- */
- long rsv_adjust;
- rsv_adjust = hugepage_subpool_put_pages(spool, 1);
- hugetlb_acct_memory(h, -rsv_adjust);
- if (deferred_reserve)
- hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h),
- pages_per_huge_page(h), page);
- }
- return page;
- out_uncharge_cgroup:
- hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg);
- out_uncharge_cgroup_reservation:
- if (deferred_reserve)
- hugetlb_cgroup_uncharge_cgroup_rsvd(idx, pages_per_huge_page(h),
- h_cg);
- out_subpool_put:
- if (map_chg || avoid_reserve)
- hugepage_subpool_put_pages(spool, 1);
- vma_end_reservation(h, vma, addr);
- return ERR_PTR(-ENOSPC);
- }
- int alloc_bootmem_huge_page(struct hstate *h)
- __attribute__ ((weak, alias("__alloc_bootmem_huge_page")));
- int __alloc_bootmem_huge_page(struct hstate *h)
- {
- struct huge_bootmem_page *m;
- int nr_nodes, node;
- for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) {
- void *addr;
- addr = memblock_alloc_try_nid_raw(
- huge_page_size(h), huge_page_size(h),
- 0, MEMBLOCK_ALLOC_ACCESSIBLE, node);
- if (addr) {
- /*
- * Use the beginning of the huge page to store the
- * huge_bootmem_page struct (until gather_bootmem
- * puts them into the mem_map).
- */
- m = addr;
- goto found;
- }
- }
- return 0;
- found:
- BUG_ON(!IS_ALIGNED(virt_to_phys(m), huge_page_size(h)));
- /* Put them into a private list first because mem_map is not up yet */
- INIT_LIST_HEAD(&m->list);
- list_add(&m->list, &huge_boot_pages);
- m->hstate = h;
- return 1;
- }
- /*
- * Put bootmem huge pages into the standard lists after mem_map is up.
- * Note: This only applies to gigantic (order > MAX_ORDER) pages.
- */
- static void __init gather_bootmem_prealloc(void)
- {
- struct huge_bootmem_page *m;
- list_for_each_entry(m, &huge_boot_pages, list) {
- struct page *page = virt_to_page(m);
- struct hstate *h = m->hstate;
- VM_BUG_ON(!hstate_is_gigantic(h));
- WARN_ON(page_count(page) != 1);
- prep_compound_gigantic_page(page, huge_page_order(h));
- WARN_ON(PageReserved(page));
- prep_new_huge_page(h, page, page_to_nid(page));
- put_page(page); /* free it into the hugepage allocator */
- /*
- * We need to restore the 'stolen' pages to totalram_pages
- * in order to fix confusing memory reports from free(1) and
- * other side-effects, like CommitLimit going negative.
- */
- adjust_managed_page_count(page, pages_per_huge_page(h));
- cond_resched();
- }
- }
- static void __init hugetlb_hstate_alloc_pages(struct hstate *h)
- {
- unsigned long i;
- nodemask_t *node_alloc_noretry;
- if (!hstate_is_gigantic(h)) {
- /*
- * Bit mask controlling how hard we retry per-node allocations.
- * Ignore errors as lower level routines can deal with
- * node_alloc_noretry == NULL. If this kmalloc fails at boot
- * time, we are likely in bigger trouble.
- */
- node_alloc_noretry = kmalloc(sizeof(*node_alloc_noretry),
- GFP_KERNEL);
- } else {
- /* allocations done at boot time */
- node_alloc_noretry = NULL;
- }
- /* bit mask controlling how hard we retry per-node allocations */
- if (node_alloc_noretry)
- nodes_clear(*node_alloc_noretry);
- for (i = 0; i < h->max_huge_pages; ++i) {
- if (hstate_is_gigantic(h)) {
- if (hugetlb_cma_size) {
- pr_warn_once("HugeTLB: hugetlb_cma is enabled, skip boot time allocation\n");
- goto free;
- }
- if (!alloc_bootmem_huge_page(h))
- break;
- } else if (!alloc_pool_huge_page(h,
- &node_states[N_MEMORY],
- node_alloc_noretry))
- break;
- cond_resched();
- }
- if (i < h->max_huge_pages) {
- char buf[32];
- string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
- pr_warn("HugeTLB: allocating %lu of page size %s failed. Only allocated %lu hugepages.\n",
- h->max_huge_pages, buf, i);
- h->max_huge_pages = i;
- }
- free:
- kfree(node_alloc_noretry);
- }
- static void __init hugetlb_init_hstates(void)
- {
- struct hstate *h;
- for_each_hstate(h) {
- if (minimum_order > huge_page_order(h))
- minimum_order = huge_page_order(h);
- /* oversize hugepages were init'ed in early boot */
- if (!hstate_is_gigantic(h))
- hugetlb_hstate_alloc_pages(h);
- }
- VM_BUG_ON(minimum_order == UINT_MAX);
- }
- static void __init report_hugepages(void)
- {
- struct hstate *h;
- for_each_hstate(h) {
- char buf[32];
- string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32);
- pr_info("HugeTLB registered %s page size, pre-allocated %ld pages\n",
- buf, h->free_huge_pages);
- }
- }
- #ifdef CONFIG_HIGHMEM
- static void try_to_free_low(struct hstate *h, unsigned long count,
- nodemask_t *nodes_allowed)
- {
- int i;
- if (hstate_is_gigantic(h))
- return;
- for_each_node_mask(i, *nodes_allowed) {
- struct page *page, *next;
- struct list_head *freel = &h->hugepage_freelists[i];
- list_for_each_entry_safe(page, next, freel, lru) {
- if (count >= h->nr_huge_pages)
- return;
- if (PageHighMem(page))
- continue;
- list_del(&page->lru);
- update_and_free_page(h, page);
- h->free_huge_pages--;
- h->free_huge_pages_node[page_to_nid(page)]--;
- }
- }
- }
- #else
- static inline void try_to_free_low(struct hstate *h, unsigned long count,
- nodemask_t *nodes_allowed)
- {
- }
- #endif
- /*
- * Increment or decrement surplus_huge_pages. Keep node-specific counters
- * balanced by operating on them in a round-robin fashion.
- * Returns 1 if an adjustment was made.
- */
- static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed,
- int delta)
- {
- int nr_nodes, node;
- VM_BUG_ON(delta != -1 && delta != 1);
- if (delta < 0) {
- for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) {
- if (h->surplus_huge_pages_node[node])
- goto found;
- }
- } else {
- for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) {
- if (h->surplus_huge_pages_node[node] <
- h->nr_huge_pages_node[node])
- goto found;
- }
- }
- return 0;
- found:
- h->surplus_huge_pages += delta;
- h->surplus_huge_pages_node[node] += delta;
- return 1;
- }
- #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages)
- static int set_max_huge_pages(struct hstate *h, unsigned long count, int nid,
- nodemask_t *nodes_allowed)
- {
- unsigned long min_count, ret;
- NODEMASK_ALLOC(nodemask_t, node_alloc_noretry, GFP_KERNEL);
- /*
- * Bit mask controlling how hard we retry per-node allocations.
- * If we can not allocate the bit mask, do not attempt to allocate
- * the requested huge pages.
- */
- if (node_alloc_noretry)
- nodes_clear(*node_alloc_noretry);
- else
- return -ENOMEM;
- spin_lock(&hugetlb_lock);
- /*
- * Check for a node specific request.
- * Changing node specific huge page count may require a corresponding
- * change to the global count. In any case, the passed node mask
- * (nodes_allowed) will restrict alloc/free to the specified node.
- */
- if (nid != NUMA_NO_NODE) {
- unsigned long old_count = count;
- count += h->nr_huge_pages - h->nr_huge_pages_node[nid];
- /*
- * User may have specified a large count value which caused the
- * above calculation to overflow. In this case, they wanted
- * to allocate as many huge pages as possible. Set count to
- * largest possible value to align with their intention.
- */
- if (count < old_count)
- count = ULONG_MAX;
- }
- /*
- * Gigantic pages runtime allocation depend on the capability for large
- * page range allocation.
- * If the system does not provide this feature, return an error when
- * the user tries to allocate gigantic pages but let the user free the
- * boottime allocated gigantic pages.
- */
- if (hstate_is_gigantic(h) && !IS_ENABLED(CONFIG_CONTIG_ALLOC)) {
- if (count > persistent_huge_pages(h)) {
- spin_unlock(&hugetlb_lock);
- NODEMASK_FREE(node_alloc_noretry);
- return -EINVAL;
- }
- /* Fall through to decrease pool */
- }
- /*
- * Increase the pool size
- * First take pages out of surplus state. Then make up the
- * remaining difference by allocating fresh huge pages.
- *
- * We might race with alloc_surplus_huge_page() here and be unable
- * to convert a surplus huge page to a normal huge page. That is
- * not critical, though, it just means the overall size of the
- * pool might be one hugepage larger than it needs to be, but
- * within all the constraints specified by the sysctls.
- */
- while (h->surplus_huge_pages && count > persistent_huge_pages(h)) {
- if (!adjust_pool_surplus(h, nodes_allowed, -1))
- break;
- }
- while (count > persistent_huge_pages(h)) {
- /*
- * If this allocation races such that we no longer need the
- * page, free_huge_page will handle it by freeing the page
- * and reducing the surplus.
- */
- spin_unlock(&hugetlb_lock);
- /* yield cpu to avoid soft lockup */
- cond_resched();
- ret = alloc_pool_huge_page(h, nodes_allowed,
- node_alloc_noretry);
- spin_lock(&hugetlb_lock);
- if (!ret)
- goto out;
- /* Bail for signals. Probably ctrl-c from user */
- if (signal_pending(current))
- goto out;
- }
- /*
- * Decrease the pool size
- * First return free pages to the buddy allocator (being careful
- * to keep enough around to satisfy reservations). Then place
- * pages into surplus state as needed so the pool will shrink
- * to the desired size as pages become free.
- *
- * By placing pages into the surplus state independent of the
- * overcommit value, we are allowing the surplus pool size to
- * exceed overcommit. There are few sane options here. Since
- * alloc_surplus_huge_page() is checking the global counter,
- * though, we'll note that we're not allowed to exceed surplus
- * and won't grow the pool anywhere else. Not until one of the
- * sysctls are changed, or the surplus pages go out of use.
- */
- min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages;
- min_count = max(count, min_count);
- try_to_free_low(h, min_count, nodes_allowed);
- while (min_count < persistent_huge_pages(h)) {
- if (!free_pool_huge_page(h, nodes_allowed, 0))
- break;
- cond_resched_lock(&hugetlb_lock);
- }
- while (count < persistent_huge_pages(h)) {
- if (!adjust_pool_surplus(h, nodes_allowed, 1))
- break;
- }
- out:
- h->max_huge_pages = persistent_huge_pages(h);
- spin_unlock(&hugetlb_lock);
- NODEMASK_FREE(node_alloc_noretry);
- return 0;
- }
- #define HSTATE_ATTR_RO(_name) \
- static struct kobj_attribute _name##_attr = __ATTR_RO(_name)
- #define HSTATE_ATTR(_name) \
- static struct kobj_attribute _name##_attr = \
- __ATTR(_name, 0644, _name##_show, _name##_store)
- static struct kobject *hugepages_kobj;
- static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
- static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp);
- static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp)
- {
- int i;
- for (i = 0; i < HUGE_MAX_HSTATE; i++)
- if (hstate_kobjs[i] == kobj) {
- if (nidp)
- *nidp = NUMA_NO_NODE;
- return &hstates[i];
- }
- return kobj_to_node_hstate(kobj, nidp);
- }
- static ssize_t nr_hugepages_show_common(struct kobject *kobj,
- struct kobj_attribute *attr, char *buf)
- {
- struct hstate *h;
- unsigned long nr_huge_pages;
- int nid;
- h = kobj_to_hstate(kobj, &nid);
- if (nid == NUMA_NO_NODE)
- nr_huge_pages = h->nr_huge_pages;
- else
- nr_huge_pages = h->nr_huge_pages_node[nid];
- return sprintf(buf, "%lu\n", nr_huge_pages);
- }
- static ssize_t __nr_hugepages_store_common(bool obey_mempolicy,
- struct hstate *h, int nid,
- unsigned long count, size_t len)
- {
- int err;
- nodemask_t nodes_allowed, *n_mask;
- if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
- return -EINVAL;
- if (nid == NUMA_NO_NODE) {
- /*
- * global hstate attribute
- */
- if (!(obey_mempolicy &&
- init_nodemask_of_mempolicy(&nodes_allowed)))
- n_mask = &node_states[N_MEMORY];
- else
- n_mask = &nodes_allowed;
- } else {
- /*
- * Node specific request. count adjustment happens in
- * set_max_huge_pages() after acquiring hugetlb_lock.
- */
- init_nodemask_of_node(&nodes_allowed, nid);
- n_mask = &nodes_allowed;
- }
- err = set_max_huge_pages(h, count, nid, n_mask);
- return err ? err : len;
- }
- static ssize_t nr_hugepages_store_common(bool obey_mempolicy,
- struct kobject *kobj, const char *buf,
- size_t len)
- {
- struct hstate *h;
- unsigned long count;
- int nid;
- int err;
- err = kstrtoul(buf, 10, &count);
- if (err)
- return err;
- h = kobj_to_hstate(kobj, &nid);
- return __nr_hugepages_store_common(obey_mempolicy, h, nid, count, len);
- }
- static ssize_t nr_hugepages_show(struct kobject *kobj,
- struct kobj_attribute *attr, char *buf)
- {
- return nr_hugepages_show_common(kobj, attr, buf);
- }
- static ssize_t nr_hugepages_store(struct kobject *kobj,
- struct kobj_attribute *attr, const char *buf, size_t len)
- {
- return nr_hugepages_store_common(false, kobj, buf, len);
- }
- HSTATE_ATTR(nr_hugepages);
- #ifdef CONFIG_NUMA
- /*
- * hstate attribute for optionally mempolicy-based constraint on persistent
- * huge page alloc/free.
- */
- static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj,
- struct kobj_attribute *attr, char *buf)
- {
- return nr_hugepages_show_common(kobj, attr, buf);
- }
- static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj,
- struct kobj_attribute *attr, const char *buf, size_t len)
- {
- return nr_hugepages_store_common(true, kobj, buf, len);
- }
- HSTATE_ATTR(nr_hugepages_mempolicy);
- #endif
- static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj,
- struct kobj_attribute *attr, char *buf)
- {
- struct hstate *h = kobj_to_hstate(kobj, NULL);
- return sprintf(buf, "%lu\n", h->nr_overcommit_huge_pages);
- }
- static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj,
- struct kobj_attribute *attr, const char *buf, size_t count)
- {
- int err;
- unsigned long input;
- struct hstate *h = kobj_to_hstate(kobj, NULL);
- if (hstate_is_gigantic(h))
- return -EINVAL;
- err = kstrtoul(buf, 10, &input);
- if (err)
- return err;
- spin_lock(&hugetlb_lock);
- h->nr_overcommit_huge_pages = input;
- spin_unlock(&hugetlb_lock);
- return count;
- }
- HSTATE_ATTR(nr_overcommit_hugepages);
- static ssize_t free_hugepages_show(struct kobject *kobj,
- struct kobj_attribute *attr, char *buf)
- {
- struct hstate *h;
- unsigned long free_huge_pages;
- int nid;
- h = kobj_to_hstate(kobj, &nid);
- if (nid == NUMA_NO_NODE)
- free_huge_pages = h->free_huge_pages;
- else
- free_huge_pages = h->free_huge_pages_node[nid];
- return sprintf(buf, "%lu\n", free_huge_pages);
- }
- HSTATE_ATTR_RO(free_hugepages);
- static ssize_t resv_hugepages_show(struct kobject *kobj,
- struct kobj_attribute *attr, char *buf)
- {
- struct hstate *h = kobj_to_hstate(kobj, NULL);
- return sprintf(buf, "%lu\n", h->resv_huge_pages);
- }
- HSTATE_ATTR_RO(resv_hugepages);
- static ssize_t surplus_hugepages_show(struct kobject *kobj,
- struct kobj_attribute *attr, char *buf)
- {
- struct hstate *h;
- unsigned long surplus_huge_pages;
- int nid;
- h = kobj_to_hstate(kobj, &nid);
- if (nid == NUMA_NO_NODE)
- surplus_huge_pages = h->surplus_huge_pages;
- else
- surplus_huge_pages = h->surplus_huge_pages_node[nid];
- return sprintf(buf, "%lu\n", surplus_huge_pages);
- }
- HSTATE_ATTR_RO(surplus_hugepages);
- static struct attribute *hstate_attrs[] = {
- &nr_hugepages_attr.attr,
- &nr_overcommit_hugepages_attr.attr,
- &free_hugepages_attr.attr,
- &resv_hugepages_attr.attr,
- &surplus_hugepages_attr.attr,
- #ifdef CONFIG_NUMA
- &nr_hugepages_mempolicy_attr.attr,
- #endif
- NULL,
- };
- static const struct attribute_group hstate_attr_group = {
- .attrs = hstate_attrs,
- };
- static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent,
- struct kobject **hstate_kobjs,
- const struct attribute_group *hstate_attr_group)
- {
- int retval;
- int hi = hstate_index(h);
- hstate_kobjs[hi] = kobject_create_and_add(h->name, parent);
- if (!hstate_kobjs[hi])
- return -ENOMEM;
- retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group);
- if (retval) {
- kobject_put(hstate_kobjs[hi]);
- hstate_kobjs[hi] = NULL;
- }
- return retval;
- }
- static void __init hugetlb_sysfs_init(void)
- {
- struct hstate *h;
- int err;
- hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj);
- if (!hugepages_kobj)
- return;
- for_each_hstate(h) {
- err = hugetlb_sysfs_add_hstate(h, hugepages_kobj,
- hstate_kobjs, &hstate_attr_group);
- if (err)
- pr_err("HugeTLB: Unable to add hstate %s", h->name);
- }
- }
- #ifdef CONFIG_NUMA
- /*
- * node_hstate/s - associate per node hstate attributes, via their kobjects,
- * with node devices in node_devices[] using a parallel array. The array
- * index of a node device or _hstate == node id.
- * This is here to avoid any static dependency of the node device driver, in
- * the base kernel, on the hugetlb module.
- */
- struct node_hstate {
- struct kobject *hugepages_kobj;
- struct kobject *hstate_kobjs[HUGE_MAX_HSTATE];
- };
- static struct node_hstate node_hstates[MAX_NUMNODES];
- /*
- * A subset of global hstate attributes for node devices
- */
- static struct attribute *per_node_hstate_attrs[] = {
- &nr_hugepages_attr.attr,
- &free_hugepages_attr.attr,
- &surplus_hugepages_attr.attr,
- NULL,
- };
- static const struct attribute_group per_node_hstate_attr_group = {
- .attrs = per_node_hstate_attrs,
- };
- /*
- * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj.
- * Returns node id via non-NULL nidp.
- */
- static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
- {
- int nid;
- for (nid = 0; nid < nr_node_ids; nid++) {
- struct node_hstate *nhs = &node_hstates[nid];
- int i;
- for (i = 0; i < HUGE_MAX_HSTATE; i++)
- if (nhs->hstate_kobjs[i] == kobj) {
- if (nidp)
- *nidp = nid;
- return &hstates[i];
- }
- }
- BUG();
- return NULL;
- }
- /*
- * Unregister hstate attributes from a single node device.
- * No-op if no hstate attributes attached.
- */
- static void hugetlb_unregister_node(struct node *node)
- {
- struct hstate *h;
- struct node_hstate *nhs = &node_hstates[node->dev.id];
- if (!nhs->hugepages_kobj)
- return; /* no hstate attributes */
- for_each_hstate(h) {
- int idx = hstate_index(h);
- if (nhs->hstate_kobjs[idx]) {
- kobject_put(nhs->hstate_kobjs[idx]);
- nhs->hstate_kobjs[idx] = NULL;
- }
- }
- kobject_put(nhs->hugepages_kobj);
- nhs->hugepages_kobj = NULL;
- }
- /*
- * Register hstate attributes for a single node device.
- * No-op if attributes already registered.
- */
- static void hugetlb_register_node(struct node *node)
- {
- struct hstate *h;
- struct node_hstate *nhs = &node_hstates[node->dev.id];
- int err;
- if (nhs->hugepages_kobj)
- return; /* already allocated */
- nhs->hugepages_kobj = kobject_create_and_add("hugepages",
- &node->dev.kobj);
- if (!nhs->hugepages_kobj)
- return;
- for_each_hstate(h) {
- err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj,
- nhs->hstate_kobjs,
- &per_node_hstate_attr_group);
- if (err) {
- pr_err("HugeTLB: Unable to add hstate %s for node %d\n",
- h->name, node->dev.id);
- hugetlb_unregister_node(node);
- break;
- }
- }
- }
- /*
- * hugetlb init time: register hstate attributes for all registered node
- * devices of nodes that have memory. All on-line nodes should have
- * registered their associated device by this time.
- */
- static void __init hugetlb_register_all_nodes(void)
- {
- int nid;
- for_each_node_state(nid, N_MEMORY) {
- struct node *node = node_devices[nid];
- if (node->dev.id == nid)
- hugetlb_register_node(node);
- }
- /*
- * Let the node device driver know we're here so it can
- * [un]register hstate attributes on node hotplug.
- */
- register_hugetlbfs_with_node(hugetlb_register_node,
- hugetlb_unregister_node);
- }
- #else /* !CONFIG_NUMA */
- static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
- {
- BUG();
- if (nidp)
- *nidp = -1;
- return NULL;
- }
- static void hugetlb_register_all_nodes(void) { }
- #endif
- static int __init hugetlb_init(void)
- {
- int i;
- if (!hugepages_supported()) {
- if (hugetlb_max_hstate || default_hstate_max_huge_pages)
- pr_warn("HugeTLB: huge pages not supported, ignoring associated command-line parameters\n");
- return 0;
- }
- /*
- * Make sure HPAGE_SIZE (HUGETLB_PAGE_ORDER) hstate exists. Some
- * architectures depend on setup being done here.
- */
- hugetlb_add_hstate(HUGETLB_PAGE_ORDER);
- if (!parsed_default_hugepagesz) {
- /*
- * If we did not parse a default huge page size, set
- * default_hstate_idx to HPAGE_SIZE hstate. And, if the
- * number of huge pages for this default size was implicitly
- * specified, set that here as well.
- * Note that the implicit setting will overwrite an explicit
- * setting. A warning will be printed in this case.
- */
- default_hstate_idx = hstate_index(size_to_hstate(HPAGE_SIZE));
- if (default_hstate_max_huge_pages) {
- if (default_hstate.max_huge_pages) {
- char buf[32];
- string_get_size(huge_page_size(&default_hstate),
- 1, STRING_UNITS_2, buf, 32);
- pr_warn("HugeTLB: Ignoring hugepages=%lu associated with %s page size\n",
- default_hstate.max_huge_pages, buf);
- pr_warn("HugeTLB: Using hugepages=%lu for number of default huge pages\n",
- default_hstate_max_huge_pages);
- }
- default_hstate.max_huge_pages =
- default_hstate_max_huge_pages;
- }
- }
- hugetlb_cma_check();
- hugetlb_init_hstates();
- gather_bootmem_prealloc();
- report_hugepages();
- hugetlb_sysfs_init();
- hugetlb_register_all_nodes();
- hugetlb_cgroup_file_init();
- #ifdef CONFIG_SMP
- num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus());
- #else
- num_fault_mutexes = 1;
- #endif
- hugetlb_fault_mutex_table =
- kmalloc_array(num_fault_mutexes, sizeof(struct mutex),
- GFP_KERNEL);
- BUG_ON(!hugetlb_fault_mutex_table);
- for (i = 0; i < num_fault_mutexes; i++)
- mutex_init(&hugetlb_fault_mutex_table[i]);
- return 0;
- }
- subsys_initcall(hugetlb_init);
- /* Overwritten by architectures with more huge page sizes */
- bool __init __attribute((weak)) arch_hugetlb_valid_size(unsigned long size)
- {
- return size == HPAGE_SIZE;
- }
- void __init hugetlb_add_hstate(unsigned int order)
- {
- struct hstate *h;
- unsigned long i;
- if (size_to_hstate(PAGE_SIZE << order)) {
- return;
- }
- BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE);
- BUG_ON(order == 0);
- h = &hstates[hugetlb_max_hstate++];
- h->order = order;
- h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1);
- h->nr_huge_pages = 0;
- h->free_huge_pages = 0;
- for (i = 0; i < MAX_NUMNODES; ++i)
- INIT_LIST_HEAD(&h->hugepage_freelists[i]);
- INIT_LIST_HEAD(&h->hugepage_activelist);
- h->next_nid_to_alloc = first_memory_node;
- h->next_nid_to_free = first_memory_node;
- snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
- huge_page_size(h)/1024);
- parsed_hstate = h;
- }
- /*
- * hugepages command line processing
- * hugepages normally follows a valid hugepagsz or default_hugepagsz
- * specification. If not, ignore the hugepages value. hugepages can also
- * be the first huge page command line option in which case it implicitly
- * specifies the number of huge pages for the default size.
- */
- static int __init hugepages_setup(char *s)
- {
- unsigned long *mhp;
- static unsigned long *last_mhp;
- if (!parsed_valid_hugepagesz) {
- pr_warn("HugeTLB: hugepages=%s does not follow a valid hugepagesz, ignoring\n", s);
- parsed_valid_hugepagesz = true;
- return 0;
- }
- /*
- * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter
- * yet, so this hugepages= parameter goes to the "default hstate".
- * Otherwise, it goes with the previously parsed hugepagesz or
- * default_hugepagesz.
- */
- else if (!hugetlb_max_hstate)
- mhp = &default_hstate_max_huge_pages;
- else
- mhp = &parsed_hstate->max_huge_pages;
- if (mhp == last_mhp) {
- pr_warn("HugeTLB: hugepages= specified twice without interleaving hugepagesz=, ignoring hugepages=%s\n", s);
- return 0;
- }
- if (sscanf(s, "%lu", mhp) <= 0)
- *mhp = 0;
- /*
- * Global state is always initialized later in hugetlb_init.
- * But we need to allocate >= MAX_ORDER hstates here early to still
- * use the bootmem allocator.
- */
- if (hugetlb_max_hstate && parsed_hstate->order >= MAX_ORDER)
- hugetlb_hstate_alloc_pages(parsed_hstate);
- last_mhp = mhp;
- return 1;
- }
- __setup("hugepages=", hugepages_setup);
- /*
- * hugepagesz command line processing
- * A specific huge page size can only be specified once with hugepagesz.
- * hugepagesz is followed by hugepages on the command line. The global
- * variable 'parsed_valid_hugepagesz' is used to determine if prior
- * hugepagesz argument was valid.
- */
- static int __init hugepagesz_setup(char *s)
- {
- unsigned long size;
- struct hstate *h;
- parsed_valid_hugepagesz = false;
- size = (unsigned long)memparse(s, NULL);
- if (!arch_hugetlb_valid_size(size)) {
- pr_err("HugeTLB: unsupported hugepagesz=%s\n", s);
- return 0;
- }
- h = size_to_hstate(size);
- if (h) {
- /*
- * hstate for this size already exists. This is normally
- * an error, but is allowed if the existing hstate is the
- * default hstate. More specifically, it is only allowed if
- * the number of huge pages for the default hstate was not
- * previously specified.
- */
- if (!parsed_default_hugepagesz || h != &default_hstate ||
- default_hstate.max_huge_pages) {
- pr_warn("HugeTLB: hugepagesz=%s specified twice, ignoring\n", s);
- return 0;
- }
- /*
- * No need to call hugetlb_add_hstate() as hstate already
- * exists. But, do set parsed_hstate so that a following
- * hugepages= parameter will be applied to this hstate.
- */
- parsed_hstate = h;
- parsed_valid_hugepagesz = true;
- return 1;
- }
- hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT);
- parsed_valid_hugepagesz = true;
- return 1;
- }
- __setup("hugepagesz=", hugepagesz_setup);
- /*
- * default_hugepagesz command line input
- * Only one instance of default_hugepagesz allowed on command line.
- */
- static int __init default_hugepagesz_setup(char *s)
- {
- unsigned long size;
- parsed_valid_hugepagesz = false;
- if (parsed_default_hugepagesz) {
- pr_err("HugeTLB: default_hugepagesz previously specified, ignoring %s\n", s);
- return 0;
- }
- size = (unsigned long)memparse(s, NULL);
- if (!arch_hugetlb_valid_size(size)) {
- pr_err("HugeTLB: unsupported default_hugepagesz=%s\n", s);
- return 0;
- }
- hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT);
- parsed_valid_hugepagesz = true;
- parsed_default_hugepagesz = true;
- default_hstate_idx = hstate_index(size_to_hstate(size));
- /*
- * The number of default huge pages (for this size) could have been
- * specified as the first hugetlb parameter: hugepages=X. If so,
- * then default_hstate_max_huge_pages is set. If the default huge
- * page size is gigantic (>= MAX_ORDER), then the pages must be
- * allocated here from bootmem allocator.
- */
- if (default_hstate_max_huge_pages) {
- default_hstate.max_huge_pages = default_hstate_max_huge_pages;
- if (hstate_is_gigantic(&default_hstate))
- hugetlb_hstate_alloc_pages(&default_hstate);
- default_hstate_max_huge_pages = 0;
- }
- return 1;
- }
- __setup("default_hugepagesz=", default_hugepagesz_setup);
- static unsigned int allowed_mems_nr(struct hstate *h)
- {
- int node;
- unsigned int nr = 0;
- nodemask_t *mpol_allowed;
- unsigned int *array = h->free_huge_pages_node;
- gfp_t gfp_mask = htlb_alloc_mask(h);
- mpol_allowed = policy_nodemask_current(gfp_mask);
- for_each_node_mask(node, cpuset_current_mems_allowed) {
- if (!mpol_allowed ||
- (mpol_allowed && node_isset(node, *mpol_allowed)))
- nr += array[node];
- }
- return nr;
- }
- #ifdef CONFIG_SYSCTL
- static int proc_hugetlb_doulongvec_minmax(struct ctl_table *table, int write,
- void *buffer, size_t *length,
- loff_t *ppos, unsigned long *out)
- {
- struct ctl_table dup_table;
- /*
- * In order to avoid races with __do_proc_doulongvec_minmax(), we
- * can duplicate the @table and alter the duplicate of it.
- */
- dup_table = *table;
- dup_table.data = out;
- return proc_doulongvec_minmax(&dup_table, write, buffer, length, ppos);
- }
- static int hugetlb_sysctl_handler_common(bool obey_mempolicy,
- struct ctl_table *table, int write,
- void *buffer, size_t *length, loff_t *ppos)
- {
- struct hstate *h = &default_hstate;
- unsigned long tmp = h->max_huge_pages;
- int ret;
- if (!hugepages_supported())
- return -EOPNOTSUPP;
- ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
- &tmp);
- if (ret)
- goto out;
- if (write)
- ret = __nr_hugepages_store_common(obey_mempolicy, h,
- NUMA_NO_NODE, tmp, *length);
- out:
- return ret;
- }
- int hugetlb_sysctl_handler(struct ctl_table *table, int write,
- void *buffer, size_t *length, loff_t *ppos)
- {
- return hugetlb_sysctl_handler_common(false, table, write,
- buffer, length, ppos);
- }
- #ifdef CONFIG_NUMA
- int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write,
- void *buffer, size_t *length, loff_t *ppos)
- {
- return hugetlb_sysctl_handler_common(true, table, write,
- buffer, length, ppos);
- }
- #endif /* CONFIG_NUMA */
- int hugetlb_overcommit_handler(struct ctl_table *table, int write,
- void *buffer, size_t *length, loff_t *ppos)
- {
- struct hstate *h = &default_hstate;
- unsigned long tmp;
- int ret;
- if (!hugepages_supported())
- return -EOPNOTSUPP;
- tmp = h->nr_overcommit_huge_pages;
- if (write && hstate_is_gigantic(h))
- return -EINVAL;
- ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos,
- &tmp);
- if (ret)
- goto out;
- if (write) {
- spin_lock(&hugetlb_lock);
- h->nr_overcommit_huge_pages = tmp;
- spin_unlock(&hugetlb_lock);
- }
- out:
- return ret;
- }
- #endif /* CONFIG_SYSCTL */
- void hugetlb_report_meminfo(struct seq_file *m)
- {
- struct hstate *h;
- unsigned long total = 0;
- if (!hugepages_supported())
- return;
- for_each_hstate(h) {
- unsigned long count = h->nr_huge_pages;
- total += (PAGE_SIZE << huge_page_order(h)) * count;
- if (h == &default_hstate)
- seq_printf(m,
- "HugePages_Total: %5lu\n"
- "HugePages_Free: %5lu\n"
- "HugePages_Rsvd: %5lu\n"
- "HugePages_Surp: %5lu\n"
- "Hugepagesize: %8lu kB\n",
- count,
- h->free_huge_pages,
- h->resv_huge_pages,
- h->surplus_huge_pages,
- (PAGE_SIZE << huge_page_order(h)) / 1024);
- }
- seq_printf(m, "Hugetlb: %8lu kB\n", total / 1024);
- }
- int hugetlb_report_node_meminfo(char *buf, int len, int nid)
- {
- struct hstate *h = &default_hstate;
- if (!hugepages_supported())
- return 0;
- return sysfs_emit_at(buf, len,
- "Node %d HugePages_Total: %5u\n"
- "Node %d HugePages_Free: %5u\n"
- "Node %d HugePages_Surp: %5u\n",
- nid, h->nr_huge_pages_node[nid],
- nid, h->free_huge_pages_node[nid],
- nid, h->surplus_huge_pages_node[nid]);
- }
- void hugetlb_show_meminfo(void)
- {
- struct hstate *h;
- int nid;
- if (!hugepages_supported())
- return;
- for_each_node_state(nid, N_MEMORY)
- for_each_hstate(h)
- pr_info("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n",
- nid,
- h->nr_huge_pages_node[nid],
- h->free_huge_pages_node[nid],
- h->surplus_huge_pages_node[nid],
- 1UL << (huge_page_order(h) + PAGE_SHIFT - 10));
- }
- void hugetlb_report_usage(struct seq_file *m, struct mm_struct *mm)
- {
- seq_printf(m, "HugetlbPages:\t%8lu kB\n",
- atomic_long_read(&mm->hugetlb_usage) << (PAGE_SHIFT - 10));
- }
- /* Return the number pages of memory we physically have, in PAGE_SIZE units. */
- unsigned long hugetlb_total_pages(void)
- {
- struct hstate *h;
- unsigned long nr_total_pages = 0;
- for_each_hstate(h)
- nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h);
- return nr_total_pages;
- }
- static int hugetlb_acct_memory(struct hstate *h, long delta)
- {
- int ret = -ENOMEM;
- spin_lock(&hugetlb_lock);
- /*
- * When cpuset is configured, it breaks the strict hugetlb page
- * reservation as the accounting is done on a global variable. Such
- * reservation is completely rubbish in the presence of cpuset because
- * the reservation is not checked against page availability for the
- * current cpuset. Application can still potentially OOM'ed by kernel
- * with lack of free htlb page in cpuset that the task is in.
- * Attempt to enforce strict accounting with cpuset is almost
- * impossible (or too ugly) because cpuset is too fluid that
- * task or memory node can be dynamically moved between cpusets.
- *
- * The change of semantics for shared hugetlb mapping with cpuset is
- * undesirable. However, in order to preserve some of the semantics,
- * we fall back to check against current free page availability as
- * a best attempt and hopefully to minimize the impact of changing
- * semantics that cpuset has.
- *
- * Apart from cpuset, we also have memory policy mechanism that
- * also determines from which node the kernel will allocate memory
- * in a NUMA system. So similar to cpuset, we also should consider
- * the memory policy of the current task. Similar to the description
- * above.
- */
- if (delta > 0) {
- if (gather_surplus_pages(h, delta) < 0)
- goto out;
- if (delta > allowed_mems_nr(h)) {
- return_unused_surplus_pages(h, delta);
- goto out;
- }
- }
- ret = 0;
- if (delta < 0)
- return_unused_surplus_pages(h, (unsigned long) -delta);
- out:
- spin_unlock(&hugetlb_lock);
- return ret;
- }
- static void hugetlb_vm_op_open(struct vm_area_struct *vma)
- {
- struct resv_map *resv = vma_resv_map(vma);
- /*
- * This new VMA should share its siblings reservation map if present.
- * The VMA will only ever have a valid reservation map pointer where
- * it is being copied for another still existing VMA. As that VMA
- * has a reference to the reservation map it cannot disappear until
- * after this open call completes. It is therefore safe to take a
- * new reference here without additional locking.
- */
- if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER)) {
- resv_map_dup_hugetlb_cgroup_uncharge_info(resv);
- kref_get(&resv->refs);
- }
- }
- static void hugetlb_vm_op_close(struct vm_area_struct *vma)
- {
- struct hstate *h = hstate_vma(vma);
- struct resv_map *resv = vma_resv_map(vma);
- struct hugepage_subpool *spool = subpool_vma(vma);
- unsigned long reserve, start, end;
- long gbl_reserve;
- if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER))
- return;
- start = vma_hugecache_offset(h, vma, vma->vm_start);
- end = vma_hugecache_offset(h, vma, vma->vm_end);
- reserve = (end - start) - region_count(resv, start, end);
- hugetlb_cgroup_uncharge_counter(resv, start, end);
- if (reserve) {
- /*
- * Decrement reserve counts. The global reserve count may be
- * adjusted if the subpool has a minimum size.
- */
- gbl_reserve = hugepage_subpool_put_pages(spool, reserve);
- hugetlb_acct_memory(h, -gbl_reserve);
- }
- kref_put(&resv->refs, resv_map_release);
- }
- static int hugetlb_vm_op_split(struct vm_area_struct *vma, unsigned long addr)
- {
- if (addr & ~(huge_page_mask(hstate_vma(vma))))
- return -EINVAL;
- return 0;
- }
- static unsigned long hugetlb_vm_op_pagesize(struct vm_area_struct *vma)
- {
- struct hstate *hstate = hstate_vma(vma);
- return 1UL << huge_page_shift(hstate);
- }
- /*
- * We cannot handle pagefaults against hugetlb pages at all. They cause
- * handle_mm_fault() to try to instantiate regular-sized pages in the
- * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get
- * this far.
- */
- static vm_fault_t hugetlb_vm_op_fault(struct vm_fault *vmf)
- {
- BUG();
- return 0;
- }
- /*
- * When a new function is introduced to vm_operations_struct and added
- * to hugetlb_vm_ops, please consider adding the function to shm_vm_ops.
- * This is because under System V memory model, mappings created via
- * shmget/shmat with "huge page" specified are backed by hugetlbfs files,
- * their original vm_ops are overwritten with shm_vm_ops.
- */
- const struct vm_operations_struct hugetlb_vm_ops = {
- .fault = hugetlb_vm_op_fault,
- .open = hugetlb_vm_op_open,
- .close = hugetlb_vm_op_close,
- .split = hugetlb_vm_op_split,
- .pagesize = hugetlb_vm_op_pagesize,
- };
- static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page,
- int writable)
- {
- pte_t entry;
- if (writable) {
- entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
- vma->vm_page_prot)));
- } else {
- entry = huge_pte_wrprotect(mk_huge_pte(page,
- vma->vm_page_prot));
- }
- entry = pte_mkyoung(entry);
- entry = pte_mkhuge(entry);
- entry = arch_make_huge_pte(entry, vma, page, writable);
- return entry;
- }
- static void set_huge_ptep_writable(struct vm_area_struct *vma,
- unsigned long address, pte_t *ptep)
- {
- pte_t entry;
- entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep)));
- if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1))
- update_mmu_cache(vma, address, ptep);
- }
- bool is_hugetlb_entry_migration(pte_t pte)
- {
- swp_entry_t swp;
- if (huge_pte_none(pte) || pte_present(pte))
- return false;
- swp = pte_to_swp_entry(pte);
- if (is_migration_entry(swp))
- return true;
- else
- return false;
- }
- static bool is_hugetlb_entry_hwpoisoned(pte_t pte)
- {
- swp_entry_t swp;
- if (huge_pte_none(pte) || pte_present(pte))
- return false;
- swp = pte_to_swp_entry(pte);
- if (is_hwpoison_entry(swp))
- return true;
- else
- return false;
- }
- int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
- struct vm_area_struct *vma)
- {
- pte_t *src_pte, *dst_pte, entry, dst_entry;
- struct page *ptepage;
- unsigned long addr;
- int cow;
- struct hstate *h = hstate_vma(vma);
- unsigned long sz = huge_page_size(h);
- struct address_space *mapping = vma->vm_file->f_mapping;
- struct mmu_notifier_range range;
- int ret = 0;
- cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
- if (cow) {
- mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, src,
- vma->vm_start,
- vma->vm_end);
- mmu_notifier_invalidate_range_start(&range);
- } else {
- /*
- * For shared mappings i_mmap_rwsem must be held to call
- * huge_pte_alloc, otherwise the returned ptep could go
- * away if part of a shared pmd and another thread calls
- * huge_pmd_unshare.
- */
- i_mmap_lock_read(mapping);
- }
- for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) {
- spinlock_t *src_ptl, *dst_ptl;
- src_pte = huge_pte_offset(src, addr, sz);
- if (!src_pte)
- continue;
- dst_pte = huge_pte_alloc(dst, vma, addr, sz);
- if (!dst_pte) {
- ret = -ENOMEM;
- break;
- }
- /*
- * If the pagetables are shared don't copy or take references.
- * dst_pte == src_pte is the common case of src/dest sharing.
- *
- * However, src could have 'unshared' and dst shares with
- * another vma. If dst_pte !none, this implies sharing.
- * Check here before taking page table lock, and once again
- * after taking the lock below.
- */
- dst_entry = huge_ptep_get(dst_pte);
- if ((dst_pte == src_pte) || !huge_pte_none(dst_entry))
- continue;
- dst_ptl = huge_pte_lock(h, dst, dst_pte);
- src_ptl = huge_pte_lockptr(h, src, src_pte);
- spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
- entry = huge_ptep_get(src_pte);
- dst_entry = huge_ptep_get(dst_pte);
- if (huge_pte_none(entry) || !huge_pte_none(dst_entry)) {
- /*
- * Skip if src entry none. Also, skip in the
- * unlikely case dst entry !none as this implies
- * sharing with another vma.
- */
- ;
- } else if (unlikely(is_hugetlb_entry_migration(entry) ||
- is_hugetlb_entry_hwpoisoned(entry))) {
- swp_entry_t swp_entry = pte_to_swp_entry(entry);
- if (is_write_migration_entry(swp_entry) && cow) {
- /*
- * COW mappings require pages in both
- * parent and child to be set to read.
- */
- make_migration_entry_read(&swp_entry);
- entry = swp_entry_to_pte(swp_entry);
- set_huge_swap_pte_at(src, addr, src_pte,
- entry, sz);
- }
- set_huge_swap_pte_at(dst, addr, dst_pte, entry, sz);
- } else {
- if (cow) {
- /*
- * No need to notify as we are downgrading page
- * table protection not changing it to point
- * to a new page.
- *
- * See Documentation/vm/mmu_notifier.rst
- */
- huge_ptep_set_wrprotect(src, addr, src_pte);
- }
- entry = huge_ptep_get(src_pte);
- ptepage = pte_page(entry);
- get_page(ptepage);
- page_dup_rmap(ptepage, true);
- set_huge_pte_at(dst, addr, dst_pte, entry);
- hugetlb_count_add(pages_per_huge_page(h), dst);
- }
- spin_unlock(src_ptl);
- spin_unlock(dst_ptl);
- }
- if (cow)
- mmu_notifier_invalidate_range_end(&range);
- else
- i_mmap_unlock_read(mapping);
- return ret;
- }
- void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
- unsigned long start, unsigned long end,
- struct page *ref_page)
- {
- struct mm_struct *mm = vma->vm_mm;
- unsigned long address;
- pte_t *ptep;
- pte_t pte;
- spinlock_t *ptl;
- struct page *page;
- struct hstate *h = hstate_vma(vma);
- unsigned long sz = huge_page_size(h);
- struct mmu_notifier_range range;
- bool force_flush = false;
- WARN_ON(!is_vm_hugetlb_page(vma));
- BUG_ON(start & ~huge_page_mask(h));
- BUG_ON(end & ~huge_page_mask(h));
- /*
- * This is a hugetlb vma, all the pte entries should point
- * to huge page.
- */
- tlb_change_page_size(tlb, sz);
- tlb_start_vma(tlb, vma);
- /*
- * If sharing possible, alert mmu notifiers of worst case.
- */
- mmu_notifier_range_init(&range, MMU_NOTIFY_UNMAP, 0, vma, mm, start,
- end);
- adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
- mmu_notifier_invalidate_range_start(&range);
- address = start;
- for (; address < end; address += sz) {
- ptep = huge_pte_offset(mm, address, sz);
- if (!ptep)
- continue;
- ptl = huge_pte_lock(h, mm, ptep);
- if (huge_pmd_unshare(mm, vma, &address, ptep)) {
- spin_unlock(ptl);
- tlb_flush_pmd_range(tlb, address & PUD_MASK, PUD_SIZE);
- force_flush = true;
- continue;
- }
- pte = huge_ptep_get(ptep);
- if (huge_pte_none(pte)) {
- spin_unlock(ptl);
- continue;
- }
- /*
- * Migrating hugepage or HWPoisoned hugepage is already
- * unmapped and its refcount is dropped, so just clear pte here.
- */
- if (unlikely(!pte_present(pte))) {
- huge_pte_clear(mm, address, ptep, sz);
- spin_unlock(ptl);
- continue;
- }
- page = pte_page(pte);
- /*
- * If a reference page is supplied, it is because a specific
- * page is being unmapped, not a range. Ensure the page we
- * are about to unmap is the actual page of interest.
- */
- if (ref_page) {
- if (page != ref_page) {
- spin_unlock(ptl);
- continue;
- }
- /*
- * Mark the VMA as having unmapped its page so that
- * future faults in this VMA will fail rather than
- * looking like data was lost
- */
- set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED);
- }
- pte = huge_ptep_get_and_clear(mm, address, ptep);
- tlb_remove_huge_tlb_entry(h, tlb, ptep, address);
- if (huge_pte_dirty(pte))
- set_page_dirty(page);
- hugetlb_count_sub(pages_per_huge_page(h), mm);
- page_remove_rmap(page, true);
- spin_unlock(ptl);
- tlb_remove_page_size(tlb, page, huge_page_size(h));
- /*
- * Bail out after unmapping reference page if supplied
- */
- if (ref_page)
- break;
- }
- mmu_notifier_invalidate_range_end(&range);
- tlb_end_vma(tlb, vma);
- /*
- * If we unshared PMDs, the TLB flush was not recorded in mmu_gather. We
- * could defer the flush until now, since by holding i_mmap_rwsem we
- * guaranteed that the last refernece would not be dropped. But we must
- * do the flushing before we return, as otherwise i_mmap_rwsem will be
- * dropped and the last reference to the shared PMDs page might be
- * dropped as well.
- *
- * In theory we could defer the freeing of the PMD pages as well, but
- * huge_pmd_unshare() relies on the exact page_count for the PMD page to
- * detect sharing, so we cannot defer the release of the page either.
- * Instead, do flush now.
- */
- if (force_flush)
- tlb_flush_mmu_tlbonly(tlb);
- }
- void __unmap_hugepage_range_final(struct mmu_gather *tlb,
- struct vm_area_struct *vma, unsigned long start,
- unsigned long end, struct page *ref_page)
- {
- __unmap_hugepage_range(tlb, vma, start, end, ref_page);
- /*
- * Clear this flag so that x86's huge_pmd_share page_table_shareable
- * test will fail on a vma being torn down, and not grab a page table
- * on its way out. We're lucky that the flag has such an appropriate
- * name, and can in fact be safely cleared here. We could clear it
- * before the __unmap_hugepage_range above, but all that's necessary
- * is to clear it before releasing the i_mmap_rwsem. This works
- * because in the context this is called, the VMA is about to be
- * destroyed and the i_mmap_rwsem is held.
- */
- vma->vm_flags &= ~VM_MAYSHARE;
- }
- void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start,
- unsigned long end, struct page *ref_page)
- {
- struct mm_struct *mm;
- struct mmu_gather tlb;
- unsigned long tlb_start = start;
- unsigned long tlb_end = end;
- /*
- * If shared PMDs were possibly used within this vma range, adjust
- * start/end for worst case tlb flushing.
- * Note that we can not be sure if PMDs are shared until we try to
- * unmap pages. However, we want to make sure TLB flushing covers
- * the largest possible range.
- */
- adjust_range_if_pmd_sharing_possible(vma, &tlb_start, &tlb_end);
- mm = vma->vm_mm;
- tlb_gather_mmu(&tlb, mm, tlb_start, tlb_end);
- __unmap_hugepage_range(&tlb, vma, start, end, ref_page);
- tlb_finish_mmu(&tlb, tlb_start, tlb_end);
- }
- /*
- * This is called when the original mapper is failing to COW a MAP_PRIVATE
- * mappping it owns the reserve page for. The intention is to unmap the page
- * from other VMAs and let the children be SIGKILLed if they are faulting the
- * same region.
- */
- static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma,
- struct page *page, unsigned long address)
- {
- struct hstate *h = hstate_vma(vma);
- struct vm_area_struct *iter_vma;
- struct address_space *mapping;
- pgoff_t pgoff;
- /*
- * vm_pgoff is in PAGE_SIZE units, hence the different calculation
- * from page cache lookup which is in HPAGE_SIZE units.
- */
- address = address & huge_page_mask(h);
- pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) +
- vma->vm_pgoff;
- mapping = vma->vm_file->f_mapping;
- /*
- * Take the mapping lock for the duration of the table walk. As
- * this mapping should be shared between all the VMAs,
- * __unmap_hugepage_range() is called as the lock is already held
- */
- i_mmap_lock_write(mapping);
- vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) {
- /* Do not unmap the current VMA */
- if (iter_vma == vma)
- continue;
- /*
- * Shared VMAs have their own reserves and do not affect
- * MAP_PRIVATE accounting but it is possible that a shared
- * VMA is using the same page so check and skip such VMAs.
- */
- if (iter_vma->vm_flags & VM_MAYSHARE)
- continue;
- /*
- * Unmap the page from other VMAs without their own reserves.
- * They get marked to be SIGKILLed if they fault in these
- * areas. This is because a future no-page fault on this VMA
- * could insert a zeroed page instead of the data existing
- * from the time of fork. This would look like data corruption
- */
- if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER))
- unmap_hugepage_range(iter_vma, address,
- address + huge_page_size(h), page);
- }
- i_mmap_unlock_write(mapping);
- }
- /*
- * Hugetlb_cow() should be called with page lock of the original hugepage held.
- * Called with hugetlb_instantiation_mutex held and pte_page locked so we
- * cannot race with other handlers or page migration.
- * Keep the pte_same checks anyway to make transition from the mutex easier.
- */
- static vm_fault_t hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
- unsigned long address, pte_t *ptep,
- struct page *pagecache_page, spinlock_t *ptl)
- {
- pte_t pte;
- struct hstate *h = hstate_vma(vma);
- struct page *old_page, *new_page;
- int outside_reserve = 0;
- vm_fault_t ret = 0;
- unsigned long haddr = address & huge_page_mask(h);
- struct mmu_notifier_range range;
- pte = huge_ptep_get(ptep);
- old_page = pte_page(pte);
- retry_avoidcopy:
- /* If no-one else is actually using this page, avoid the copy
- * and just make the page writable */
- if (page_mapcount(old_page) == 1 && PageAnon(old_page)) {
- page_move_anon_rmap(old_page, vma);
- set_huge_ptep_writable(vma, haddr, ptep);
- return 0;
- }
- /*
- * If the process that created a MAP_PRIVATE mapping is about to
- * perform a COW due to a shared page count, attempt to satisfy
- * the allocation without using the existing reserves. The pagecache
- * page is used to determine if the reserve at this address was
- * consumed or not. If reserves were used, a partial faulted mapping
- * at the time of fork() could consume its reserves on COW instead
- * of the full address range.
- */
- if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) &&
- old_page != pagecache_page)
- outside_reserve = 1;
- get_page(old_page);
- /*
- * Drop page table lock as buddy allocator may be called. It will
- * be acquired again before returning to the caller, as expected.
- */
- spin_unlock(ptl);
- new_page = alloc_huge_page(vma, haddr, outside_reserve);
- if (IS_ERR(new_page)) {
- /*
- * If a process owning a MAP_PRIVATE mapping fails to COW,
- * it is due to references held by a child and an insufficient
- * huge page pool. To guarantee the original mappers
- * reliability, unmap the page from child processes. The child
- * may get SIGKILLed if it later faults.
- */
- if (outside_reserve) {
- struct address_space *mapping = vma->vm_file->f_mapping;
- pgoff_t idx;
- u32 hash;
- put_page(old_page);
- BUG_ON(huge_pte_none(pte));
- /*
- * Drop hugetlb_fault_mutex and i_mmap_rwsem before
- * unmapping. unmapping needs to hold i_mmap_rwsem
- * in write mode. Dropping i_mmap_rwsem in read mode
- * here is OK as COW mappings do not interact with
- * PMD sharing.
- *
- * Reacquire both after unmap operation.
- */
- idx = vma_hugecache_offset(h, vma, haddr);
- hash = hugetlb_fault_mutex_hash(mapping, idx);
- mutex_unlock(&hugetlb_fault_mutex_table[hash]);
- i_mmap_unlock_read(mapping);
- unmap_ref_private(mm, vma, old_page, haddr);
- i_mmap_lock_read(mapping);
- mutex_lock(&hugetlb_fault_mutex_table[hash]);
- spin_lock(ptl);
- ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
- if (likely(ptep &&
- pte_same(huge_ptep_get(ptep), pte)))
- goto retry_avoidcopy;
- /*
- * race occurs while re-acquiring page table
- * lock, and our job is done.
- */
- return 0;
- }
- ret = vmf_error(PTR_ERR(new_page));
- goto out_release_old;
- }
- /*
- * When the original hugepage is shared one, it does not have
- * anon_vma prepared.
- */
- if (unlikely(anon_vma_prepare(vma))) {
- ret = VM_FAULT_OOM;
- goto out_release_all;
- }
- copy_user_huge_page(new_page, old_page, address, vma,
- pages_per_huge_page(h));
- __SetPageUptodate(new_page);
- mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm, haddr,
- haddr + huge_page_size(h));
- mmu_notifier_invalidate_range_start(&range);
- /*
- * Retake the page table lock to check for racing updates
- * before the page tables are altered
- */
- spin_lock(ptl);
- ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
- if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) {
- ClearPagePrivate(new_page);
- /* Break COW */
- huge_ptep_clear_flush(vma, haddr, ptep);
- mmu_notifier_invalidate_range(mm, range.start, range.end);
- set_huge_pte_at(mm, haddr, ptep,
- make_huge_pte(vma, new_page, 1));
- page_remove_rmap(old_page, true);
- hugepage_add_new_anon_rmap(new_page, vma, haddr);
- set_page_huge_active(new_page);
- /* Make the old page be freed below */
- new_page = old_page;
- }
- spin_unlock(ptl);
- mmu_notifier_invalidate_range_end(&range);
- out_release_all:
- restore_reserve_on_error(h, vma, haddr, new_page);
- put_page(new_page);
- out_release_old:
- put_page(old_page);
- spin_lock(ptl); /* Caller expects lock to be held */
- return ret;
- }
- /* Return the pagecache page at a given address within a VMA */
- static struct page *hugetlbfs_pagecache_page(struct hstate *h,
- struct vm_area_struct *vma, unsigned long address)
- {
- struct address_space *mapping;
- pgoff_t idx;
- mapping = vma->vm_file->f_mapping;
- idx = vma_hugecache_offset(h, vma, address);
- return find_lock_page(mapping, idx);
- }
- /*
- * Return whether there is a pagecache page to back given address within VMA.
- * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page.
- */
- static bool hugetlbfs_pagecache_present(struct hstate *h,
- struct vm_area_struct *vma, unsigned long address)
- {
- struct address_space *mapping;
- pgoff_t idx;
- struct page *page;
- mapping = vma->vm_file->f_mapping;
- idx = vma_hugecache_offset(h, vma, address);
- page = find_get_page(mapping, idx);
- if (page)
- put_page(page);
- return page != NULL;
- }
- int huge_add_to_page_cache(struct page *page, struct address_space *mapping,
- pgoff_t idx)
- {
- struct inode *inode = mapping->host;
- struct hstate *h = hstate_inode(inode);
- int err = add_to_page_cache(page, mapping, idx, GFP_KERNEL);
- if (err)
- return err;
- ClearPagePrivate(page);
- /*
- * set page dirty so that it will not be removed from cache/file
- * by non-hugetlbfs specific code paths.
- */
- set_page_dirty(page);
- spin_lock(&inode->i_lock);
- inode->i_blocks += blocks_per_huge_page(h);
- spin_unlock(&inode->i_lock);
- return 0;
- }
- static inline vm_fault_t hugetlb_handle_userfault(struct vm_area_struct *vma,
- struct address_space *mapping,
- pgoff_t idx,
- unsigned int flags,
- unsigned long haddr,
- unsigned long reason)
- {
- vm_fault_t ret;
- u32 hash;
- struct vm_fault vmf = {
- .vma = vma,
- .address = haddr,
- .flags = flags,
- .vma_flags = vma->vm_flags,
- .vma_page_prot = vma->vm_page_prot,
- /*
- * Hard to debug if it ends up being
- * used by a callee that assumes
- * something about the other
- * uninitialized fields... same as in
- * memory.c
- */
- };
- /*
- * hugetlb_fault_mutex and i_mmap_rwsem must be
- * dropped before handling userfault. Reacquire
- * after handling fault to make calling code simpler.
- */
- hash = hugetlb_fault_mutex_hash(mapping, idx);
- mutex_unlock(&hugetlb_fault_mutex_table[hash]);
- i_mmap_unlock_read(mapping);
- ret = handle_userfault(&vmf, reason);
- i_mmap_lock_read(mapping);
- mutex_lock(&hugetlb_fault_mutex_table[hash]);
- return ret;
- }
- static vm_fault_t hugetlb_no_page(struct mm_struct *mm,
- struct vm_area_struct *vma,
- struct address_space *mapping, pgoff_t idx,
- unsigned long address, pte_t *ptep, unsigned int flags)
- {
- struct hstate *h = hstate_vma(vma);
- vm_fault_t ret = VM_FAULT_SIGBUS;
- int anon_rmap = 0;
- unsigned long size;
- struct page *page;
- pte_t new_pte;
- spinlock_t *ptl;
- unsigned long haddr = address & huge_page_mask(h);
- bool new_page = false;
- /*
- * Currently, we are forced to kill the process in the event the
- * original mapper has unmapped pages from the child due to a failed
- * COW. Warn that such a situation has occurred as it may not be obvious
- */
- if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) {
- pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n",
- current->pid);
- return ret;
- }
- /*
- * We can not race with truncation due to holding i_mmap_rwsem.
- * i_size is modified when holding i_mmap_rwsem, so check here
- * once for faults beyond end of file.
- */
- size = i_size_read(mapping->host) >> huge_page_shift(h);
- if (idx >= size)
- goto out;
- retry:
- page = find_lock_page(mapping, idx);
- if (!page) {
- /* Check for page in userfault range */
- if (userfaultfd_missing(vma)) {
- ret = hugetlb_handle_userfault(vma, mapping, idx,
- flags, haddr,
- VM_UFFD_MISSING);
- goto out;
- }
- page = alloc_huge_page(vma, haddr, 0);
- if (IS_ERR(page)) {
- /*
- * Returning error will result in faulting task being
- * sent SIGBUS. The hugetlb fault mutex prevents two
- * tasks from racing to fault in the same page which
- * could result in false unable to allocate errors.
- * Page migration does not take the fault mutex, but
- * does a clear then write of pte's under page table
- * lock. Page fault code could race with migration,
- * notice the clear pte and try to allocate a page
- * here. Before returning error, get ptl and make
- * sure there really is no pte entry.
- */
- ptl = huge_pte_lock(h, mm, ptep);
- if (!huge_pte_none(huge_ptep_get(ptep))) {
- ret = 0;
- spin_unlock(ptl);
- goto out;
- }
- spin_unlock(ptl);
- ret = vmf_error(PTR_ERR(page));
- goto out;
- }
- clear_huge_page(page, address, pages_per_huge_page(h));
- __SetPageUptodate(page);
- new_page = true;
- if (vma->vm_flags & VM_MAYSHARE) {
- int err = huge_add_to_page_cache(page, mapping, idx);
- if (err) {
- put_page(page);
- if (err == -EEXIST)
- goto retry;
- goto out;
- }
- } else {
- lock_page(page);
- if (unlikely(anon_vma_prepare(vma))) {
- ret = VM_FAULT_OOM;
- goto backout_unlocked;
- }
- anon_rmap = 1;
- }
- } else {
- /*
- * If memory error occurs between mmap() and fault, some process
- * don't have hwpoisoned swap entry for errored virtual address.
- * So we need to block hugepage fault by PG_hwpoison bit check.
- */
- if (unlikely(PageHWPoison(page))) {
- ret = VM_FAULT_HWPOISON_LARGE |
- VM_FAULT_SET_HINDEX(hstate_index(h));
- goto backout_unlocked;
- }
- /* Check for page in userfault range. */
- if (userfaultfd_minor(vma)) {
- unlock_page(page);
- put_page(page);
- ret = hugetlb_handle_userfault(vma, mapping, idx,
- flags, haddr,
- VM_UFFD_MINOR);
- goto out;
- }
- }
- /*
- * If we are going to COW a private mapping later, we examine the
- * pending reservations for this page now. This will ensure that
- * any allocations necessary to record that reservation occur outside
- * the spinlock.
- */
- if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
- if (vma_needs_reservation(h, vma, haddr) < 0) {
- ret = VM_FAULT_OOM;
- goto backout_unlocked;
- }
- /* Just decrements count, does not deallocate */
- vma_end_reservation(h, vma, haddr);
- }
- ptl = huge_pte_lock(h, mm, ptep);
- ret = 0;
- if (!huge_pte_none(huge_ptep_get(ptep)))
- goto backout;
- if (anon_rmap) {
- ClearPagePrivate(page);
- hugepage_add_new_anon_rmap(page, vma, haddr);
- } else
- page_dup_rmap(page, true);
- new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
- && (vma->vm_flags & VM_SHARED)));
- set_huge_pte_at(mm, haddr, ptep, new_pte);
- hugetlb_count_add(pages_per_huge_page(h), mm);
- if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
- /* Optimization, do the COW without a second fault */
- ret = hugetlb_cow(mm, vma, address, ptep, page, ptl);
- }
- spin_unlock(ptl);
- /*
- * Only make newly allocated pages active. Existing pages found
- * in the pagecache could be !page_huge_active() if they have been
- * isolated for migration.
- */
- if (new_page)
- set_page_huge_active(page);
- unlock_page(page);
- out:
- return ret;
- backout:
- spin_unlock(ptl);
- backout_unlocked:
- unlock_page(page);
- restore_reserve_on_error(h, vma, haddr, page);
- put_page(page);
- goto out;
- }
- #ifdef CONFIG_SMP
- u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
- {
- unsigned long key[2];
- u32 hash;
- key[0] = (unsigned long) mapping;
- key[1] = idx;
- hash = jhash2((u32 *)&key, sizeof(key)/(sizeof(u32)), 0);
- return hash & (num_fault_mutexes - 1);
- }
- #else
- /*
- * For uniprocesor systems we always use a single mutex, so just
- * return 0 and avoid the hashing overhead.
- */
- u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx)
- {
- return 0;
- }
- #endif
- vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
- unsigned long address, unsigned int flags)
- {
- pte_t *ptep, entry;
- spinlock_t *ptl;
- vm_fault_t ret;
- u32 hash;
- pgoff_t idx;
- struct page *page = NULL;
- struct page *pagecache_page = NULL;
- struct hstate *h = hstate_vma(vma);
- struct address_space *mapping;
- int need_wait_lock = 0;
- unsigned long haddr = address & huge_page_mask(h);
- ptep = huge_pte_offset(mm, haddr, huge_page_size(h));
- if (ptep) {
- /*
- * Since we hold no locks, ptep could be stale. That is
- * OK as we are only making decisions based on content and
- * not actually modifying content here.
- */
- entry = huge_ptep_get(ptep);
- if (unlikely(is_hugetlb_entry_migration(entry))) {
- migration_entry_wait_huge(vma, mm, ptep);
- return 0;
- } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry)))
- return VM_FAULT_HWPOISON_LARGE |
- VM_FAULT_SET_HINDEX(hstate_index(h));
- }
- /*
- * Acquire i_mmap_rwsem before calling huge_pte_alloc and hold
- * until finished with ptep. This serves two purposes:
- * 1) It prevents huge_pmd_unshare from being called elsewhere
- * and making the ptep no longer valid.
- * 2) It synchronizes us with i_size modifications during truncation.
- *
- * ptep could have already be assigned via huge_pte_offset. That
- * is OK, as huge_pte_alloc will return the same value unless
- * something has changed.
- */
- mapping = vma->vm_file->f_mapping;
- i_mmap_lock_read(mapping);
- ptep = huge_pte_alloc(mm, vma, haddr, huge_page_size(h));
- if (!ptep) {
- i_mmap_unlock_read(mapping);
- return VM_FAULT_OOM;
- }
- /*
- * Serialize hugepage allocation and instantiation, so that we don't
- * get spurious allocation failures if two CPUs race to instantiate
- * the same page in the page cache.
- */
- idx = vma_hugecache_offset(h, vma, haddr);
- hash = hugetlb_fault_mutex_hash(mapping, idx);
- mutex_lock(&hugetlb_fault_mutex_table[hash]);
- entry = huge_ptep_get(ptep);
- if (huge_pte_none(entry)) {
- ret = hugetlb_no_page(mm, vma, mapping, idx, address, ptep, flags);
- goto out_mutex;
- }
- ret = 0;
- /*
- * entry could be a migration/hwpoison entry at this point, so this
- * check prevents the kernel from going below assuming that we have
- * an active hugepage in pagecache. This goto expects the 2nd page
- * fault, and is_hugetlb_entry_(migration|hwpoisoned) check will
- * properly handle it.
- */
- if (!pte_present(entry))
- goto out_mutex;
- /*
- * If we are going to COW the mapping later, we examine the pending
- * reservations for this page now. This will ensure that any
- * allocations necessary to record that reservation occur outside the
- * spinlock. For private mappings, we also lookup the pagecache
- * page now as it is used to determine if a reservation has been
- * consumed.
- */
- if ((flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) {
- if (vma_needs_reservation(h, vma, haddr) < 0) {
- ret = VM_FAULT_OOM;
- goto out_mutex;
- }
- /* Just decrements count, does not deallocate */
- vma_end_reservation(h, vma, haddr);
- if (!(vma->vm_flags & VM_MAYSHARE))
- pagecache_page = hugetlbfs_pagecache_page(h,
- vma, haddr);
- }
- ptl = huge_pte_lock(h, mm, ptep);
- /* Check for a racing update before calling hugetlb_cow */
- if (unlikely(!pte_same(entry, huge_ptep_get(ptep))))
- goto out_ptl;
- /*
- * hugetlb_cow() requires page locks of pte_page(entry) and
- * pagecache_page, so here we need take the former one
- * when page != pagecache_page or !pagecache_page.
- */
- page = pte_page(entry);
- if (page != pagecache_page)
- if (!trylock_page(page)) {
- need_wait_lock = 1;
- goto out_ptl;
- }
- get_page(page);
- if (flags & FAULT_FLAG_WRITE) {
- if (!huge_pte_write(entry)) {
- ret = hugetlb_cow(mm, vma, address, ptep,
- pagecache_page, ptl);
- goto out_put_page;
- }
- entry = huge_pte_mkdirty(entry);
- }
- entry = pte_mkyoung(entry);
- if (huge_ptep_set_access_flags(vma, haddr, ptep, entry,
- flags & FAULT_FLAG_WRITE))
- update_mmu_cache(vma, haddr, ptep);
- out_put_page:
- if (page != pagecache_page)
- unlock_page(page);
- put_page(page);
- out_ptl:
- spin_unlock(ptl);
- if (pagecache_page) {
- unlock_page(pagecache_page);
- put_page(pagecache_page);
- }
- out_mutex:
- mutex_unlock(&hugetlb_fault_mutex_table[hash]);
- i_mmap_unlock_read(mapping);
- /*
- * Generally it's safe to hold refcount during waiting page lock. But
- * here we just wait to defer the next page fault to avoid busy loop and
- * the page is not used after unlocked before returning from the current
- * page fault. So we are safe from accessing freed page, even if we wait
- * here without taking refcount.
- */
- if (need_wait_lock)
- wait_on_page_locked(page);
- return ret;
- }
- #ifdef CONFIG_USERFAULTFD
- /*
- * Used by userfaultfd UFFDIO_COPY. Based on mcopy_atomic_pte with
- * modifications for huge pages.
- */
- int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
- pte_t *dst_pte,
- struct vm_area_struct *dst_vma,
- unsigned long dst_addr,
- unsigned long src_addr,
- enum mcopy_atomic_mode mode,
- struct page **pagep)
- {
- bool is_continue = (mode == MCOPY_ATOMIC_CONTINUE);
- struct address_space *mapping;
- pgoff_t idx;
- unsigned long size;
- int vm_shared = dst_vma->vm_flags & VM_SHARED;
- struct hstate *h = hstate_vma(dst_vma);
- pte_t _dst_pte;
- spinlock_t *ptl;
- int ret;
- struct page *page;
- int writable;
- mapping = dst_vma->vm_file->f_mapping;
- idx = vma_hugecache_offset(h, dst_vma, dst_addr);
- if (is_continue) {
- ret = -EFAULT;
- page = find_lock_page(mapping, idx);
- if (!page)
- goto out;
- } else if (!*pagep) {
- /* If a page already exists, then it's UFFDIO_COPY for
- * a non-missing case. Return -EEXIST.
- */
- if (vm_shared &&
- hugetlbfs_pagecache_present(h, dst_vma, dst_addr)) {
- ret = -EEXIST;
- goto out;
- }
- page = alloc_huge_page(dst_vma, dst_addr, 0);
- if (IS_ERR(page)) {
- ret = -ENOMEM;
- goto out;
- }
- ret = copy_huge_page_from_user(page,
- (const void __user *) src_addr,
- pages_per_huge_page(h), false);
- /* fallback to copy_from_user outside mmap_lock */
- if (unlikely(ret)) {
- ret = -ENOENT;
- *pagep = page;
- /* don't free the page */
- goto out;
- }
- } else {
- page = *pagep;
- *pagep = NULL;
- }
- /*
- * The memory barrier inside __SetPageUptodate makes sure that
- * preceding stores to the page contents become visible before
- * the set_pte_at() write.
- */
- __SetPageUptodate(page);
- /* Add shared, newly allocated pages to the page cache. */
- if (vm_shared && !is_continue) {
- size = i_size_read(mapping->host) >> huge_page_shift(h);
- ret = -EFAULT;
- if (idx >= size)
- goto out_release_nounlock;
- /*
- * Serialization between remove_inode_hugepages() and
- * huge_add_to_page_cache() below happens through the
- * hugetlb_fault_mutex_table that here must be hold by
- * the caller.
- */
- ret = huge_add_to_page_cache(page, mapping, idx);
- if (ret)
- goto out_release_nounlock;
- }
- ptl = huge_pte_lockptr(h, dst_mm, dst_pte);
- spin_lock(ptl);
- /*
- * Recheck the i_size after holding PT lock to make sure not
- * to leave any page mapped (as page_mapped()) beyond the end
- * of the i_size (remove_inode_hugepages() is strict about
- * enforcing that). If we bail out here, we'll also leave a
- * page in the radix tree in the vm_shared case beyond the end
- * of the i_size, but remove_inode_hugepages() will take care
- * of it as soon as we drop the hugetlb_fault_mutex_table.
- */
- size = i_size_read(mapping->host) >> huge_page_shift(h);
- ret = -EFAULT;
- if (idx >= size)
- goto out_release_unlock;
- ret = -EEXIST;
- if (!huge_pte_none(huge_ptep_get(dst_pte)))
- goto out_release_unlock;
- if (vm_shared) {
- page_dup_rmap(page, true);
- } else {
- ClearPagePrivate(page);
- hugepage_add_new_anon_rmap(page, dst_vma, dst_addr);
- }
- /* For CONTINUE on a non-shared VMA, don't set VM_WRITE for CoW. */
- if (is_continue && !vm_shared)
- writable = 0;
- else
- writable = dst_vma->vm_flags & VM_WRITE;
- _dst_pte = make_huge_pte(dst_vma, page, writable);
- if (writable)
- _dst_pte = huge_pte_mkdirty(_dst_pte);
- _dst_pte = pte_mkyoung(_dst_pte);
- set_huge_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte);
- (void)huge_ptep_set_access_flags(dst_vma, dst_addr, dst_pte, _dst_pte,
- dst_vma->vm_flags & VM_WRITE);
- hugetlb_count_add(pages_per_huge_page(h), dst_mm);
- /* No need to invalidate - it was non-present before */
- update_mmu_cache(dst_vma, dst_addr, dst_pte);
- spin_unlock(ptl);
- if (!is_continue)
- set_page_huge_active(page);
- if (vm_shared || is_continue)
- unlock_page(page);
- ret = 0;
- out:
- return ret;
- out_release_unlock:
- spin_unlock(ptl);
- if (vm_shared || is_continue)
- unlock_page(page);
- out_release_nounlock:
- put_page(page);
- goto out;
- }
- #endif /* CONFIG_USERFAULTFD */
- long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
- struct page **pages, struct vm_area_struct **vmas,
- unsigned long *position, unsigned long *nr_pages,
- long i, unsigned int flags, int *locked)
- {
- unsigned long pfn_offset;
- unsigned long vaddr = *position;
- unsigned long remainder = *nr_pages;
- struct hstate *h = hstate_vma(vma);
- int err = -EFAULT;
- while (vaddr < vma->vm_end && remainder) {
- pte_t *pte;
- spinlock_t *ptl = NULL;
- int absent;
- struct page *page;
- /*
- * If we have a pending SIGKILL, don't keep faulting pages and
- * potentially allocating memory.
- */
- if (fatal_signal_pending(current)) {
- remainder = 0;
- break;
- }
- /*
- * Some archs (sparc64, sh*) have multiple pte_ts to
- * each hugepage. We have to make sure we get the
- * first, for the page indexing below to work.
- *
- * Note that page table lock is not held when pte is null.
- */
- pte = huge_pte_offset(mm, vaddr & huge_page_mask(h),
- huge_page_size(h));
- if (pte)
- ptl = huge_pte_lock(h, mm, pte);
- absent = !pte || huge_pte_none(huge_ptep_get(pte));
- /*
- * When coredumping, it suits get_dump_page if we just return
- * an error where there's an empty slot with no huge pagecache
- * to back it. This way, we avoid allocating a hugepage, and
- * the sparse dumpfile avoids allocating disk blocks, but its
- * huge holes still show up with zeroes where they need to be.
- */
- if (absent && (flags & FOLL_DUMP) &&
- !hugetlbfs_pagecache_present(h, vma, vaddr)) {
- if (pte)
- spin_unlock(ptl);
- remainder = 0;
- break;
- }
- /*
- * We need call hugetlb_fault for both hugepages under migration
- * (in which case hugetlb_fault waits for the migration,) and
- * hwpoisoned hugepages (in which case we need to prevent the
- * caller from accessing to them.) In order to do this, we use
- * here is_swap_pte instead of is_hugetlb_entry_migration and
- * is_hugetlb_entry_hwpoisoned. This is because it simply covers
- * both cases, and because we can't follow correct pages
- * directly from any kind of swap entries.
- */
- if (absent || is_swap_pte(huge_ptep_get(pte)) ||
- ((flags & FOLL_WRITE) &&
- !huge_pte_write(huge_ptep_get(pte)))) {
- vm_fault_t ret;
- unsigned int fault_flags = 0;
- if (pte)
- spin_unlock(ptl);
- if (flags & FOLL_WRITE)
- fault_flags |= FAULT_FLAG_WRITE;
- if (locked)
- fault_flags |= FAULT_FLAG_ALLOW_RETRY |
- FAULT_FLAG_KILLABLE;
- if (flags & FOLL_NOWAIT)
- fault_flags |= FAULT_FLAG_ALLOW_RETRY |
- FAULT_FLAG_RETRY_NOWAIT;
- if (flags & FOLL_TRIED) {
- /*
- * Note: FAULT_FLAG_ALLOW_RETRY and
- * FAULT_FLAG_TRIED can co-exist
- */
- fault_flags |= FAULT_FLAG_TRIED;
- }
- ret = hugetlb_fault(mm, vma, vaddr, fault_flags);
- if (ret & VM_FAULT_ERROR) {
- err = vm_fault_to_errno(ret, flags);
- remainder = 0;
- break;
- }
- if (ret & VM_FAULT_RETRY) {
- if (locked &&
- !(fault_flags & FAULT_FLAG_RETRY_NOWAIT))
- *locked = 0;
- *nr_pages = 0;
- /*
- * VM_FAULT_RETRY must not return an
- * error, it will return zero
- * instead.
- *
- * No need to update "position" as the
- * caller will not check it after
- * *nr_pages is set to 0.
- */
- return i;
- }
- continue;
- }
- pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT;
- page = pte_page(huge_ptep_get(pte));
- /*
- * If subpage information not requested, update counters
- * and skip the same_page loop below.
- */
- if (!pages && !vmas && !pfn_offset &&
- (vaddr + huge_page_size(h) < vma->vm_end) &&
- (remainder >= pages_per_huge_page(h))) {
- vaddr += huge_page_size(h);
- remainder -= pages_per_huge_page(h);
- i += pages_per_huge_page(h);
- spin_unlock(ptl);
- continue;
- }
- same_page:
- if (pages) {
- pages[i] = mem_map_offset(page, pfn_offset);
- /*
- * try_grab_page() should always succeed here, because:
- * a) we hold the ptl lock, and b) we've just checked
- * that the huge page is present in the page tables. If
- * the huge page is present, then the tail pages must
- * also be present. The ptl prevents the head page and
- * tail pages from being rearranged in any way. So this
- * page must be available at this point, unless the page
- * refcount overflowed:
- */
- if (WARN_ON_ONCE(!try_grab_page(pages[i], flags))) {
- spin_unlock(ptl);
- remainder = 0;
- err = -ENOMEM;
- break;
- }
- }
- if (vmas)
- vmas[i] = vma;
- vaddr += PAGE_SIZE;
- ++pfn_offset;
- --remainder;
- ++i;
- if (vaddr < vma->vm_end && remainder &&
- pfn_offset < pages_per_huge_page(h)) {
- /*
- * We use pfn_offset to avoid touching the pageframes
- * of this compound page.
- */
- goto same_page;
- }
- spin_unlock(ptl);
- }
- *nr_pages = remainder;
- /*
- * setting position is actually required only if remainder is
- * not zero but it's faster not to add a "if (remainder)"
- * branch.
- */
- *position = vaddr;
- return i ? i : err;
- }
- unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
- unsigned long address, unsigned long end, pgprot_t newprot)
- {
- struct mm_struct *mm = vma->vm_mm;
- unsigned long start = address;
- pte_t *ptep;
- pte_t pte;
- struct hstate *h = hstate_vma(vma);
- unsigned long pages = 0;
- bool shared_pmd = false;
- struct mmu_notifier_range range;
- /*
- * In the case of shared PMDs, the area to flush could be beyond
- * start/end. Set range.start/range.end to cover the maximum possible
- * range if PMD sharing is possible.
- */
- mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_VMA,
- 0, vma, mm, start, end);
- adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
- BUG_ON(address >= end);
- flush_cache_range(vma, range.start, range.end);
- mmu_notifier_invalidate_range_start(&range);
- i_mmap_lock_write(vma->vm_file->f_mapping);
- for (; address < end; address += huge_page_size(h)) {
- spinlock_t *ptl;
- ptep = huge_pte_offset(mm, address, huge_page_size(h));
- if (!ptep)
- continue;
- ptl = huge_pte_lock(h, mm, ptep);
- if (huge_pmd_unshare(mm, vma, &address, ptep)) {
- pages++;
- spin_unlock(ptl);
- shared_pmd = true;
- continue;
- }
- pte = huge_ptep_get(ptep);
- if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) {
- spin_unlock(ptl);
- continue;
- }
- if (unlikely(is_hugetlb_entry_migration(pte))) {
- swp_entry_t entry = pte_to_swp_entry(pte);
- if (is_write_migration_entry(entry)) {
- pte_t newpte;
- make_migration_entry_read(&entry);
- newpte = swp_entry_to_pte(entry);
- set_huge_swap_pte_at(mm, address, ptep,
- newpte, huge_page_size(h));
- pages++;
- }
- spin_unlock(ptl);
- continue;
- }
- if (!huge_pte_none(pte)) {
- pte_t old_pte;
- old_pte = huge_ptep_modify_prot_start(vma, address, ptep);
- pte = pte_mkhuge(huge_pte_modify(old_pte, newprot));
- pte = arch_make_huge_pte(pte, vma, NULL, 0);
- huge_ptep_modify_prot_commit(vma, address, ptep, old_pte, pte);
- pages++;
- }
- spin_unlock(ptl);
- }
- /*
- * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare
- * may have cleared our pud entry and done put_page on the page table:
- * once we release i_mmap_rwsem, another task can do the final put_page
- * and that page table be reused and filled with junk. If we actually
- * did unshare a page of pmds, flush the range corresponding to the pud.
- */
- if (shared_pmd)
- flush_hugetlb_tlb_range(vma, range.start, range.end);
- else
- flush_hugetlb_tlb_range(vma, start, end);
- /*
- * No need to call mmu_notifier_invalidate_range() we are downgrading
- * page table protection not changing it to point to a new page.
- *
- * See Documentation/vm/mmu_notifier.rst
- */
- i_mmap_unlock_write(vma->vm_file->f_mapping);
- mmu_notifier_invalidate_range_end(&range);
- return pages << h->order;
- }
- int hugetlb_reserve_pages(struct inode *inode,
- long from, long to,
- struct vm_area_struct *vma,
- vm_flags_t vm_flags)
- {
- long ret, chg, add = -1;
- struct hstate *h = hstate_inode(inode);
- struct hugepage_subpool *spool = subpool_inode(inode);
- struct resv_map *resv_map;
- struct hugetlb_cgroup *h_cg = NULL;
- long gbl_reserve, regions_needed = 0;
- /* This should never happen */
- if (from > to) {
- VM_WARN(1, "%s called with a negative range\n", __func__);
- return -EINVAL;
- }
- /*
- * Only apply hugepage reservation if asked. At fault time, an
- * attempt will be made for VM_NORESERVE to allocate a page
- * without using reserves
- */
- if (vm_flags & VM_NORESERVE)
- return 0;
- /*
- * Shared mappings base their reservation on the number of pages that
- * are already allocated on behalf of the file. Private mappings need
- * to reserve the full area even if read-only as mprotect() may be
- * called to make the mapping read-write. Assume !vma is a shm mapping
- */
- if (!vma || vma->vm_flags & VM_MAYSHARE) {
- /*
- * resv_map can not be NULL as hugetlb_reserve_pages is only
- * called for inodes for which resv_maps were created (see
- * hugetlbfs_get_inode).
- */
- resv_map = inode_resv_map(inode);
- chg = region_chg(resv_map, from, to, ®ions_needed);
- } else {
- /* Private mapping. */
- resv_map = resv_map_alloc();
- if (!resv_map)
- return -ENOMEM;
- chg = to - from;
- set_vma_resv_map(vma, resv_map);
- set_vma_resv_flags(vma, HPAGE_RESV_OWNER);
- }
- if (chg < 0) {
- ret = chg;
- goto out_err;
- }
- ret = hugetlb_cgroup_charge_cgroup_rsvd(
- hstate_index(h), chg * pages_per_huge_page(h), &h_cg);
- if (ret < 0) {
- ret = -ENOMEM;
- goto out_err;
- }
- if (vma && !(vma->vm_flags & VM_MAYSHARE) && h_cg) {
- /* For private mappings, the hugetlb_cgroup uncharge info hangs
- * of the resv_map.
- */
- resv_map_set_hugetlb_cgroup_uncharge_info(resv_map, h_cg, h);
- }
- /*
- * There must be enough pages in the subpool for the mapping. If
- * the subpool has a minimum size, there may be some global
- * reservations already in place (gbl_reserve).
- */
- gbl_reserve = hugepage_subpool_get_pages(spool, chg);
- if (gbl_reserve < 0) {
- ret = -ENOSPC;
- goto out_uncharge_cgroup;
- }
- /*
- * Check enough hugepages are available for the reservation.
- * Hand the pages back to the subpool if there are not
- */
- ret = hugetlb_acct_memory(h, gbl_reserve);
- if (ret < 0) {
- goto out_put_pages;
- }
- /*
- * Account for the reservations made. Shared mappings record regions
- * that have reservations as they are shared by multiple VMAs.
- * When the last VMA disappears, the region map says how much
- * the reservation was and the page cache tells how much of
- * the reservation was consumed. Private mappings are per-VMA and
- * only the consumed reservations are tracked. When the VMA
- * disappears, the original reservation is the VMA size and the
- * consumed reservations are stored in the map. Hence, nothing
- * else has to be done for private mappings here
- */
- if (!vma || vma->vm_flags & VM_MAYSHARE) {
- add = region_add(resv_map, from, to, regions_needed, h, h_cg);
- if (unlikely(add < 0)) {
- hugetlb_acct_memory(h, -gbl_reserve);
- ret = add;
- goto out_put_pages;
- } else if (unlikely(chg > add)) {
- /*
- * pages in this range were added to the reserve
- * map between region_chg and region_add. This
- * indicates a race with alloc_huge_page. Adjust
- * the subpool and reserve counts modified above
- * based on the difference.
- */
- long rsv_adjust;
- /*
- * hugetlb_cgroup_uncharge_cgroup_rsvd() will put the
- * reference to h_cg->css. See comment below for detail.
- */
- hugetlb_cgroup_uncharge_cgroup_rsvd(
- hstate_index(h),
- (chg - add) * pages_per_huge_page(h), h_cg);
- rsv_adjust = hugepage_subpool_put_pages(spool,
- chg - add);
- hugetlb_acct_memory(h, -rsv_adjust);
- } else if (h_cg) {
- /*
- * The file_regions will hold their own reference to
- * h_cg->css. So we should release the reference held
- * via hugetlb_cgroup_charge_cgroup_rsvd() when we are
- * done.
- */
- hugetlb_cgroup_put_rsvd_cgroup(h_cg);
- }
- }
- return 0;
- out_put_pages:
- /* put back original number of pages, chg */
- (void)hugepage_subpool_put_pages(spool, chg);
- out_uncharge_cgroup:
- hugetlb_cgroup_uncharge_cgroup_rsvd(hstate_index(h),
- chg * pages_per_huge_page(h), h_cg);
- out_err:
- if (!vma || vma->vm_flags & VM_MAYSHARE)
- /* Only call region_abort if the region_chg succeeded but the
- * region_add failed or didn't run.
- */
- if (chg >= 0 && add < 0)
- region_abort(resv_map, from, to, regions_needed);
- if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER))
- kref_put(&resv_map->refs, resv_map_release);
- return ret;
- }
- long hugetlb_unreserve_pages(struct inode *inode, long start, long end,
- long freed)
- {
- struct hstate *h = hstate_inode(inode);
- struct resv_map *resv_map = inode_resv_map(inode);
- long chg = 0;
- struct hugepage_subpool *spool = subpool_inode(inode);
- long gbl_reserve;
- /*
- * Since this routine can be called in the evict inode path for all
- * hugetlbfs inodes, resv_map could be NULL.
- */
- if (resv_map) {
- chg = region_del(resv_map, start, end);
- /*
- * region_del() can fail in the rare case where a region
- * must be split and another region descriptor can not be
- * allocated. If end == LONG_MAX, it will not fail.
- */
- if (chg < 0)
- return chg;
- }
- spin_lock(&inode->i_lock);
- inode->i_blocks -= (blocks_per_huge_page(h) * freed);
- spin_unlock(&inode->i_lock);
- /*
- * If the subpool has a minimum size, the number of global
- * reservations to be released may be adjusted.
- */
- gbl_reserve = hugepage_subpool_put_pages(spool, (chg - freed));
- hugetlb_acct_memory(h, -gbl_reserve);
- return 0;
- }
- #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
- static unsigned long page_table_shareable(struct vm_area_struct *svma,
- struct vm_area_struct *vma,
- unsigned long addr, pgoff_t idx)
- {
- unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) +
- svma->vm_start;
- unsigned long sbase = saddr & PUD_MASK;
- unsigned long s_end = sbase + PUD_SIZE;
- /* Allow segments to share if only one is marked locked */
- unsigned long vm_flags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;
- unsigned long svm_flags = svma->vm_flags & VM_LOCKED_CLEAR_MASK;
- /*
- * match the virtual addresses, permission and the alignment of the
- * page table page.
- */
- if (pmd_index(addr) != pmd_index(saddr) ||
- vm_flags != svm_flags ||
- sbase < svma->vm_start || svma->vm_end < s_end)
- return 0;
- return saddr;
- }
- static bool vma_shareable(struct vm_area_struct *vma, unsigned long addr)
- {
- unsigned long base = addr & PUD_MASK;
- unsigned long end = base + PUD_SIZE;
- /*
- * check on proper vm_flags and page table alignment
- */
- if (vma->vm_flags & VM_MAYSHARE && range_in_vma(vma, base, end))
- return true;
- return false;
- }
- bool want_pmd_share(struct vm_area_struct *vma, unsigned long addr)
- {
- #ifdef CONFIG_USERFAULTFD
- if (uffd_disable_huge_pmd_share(vma))
- return false;
- #endif
- return vma_shareable(vma, addr);
- }
- /*
- * Determine if start,end range within vma could be mapped by shared pmd.
- * If yes, adjust start and end to cover range associated with possible
- * shared pmd mappings.
- */
- void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
- unsigned long *start, unsigned long *end)
- {
- unsigned long v_start = ALIGN(vma->vm_start, PUD_SIZE),
- v_end = ALIGN_DOWN(vma->vm_end, PUD_SIZE);
- /*
- * vma need span at least one aligned PUD size and the start,end range
- * must at least partialy within it.
- */
- if (!(vma->vm_flags & VM_MAYSHARE) || !(v_end > v_start) ||
- (*end <= v_start) || (*start >= v_end))
- return;
- /* Extend the range to be PUD aligned for a worst case scenario */
- if (*start > v_start)
- *start = ALIGN_DOWN(*start, PUD_SIZE);
- if (*end < v_end)
- *end = ALIGN(*end, PUD_SIZE);
- }
- /*
- * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc()
- * and returns the corresponding pte. While this is not necessary for the
- * !shared pmd case because we can allocate the pmd later as well, it makes the
- * code much cleaner.
- *
- * This routine must be called with i_mmap_rwsem held in at least read mode if
- * sharing is possible. For hugetlbfs, this prevents removal of any page
- * table entries associated with the address space. This is important as we
- * are setting up sharing based on existing page table entries (mappings).
- *
- * NOTE: This routine is only called from huge_pte_alloc. Some callers of
- * huge_pte_alloc know that sharing is not possible and do not take
- * i_mmap_rwsem as a performance optimization. This is handled by the
- * if !vma_shareable check at the beginning of the routine. i_mmap_rwsem is
- * only required for subsequent processing.
- */
- pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma,
- unsigned long addr, pud_t *pud)
- {
- struct address_space *mapping = vma->vm_file->f_mapping;
- pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) +
- vma->vm_pgoff;
- struct vm_area_struct *svma;
- unsigned long saddr;
- pte_t *spte = NULL;
- pte_t *pte;
- spinlock_t *ptl;
- i_mmap_assert_locked(mapping);
- vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
- if (svma == vma)
- continue;
- saddr = page_table_shareable(svma, vma, addr, idx);
- if (saddr) {
- spte = huge_pte_offset(svma->vm_mm, saddr,
- vma_mmu_pagesize(svma));
- if (spte) {
- get_page(virt_to_page(spte));
- break;
- }
- }
- }
- if (!spte)
- goto out;
- ptl = huge_pte_lock(hstate_vma(vma), mm, spte);
- if (pud_none(*pud)) {
- pud_populate(mm, pud,
- (pmd_t *)((unsigned long)spte & PAGE_MASK));
- mm_inc_nr_pmds(mm);
- } else {
- put_page(virt_to_page(spte));
- }
- spin_unlock(ptl);
- out:
- pte = (pte_t *)pmd_alloc(mm, pud, addr);
- return pte;
- }
- /*
- * unmap huge page backed by shared pte.
- *
- * Hugetlb pte page is ref counted at the time of mapping. If pte is shared
- * indicated by page_count > 1, unmap is achieved by clearing pud and
- * decrementing the ref count. If count == 1, the pte page is not shared.
- *
- * Called with page table lock held and i_mmap_rwsem held in write mode.
- *
- * returns: 1 successfully unmapped a shared pte page
- * 0 the underlying pte page is not shared, or it is the last user
- */
- int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma,
- unsigned long *addr, pte_t *ptep)
- {
- pgd_t *pgd = pgd_offset(mm, *addr);
- p4d_t *p4d = p4d_offset(pgd, *addr);
- pud_t *pud = pud_offset(p4d, *addr);
- i_mmap_assert_write_locked(vma->vm_file->f_mapping);
- BUG_ON(page_count(virt_to_page(ptep)) == 0);
- if (page_count(virt_to_page(ptep)) == 1)
- return 0;
- pud_clear(pud);
- put_page(virt_to_page(ptep));
- mm_dec_nr_pmds(mm);
- *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE;
- return 1;
- }
- #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
- pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma,
- unsigned long addr, pud_t *pud)
- {
- return NULL;
- }
- int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma,
- unsigned long *addr, pte_t *ptep)
- {
- return 0;
- }
- void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
- unsigned long *start, unsigned long *end)
- {
- }
- bool want_pmd_share(struct vm_area_struct *vma, unsigned long addr)
- {
- return false;
- }
- #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
- #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
- pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
- unsigned long addr, unsigned long sz)
- {
- pgd_t *pgd;
- p4d_t *p4d;
- pud_t *pud;
- pte_t *pte = NULL;
- pgd = pgd_offset(mm, addr);
- p4d = p4d_alloc(mm, pgd, addr);
- if (!p4d)
- return NULL;
- pud = pud_alloc(mm, p4d, addr);
- if (pud) {
- if (sz == PUD_SIZE) {
- pte = (pte_t *)pud;
- } else {
- BUG_ON(sz != PMD_SIZE);
- if (want_pmd_share(vma, addr) && pud_none(*pud))
- pte = huge_pmd_share(mm, vma, addr, pud);
- else
- pte = (pte_t *)pmd_alloc(mm, pud, addr);
- }
- }
- BUG_ON(pte && pte_present(*pte) && !pte_huge(*pte));
- return pte;
- }
- /*
- * huge_pte_offset() - Walk the page table to resolve the hugepage
- * entry at address @addr
- *
- * Return: Pointer to page table entry (PUD or PMD) for
- * address @addr, or NULL if a !p*d_present() entry is encountered and the
- * size @sz doesn't match the hugepage size at this level of the page
- * table.
- */
- pte_t *huge_pte_offset(struct mm_struct *mm,
- unsigned long addr, unsigned long sz)
- {
- pgd_t *pgd;
- p4d_t *p4d;
- pud_t *pud;
- pmd_t *pmd;
- pgd = pgd_offset(mm, addr);
- if (!pgd_present(*pgd))
- return NULL;
- p4d = p4d_offset(pgd, addr);
- if (!p4d_present(*p4d))
- return NULL;
- pud = pud_offset(p4d, addr);
- if (sz == PUD_SIZE)
- /* must be pud huge, non-present or none */
- return (pte_t *)pud;
- if (!pud_present(*pud))
- return NULL;
- /* must have a valid entry and size to go further */
- pmd = pmd_offset(pud, addr);
- /* must be pmd huge, non-present or none */
- return (pte_t *)pmd;
- }
- #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
- /*
- * These functions are overwritable if your architecture needs its own
- * behavior.
- */
- struct page * __weak
- follow_huge_addr(struct mm_struct *mm, unsigned long address,
- int write)
- {
- return ERR_PTR(-EINVAL);
- }
- struct page * __weak
- follow_huge_pd(struct vm_area_struct *vma,
- unsigned long address, hugepd_t hpd, int flags, int pdshift)
- {
- WARN(1, "hugepd follow called with no support for hugepage directory format\n");
- return NULL;
- }
- struct page * __weak
- follow_huge_pmd(struct mm_struct *mm, unsigned long address,
- pmd_t *pmd, int flags)
- {
- struct page *page = NULL;
- spinlock_t *ptl;
- pte_t pte;
- /* FOLL_GET and FOLL_PIN are mutually exclusive. */
- if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) ==
- (FOLL_PIN | FOLL_GET)))
- return NULL;
- retry:
- ptl = pmd_lockptr(mm, pmd);
- spin_lock(ptl);
- /*
- * make sure that the address range covered by this pmd is not
- * unmapped from other threads.
- */
- if (!pmd_huge(*pmd))
- goto out;
- pte = huge_ptep_get((pte_t *)pmd);
- if (pte_present(pte)) {
- page = pmd_page(*pmd) + ((address & ~PMD_MASK) >> PAGE_SHIFT);
- /*
- * try_grab_page() should always succeed here, because: a) we
- * hold the pmd (ptl) lock, and b) we've just checked that the
- * huge pmd (head) page is present in the page tables. The ptl
- * prevents the head page and tail pages from being rearranged
- * in any way. So this page must be available at this point,
- * unless the page refcount overflowed:
- */
- if (WARN_ON_ONCE(!try_grab_page(page, flags))) {
- page = NULL;
- goto out;
- }
- } else {
- if (is_hugetlb_entry_migration(pte)) {
- spin_unlock(ptl);
- __migration_entry_wait(mm, (pte_t *)pmd, ptl);
- goto retry;
- }
- /*
- * hwpoisoned entry is treated as no_page_table in
- * follow_page_mask().
- */
- }
- out:
- spin_unlock(ptl);
- return page;
- }
- struct page * __weak
- follow_huge_pud(struct mm_struct *mm, unsigned long address,
- pud_t *pud, int flags)
- {
- if (flags & (FOLL_GET | FOLL_PIN))
- return NULL;
- return pte_page(*(pte_t *)pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
- }
- struct page * __weak
- follow_huge_pgd(struct mm_struct *mm, unsigned long address, pgd_t *pgd, int flags)
- {
- if (flags & (FOLL_GET | FOLL_PIN))
- return NULL;
- return pte_page(*(pte_t *)pgd) + ((address & ~PGDIR_MASK) >> PAGE_SHIFT);
- }
- bool isolate_huge_page(struct page *page, struct list_head *list)
- {
- bool ret = true;
- spin_lock(&hugetlb_lock);
- if (!PageHeadHuge(page) || !page_huge_active(page) ||
- !get_page_unless_zero(page)) {
- ret = false;
- goto unlock;
- }
- clear_page_huge_active(page);
- list_move_tail(&page->lru, list);
- unlock:
- spin_unlock(&hugetlb_lock);
- return ret;
- }
- void putback_active_hugepage(struct page *page)
- {
- VM_BUG_ON_PAGE(!PageHead(page), page);
- spin_lock(&hugetlb_lock);
- set_page_huge_active(page);
- list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
- spin_unlock(&hugetlb_lock);
- put_page(page);
- }
- void move_hugetlb_state(struct page *oldpage, struct page *newpage, int reason)
- {
- struct hstate *h = page_hstate(oldpage);
- hugetlb_cgroup_migrate(oldpage, newpage);
- set_page_owner_migrate_reason(newpage, reason);
- /*
- * transfer temporary state of the new huge page. This is
- * reverse to other transitions because the newpage is going to
- * be final while the old one will be freed so it takes over
- * the temporary status.
- *
- * Also note that we have to transfer the per-node surplus state
- * here as well otherwise the global surplus count will not match
- * the per-node's.
- */
- if (PageHugeTemporary(newpage)) {
- int old_nid = page_to_nid(oldpage);
- int new_nid = page_to_nid(newpage);
- SetPageHugeTemporary(oldpage);
- ClearPageHugeTemporary(newpage);
- spin_lock(&hugetlb_lock);
- if (h->surplus_huge_pages_node[old_nid]) {
- h->surplus_huge_pages_node[old_nid]--;
- h->surplus_huge_pages_node[new_nid]++;
- }
- spin_unlock(&hugetlb_lock);
- }
- }
- /*
- * This function will unconditionally remove all the shared pmd pgtable entries
- * within the specific vma for a hugetlbfs memory range.
- */
- void hugetlb_unshare_all_pmds(struct vm_area_struct *vma)
- {
- struct hstate *h = hstate_vma(vma);
- unsigned long sz = huge_page_size(h);
- struct mm_struct *mm = vma->vm_mm;
- struct mmu_notifier_range range;
- unsigned long address, start, end;
- spinlock_t *ptl;
- pte_t *ptep;
- if (!(vma->vm_flags & VM_MAYSHARE))
- return;
- start = ALIGN(vma->vm_start, PUD_SIZE);
- end = ALIGN_DOWN(vma->vm_end, PUD_SIZE);
- if (start >= end)
- return;
- /*
- * No need to call adjust_range_if_pmd_sharing_possible(), because
- * we have already done the PUD_SIZE alignment.
- */
- mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm,
- start, end);
- mmu_notifier_invalidate_range_start(&range);
- i_mmap_lock_write(vma->vm_file->f_mapping);
- for (address = start; address < end; address += PUD_SIZE) {
- unsigned long tmp = address;
- ptep = huge_pte_offset(mm, address, sz);
- if (!ptep)
- continue;
- ptl = huge_pte_lock(h, mm, ptep);
- /* We don't want 'address' to be changed */
- huge_pmd_unshare(mm, vma, &tmp, ptep);
- spin_unlock(ptl);
- }
- flush_hugetlb_tlb_range(vma, start, end);
- i_mmap_unlock_write(vma->vm_file->f_mapping);
- /*
- * No need to call mmu_notifier_invalidate_range(), see
- * Documentation/vm/mmu_notifier.rst.
- */
- mmu_notifier_invalidate_range_end(&range);
- }
- #ifdef CONFIG_CMA
- static bool cma_reserve_called __initdata;
- static int __init cmdline_parse_hugetlb_cma(char *p)
- {
- hugetlb_cma_size = memparse(p, &p);
- return 0;
- }
- early_param("hugetlb_cma", cmdline_parse_hugetlb_cma);
- void __init hugetlb_cma_reserve(int order)
- {
- unsigned long size, reserved, per_node;
- int nid;
- cma_reserve_called = true;
- if (!hugetlb_cma_size)
- return;
- if (hugetlb_cma_size < (PAGE_SIZE << order)) {
- pr_warn("hugetlb_cma: cma area should be at least %lu MiB\n",
- (PAGE_SIZE << order) / SZ_1M);
- return;
- }
- /*
- * If 3 GB area is requested on a machine with 4 numa nodes,
- * let's allocate 1 GB on first three nodes and ignore the last one.
- */
- per_node = DIV_ROUND_UP(hugetlb_cma_size, nr_online_nodes);
- pr_info("hugetlb_cma: reserve %lu MiB, up to %lu MiB per node\n",
- hugetlb_cma_size / SZ_1M, per_node / SZ_1M);
- reserved = 0;
- for_each_node_state(nid, N_ONLINE) {
- int res;
- char name[CMA_MAX_NAME];
- size = min(per_node, hugetlb_cma_size - reserved);
- size = round_up(size, PAGE_SIZE << order);
- snprintf(name, sizeof(name), "hugetlb%d", nid);
- res = cma_declare_contiguous_nid(0, size, 0, PAGE_SIZE << order,
- 0, false, name,
- &hugetlb_cma[nid], nid);
- if (res) {
- pr_warn("hugetlb_cma: reservation failed: err %d, node %d",
- res, nid);
- continue;
- }
- reserved += size;
- pr_info("hugetlb_cma: reserved %lu MiB on node %d\n",
- size / SZ_1M, nid);
- if (reserved >= hugetlb_cma_size)
- break;
- }
- }
- void __init hugetlb_cma_check(void)
- {
- if (!hugetlb_cma_size || cma_reserve_called)
- return;
- pr_warn("hugetlb_cma: the option isn't supported by current arch\n");
- }
- #endif /* CONFIG_CMA */
|