1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889909192939495969798991001011021031041051061071081091101111121131141151161171181191201211221231241251261271281291301311321331341351361371381391401411421431441451461471481491501511521531541551561571581591601611621631641651661671681691701711721731741751761771781791801811821831841851861871881891901911921931941951961971981992002012022032042052062072082092102112122132142152162172182192202212222232242252262272282292302312322332342352362372382392402412422432442452462472482492502512522532542552562572582592602612622632642652662672682692702712722732742752762772782792802812822832842852862872882892902912922932942952962972982993003013023033043053063073083093103113123133143153163173183193203213223233243253263273283293303313323333343353363373383393403413423433443453463473483493503513523533543553563573583593603613623633643653663673683693703713723733743753763773783793803813823833843853863873883893903913923933943953963973983994004014024034044054064074084094104114124134144154164174184194204214224234244254264274284294304314324334344354364374384394404414424434444454464474484494504514524534544554564574584594604614624634644654664674684694704714724734744754764774784794804814824834844854864874884894904914924934944954964974984995005015025035045055065075085095105115125135145155165175185195205215225235245255265275285295305315325335345355365375385395405415425435445455465475485495505515525535545555565575585595605615625635645655665675685695705715725735745755765775785795805815825835845855865875885895905915925935945955965975985996006016026036046056066076086096106116126136146156166176186196206216226236246256266276286296306316326336346356366376386396406416426436446456466476486496506516526536546556566576586596606616626636646656666676686696706716726736746756766776786796806816826836846856866876886896906916926936946956966976986997007017027037047057067077087097107117127137147157167177187197207217227237247257267277287297307317327337347357367377387397407417427437447457467477487497507517527537547557567577587597607617627637647657667677687697707717727737747757767777787797807817827837847857867877887897907917927937947957967977987998008018028038048058068078088098108118128138148158168178188198208218228238248258268278288298308318328338348358368378388398408418428438448458468478488498508518528538548558568578588598608618628638648658668678688698708718728738748758768778788798808818828838848858868878888898908918928938948958968978988999009019029039049059069079089099109119129139149159169179189199209219229239249259269279289299309319329339349359369379389399409419429439449459469479489499509519529539549559569579589599609619629639649659669679689699709719729739749759769779789799809819829839849859869879889899909919929939949959969979989991000100110021003100410051006100710081009101010111012101310141015101610171018101910201021102210231024102510261027102810291030103110321033103410351036103710381039104010411042104310441045104610471048104910501051105210531054105510561057105810591060106110621063106410651066106710681069107010711072107310741075107610771078107910801081108210831084108510861087108810891090109110921093109410951096109710981099110011011102110311041105110611071108110911101111111211131114111511161117111811191120112111221123112411251126112711281129113011311132113311341135113611371138113911401141114211431144114511461147114811491150115111521153115411551156115711581159116011611162116311641165116611671168116911701171117211731174117511761177117811791180118111821183118411851186118711881189119011911192119311941195119611971198119912001201120212031204120512061207120812091210121112121213121412151216121712181219122012211222122312241225122612271228122912301231123212331234123512361237123812391240124112421243124412451246124712481249125012511252125312541255125612571258125912601261126212631264126512661267126812691270127112721273127412751276127712781279128012811282128312841285128612871288128912901291129212931294129512961297129812991300130113021303130413051306130713081309131013111312131313141315131613171318131913201321132213231324132513261327132813291330133113321333133413351336133713381339134013411342134313441345134613471348134913501351135213531354135513561357135813591360136113621363136413651366136713681369137013711372137313741375137613771378137913801381138213831384138513861387138813891390139113921393139413951396139713981399140014011402140314041405140614071408140914101411141214131414141514161417141814191420142114221423142414251426142714281429143014311432143314341435143614371438143914401441144214431444144514461447144814491450145114521453145414551456145714581459146014611462146314641465146614671468146914701471147214731474147514761477147814791480148114821483148414851486148714881489149014911492149314941495149614971498149915001501150215031504150515061507150815091510151115121513151415151516151715181519152015211522152315241525152615271528152915301531153215331534153515361537153815391540154115421543154415451546154715481549155015511552155315541555155615571558155915601561156215631564156515661567156815691570157115721573157415751576157715781579158015811582158315841585158615871588158915901591159215931594159515961597159815991600160116021603160416051606160716081609161016111612161316141615161616171618161916201621162216231624162516261627162816291630163116321633163416351636163716381639164016411642164316441645164616471648164916501651165216531654165516561657165816591660166116621663166416651666166716681669167016711672167316741675167616771678167916801681168216831684168516861687168816891690169116921693169416951696169716981699170017011702170317041705170617071708170917101711171217131714171517161717171817191720172117221723172417251726172717281729173017311732173317341735173617371738173917401741174217431744174517461747174817491750175117521753175417551756175717581759176017611762176317641765176617671768176917701771177217731774177517761777177817791780178117821783178417851786178717881789179017911792179317941795179617971798179918001801180218031804180518061807180818091810181118121813181418151816181718181819182018211822182318241825182618271828182918301831183218331834183518361837183818391840184118421843184418451846184718481849185018511852185318541855185618571858185918601861186218631864186518661867186818691870187118721873187418751876187718781879188018811882188318841885188618871888188918901891189218931894189518961897189818991900190119021903190419051906190719081909191019111912191319141915191619171918191919201921192219231924192519261927192819291930193119321933193419351936193719381939194019411942194319441945194619471948194919501951195219531954195519561957195819591960196119621963196419651966196719681969197019711972197319741975197619771978197919801981198219831984198519861987198819891990199119921993199419951996199719981999200020012002200320042005200620072008200920102011201220132014201520162017201820192020202120222023202420252026202720282029203020312032203320342035203620372038203920402041204220432044204520462047204820492050205120522053205420552056205720582059206020612062206320642065206620672068206920702071207220732074207520762077207820792080208120822083208420852086208720882089209020912092209320942095209620972098209921002101210221032104210521062107210821092110211121122113211421152116211721182119212021212122212321242125212621272128212921302131213221332134213521362137213821392140214121422143214421452146214721482149215021512152215321542155215621572158215921602161216221632164216521662167216821692170217121722173217421752176217721782179218021812182218321842185218621872188218921902191219221932194219521962197219821992200220122022203220422052206220722082209221022112212221322142215221622172218221922202221222222232224222522262227222822292230223122322233223422352236223722382239224022412242224322442245224622472248224922502251225222532254225522562257225822592260226122622263226422652266226722682269227022712272227322742275227622772278227922802281228222832284228522862287228822892290229122922293229422952296229722982299230023012302230323042305230623072308230923102311231223132314231523162317231823192320232123222323232423252326232723282329233023312332233323342335233623372338233923402341234223432344234523462347234823492350235123522353235423552356235723582359236023612362236323642365236623672368236923702371237223732374237523762377237823792380238123822383238423852386238723882389239023912392239323942395239623972398239924002401240224032404240524062407240824092410241124122413241424152416241724182419242024212422242324242425242624272428242924302431243224332434243524362437243824392440244124422443244424452446244724482449245024512452245324542455245624572458245924602461246224632464246524662467246824692470247124722473247424752476247724782479248024812482248324842485248624872488248924902491249224932494249524962497249824992500250125022503250425052506250725082509251025112512251325142515251625172518251925202521252225232524252525262527252825292530253125322533253425352536253725382539254025412542254325442545254625472548254925502551255225532554255525562557255825592560256125622563256425652566256725682569257025712572257325742575257625772578257925802581258225832584258525862587258825892590259125922593259425952596259725982599260026012602260326042605260626072608260926102611261226132614261526162617261826192620262126222623262426252626262726282629263026312632263326342635263626372638263926402641264226432644264526462647264826492650265126522653265426552656265726582659266026612662266326642665266626672668266926702671267226732674267526762677267826792680268126822683268426852686268726882689269026912692269326942695269626972698269927002701270227032704270527062707270827092710271127122713271427152716271727182719272027212722272327242725272627272728272927302731273227332734273527362737273827392740274127422743274427452746274727482749275027512752275327542755275627572758275927602761276227632764276527662767276827692770277127722773277427752776277727782779278027812782278327842785278627872788278927902791279227932794279527962797279827992800280128022803280428052806280728082809281028112812281328142815281628172818281928202821282228232824282528262827282828292830283128322833283428352836283728382839284028412842284328442845284628472848284928502851285228532854285528562857285828592860286128622863286428652866286728682869287028712872287328742875287628772878287928802881288228832884288528862887288828892890289128922893289428952896289728982899290029012902290329042905290629072908290929102911291229132914291529162917291829192920292129222923292429252926292729282929293029312932293329342935293629372938293929402941294229432944294529462947294829492950295129522953295429552956295729582959296029612962296329642965296629672968296929702971297229732974297529762977297829792980298129822983298429852986298729882989299029912992299329942995299629972998299930003001300230033004300530063007300830093010301130123013301430153016301730183019302030213022302330243025302630273028302930303031303230333034303530363037303830393040304130423043304430453046304730483049305030513052305330543055305630573058305930603061306230633064306530663067306830693070307130723073307430753076307730783079308030813082308330843085308630873088308930903091309230933094309530963097309830993100310131023103310431053106310731083109311031113112311331143115311631173118311931203121312231233124312531263127312831293130313131323133313431353136313731383139314031413142314331443145314631473148314931503151315231533154315531563157315831593160316131623163316431653166316731683169317031713172317331743175317631773178317931803181318231833184318531863187318831893190319131923193319431953196319731983199320032013202320332043205320632073208320932103211321232133214321532163217321832193220322132223223322432253226322732283229323032313232323332343235323632373238323932403241324232433244324532463247324832493250325132523253325432553256325732583259326032613262326332643265326632673268326932703271327232733274327532763277327832793280328132823283328432853286328732883289329032913292329332943295329632973298329933003301330233033304330533063307330833093310331133123313331433153316331733183319332033213322332333243325332633273328332933303331333233333334333533363337333833393340334133423343334433453346334733483349335033513352335333543355335633573358335933603361336233633364336533663367336833693370337133723373337433753376337733783379338033813382338333843385338633873388338933903391339233933394339533963397339833993400340134023403340434053406340734083409341034113412341334143415341634173418341934203421342234233424342534263427342834293430343134323433343434353436343734383439344034413442344334443445344634473448344934503451345234533454345534563457345834593460346134623463346434653466346734683469347034713472347334743475347634773478347934803481348234833484348534863487348834893490349134923493349434953496349734983499350035013502350335043505350635073508350935103511351235133514351535163517351835193520352135223523352435253526352735283529353035313532353335343535353635373538353935403541354235433544354535463547354835493550355135523553355435553556355735583559356035613562356335643565356635673568356935703571357235733574357535763577357835793580358135823583358435853586358735883589359035913592359335943595359635973598359936003601360236033604360536063607360836093610361136123613361436153616361736183619362036213622362336243625362636273628362936303631363236333634363536363637363836393640364136423643364436453646364736483649365036513652365336543655365636573658365936603661366236633664366536663667366836693670367136723673367436753676367736783679368036813682368336843685368636873688368936903691369236933694369536963697369836993700370137023703370437053706370737083709371037113712371337143715 |
- /*
- * kernel/cpuset.c
- *
- * Processor and Memory placement constraints for sets of tasks.
- *
- * Copyright (C) 2003 BULL SA.
- * Copyright (C) 2004-2007 Silicon Graphics, Inc.
- * Copyright (C) 2006 Google, Inc
- *
- * Portions derived from Patrick Mochel's sysfs code.
- * sysfs is Copyright (c) 2001-3 Patrick Mochel
- *
- * 2003-10-10 Written by Simon Derr.
- * 2003-10-22 Updates by Stephen Hemminger.
- * 2004 May-July Rework by Paul Jackson.
- * 2006 Rework by Paul Menage to use generic cgroups
- * 2008 Rework of the scheduler domains and CPU hotplug handling
- * by Max Krasnyansky
- *
- * This file is subject to the terms and conditions of the GNU General Public
- * License. See the file COPYING in the main directory of the Linux
- * distribution for more details.
- */
- #include <linux/cpu.h>
- #include <linux/cpumask.h>
- #include <linux/cpuset.h>
- #include <linux/err.h>
- #include <linux/errno.h>
- #include <linux/file.h>
- #include <linux/fs.h>
- #include <linux/init.h>
- #include <linux/interrupt.h>
- #include <linux/kernel.h>
- #include <linux/kmod.h>
- #include <linux/list.h>
- #include <linux/mempolicy.h>
- #include <linux/mm.h>
- #include <linux/memory.h>
- #include <linux/export.h>
- #include <linux/mount.h>
- #include <linux/fs_context.h>
- #include <linux/namei.h>
- #include <linux/pagemap.h>
- #include <linux/proc_fs.h>
- #include <linux/rcupdate.h>
- #include <linux/sched.h>
- #include <linux/sched/deadline.h>
- #include <linux/sched/mm.h>
- #include <linux/sched/task.h>
- #include <linux/seq_file.h>
- #include <linux/security.h>
- #include <linux/slab.h>
- #include <linux/spinlock.h>
- #include <linux/stat.h>
- #include <linux/string.h>
- #include <linux/time.h>
- #include <linux/time64.h>
- #include <linux/backing-dev.h>
- #include <linux/sort.h>
- #include <linux/oom.h>
- #include <linux/sched/isolation.h>
- #include <linux/uaccess.h>
- #include <linux/atomic.h>
- #include <linux/mutex.h>
- #include <linux/cgroup.h>
- #include <linux/wait.h>
- #include <trace/hooks/sched.h>
- #include <trace/hooks/cgroup.h>
- DEFINE_STATIC_KEY_FALSE(cpusets_pre_enable_key);
- DEFINE_STATIC_KEY_FALSE(cpusets_enabled_key);
- /* See "Frequency meter" comments, below. */
- struct fmeter {
- int cnt; /* unprocessed events count */
- int val; /* most recent output value */
- time64_t time; /* clock (secs) when val computed */
- spinlock_t lock; /* guards read or write of above */
- };
- struct cpuset {
- struct cgroup_subsys_state css;
- unsigned long flags; /* "unsigned long" so bitops work */
- /*
- * On default hierarchy:
- *
- * The user-configured masks can only be changed by writing to
- * cpuset.cpus and cpuset.mems, and won't be limited by the
- * parent masks.
- *
- * The effective masks is the real masks that apply to the tasks
- * in the cpuset. They may be changed if the configured masks are
- * changed or hotplug happens.
- *
- * effective_mask == configured_mask & parent's effective_mask,
- * and if it ends up empty, it will inherit the parent's mask.
- *
- *
- * On legacy hierachy:
- *
- * The user-configured masks are always the same with effective masks.
- */
- /* user-configured CPUs and Memory Nodes allow to tasks */
- cpumask_var_t cpus_allowed;
- cpumask_var_t cpus_requested;
- nodemask_t mems_allowed;
- /* effective CPUs and Memory Nodes allow to tasks */
- cpumask_var_t effective_cpus;
- nodemask_t effective_mems;
- /*
- * CPUs allocated to child sub-partitions (default hierarchy only)
- * - CPUs granted by the parent = effective_cpus U subparts_cpus
- * - effective_cpus and subparts_cpus are mutually exclusive.
- *
- * effective_cpus contains only onlined CPUs, but subparts_cpus
- * may have offlined ones.
- */
- cpumask_var_t subparts_cpus;
- /*
- * This is old Memory Nodes tasks took on.
- *
- * - top_cpuset.old_mems_allowed is initialized to mems_allowed.
- * - A new cpuset's old_mems_allowed is initialized when some
- * task is moved into it.
- * - old_mems_allowed is used in cpuset_migrate_mm() when we change
- * cpuset.mems_allowed and have tasks' nodemask updated, and
- * then old_mems_allowed is updated to mems_allowed.
- */
- nodemask_t old_mems_allowed;
- struct fmeter fmeter; /* memory_pressure filter */
- /*
- * Tasks are being attached to this cpuset. Used to prevent
- * zeroing cpus/mems_allowed between ->can_attach() and ->attach().
- */
- int attach_in_progress;
- /* partition number for rebuild_sched_domains() */
- int pn;
- /* for custom sched domain */
- int relax_domain_level;
- /* number of CPUs in subparts_cpus */
- int nr_subparts_cpus;
- /* partition root state */
- int partition_root_state;
- /*
- * Default hierarchy only:
- * use_parent_ecpus - set if using parent's effective_cpus
- * child_ecpus_count - # of children with use_parent_ecpus set
- */
- int use_parent_ecpus;
- int child_ecpus_count;
- };
- /*
- * Partition root states:
- *
- * 0 - not a partition root
- *
- * 1 - partition root
- *
- * -1 - invalid partition root
- * None of the cpus in cpus_allowed can be put into the parent's
- * subparts_cpus. In this case, the cpuset is not a real partition
- * root anymore. However, the CPU_EXCLUSIVE bit will still be set
- * and the cpuset can be restored back to a partition root if the
- * parent cpuset can give more CPUs back to this child cpuset.
- */
- #define PRS_DISABLED 0
- #define PRS_ENABLED 1
- #define PRS_ERROR -1
- /*
- * Temporary cpumasks for working with partitions that are passed among
- * functions to avoid memory allocation in inner functions.
- */
- struct tmpmasks {
- cpumask_var_t addmask, delmask; /* For partition root */
- cpumask_var_t new_cpus; /* For update_cpumasks_hier() */
- };
- static inline struct cpuset *css_cs(struct cgroup_subsys_state *css)
- {
- return css ? container_of(css, struct cpuset, css) : NULL;
- }
- /* Retrieve the cpuset for a task */
- static inline struct cpuset *task_cs(struct task_struct *task)
- {
- return css_cs(task_css(task, cpuset_cgrp_id));
- }
- static inline struct cpuset *parent_cs(struct cpuset *cs)
- {
- return css_cs(cs->css.parent);
- }
- /* bits in struct cpuset flags field */
- typedef enum {
- CS_ONLINE,
- CS_CPU_EXCLUSIVE,
- CS_MEM_EXCLUSIVE,
- CS_MEM_HARDWALL,
- CS_MEMORY_MIGRATE,
- CS_SCHED_LOAD_BALANCE,
- CS_SPREAD_PAGE,
- CS_SPREAD_SLAB,
- } cpuset_flagbits_t;
- /* convenient tests for these bits */
- static inline bool is_cpuset_online(struct cpuset *cs)
- {
- return test_bit(CS_ONLINE, &cs->flags) && !css_is_dying(&cs->css);
- }
- static inline int is_cpu_exclusive(const struct cpuset *cs)
- {
- return test_bit(CS_CPU_EXCLUSIVE, &cs->flags);
- }
- static inline int is_mem_exclusive(const struct cpuset *cs)
- {
- return test_bit(CS_MEM_EXCLUSIVE, &cs->flags);
- }
- static inline int is_mem_hardwall(const struct cpuset *cs)
- {
- return test_bit(CS_MEM_HARDWALL, &cs->flags);
- }
- static inline int is_sched_load_balance(const struct cpuset *cs)
- {
- return test_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
- }
- static inline int is_memory_migrate(const struct cpuset *cs)
- {
- return test_bit(CS_MEMORY_MIGRATE, &cs->flags);
- }
- static inline int is_spread_page(const struct cpuset *cs)
- {
- return test_bit(CS_SPREAD_PAGE, &cs->flags);
- }
- static inline int is_spread_slab(const struct cpuset *cs)
- {
- return test_bit(CS_SPREAD_SLAB, &cs->flags);
- }
- static inline int is_partition_root(const struct cpuset *cs)
- {
- return cs->partition_root_state > 0;
- }
- static struct cpuset top_cpuset = {
- .flags = ((1 << CS_ONLINE) | (1 << CS_CPU_EXCLUSIVE) |
- (1 << CS_MEM_EXCLUSIVE)),
- .partition_root_state = PRS_ENABLED,
- };
- /**
- * cpuset_for_each_child - traverse online children of a cpuset
- * @child_cs: loop cursor pointing to the current child
- * @pos_css: used for iteration
- * @parent_cs: target cpuset to walk children of
- *
- * Walk @child_cs through the online children of @parent_cs. Must be used
- * with RCU read locked.
- */
- #define cpuset_for_each_child(child_cs, pos_css, parent_cs) \
- css_for_each_child((pos_css), &(parent_cs)->css) \
- if (is_cpuset_online(((child_cs) = css_cs((pos_css)))))
- /**
- * cpuset_for_each_descendant_pre - pre-order walk of a cpuset's descendants
- * @des_cs: loop cursor pointing to the current descendant
- * @pos_css: used for iteration
- * @root_cs: target cpuset to walk ancestor of
- *
- * Walk @des_cs through the online descendants of @root_cs. Must be used
- * with RCU read locked. The caller may modify @pos_css by calling
- * css_rightmost_descendant() to skip subtree. @root_cs is included in the
- * iteration and the first node to be visited.
- */
- #define cpuset_for_each_descendant_pre(des_cs, pos_css, root_cs) \
- css_for_each_descendant_pre((pos_css), &(root_cs)->css) \
- if (is_cpuset_online(((des_cs) = css_cs((pos_css)))))
- /*
- * There are two global locks guarding cpuset structures - cpuset_mutex and
- * callback_lock. We also require taking task_lock() when dereferencing a
- * task's cpuset pointer. See "The task_lock() exception", at the end of this
- * comment.
- *
- * A task must hold both locks to modify cpusets. If a task holds
- * cpuset_mutex, then it blocks others wanting that mutex, ensuring that it
- * is the only task able to also acquire callback_lock and be able to
- * modify cpusets. It can perform various checks on the cpuset structure
- * first, knowing nothing will change. It can also allocate memory while
- * just holding cpuset_mutex. While it is performing these checks, various
- * callback routines can briefly acquire callback_lock to query cpusets.
- * Once it is ready to make the changes, it takes callback_lock, blocking
- * everyone else.
- *
- * Calls to the kernel memory allocator can not be made while holding
- * callback_lock, as that would risk double tripping on callback_lock
- * from one of the callbacks into the cpuset code from within
- * __alloc_pages().
- *
- * If a task is only holding callback_lock, then it has read-only
- * access to cpusets.
- *
- * Now, the task_struct fields mems_allowed and mempolicy may be changed
- * by other task, we use alloc_lock in the task_struct fields to protect
- * them.
- *
- * The cpuset_common_file_read() handlers only hold callback_lock across
- * small pieces of code, such as when reading out possibly multi-word
- * cpumasks and nodemasks.
- *
- * Accessing a task's cpuset should be done in accordance with the
- * guidelines for accessing subsystem state in kernel/cgroup.c
- */
- static DEFINE_MUTEX(cpuset_mutex);
- static DEFINE_SPINLOCK(callback_lock);
- static struct workqueue_struct *cpuset_migrate_mm_wq;
- /*
- * CPU / memory hotplug is handled asynchronously
- * for hotplug, synchronously for resume_cpus
- */
- static DECLARE_WORK(cpuset_hotplug_work, cpuset_hotplug_workfn);
- static DECLARE_WAIT_QUEUE_HEAD(cpuset_attach_wq);
- /*
- * Cgroup v2 behavior is used on the "cpus" and "mems" control files when
- * on default hierarchy or when the cpuset_v2_mode flag is set by mounting
- * the v1 cpuset cgroup filesystem with the "cpuset_v2_mode" mount option.
- * With v2 behavior, "cpus" and "mems" are always what the users have
- * requested and won't be changed by hotplug events. Only the effective
- * cpus or mems will be affected.
- */
- static inline bool is_in_v2_mode(void)
- {
- return cgroup_subsys_on_dfl(cpuset_cgrp_subsys) ||
- (cpuset_cgrp_subsys.root->flags & CGRP_ROOT_CPUSET_V2_MODE);
- }
- /*
- * Return in pmask the portion of a task's cpusets's cpus_allowed that
- * are online and are capable of running the task. If none are found,
- * walk up the cpuset hierarchy until we find one that does have some
- * appropriate cpus.
- *
- * One way or another, we guarantee to return some non-empty subset
- * of cpu_active_mask.
- *
- * Call with callback_lock or cpuset_mutex held.
- */
- static void guarantee_online_cpus(struct task_struct *tsk,
- struct cpumask *pmask)
- {
- const struct cpumask *possible_mask = task_cpu_possible_mask(tsk);
- struct cpuset *cs;
- if (WARN_ON(!cpumask_and(pmask, possible_mask, cpu_active_mask)))
- cpumask_copy(pmask, cpu_active_mask);
- rcu_read_lock();
- cs = task_cs(tsk);
- while (!cpumask_intersects(cs->effective_cpus, pmask)) {
- cs = parent_cs(cs);
- if (unlikely(!cs)) {
- /*
- * The top cpuset doesn't have any online cpu as a
- * consequence of a race between cpuset_hotplug_work
- * and cpu hotplug notifier. But we know the top
- * cpuset's effective_cpus is on its way to be
- * identical to cpu_online_mask.
- */
- goto out_unlock;
- }
- }
- cpumask_and(pmask, pmask, cs->effective_cpus);
- out_unlock:
- rcu_read_unlock();
- }
- /*
- * Return in *pmask the portion of a cpusets's mems_allowed that
- * are online, with memory. If none are online with memory, walk
- * up the cpuset hierarchy until we find one that does have some
- * online mems. The top cpuset always has some mems online.
- *
- * One way or another, we guarantee to return some non-empty subset
- * of node_states[N_MEMORY].
- *
- * Call with callback_lock or cpuset_mutex held.
- */
- static void guarantee_online_mems(struct cpuset *cs, nodemask_t *pmask)
- {
- while (!nodes_intersects(cs->effective_mems, node_states[N_MEMORY]))
- cs = parent_cs(cs);
- nodes_and(*pmask, cs->effective_mems, node_states[N_MEMORY]);
- }
- /*
- * update task's spread flag if cpuset's page/slab spread flag is set
- *
- * Call with callback_lock or cpuset_mutex held.
- */
- static void cpuset_update_task_spread_flag(struct cpuset *cs,
- struct task_struct *tsk)
- {
- if (is_spread_page(cs))
- task_set_spread_page(tsk);
- else
- task_clear_spread_page(tsk);
- if (is_spread_slab(cs))
- task_set_spread_slab(tsk);
- else
- task_clear_spread_slab(tsk);
- }
- /*
- * is_cpuset_subset(p, q) - Is cpuset p a subset of cpuset q?
- *
- * One cpuset is a subset of another if all its allowed CPUs and
- * Memory Nodes are a subset of the other, and its exclusive flags
- * are only set if the other's are set. Call holding cpuset_mutex.
- */
- static int is_cpuset_subset(const struct cpuset *p, const struct cpuset *q)
- {
- return cpumask_subset(p->cpus_requested, q->cpus_requested) &&
- nodes_subset(p->mems_allowed, q->mems_allowed) &&
- is_cpu_exclusive(p) <= is_cpu_exclusive(q) &&
- is_mem_exclusive(p) <= is_mem_exclusive(q);
- }
- /**
- * alloc_cpumasks - allocate three cpumasks for cpuset
- * @cs: the cpuset that have cpumasks to be allocated.
- * @tmp: the tmpmasks structure pointer
- * Return: 0 if successful, -ENOMEM otherwise.
- *
- * Only one of the two input arguments should be non-NULL.
- */
- static inline int alloc_cpumasks(struct cpuset *cs, struct tmpmasks *tmp)
- {
- cpumask_var_t *pmask1, *pmask2, *pmask3;
- if (cs) {
- pmask1 = &cs->cpus_allowed;
- pmask2 = &cs->effective_cpus;
- pmask3 = &cs->subparts_cpus;
- } else {
- pmask1 = &tmp->new_cpus;
- pmask2 = &tmp->addmask;
- pmask3 = &tmp->delmask;
- }
- if (!zalloc_cpumask_var(pmask1, GFP_KERNEL))
- return -ENOMEM;
- if (!zalloc_cpumask_var(pmask2, GFP_KERNEL))
- goto free_one;
- if (!zalloc_cpumask_var(pmask3, GFP_KERNEL))
- goto free_two;
- if (cs && !zalloc_cpumask_var(&cs->cpus_requested, GFP_KERNEL))
- goto free_three;
- return 0;
- free_three:
- free_cpumask_var(*pmask3);
- free_two:
- free_cpumask_var(*pmask2);
- free_one:
- free_cpumask_var(*pmask1);
- return -ENOMEM;
- }
- /**
- * free_cpumasks - free cpumasks in a tmpmasks structure
- * @cs: the cpuset that have cpumasks to be free.
- * @tmp: the tmpmasks structure pointer
- */
- static inline void free_cpumasks(struct cpuset *cs, struct tmpmasks *tmp)
- {
- if (cs) {
- free_cpumask_var(cs->cpus_allowed);
- free_cpumask_var(cs->cpus_requested);
- free_cpumask_var(cs->effective_cpus);
- free_cpumask_var(cs->subparts_cpus);
- }
- if (tmp) {
- free_cpumask_var(tmp->new_cpus);
- free_cpumask_var(tmp->addmask);
- free_cpumask_var(tmp->delmask);
- }
- }
- /**
- * alloc_trial_cpuset - allocate a trial cpuset
- * @cs: the cpuset that the trial cpuset duplicates
- */
- static struct cpuset *alloc_trial_cpuset(struct cpuset *cs)
- {
- struct cpuset *trial;
- trial = kmemdup(cs, sizeof(*cs), GFP_KERNEL);
- if (!trial)
- return NULL;
- if (alloc_cpumasks(trial, NULL)) {
- kfree(trial);
- return NULL;
- }
- cpumask_copy(trial->cpus_allowed, cs->cpus_allowed);
- cpumask_copy(trial->cpus_requested, cs->cpus_requested);
- cpumask_copy(trial->effective_cpus, cs->effective_cpus);
- return trial;
- }
- /**
- * free_cpuset - free the cpuset
- * @cs: the cpuset to be freed
- */
- static inline void free_cpuset(struct cpuset *cs)
- {
- free_cpumasks(cs, NULL);
- kfree(cs);
- }
- /*
- * validate_change() - Used to validate that any proposed cpuset change
- * follows the structural rules for cpusets.
- *
- * If we replaced the flag and mask values of the current cpuset
- * (cur) with those values in the trial cpuset (trial), would
- * our various subset and exclusive rules still be valid? Presumes
- * cpuset_mutex held.
- *
- * 'cur' is the address of an actual, in-use cpuset. Operations
- * such as list traversal that depend on the actual address of the
- * cpuset in the list must use cur below, not trial.
- *
- * 'trial' is the address of bulk structure copy of cur, with
- * perhaps one or more of the fields cpus_allowed, mems_allowed,
- * or flags changed to new, trial values.
- *
- * Return 0 if valid, -errno if not.
- */
- static int validate_change(struct cpuset *cur, struct cpuset *trial)
- {
- struct cgroup_subsys_state *css;
- struct cpuset *c, *par;
- int ret;
- rcu_read_lock();
- /* Each of our child cpusets must be a subset of us */
- ret = -EBUSY;
- cpuset_for_each_child(c, css, cur)
- if (!is_cpuset_subset(c, trial))
- goto out;
- /* Remaining checks don't apply to root cpuset */
- ret = 0;
- if (cur == &top_cpuset)
- goto out;
- par = parent_cs(cur);
- /* On legacy hiearchy, we must be a subset of our parent cpuset. */
- ret = -EACCES;
- if (!is_in_v2_mode() && !is_cpuset_subset(trial, par))
- goto out;
- /*
- * If either I or some sibling (!= me) is exclusive, we can't
- * overlap
- */
- ret = -EINVAL;
- cpuset_for_each_child(c, css, par) {
- if ((is_cpu_exclusive(trial) || is_cpu_exclusive(c)) &&
- c != cur &&
- cpumask_intersects(trial->cpus_requested, c->cpus_requested))
- goto out;
- if ((is_mem_exclusive(trial) || is_mem_exclusive(c)) &&
- c != cur &&
- nodes_intersects(trial->mems_allowed, c->mems_allowed))
- goto out;
- }
- /*
- * Cpusets with tasks - existing or newly being attached - can't
- * be changed to have empty cpus_allowed or mems_allowed.
- */
- ret = -ENOSPC;
- if ((cgroup_is_populated(cur->css.cgroup) || cur->attach_in_progress)) {
- if (!cpumask_empty(cur->cpus_allowed) &&
- cpumask_empty(trial->cpus_allowed))
- goto out;
- if (!nodes_empty(cur->mems_allowed) &&
- nodes_empty(trial->mems_allowed))
- goto out;
- }
- /*
- * We can't shrink if we won't have enough room for SCHED_DEADLINE
- * tasks.
- */
- ret = -EBUSY;
- if (is_cpu_exclusive(cur) &&
- !cpuset_cpumask_can_shrink(cur->cpus_allowed,
- trial->cpus_allowed))
- goto out;
- ret = 0;
- out:
- rcu_read_unlock();
- return ret;
- }
- #ifdef CONFIG_SMP
- /*
- * Helper routine for generate_sched_domains().
- * Do cpusets a, b have overlapping effective cpus_allowed masks?
- */
- static int cpusets_overlap(struct cpuset *a, struct cpuset *b)
- {
- return cpumask_intersects(a->effective_cpus, b->effective_cpus);
- }
- static void
- update_domain_attr(struct sched_domain_attr *dattr, struct cpuset *c)
- {
- if (dattr->relax_domain_level < c->relax_domain_level)
- dattr->relax_domain_level = c->relax_domain_level;
- return;
- }
- static void update_domain_attr_tree(struct sched_domain_attr *dattr,
- struct cpuset *root_cs)
- {
- struct cpuset *cp;
- struct cgroup_subsys_state *pos_css;
- rcu_read_lock();
- cpuset_for_each_descendant_pre(cp, pos_css, root_cs) {
- /* skip the whole subtree if @cp doesn't have any CPU */
- if (cpumask_empty(cp->cpus_allowed)) {
- pos_css = css_rightmost_descendant(pos_css);
- continue;
- }
- if (is_sched_load_balance(cp))
- update_domain_attr(dattr, cp);
- }
- rcu_read_unlock();
- }
- /* Must be called with cpuset_mutex held. */
- static inline int nr_cpusets(void)
- {
- /* jump label reference count + the top-level cpuset */
- return static_key_count(&cpusets_enabled_key.key) + 1;
- }
- /*
- * generate_sched_domains()
- *
- * This function builds a partial partition of the systems CPUs
- * A 'partial partition' is a set of non-overlapping subsets whose
- * union is a subset of that set.
- * The output of this function needs to be passed to kernel/sched/core.c
- * partition_sched_domains() routine, which will rebuild the scheduler's
- * load balancing domains (sched domains) as specified by that partial
- * partition.
- *
- * See "What is sched_load_balance" in Documentation/admin-guide/cgroup-v1/cpusets.rst
- * for a background explanation of this.
- *
- * Does not return errors, on the theory that the callers of this
- * routine would rather not worry about failures to rebuild sched
- * domains when operating in the severe memory shortage situations
- * that could cause allocation failures below.
- *
- * Must be called with cpuset_mutex held.
- *
- * The three key local variables below are:
- * cp - cpuset pointer, used (together with pos_css) to perform a
- * top-down scan of all cpusets. For our purposes, rebuilding
- * the schedulers sched domains, we can ignore !is_sched_load_
- * balance cpusets.
- * csa - (for CpuSet Array) Array of pointers to all the cpusets
- * that need to be load balanced, for convenient iterative
- * access by the subsequent code that finds the best partition,
- * i.e the set of domains (subsets) of CPUs such that the
- * cpus_allowed of every cpuset marked is_sched_load_balance
- * is a subset of one of these domains, while there are as
- * many such domains as possible, each as small as possible.
- * doms - Conversion of 'csa' to an array of cpumasks, for passing to
- * the kernel/sched/core.c routine partition_sched_domains() in a
- * convenient format, that can be easily compared to the prior
- * value to determine what partition elements (sched domains)
- * were changed (added or removed.)
- *
- * Finding the best partition (set of domains):
- * The triple nested loops below over i, j, k scan over the
- * load balanced cpusets (using the array of cpuset pointers in
- * csa[]) looking for pairs of cpusets that have overlapping
- * cpus_allowed, but which don't have the same 'pn' partition
- * number and gives them in the same partition number. It keeps
- * looping on the 'restart' label until it can no longer find
- * any such pairs.
- *
- * The union of the cpus_allowed masks from the set of
- * all cpusets having the same 'pn' value then form the one
- * element of the partition (one sched domain) to be passed to
- * partition_sched_domains().
- */
- static int generate_sched_domains(cpumask_var_t **domains,
- struct sched_domain_attr **attributes)
- {
- struct cpuset *cp; /* top-down scan of cpusets */
- struct cpuset **csa; /* array of all cpuset ptrs */
- int csn; /* how many cpuset ptrs in csa so far */
- int i, j, k; /* indices for partition finding loops */
- cpumask_var_t *doms; /* resulting partition; i.e. sched domains */
- struct sched_domain_attr *dattr; /* attributes for custom domains */
- int ndoms = 0; /* number of sched domains in result */
- int nslot; /* next empty doms[] struct cpumask slot */
- struct cgroup_subsys_state *pos_css;
- bool root_load_balance = is_sched_load_balance(&top_cpuset);
- doms = NULL;
- dattr = NULL;
- csa = NULL;
- /* Special case for the 99% of systems with one, full, sched domain */
- if (root_load_balance && !top_cpuset.nr_subparts_cpus) {
- ndoms = 1;
- doms = alloc_sched_domains(ndoms);
- if (!doms)
- goto done;
- dattr = kmalloc(sizeof(struct sched_domain_attr), GFP_KERNEL);
- if (dattr) {
- *dattr = SD_ATTR_INIT;
- update_domain_attr_tree(dattr, &top_cpuset);
- }
- cpumask_and(doms[0], top_cpuset.effective_cpus,
- housekeeping_cpumask(HK_FLAG_DOMAIN));
- goto done;
- }
- csa = kmalloc_array(nr_cpusets(), sizeof(cp), GFP_KERNEL);
- if (!csa)
- goto done;
- csn = 0;
- rcu_read_lock();
- if (root_load_balance)
- csa[csn++] = &top_cpuset;
- cpuset_for_each_descendant_pre(cp, pos_css, &top_cpuset) {
- if (cp == &top_cpuset)
- continue;
- /*
- * Continue traversing beyond @cp iff @cp has some CPUs and
- * isn't load balancing. The former is obvious. The
- * latter: All child cpusets contain a subset of the
- * parent's cpus, so just skip them, and then we call
- * update_domain_attr_tree() to calc relax_domain_level of
- * the corresponding sched domain.
- *
- * If root is load-balancing, we can skip @cp if it
- * is a subset of the root's effective_cpus.
- */
- if (!cpumask_empty(cp->cpus_allowed) &&
- !(is_sched_load_balance(cp) &&
- cpumask_intersects(cp->cpus_allowed,
- housekeeping_cpumask(HK_FLAG_DOMAIN))))
- continue;
- if (root_load_balance &&
- cpumask_subset(cp->cpus_allowed, top_cpuset.effective_cpus))
- continue;
- if (is_sched_load_balance(cp) &&
- !cpumask_empty(cp->effective_cpus))
- csa[csn++] = cp;
- /* skip @cp's subtree if not a partition root */
- if (!is_partition_root(cp))
- pos_css = css_rightmost_descendant(pos_css);
- }
- rcu_read_unlock();
- for (i = 0; i < csn; i++)
- csa[i]->pn = i;
- ndoms = csn;
- restart:
- /* Find the best partition (set of sched domains) */
- for (i = 0; i < csn; i++) {
- struct cpuset *a = csa[i];
- int apn = a->pn;
- for (j = 0; j < csn; j++) {
- struct cpuset *b = csa[j];
- int bpn = b->pn;
- if (apn != bpn && cpusets_overlap(a, b)) {
- for (k = 0; k < csn; k++) {
- struct cpuset *c = csa[k];
- if (c->pn == bpn)
- c->pn = apn;
- }
- ndoms--; /* one less element */
- goto restart;
- }
- }
- }
- /*
- * Now we know how many domains to create.
- * Convert <csn, csa> to <ndoms, doms> and populate cpu masks.
- */
- doms = alloc_sched_domains(ndoms);
- if (!doms)
- goto done;
- /*
- * The rest of the code, including the scheduler, can deal with
- * dattr==NULL case. No need to abort if alloc fails.
- */
- dattr = kmalloc_array(ndoms, sizeof(struct sched_domain_attr),
- GFP_KERNEL);
- for (nslot = 0, i = 0; i < csn; i++) {
- struct cpuset *a = csa[i];
- struct cpumask *dp;
- int apn = a->pn;
- if (apn < 0) {
- /* Skip completed partitions */
- continue;
- }
- dp = doms[nslot];
- if (nslot == ndoms) {
- static int warnings = 10;
- if (warnings) {
- pr_warn("rebuild_sched_domains confused: nslot %d, ndoms %d, csn %d, i %d, apn %d\n",
- nslot, ndoms, csn, i, apn);
- warnings--;
- }
- continue;
- }
- cpumask_clear(dp);
- if (dattr)
- *(dattr + nslot) = SD_ATTR_INIT;
- for (j = i; j < csn; j++) {
- struct cpuset *b = csa[j];
- if (apn == b->pn) {
- cpumask_or(dp, dp, b->effective_cpus);
- cpumask_and(dp, dp, housekeeping_cpumask(HK_FLAG_DOMAIN));
- if (dattr)
- update_domain_attr_tree(dattr + nslot, b);
- /* Done with this partition */
- b->pn = -1;
- }
- }
- nslot++;
- }
- BUG_ON(nslot != ndoms);
- done:
- kfree(csa);
- /*
- * Fallback to the default domain if kmalloc() failed.
- * See comments in partition_sched_domains().
- */
- if (doms == NULL)
- ndoms = 1;
- *domains = doms;
- *attributes = dattr;
- return ndoms;
- }
- static void update_tasks_root_domain(struct cpuset *cs)
- {
- struct css_task_iter it;
- struct task_struct *task;
- css_task_iter_start(&cs->css, 0, &it);
- while ((task = css_task_iter_next(&it)))
- dl_add_task_root_domain(task);
- css_task_iter_end(&it);
- }
- static void rebuild_root_domains(void)
- {
- struct cpuset *cs = NULL;
- struct cgroup_subsys_state *pos_css;
- lockdep_assert_held(&cpuset_mutex);
- lockdep_assert_cpus_held();
- lockdep_assert_held(&sched_domains_mutex);
- rcu_read_lock();
- /*
- * Clear default root domain DL accounting, it will be computed again
- * if a task belongs to it.
- */
- dl_clear_root_domain(&def_root_domain);
- cpuset_for_each_descendant_pre(cs, pos_css, &top_cpuset) {
- if (cpumask_empty(cs->effective_cpus)) {
- pos_css = css_rightmost_descendant(pos_css);
- continue;
- }
- css_get(&cs->css);
- rcu_read_unlock();
- update_tasks_root_domain(cs);
- rcu_read_lock();
- css_put(&cs->css);
- }
- rcu_read_unlock();
- }
- static void
- partition_and_rebuild_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
- struct sched_domain_attr *dattr_new)
- {
- mutex_lock(&sched_domains_mutex);
- partition_sched_domains_locked(ndoms_new, doms_new, dattr_new);
- rebuild_root_domains();
- mutex_unlock(&sched_domains_mutex);
- }
- /*
- * Rebuild scheduler domains.
- *
- * If the flag 'sched_load_balance' of any cpuset with non-empty
- * 'cpus' changes, or if the 'cpus' allowed changes in any cpuset
- * which has that flag enabled, or if any cpuset with a non-empty
- * 'cpus' is removed, then call this routine to rebuild the
- * scheduler's dynamic sched domains.
- *
- * Call with cpuset_mutex held. Takes get_online_cpus().
- */
- static void rebuild_sched_domains_locked(void)
- {
- struct cgroup_subsys_state *pos_css;
- struct sched_domain_attr *attr;
- cpumask_var_t *doms;
- struct cpuset *cs;
- int ndoms;
- lockdep_assert_held(&cpuset_mutex);
- /*
- * If we have raced with CPU hotplug, return early to avoid
- * passing doms with offlined cpu to partition_sched_domains().
- * Anyways, cpuset_hotplug_workfn() will rebuild sched domains.
- *
- * With no CPUs in any subpartitions, top_cpuset's effective CPUs
- * should be the same as the active CPUs, so checking only top_cpuset
- * is enough to detect racing CPU offlines.
- */
- if (!top_cpuset.nr_subparts_cpus &&
- !cpumask_equal(top_cpuset.effective_cpus, cpu_active_mask))
- return;
- /*
- * With subpartition CPUs, however, the effective CPUs of a partition
- * root should be only a subset of the active CPUs. Since a CPU in any
- * partition root could be offlined, all must be checked.
- */
- if (top_cpuset.nr_subparts_cpus) {
- rcu_read_lock();
- cpuset_for_each_descendant_pre(cs, pos_css, &top_cpuset) {
- if (!is_partition_root(cs)) {
- pos_css = css_rightmost_descendant(pos_css);
- continue;
- }
- if (!cpumask_subset(cs->effective_cpus,
- cpu_active_mask)) {
- rcu_read_unlock();
- return;
- }
- }
- rcu_read_unlock();
- }
- /* Generate domain masks and attrs */
- ndoms = generate_sched_domains(&doms, &attr);
- /* Have scheduler rebuild the domains */
- partition_and_rebuild_sched_domains(ndoms, doms, attr);
- }
- #else /* !CONFIG_SMP */
- static void rebuild_sched_domains_locked(void)
- {
- }
- #endif /* CONFIG_SMP */
- void rebuild_sched_domains(void)
- {
- get_online_cpus();
- mutex_lock(&cpuset_mutex);
- rebuild_sched_domains_locked();
- mutex_unlock(&cpuset_mutex);
- put_online_cpus();
- }
- static int update_cpus_allowed(struct cpuset *cs, struct task_struct *p,
- const struct cpumask *new_mask)
- {
- int ret = -EINVAL;
- trace_android_rvh_update_cpus_allowed(p, cs->cpus_requested, new_mask, &ret);
- if (!ret)
- return ret;
- return set_cpus_allowed_ptr(p, new_mask);
- }
- /**
- * update_tasks_cpumask - Update the cpumasks of tasks in the cpuset.
- * @cs: the cpuset in which each task's cpus_allowed mask needs to be changed
- *
- * Iterate through each task of @cs updating its cpus_allowed to the
- * effective cpuset's. As this function is called with cpuset_mutex held,
- * cpuset membership stays stable.
- */
- static void update_tasks_cpumask(struct cpuset *cs)
- {
- struct css_task_iter it;
- struct task_struct *task;
- css_task_iter_start(&cs->css, 0, &it);
- while ((task = css_task_iter_next(&it)))
- update_cpus_allowed(cs, task, cs->effective_cpus);
- css_task_iter_end(&it);
- }
- /**
- * compute_effective_cpumask - Compute the effective cpumask of the cpuset
- * @new_cpus: the temp variable for the new effective_cpus mask
- * @cs: the cpuset the need to recompute the new effective_cpus mask
- * @parent: the parent cpuset
- *
- * If the parent has subpartition CPUs, include them in the list of
- * allowable CPUs in computing the new effective_cpus mask. Since offlined
- * CPUs are not removed from subparts_cpus, we have to use cpu_active_mask
- * to mask those out.
- */
- static void compute_effective_cpumask(struct cpumask *new_cpus,
- struct cpuset *cs, struct cpuset *parent)
- {
- if (parent->nr_subparts_cpus) {
- cpumask_or(new_cpus, parent->effective_cpus,
- parent->subparts_cpus);
- cpumask_and(new_cpus, new_cpus, cs->cpus_requested);
- cpumask_and(new_cpus, new_cpus, cpu_active_mask);
- } else {
- cpumask_and(new_cpus, cs->cpus_requested, parent_cs(cs)->effective_cpus);
- }
- }
- /*
- * Commands for update_parent_subparts_cpumask
- */
- enum subparts_cmd {
- partcmd_enable, /* Enable partition root */
- partcmd_disable, /* Disable partition root */
- partcmd_update, /* Update parent's subparts_cpus */
- };
- /**
- * update_parent_subparts_cpumask - update subparts_cpus mask of parent cpuset
- * @cpuset: The cpuset that requests change in partition root state
- * @cmd: Partition root state change command
- * @newmask: Optional new cpumask for partcmd_update
- * @tmp: Temporary addmask and delmask
- * Return: 0, 1 or an error code
- *
- * For partcmd_enable, the cpuset is being transformed from a non-partition
- * root to a partition root. The cpus_allowed mask of the given cpuset will
- * be put into parent's subparts_cpus and taken away from parent's
- * effective_cpus. The function will return 0 if all the CPUs listed in
- * cpus_allowed can be granted or an error code will be returned.
- *
- * For partcmd_disable, the cpuset is being transofrmed from a partition
- * root back to a non-partition root. Any CPUs in cpus_allowed that are in
- * parent's subparts_cpus will be taken away from that cpumask and put back
- * into parent's effective_cpus. 0 should always be returned.
- *
- * For partcmd_update, if the optional newmask is specified, the cpu
- * list is to be changed from cpus_allowed to newmask. Otherwise,
- * cpus_allowed is assumed to remain the same. The cpuset should either
- * be a partition root or an invalid partition root. The partition root
- * state may change if newmask is NULL and none of the requested CPUs can
- * be granted by the parent. The function will return 1 if changes to
- * parent's subparts_cpus and effective_cpus happen or 0 otherwise.
- * Error code should only be returned when newmask is non-NULL.
- *
- * The partcmd_enable and partcmd_disable commands are used by
- * update_prstate(). The partcmd_update command is used by
- * update_cpumasks_hier() with newmask NULL and update_cpumask() with
- * newmask set.
- *
- * The checking is more strict when enabling partition root than the
- * other two commands.
- *
- * Because of the implicit cpu exclusive nature of a partition root,
- * cpumask changes that violates the cpu exclusivity rule will not be
- * permitted when checked by validate_change(). The validate_change()
- * function will also prevent any changes to the cpu list if it is not
- * a superset of children's cpu lists.
- */
- static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd,
- struct cpumask *newmask,
- struct tmpmasks *tmp)
- {
- struct cpuset *parent = parent_cs(cpuset);
- int adding; /* Moving cpus from effective_cpus to subparts_cpus */
- int deleting; /* Moving cpus from subparts_cpus to effective_cpus */
- int new_prs;
- bool part_error = false; /* Partition error? */
- lockdep_assert_held(&cpuset_mutex);
- /*
- * The parent must be a partition root.
- * The new cpumask, if present, or the current cpus_allowed must
- * not be empty.
- */
- if (!is_partition_root(parent) ||
- (newmask && cpumask_empty(newmask)) ||
- (!newmask && cpumask_empty(cpuset->cpus_allowed)))
- return -EINVAL;
- /*
- * Enabling/disabling partition root is not allowed if there are
- * online children.
- */
- if ((cmd != partcmd_update) && css_has_online_children(&cpuset->css))
- return -EBUSY;
- /*
- * Enabling partition root is not allowed if not all the CPUs
- * can be granted from parent's effective_cpus or at least one
- * CPU will be left after that.
- */
- if ((cmd == partcmd_enable) &&
- (!cpumask_subset(cpuset->cpus_allowed, parent->effective_cpus) ||
- cpumask_equal(cpuset->cpus_allowed, parent->effective_cpus)))
- return -EINVAL;
- /*
- * A cpumask update cannot make parent's effective_cpus become empty.
- */
- adding = deleting = false;
- new_prs = cpuset->partition_root_state;
- if (cmd == partcmd_enable) {
- cpumask_copy(tmp->addmask, cpuset->cpus_allowed);
- adding = true;
- } else if (cmd == partcmd_disable) {
- deleting = cpumask_and(tmp->delmask, cpuset->cpus_allowed,
- parent->subparts_cpus);
- } else if (newmask) {
- /*
- * partcmd_update with newmask:
- *
- * delmask = cpus_allowed & ~newmask & parent->subparts_cpus
- * addmask = newmask & parent->effective_cpus
- * & ~parent->subparts_cpus
- */
- cpumask_andnot(tmp->delmask, cpuset->cpus_allowed, newmask);
- deleting = cpumask_and(tmp->delmask, tmp->delmask,
- parent->subparts_cpus);
- cpumask_and(tmp->addmask, newmask, parent->effective_cpus);
- adding = cpumask_andnot(tmp->addmask, tmp->addmask,
- parent->subparts_cpus);
- /*
- * Return error if the new effective_cpus could become empty.
- */
- if (adding &&
- cpumask_equal(parent->effective_cpus, tmp->addmask)) {
- if (!deleting)
- return -EINVAL;
- /*
- * As some of the CPUs in subparts_cpus might have
- * been offlined, we need to compute the real delmask
- * to confirm that.
- */
- if (!cpumask_and(tmp->addmask, tmp->delmask,
- cpu_active_mask))
- return -EINVAL;
- cpumask_copy(tmp->addmask, parent->effective_cpus);
- }
- } else {
- /*
- * partcmd_update w/o newmask:
- *
- * addmask = cpus_allowed & parent->effective_cpus
- *
- * Note that parent's subparts_cpus may have been
- * pre-shrunk in case there is a change in the cpu list.
- * So no deletion is needed.
- */
- adding = cpumask_and(tmp->addmask, cpuset->cpus_allowed,
- parent->effective_cpus);
- part_error = cpumask_equal(tmp->addmask,
- parent->effective_cpus);
- }
- if (cmd == partcmd_update) {
- int prev_prs = cpuset->partition_root_state;
- /*
- * Check for possible transition between PRS_ENABLED
- * and PRS_ERROR.
- */
- switch (cpuset->partition_root_state) {
- case PRS_ENABLED:
- if (part_error)
- new_prs = PRS_ERROR;
- break;
- case PRS_ERROR:
- if (!part_error)
- new_prs = PRS_ENABLED;
- break;
- }
- /*
- * Set part_error if previously in invalid state.
- */
- part_error = (prev_prs == PRS_ERROR);
- }
- if (!part_error && (new_prs == PRS_ERROR))
- return 0; /* Nothing need to be done */
- if (new_prs == PRS_ERROR) {
- /*
- * Remove all its cpus from parent's subparts_cpus.
- */
- adding = false;
- deleting = cpumask_and(tmp->delmask, cpuset->cpus_allowed,
- parent->subparts_cpus);
- }
- if (!adding && !deleting && (new_prs == cpuset->partition_root_state))
- return 0;
- /*
- * Change the parent's subparts_cpus.
- * Newly added CPUs will be removed from effective_cpus and
- * newly deleted ones will be added back to effective_cpus.
- */
- spin_lock_irq(&callback_lock);
- if (adding) {
- cpumask_or(parent->subparts_cpus,
- parent->subparts_cpus, tmp->addmask);
- cpumask_andnot(parent->effective_cpus,
- parent->effective_cpus, tmp->addmask);
- }
- if (deleting) {
- cpumask_andnot(parent->subparts_cpus,
- parent->subparts_cpus, tmp->delmask);
- /*
- * Some of the CPUs in subparts_cpus might have been offlined.
- */
- cpumask_and(tmp->delmask, tmp->delmask, cpu_active_mask);
- cpumask_or(parent->effective_cpus,
- parent->effective_cpus, tmp->delmask);
- }
- parent->nr_subparts_cpus = cpumask_weight(parent->subparts_cpus);
- if (cpuset->partition_root_state != new_prs)
- cpuset->partition_root_state = new_prs;
- spin_unlock_irq(&callback_lock);
- return cmd == partcmd_update;
- }
- /*
- * update_cpumasks_hier - Update effective cpumasks and tasks in the subtree
- * @cs: the cpuset to consider
- * @tmp: temp variables for calculating effective_cpus & partition setup
- *
- * When congifured cpumask is changed, the effective cpumasks of this cpuset
- * and all its descendants need to be updated.
- *
- * On legacy hierachy, effective_cpus will be the same with cpu_allowed.
- *
- * Called with cpuset_mutex held
- */
- static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp)
- {
- struct cpuset *cp;
- struct cgroup_subsys_state *pos_css;
- bool need_rebuild_sched_domains = false;
- int new_prs;
- rcu_read_lock();
- cpuset_for_each_descendant_pre(cp, pos_css, cs) {
- struct cpuset *parent = parent_cs(cp);
- compute_effective_cpumask(tmp->new_cpus, cp, parent);
- /*
- * If it becomes empty, inherit the effective mask of the
- * parent, which is guaranteed to have some CPUs.
- */
- if (is_in_v2_mode() && cpumask_empty(tmp->new_cpus)) {
- cpumask_copy(tmp->new_cpus, parent->effective_cpus);
- if (!cp->use_parent_ecpus) {
- cp->use_parent_ecpus = true;
- parent->child_ecpus_count++;
- }
- } else if (cp->use_parent_ecpus) {
- cp->use_parent_ecpus = false;
- WARN_ON_ONCE(!parent->child_ecpus_count);
- parent->child_ecpus_count--;
- }
- /*
- * Skip the whole subtree if the cpumask remains the same
- * and has no partition root state.
- */
- if (!cp->partition_root_state &&
- cpumask_equal(tmp->new_cpus, cp->effective_cpus)) {
- pos_css = css_rightmost_descendant(pos_css);
- continue;
- }
- /*
- * update_parent_subparts_cpumask() should have been called
- * for cs already in update_cpumask(). We should also call
- * update_tasks_cpumask() again for tasks in the parent
- * cpuset if the parent's subparts_cpus changes.
- */
- new_prs = cp->partition_root_state;
- if ((cp != cs) && new_prs) {
- switch (parent->partition_root_state) {
- case PRS_DISABLED:
- /*
- * If parent is not a partition root or an
- * invalid partition root, clear its state
- * and its CS_CPU_EXCLUSIVE flag.
- */
- WARN_ON_ONCE(cp->partition_root_state
- != PRS_ERROR);
- new_prs = PRS_DISABLED;
- /*
- * clear_bit() is an atomic operation and
- * readers aren't interested in the state
- * of CS_CPU_EXCLUSIVE anyway. So we can
- * just update the flag without holding
- * the callback_lock.
- */
- clear_bit(CS_CPU_EXCLUSIVE, &cp->flags);
- break;
- case PRS_ENABLED:
- if (update_parent_subparts_cpumask(cp, partcmd_update, NULL, tmp))
- update_tasks_cpumask(parent);
- break;
- case PRS_ERROR:
- /*
- * When parent is invalid, it has to be too.
- */
- new_prs = PRS_ERROR;
- break;
- }
- }
- if (!css_tryget_online(&cp->css))
- continue;
- rcu_read_unlock();
- spin_lock_irq(&callback_lock);
- cpumask_copy(cp->effective_cpus, tmp->new_cpus);
- if (cp->nr_subparts_cpus && (new_prs != PRS_ENABLED)) {
- cp->nr_subparts_cpus = 0;
- cpumask_clear(cp->subparts_cpus);
- } else if (cp->nr_subparts_cpus) {
- /*
- * Make sure that effective_cpus & subparts_cpus
- * are mutually exclusive.
- *
- * In the unlikely event that effective_cpus
- * becomes empty. we clear cp->nr_subparts_cpus and
- * let its child partition roots to compete for
- * CPUs again.
- */
- cpumask_andnot(cp->effective_cpus, cp->effective_cpus,
- cp->subparts_cpus);
- if (cpumask_empty(cp->effective_cpus)) {
- cpumask_copy(cp->effective_cpus, tmp->new_cpus);
- cpumask_clear(cp->subparts_cpus);
- cp->nr_subparts_cpus = 0;
- } else if (!cpumask_subset(cp->subparts_cpus,
- tmp->new_cpus)) {
- cpumask_andnot(cp->subparts_cpus,
- cp->subparts_cpus, tmp->new_cpus);
- cp->nr_subparts_cpus
- = cpumask_weight(cp->subparts_cpus);
- }
- }
- if (new_prs != cp->partition_root_state)
- cp->partition_root_state = new_prs;
- spin_unlock_irq(&callback_lock);
- WARN_ON(!is_in_v2_mode() &&
- !cpumask_equal(cp->cpus_allowed, cp->effective_cpus));
- update_tasks_cpumask(cp);
- /*
- * On legacy hierarchy, if the effective cpumask of any non-
- * empty cpuset is changed, we need to rebuild sched domains.
- * On default hierarchy, the cpuset needs to be a partition
- * root as well.
- */
- if (!cpumask_empty(cp->cpus_allowed) &&
- is_sched_load_balance(cp) &&
- (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) ||
- is_partition_root(cp)))
- need_rebuild_sched_domains = true;
- rcu_read_lock();
- css_put(&cp->css);
- }
- rcu_read_unlock();
- if (need_rebuild_sched_domains)
- rebuild_sched_domains_locked();
- }
- /**
- * update_sibling_cpumasks - Update siblings cpumasks
- * @parent: Parent cpuset
- * @cs: Current cpuset
- * @tmp: Temp variables
- */
- static void update_sibling_cpumasks(struct cpuset *parent, struct cpuset *cs,
- struct tmpmasks *tmp)
- {
- struct cpuset *sibling;
- struct cgroup_subsys_state *pos_css;
- lockdep_assert_held(&cpuset_mutex);
- /*
- * Check all its siblings and call update_cpumasks_hier()
- * if their use_parent_ecpus flag is set in order for them
- * to use the right effective_cpus value.
- *
- * The update_cpumasks_hier() function may sleep. So we have to
- * release the RCU read lock before calling it.
- */
- rcu_read_lock();
- cpuset_for_each_child(sibling, pos_css, parent) {
- if (sibling == cs)
- continue;
- if (!sibling->use_parent_ecpus)
- continue;
- if (!css_tryget_online(&sibling->css))
- continue;
- rcu_read_unlock();
- update_cpumasks_hier(sibling, tmp);
- rcu_read_lock();
- css_put(&sibling->css);
- }
- rcu_read_unlock();
- }
- /**
- * update_cpumask - update the cpus_allowed mask of a cpuset and all tasks in it
- * @cs: the cpuset to consider
- * @trialcs: trial cpuset
- * @buf: buffer of cpu numbers written to this cpuset
- */
- static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
- const char *buf)
- {
- int retval;
- struct tmpmasks tmp;
- /* top_cpuset.cpus_allowed tracks cpu_online_mask; it's read-only */
- if (cs == &top_cpuset)
- return -EACCES;
- /*
- * An empty cpus_requested is ok only if the cpuset has no tasks.
- * Since cpulist_parse() fails on an empty mask, we special case
- * that parsing. The validate_change() call ensures that cpusets
- * with tasks have cpus.
- */
- if (!*buf) {
- cpumask_clear(trialcs->cpus_requested);
- } else {
- retval = cpulist_parse(buf, trialcs->cpus_requested);
- if (retval < 0)
- return retval;
- }
- if (!cpumask_subset(trialcs->cpus_requested, cpu_present_mask))
- return -EINVAL;
- cpumask_and(trialcs->cpus_allowed, trialcs->cpus_requested, cpu_active_mask);
- /* Nothing to do if the cpus didn't change */
- if (cpumask_equal(cs->cpus_requested, trialcs->cpus_requested))
- return 0;
- retval = validate_change(cs, trialcs);
- if (retval < 0)
- return retval;
- #ifdef CONFIG_CPUMASK_OFFSTACK
- /*
- * Use the cpumasks in trialcs for tmpmasks when they are pointers
- * to allocated cpumasks.
- */
- tmp.addmask = trialcs->subparts_cpus;
- tmp.delmask = trialcs->effective_cpus;
- tmp.new_cpus = trialcs->cpus_allowed;
- #endif
- if (cs->partition_root_state) {
- /* Cpumask of a partition root cannot be empty */
- if (cpumask_empty(trialcs->cpus_allowed))
- return -EINVAL;
- if (update_parent_subparts_cpumask(cs, partcmd_update,
- trialcs->cpus_allowed, &tmp) < 0)
- return -EINVAL;
- }
- spin_lock_irq(&callback_lock);
- cpumask_copy(cs->cpus_allowed, trialcs->cpus_allowed);
- cpumask_copy(cs->cpus_requested, trialcs->cpus_requested);
- /*
- * Make sure that subparts_cpus is a subset of cpus_allowed.
- */
- if (cs->nr_subparts_cpus) {
- cpumask_and(cs->subparts_cpus, cs->subparts_cpus, cs->cpus_allowed);
- cs->nr_subparts_cpus = cpumask_weight(cs->subparts_cpus);
- }
- spin_unlock_irq(&callback_lock);
- update_cpumasks_hier(cs, &tmp);
- if (cs->partition_root_state) {
- struct cpuset *parent = parent_cs(cs);
- /*
- * For partition root, update the cpumasks of sibling
- * cpusets if they use parent's effective_cpus.
- */
- if (parent->child_ecpus_count)
- update_sibling_cpumasks(parent, cs, &tmp);
- }
- return 0;
- }
- /*
- * Migrate memory region from one set of nodes to another. This is
- * performed asynchronously as it can be called from process migration path
- * holding locks involved in process management. All mm migrations are
- * performed in the queued order and can be waited for by flushing
- * cpuset_migrate_mm_wq.
- */
- struct cpuset_migrate_mm_work {
- struct work_struct work;
- struct mm_struct *mm;
- nodemask_t from;
- nodemask_t to;
- };
- static void cpuset_migrate_mm_workfn(struct work_struct *work)
- {
- struct cpuset_migrate_mm_work *mwork =
- container_of(work, struct cpuset_migrate_mm_work, work);
- /* on a wq worker, no need to worry about %current's mems_allowed */
- do_migrate_pages(mwork->mm, &mwork->from, &mwork->to, MPOL_MF_MOVE_ALL);
- mmput(mwork->mm);
- kfree(mwork);
- }
- static void cpuset_migrate_mm(struct mm_struct *mm, const nodemask_t *from,
- const nodemask_t *to)
- {
- struct cpuset_migrate_mm_work *mwork;
- mwork = kzalloc(sizeof(*mwork), GFP_KERNEL);
- if (mwork) {
- mwork->mm = mm;
- mwork->from = *from;
- mwork->to = *to;
- INIT_WORK(&mwork->work, cpuset_migrate_mm_workfn);
- queue_work(cpuset_migrate_mm_wq, &mwork->work);
- } else {
- mmput(mm);
- }
- }
- static void cpuset_post_attach(void)
- {
- flush_workqueue(cpuset_migrate_mm_wq);
- }
- /*
- * cpuset_change_task_nodemask - change task's mems_allowed and mempolicy
- * @tsk: the task to change
- * @newmems: new nodes that the task will be set
- *
- * We use the mems_allowed_seq seqlock to safely update both tsk->mems_allowed
- * and rebind an eventual tasks' mempolicy. If the task is allocating in
- * parallel, it might temporarily see an empty intersection, which results in
- * a seqlock check and retry before OOM or allocation failure.
- */
- static void cpuset_change_task_nodemask(struct task_struct *tsk,
- nodemask_t *newmems)
- {
- task_lock(tsk);
- local_irq_disable();
- write_seqcount_begin(&tsk->mems_allowed_seq);
- nodes_or(tsk->mems_allowed, tsk->mems_allowed, *newmems);
- mpol_rebind_task(tsk, newmems);
- tsk->mems_allowed = *newmems;
- write_seqcount_end(&tsk->mems_allowed_seq);
- local_irq_enable();
- task_unlock(tsk);
- }
- static void *cpuset_being_rebound;
- /**
- * update_tasks_nodemask - Update the nodemasks of tasks in the cpuset.
- * @cs: the cpuset in which each task's mems_allowed mask needs to be changed
- *
- * Iterate through each task of @cs updating its mems_allowed to the
- * effective cpuset's. As this function is called with cpuset_mutex held,
- * cpuset membership stays stable.
- */
- static void update_tasks_nodemask(struct cpuset *cs)
- {
- static nodemask_t newmems; /* protected by cpuset_mutex */
- struct css_task_iter it;
- struct task_struct *task;
- cpuset_being_rebound = cs; /* causes mpol_dup() rebind */
- guarantee_online_mems(cs, &newmems);
- /*
- * The mpol_rebind_mm() call takes mmap_lock, which we couldn't
- * take while holding tasklist_lock. Forks can happen - the
- * mpol_dup() cpuset_being_rebound check will catch such forks,
- * and rebind their vma mempolicies too. Because we still hold
- * the global cpuset_mutex, we know that no other rebind effort
- * will be contending for the global variable cpuset_being_rebound.
- * It's ok if we rebind the same mm twice; mpol_rebind_mm()
- * is idempotent. Also migrate pages in each mm to new nodes.
- */
- css_task_iter_start(&cs->css, 0, &it);
- while ((task = css_task_iter_next(&it))) {
- struct mm_struct *mm;
- bool migrate;
- cpuset_change_task_nodemask(task, &newmems);
- mm = get_task_mm(task);
- if (!mm)
- continue;
- migrate = is_memory_migrate(cs);
- mpol_rebind_mm(mm, &cs->mems_allowed);
- if (migrate)
- cpuset_migrate_mm(mm, &cs->old_mems_allowed, &newmems);
- else
- mmput(mm);
- }
- css_task_iter_end(&it);
- /*
- * All the tasks' nodemasks have been updated, update
- * cs->old_mems_allowed.
- */
- cs->old_mems_allowed = newmems;
- /* We're done rebinding vmas to this cpuset's new mems_allowed. */
- cpuset_being_rebound = NULL;
- }
- /*
- * update_nodemasks_hier - Update effective nodemasks and tasks in the subtree
- * @cs: the cpuset to consider
- * @new_mems: a temp variable for calculating new effective_mems
- *
- * When configured nodemask is changed, the effective nodemasks of this cpuset
- * and all its descendants need to be updated.
- *
- * On legacy hiearchy, effective_mems will be the same with mems_allowed.
- *
- * Called with cpuset_mutex held
- */
- static void update_nodemasks_hier(struct cpuset *cs, nodemask_t *new_mems)
- {
- struct cpuset *cp;
- struct cgroup_subsys_state *pos_css;
- rcu_read_lock();
- cpuset_for_each_descendant_pre(cp, pos_css, cs) {
- struct cpuset *parent = parent_cs(cp);
- nodes_and(*new_mems, cp->mems_allowed, parent->effective_mems);
- /*
- * If it becomes empty, inherit the effective mask of the
- * parent, which is guaranteed to have some MEMs.
- */
- if (is_in_v2_mode() && nodes_empty(*new_mems))
- *new_mems = parent->effective_mems;
- /* Skip the whole subtree if the nodemask remains the same. */
- if (nodes_equal(*new_mems, cp->effective_mems)) {
- pos_css = css_rightmost_descendant(pos_css);
- continue;
- }
- if (!css_tryget_online(&cp->css))
- continue;
- rcu_read_unlock();
- spin_lock_irq(&callback_lock);
- cp->effective_mems = *new_mems;
- spin_unlock_irq(&callback_lock);
- WARN_ON(!is_in_v2_mode() &&
- !nodes_equal(cp->mems_allowed, cp->effective_mems));
- update_tasks_nodemask(cp);
- rcu_read_lock();
- css_put(&cp->css);
- }
- rcu_read_unlock();
- }
- /*
- * Handle user request to change the 'mems' memory placement
- * of a cpuset. Needs to validate the request, update the
- * cpusets mems_allowed, and for each task in the cpuset,
- * update mems_allowed and rebind task's mempolicy and any vma
- * mempolicies and if the cpuset is marked 'memory_migrate',
- * migrate the tasks pages to the new memory.
- *
- * Call with cpuset_mutex held. May take callback_lock during call.
- * Will take tasklist_lock, scan tasklist for tasks in cpuset cs,
- * lock each such tasks mm->mmap_lock, scan its vma's and rebind
- * their mempolicies to the cpusets new mems_allowed.
- */
- static int update_nodemask(struct cpuset *cs, struct cpuset *trialcs,
- const char *buf)
- {
- int retval;
- /*
- * top_cpuset.mems_allowed tracks node_stats[N_MEMORY];
- * it's read-only
- */
- if (cs == &top_cpuset) {
- retval = -EACCES;
- goto done;
- }
- /*
- * An empty mems_allowed is ok iff there are no tasks in the cpuset.
- * Since nodelist_parse() fails on an empty mask, we special case
- * that parsing. The validate_change() call ensures that cpusets
- * with tasks have memory.
- */
- if (!*buf) {
- nodes_clear(trialcs->mems_allowed);
- } else {
- retval = nodelist_parse(buf, trialcs->mems_allowed);
- if (retval < 0)
- goto done;
- if (!nodes_subset(trialcs->mems_allowed,
- top_cpuset.mems_allowed)) {
- retval = -EINVAL;
- goto done;
- }
- }
- if (nodes_equal(cs->mems_allowed, trialcs->mems_allowed)) {
- retval = 0; /* Too easy - nothing to do */
- goto done;
- }
- retval = validate_change(cs, trialcs);
- if (retval < 0)
- goto done;
- spin_lock_irq(&callback_lock);
- cs->mems_allowed = trialcs->mems_allowed;
- spin_unlock_irq(&callback_lock);
- /* use trialcs->mems_allowed as a temp variable */
- update_nodemasks_hier(cs, &trialcs->mems_allowed);
- done:
- return retval;
- }
- bool current_cpuset_is_being_rebound(void)
- {
- bool ret;
- rcu_read_lock();
- ret = task_cs(current) == cpuset_being_rebound;
- rcu_read_unlock();
- return ret;
- }
- static int update_relax_domain_level(struct cpuset *cs, s64 val)
- {
- #ifdef CONFIG_SMP
- if (val < -1 || val >= sched_domain_level_max)
- return -EINVAL;
- #endif
- if (val != cs->relax_domain_level) {
- cs->relax_domain_level = val;
- if (!cpumask_empty(cs->cpus_allowed) &&
- is_sched_load_balance(cs))
- rebuild_sched_domains_locked();
- }
- return 0;
- }
- /**
- * update_tasks_flags - update the spread flags of tasks in the cpuset.
- * @cs: the cpuset in which each task's spread flags needs to be changed
- *
- * Iterate through each task of @cs updating its spread flags. As this
- * function is called with cpuset_mutex held, cpuset membership stays
- * stable.
- */
- static void update_tasks_flags(struct cpuset *cs)
- {
- struct css_task_iter it;
- struct task_struct *task;
- css_task_iter_start(&cs->css, 0, &it);
- while ((task = css_task_iter_next(&it)))
- cpuset_update_task_spread_flag(cs, task);
- css_task_iter_end(&it);
- }
- /*
- * update_flag - read a 0 or a 1 in a file and update associated flag
- * bit: the bit to update (see cpuset_flagbits_t)
- * cs: the cpuset to update
- * turning_on: whether the flag is being set or cleared
- *
- * Call with cpuset_mutex held.
- */
- static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
- int turning_on)
- {
- struct cpuset *trialcs;
- int balance_flag_changed;
- int spread_flag_changed;
- int err;
- trialcs = alloc_trial_cpuset(cs);
- if (!trialcs)
- return -ENOMEM;
- if (turning_on)
- set_bit(bit, &trialcs->flags);
- else
- clear_bit(bit, &trialcs->flags);
- err = validate_change(cs, trialcs);
- if (err < 0)
- goto out;
- balance_flag_changed = (is_sched_load_balance(cs) !=
- is_sched_load_balance(trialcs));
- spread_flag_changed = ((is_spread_slab(cs) != is_spread_slab(trialcs))
- || (is_spread_page(cs) != is_spread_page(trialcs)));
- spin_lock_irq(&callback_lock);
- cs->flags = trialcs->flags;
- spin_unlock_irq(&callback_lock);
- if (!cpumask_empty(trialcs->cpus_allowed) && balance_flag_changed)
- rebuild_sched_domains_locked();
- if (spread_flag_changed)
- update_tasks_flags(cs);
- out:
- free_cpuset(trialcs);
- return err;
- }
- /*
- * update_prstate - update partititon_root_state
- * cs: the cpuset to update
- * new_prs: new partition root state
- *
- * Call with cpuset_mutex held.
- */
- static int update_prstate(struct cpuset *cs, int new_prs)
- {
- int err, old_prs = cs->partition_root_state;
- struct cpuset *parent = parent_cs(cs);
- struct tmpmasks tmpmask;
- if (old_prs == new_prs)
- return 0;
- /*
- * Cannot force a partial or invalid partition root to a full
- * partition root.
- */
- if (new_prs && (old_prs == PRS_ERROR))
- return -EINVAL;
- if (alloc_cpumasks(NULL, &tmpmask))
- return -ENOMEM;
- err = -EINVAL;
- if (!old_prs) {
- /*
- * Turning on partition root requires setting the
- * CS_CPU_EXCLUSIVE bit implicitly as well and cpus_allowed
- * cannot be NULL.
- */
- if (cpumask_empty(cs->cpus_allowed))
- goto out;
- err = update_flag(CS_CPU_EXCLUSIVE, cs, 1);
- if (err)
- goto out;
- err = update_parent_subparts_cpumask(cs, partcmd_enable,
- NULL, &tmpmask);
- if (err) {
- update_flag(CS_CPU_EXCLUSIVE, cs, 0);
- goto out;
- }
- } else {
- /*
- * Turning off partition root will clear the
- * CS_CPU_EXCLUSIVE bit.
- */
- if (old_prs == PRS_ERROR) {
- update_flag(CS_CPU_EXCLUSIVE, cs, 0);
- err = 0;
- goto out;
- }
- err = update_parent_subparts_cpumask(cs, partcmd_disable,
- NULL, &tmpmask);
- if (err)
- goto out;
- /* Turning off CS_CPU_EXCLUSIVE will not return error */
- update_flag(CS_CPU_EXCLUSIVE, cs, 0);
- }
- /*
- * Update cpumask of parent's tasks except when it is the top
- * cpuset as some system daemons cannot be mapped to other CPUs.
- */
- if (parent != &top_cpuset)
- update_tasks_cpumask(parent);
- if (parent->child_ecpus_count)
- update_sibling_cpumasks(parent, cs, &tmpmask);
- rebuild_sched_domains_locked();
- out:
- if (!err) {
- spin_lock_irq(&callback_lock);
- cs->partition_root_state = new_prs;
- spin_unlock_irq(&callback_lock);
- }
- free_cpumasks(NULL, &tmpmask);
- return err;
- }
- /*
- * Frequency meter - How fast is some event occurring?
- *
- * These routines manage a digitally filtered, constant time based,
- * event frequency meter. There are four routines:
- * fmeter_init() - initialize a frequency meter.
- * fmeter_markevent() - called each time the event happens.
- * fmeter_getrate() - returns the recent rate of such events.
- * fmeter_update() - internal routine used to update fmeter.
- *
- * A common data structure is passed to each of these routines,
- * which is used to keep track of the state required to manage the
- * frequency meter and its digital filter.
- *
- * The filter works on the number of events marked per unit time.
- * The filter is single-pole low-pass recursive (IIR). The time unit
- * is 1 second. Arithmetic is done using 32-bit integers scaled to
- * simulate 3 decimal digits of precision (multiplied by 1000).
- *
- * With an FM_COEF of 933, and a time base of 1 second, the filter
- * has a half-life of 10 seconds, meaning that if the events quit
- * happening, then the rate returned from the fmeter_getrate()
- * will be cut in half each 10 seconds, until it converges to zero.
- *
- * It is not worth doing a real infinitely recursive filter. If more
- * than FM_MAXTICKS ticks have elapsed since the last filter event,
- * just compute FM_MAXTICKS ticks worth, by which point the level
- * will be stable.
- *
- * Limit the count of unprocessed events to FM_MAXCNT, so as to avoid
- * arithmetic overflow in the fmeter_update() routine.
- *
- * Given the simple 32 bit integer arithmetic used, this meter works
- * best for reporting rates between one per millisecond (msec) and
- * one per 32 (approx) seconds. At constant rates faster than one
- * per msec it maxes out at values just under 1,000,000. At constant
- * rates between one per msec, and one per second it will stabilize
- * to a value N*1000, where N is the rate of events per second.
- * At constant rates between one per second and one per 32 seconds,
- * it will be choppy, moving up on the seconds that have an event,
- * and then decaying until the next event. At rates slower than
- * about one in 32 seconds, it decays all the way back to zero between
- * each event.
- */
- #define FM_COEF 933 /* coefficient for half-life of 10 secs */
- #define FM_MAXTICKS ((u32)99) /* useless computing more ticks than this */
- #define FM_MAXCNT 1000000 /* limit cnt to avoid overflow */
- #define FM_SCALE 1000 /* faux fixed point scale */
- /* Initialize a frequency meter */
- static void fmeter_init(struct fmeter *fmp)
- {
- fmp->cnt = 0;
- fmp->val = 0;
- fmp->time = 0;
- spin_lock_init(&fmp->lock);
- }
- /* Internal meter update - process cnt events and update value */
- static void fmeter_update(struct fmeter *fmp)
- {
- time64_t now;
- u32 ticks;
- now = ktime_get_seconds();
- ticks = now - fmp->time;
- if (ticks == 0)
- return;
- ticks = min(FM_MAXTICKS, ticks);
- while (ticks-- > 0)
- fmp->val = (FM_COEF * fmp->val) / FM_SCALE;
- fmp->time = now;
- fmp->val += ((FM_SCALE - FM_COEF) * fmp->cnt) / FM_SCALE;
- fmp->cnt = 0;
- }
- /* Process any previous ticks, then bump cnt by one (times scale). */
- static void fmeter_markevent(struct fmeter *fmp)
- {
- spin_lock(&fmp->lock);
- fmeter_update(fmp);
- fmp->cnt = min(FM_MAXCNT, fmp->cnt + FM_SCALE);
- spin_unlock(&fmp->lock);
- }
- /* Process any previous ticks, then return current value. */
- static int fmeter_getrate(struct fmeter *fmp)
- {
- int val;
- spin_lock(&fmp->lock);
- fmeter_update(fmp);
- val = fmp->val;
- spin_unlock(&fmp->lock);
- return val;
- }
- static struct cpuset *cpuset_attach_old_cs;
- /* Called by cgroups to determine if a cpuset is usable; cpuset_mutex held */
- static int cpuset_can_attach(struct cgroup_taskset *tset)
- {
- struct cgroup_subsys_state *css;
- struct cpuset *cs;
- struct task_struct *task;
- int ret;
- /* used later by cpuset_attach() */
- cpuset_attach_old_cs = task_cs(cgroup_taskset_first(tset, &css));
- cs = css_cs(css);
- mutex_lock(&cpuset_mutex);
- /* allow moving tasks into an empty cpuset if on default hierarchy */
- ret = -ENOSPC;
- if (!is_in_v2_mode() &&
- (cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed)))
- goto out_unlock;
- cgroup_taskset_for_each(task, css, tset) {
- ret = task_can_attach(task, cs->cpus_allowed);
- if (ret)
- goto out_unlock;
- ret = security_task_setscheduler(task);
- if (ret)
- goto out_unlock;
- }
- /*
- * Mark attach is in progress. This makes validate_change() fail
- * changes which zero cpus/mems_allowed.
- */
- cs->attach_in_progress++;
- ret = 0;
- out_unlock:
- mutex_unlock(&cpuset_mutex);
- return ret;
- }
- static void cpuset_cancel_attach(struct cgroup_taskset *tset)
- {
- struct cgroup_subsys_state *css;
- cgroup_taskset_first(tset, &css);
- mutex_lock(&cpuset_mutex);
- css_cs(css)->attach_in_progress--;
- mutex_unlock(&cpuset_mutex);
- }
- /*
- * Protected by cpuset_mutex. cpus_attach is used only by cpuset_attach()
- * but we can't allocate it dynamically there. Define it global and
- * allocate from cpuset_init().
- */
- static cpumask_var_t cpus_attach;
- static void cpuset_attach(struct cgroup_taskset *tset)
- {
- /* static buf protected by cpuset_mutex */
- static nodemask_t cpuset_attach_nodemask_to;
- struct task_struct *task;
- struct task_struct *leader;
- struct cgroup_subsys_state *css;
- struct cpuset *cs;
- struct cpuset *oldcs = cpuset_attach_old_cs;
- cgroup_taskset_first(tset, &css);
- cs = css_cs(css);
- cpus_read_lock();
- mutex_lock(&cpuset_mutex);
- guarantee_online_mems(cs, &cpuset_attach_nodemask_to);
- cgroup_taskset_for_each(task, css, tset) {
- if (cs != &top_cpuset)
- guarantee_online_cpus(task, cpus_attach);
- else
- cpumask_copy(cpus_attach, task_cpu_possible_mask(task));
- /*
- * can_attach beforehand should guarantee that this doesn't
- * fail. TODO: have a better way to handle failure here
- */
- WARN_ON_ONCE(update_cpus_allowed(cs, task, cpus_attach));
- cpuset_change_task_nodemask(task, &cpuset_attach_nodemask_to);
- cpuset_update_task_spread_flag(cs, task);
- }
- /*
- * Change mm for all threadgroup leaders. This is expensive and may
- * sleep and should be moved outside migration path proper.
- */
- cpuset_attach_nodemask_to = cs->effective_mems;
- cgroup_taskset_for_each_leader(leader, css, tset) {
- struct mm_struct *mm = get_task_mm(leader);
- if (mm) {
- mpol_rebind_mm(mm, &cpuset_attach_nodemask_to);
- /*
- * old_mems_allowed is the same with mems_allowed
- * here, except if this task is being moved
- * automatically due to hotplug. In that case
- * @mems_allowed has been updated and is empty, so
- * @old_mems_allowed is the right nodesets that we
- * migrate mm from.
- */
- if (is_memory_migrate(cs))
- cpuset_migrate_mm(mm, &oldcs->old_mems_allowed,
- &cpuset_attach_nodemask_to);
- else
- mmput(mm);
- }
- }
- cs->old_mems_allowed = cpuset_attach_nodemask_to;
- cs->attach_in_progress--;
- if (!cs->attach_in_progress)
- wake_up(&cpuset_attach_wq);
- mutex_unlock(&cpuset_mutex);
- cpus_read_unlock();
- }
- /* The various types of files and directories in a cpuset file system */
- typedef enum {
- FILE_MEMORY_MIGRATE,
- FILE_CPULIST,
- FILE_MEMLIST,
- FILE_EFFECTIVE_CPULIST,
- FILE_EFFECTIVE_MEMLIST,
- FILE_SUBPARTS_CPULIST,
- FILE_CPU_EXCLUSIVE,
- FILE_MEM_EXCLUSIVE,
- FILE_MEM_HARDWALL,
- FILE_SCHED_LOAD_BALANCE,
- FILE_PARTITION_ROOT,
- FILE_SCHED_RELAX_DOMAIN_LEVEL,
- FILE_MEMORY_PRESSURE_ENABLED,
- FILE_MEMORY_PRESSURE,
- FILE_SPREAD_PAGE,
- FILE_SPREAD_SLAB,
- } cpuset_filetype_t;
- static int cpuset_write_u64(struct cgroup_subsys_state *css, struct cftype *cft,
- u64 val)
- {
- struct cpuset *cs = css_cs(css);
- cpuset_filetype_t type = cft->private;
- int retval = 0;
- get_online_cpus();
- mutex_lock(&cpuset_mutex);
- if (!is_cpuset_online(cs)) {
- retval = -ENODEV;
- goto out_unlock;
- }
- switch (type) {
- case FILE_CPU_EXCLUSIVE:
- retval = update_flag(CS_CPU_EXCLUSIVE, cs, val);
- break;
- case FILE_MEM_EXCLUSIVE:
- retval = update_flag(CS_MEM_EXCLUSIVE, cs, val);
- break;
- case FILE_MEM_HARDWALL:
- retval = update_flag(CS_MEM_HARDWALL, cs, val);
- break;
- case FILE_SCHED_LOAD_BALANCE:
- retval = update_flag(CS_SCHED_LOAD_BALANCE, cs, val);
- break;
- case FILE_MEMORY_MIGRATE:
- retval = update_flag(CS_MEMORY_MIGRATE, cs, val);
- break;
- case FILE_MEMORY_PRESSURE_ENABLED:
- cpuset_memory_pressure_enabled = !!val;
- break;
- case FILE_SPREAD_PAGE:
- retval = update_flag(CS_SPREAD_PAGE, cs, val);
- break;
- case FILE_SPREAD_SLAB:
- retval = update_flag(CS_SPREAD_SLAB, cs, val);
- break;
- default:
- retval = -EINVAL;
- break;
- }
- out_unlock:
- mutex_unlock(&cpuset_mutex);
- put_online_cpus();
- return retval;
- }
- static int cpuset_write_s64(struct cgroup_subsys_state *css, struct cftype *cft,
- s64 val)
- {
- struct cpuset *cs = css_cs(css);
- cpuset_filetype_t type = cft->private;
- int retval = -ENODEV;
- get_online_cpus();
- mutex_lock(&cpuset_mutex);
- if (!is_cpuset_online(cs))
- goto out_unlock;
- switch (type) {
- case FILE_SCHED_RELAX_DOMAIN_LEVEL:
- retval = update_relax_domain_level(cs, val);
- break;
- default:
- retval = -EINVAL;
- break;
- }
- out_unlock:
- mutex_unlock(&cpuset_mutex);
- put_online_cpus();
- return retval;
- }
- /*
- * Common handling for a write to a "cpus" or "mems" file.
- */
- static ssize_t cpuset_write_resmask(struct kernfs_open_file *of,
- char *buf, size_t nbytes, loff_t off)
- {
- struct cpuset *cs = css_cs(of_css(of));
- struct cpuset *trialcs;
- int retval = -ENODEV;
- buf = strstrip(buf);
- /*
- * CPU or memory hotunplug may leave @cs w/o any execution
- * resources, in which case the hotplug code asynchronously updates
- * configuration and transfers all tasks to the nearest ancestor
- * which can execute.
- *
- * As writes to "cpus" or "mems" may restore @cs's execution
- * resources, wait for the previously scheduled operations before
- * proceeding, so that we don't end up keep removing tasks added
- * after execution capability is restored.
- *
- * cpuset_hotplug_work calls back into cgroup core via
- * cgroup_transfer_tasks() and waiting for it from a cgroupfs
- * operation like this one can lead to a deadlock through kernfs
- * active_ref protection. Let's break the protection. Losing the
- * protection is okay as we check whether @cs is online after
- * grabbing cpuset_mutex anyway. This only happens on the legacy
- * hierarchies.
- */
- css_get(&cs->css);
- kernfs_break_active_protection(of->kn);
- flush_work(&cpuset_hotplug_work);
- get_online_cpus();
- mutex_lock(&cpuset_mutex);
- if (!is_cpuset_online(cs))
- goto out_unlock;
- trialcs = alloc_trial_cpuset(cs);
- if (!trialcs) {
- retval = -ENOMEM;
- goto out_unlock;
- }
- switch (of_cft(of)->private) {
- case FILE_CPULIST:
- retval = update_cpumask(cs, trialcs, buf);
- break;
- case FILE_MEMLIST:
- retval = update_nodemask(cs, trialcs, buf);
- break;
- default:
- retval = -EINVAL;
- break;
- }
- free_cpuset(trialcs);
- out_unlock:
- mutex_unlock(&cpuset_mutex);
- put_online_cpus();
- kernfs_unbreak_active_protection(of->kn);
- css_put(&cs->css);
- flush_workqueue(cpuset_migrate_mm_wq);
- return retval ?: nbytes;
- }
- /*
- * These ascii lists should be read in a single call, by using a user
- * buffer large enough to hold the entire map. If read in smaller
- * chunks, there is no guarantee of atomicity. Since the display format
- * used, list of ranges of sequential numbers, is variable length,
- * and since these maps can change value dynamically, one could read
- * gibberish by doing partial reads while a list was changing.
- */
- static int cpuset_common_seq_show(struct seq_file *sf, void *v)
- {
- struct cpuset *cs = css_cs(seq_css(sf));
- cpuset_filetype_t type = seq_cft(sf)->private;
- int ret = 0;
- spin_lock_irq(&callback_lock);
- switch (type) {
- case FILE_CPULIST:
- seq_printf(sf, "%*pbl\n", cpumask_pr_args(cs->cpus_requested));
- break;
- case FILE_MEMLIST:
- seq_printf(sf, "%*pbl\n", nodemask_pr_args(&cs->mems_allowed));
- break;
- case FILE_EFFECTIVE_CPULIST:
- seq_printf(sf, "%*pbl\n", cpumask_pr_args(cs->effective_cpus));
- break;
- case FILE_EFFECTIVE_MEMLIST:
- seq_printf(sf, "%*pbl\n", nodemask_pr_args(&cs->effective_mems));
- break;
- case FILE_SUBPARTS_CPULIST:
- seq_printf(sf, "%*pbl\n", cpumask_pr_args(cs->subparts_cpus));
- break;
- default:
- ret = -EINVAL;
- }
- spin_unlock_irq(&callback_lock);
- return ret;
- }
- static u64 cpuset_read_u64(struct cgroup_subsys_state *css, struct cftype *cft)
- {
- struct cpuset *cs = css_cs(css);
- cpuset_filetype_t type = cft->private;
- switch (type) {
- case FILE_CPU_EXCLUSIVE:
- return is_cpu_exclusive(cs);
- case FILE_MEM_EXCLUSIVE:
- return is_mem_exclusive(cs);
- case FILE_MEM_HARDWALL:
- return is_mem_hardwall(cs);
- case FILE_SCHED_LOAD_BALANCE:
- return is_sched_load_balance(cs);
- case FILE_MEMORY_MIGRATE:
- return is_memory_migrate(cs);
- case FILE_MEMORY_PRESSURE_ENABLED:
- return cpuset_memory_pressure_enabled;
- case FILE_MEMORY_PRESSURE:
- return fmeter_getrate(&cs->fmeter);
- case FILE_SPREAD_PAGE:
- return is_spread_page(cs);
- case FILE_SPREAD_SLAB:
- return is_spread_slab(cs);
- default:
- BUG();
- }
- /* Unreachable but makes gcc happy */
- return 0;
- }
- static s64 cpuset_read_s64(struct cgroup_subsys_state *css, struct cftype *cft)
- {
- struct cpuset *cs = css_cs(css);
- cpuset_filetype_t type = cft->private;
- switch (type) {
- case FILE_SCHED_RELAX_DOMAIN_LEVEL:
- return cs->relax_domain_level;
- default:
- BUG();
- }
- /* Unrechable but makes gcc happy */
- return 0;
- }
- static int sched_partition_show(struct seq_file *seq, void *v)
- {
- struct cpuset *cs = css_cs(seq_css(seq));
- switch (cs->partition_root_state) {
- case PRS_ENABLED:
- seq_puts(seq, "root\n");
- break;
- case PRS_DISABLED:
- seq_puts(seq, "member\n");
- break;
- case PRS_ERROR:
- seq_puts(seq, "root invalid\n");
- break;
- }
- return 0;
- }
- static ssize_t sched_partition_write(struct kernfs_open_file *of, char *buf,
- size_t nbytes, loff_t off)
- {
- struct cpuset *cs = css_cs(of_css(of));
- int val;
- int retval = -ENODEV;
- buf = strstrip(buf);
- /*
- * Convert "root" to ENABLED, and convert "member" to DISABLED.
- */
- if (!strcmp(buf, "root"))
- val = PRS_ENABLED;
- else if (!strcmp(buf, "member"))
- val = PRS_DISABLED;
- else
- return -EINVAL;
- css_get(&cs->css);
- get_online_cpus();
- mutex_lock(&cpuset_mutex);
- if (!is_cpuset_online(cs))
- goto out_unlock;
- retval = update_prstate(cs, val);
- out_unlock:
- mutex_unlock(&cpuset_mutex);
- put_online_cpus();
- css_put(&cs->css);
- return retval ?: nbytes;
- }
- /*
- * for the common functions, 'private' gives the type of file
- */
- static struct cftype legacy_files[] = {
- {
- .name = "cpus",
- .seq_show = cpuset_common_seq_show,
- .write = cpuset_write_resmask,
- .max_write_len = (100U + 6 * NR_CPUS),
- .private = FILE_CPULIST,
- },
- {
- .name = "mems",
- .seq_show = cpuset_common_seq_show,
- .write = cpuset_write_resmask,
- .max_write_len = (100U + 6 * MAX_NUMNODES),
- .private = FILE_MEMLIST,
- },
- {
- .name = "effective_cpus",
- .seq_show = cpuset_common_seq_show,
- .private = FILE_EFFECTIVE_CPULIST,
- },
- {
- .name = "effective_mems",
- .seq_show = cpuset_common_seq_show,
- .private = FILE_EFFECTIVE_MEMLIST,
- },
- {
- .name = "cpu_exclusive",
- .read_u64 = cpuset_read_u64,
- .write_u64 = cpuset_write_u64,
- .private = FILE_CPU_EXCLUSIVE,
- },
- {
- .name = "mem_exclusive",
- .read_u64 = cpuset_read_u64,
- .write_u64 = cpuset_write_u64,
- .private = FILE_MEM_EXCLUSIVE,
- },
- {
- .name = "mem_hardwall",
- .read_u64 = cpuset_read_u64,
- .write_u64 = cpuset_write_u64,
- .private = FILE_MEM_HARDWALL,
- },
- {
- .name = "sched_load_balance",
- .read_u64 = cpuset_read_u64,
- .write_u64 = cpuset_write_u64,
- .private = FILE_SCHED_LOAD_BALANCE,
- },
- {
- .name = "sched_relax_domain_level",
- .read_s64 = cpuset_read_s64,
- .write_s64 = cpuset_write_s64,
- .private = FILE_SCHED_RELAX_DOMAIN_LEVEL,
- },
- {
- .name = "memory_migrate",
- .read_u64 = cpuset_read_u64,
- .write_u64 = cpuset_write_u64,
- .private = FILE_MEMORY_MIGRATE,
- },
- {
- .name = "memory_pressure",
- .read_u64 = cpuset_read_u64,
- .private = FILE_MEMORY_PRESSURE,
- },
- {
- .name = "memory_spread_page",
- .read_u64 = cpuset_read_u64,
- .write_u64 = cpuset_write_u64,
- .private = FILE_SPREAD_PAGE,
- },
- {
- .name = "memory_spread_slab",
- .read_u64 = cpuset_read_u64,
- .write_u64 = cpuset_write_u64,
- .private = FILE_SPREAD_SLAB,
- },
- {
- .name = "memory_pressure_enabled",
- .flags = CFTYPE_ONLY_ON_ROOT,
- .read_u64 = cpuset_read_u64,
- .write_u64 = cpuset_write_u64,
- .private = FILE_MEMORY_PRESSURE_ENABLED,
- },
- { } /* terminate */
- };
- /*
- * This is currently a minimal set for the default hierarchy. It can be
- * expanded later on by migrating more features and control files from v1.
- */
- static struct cftype dfl_files[] = {
- {
- .name = "cpus",
- .seq_show = cpuset_common_seq_show,
- .write = cpuset_write_resmask,
- .max_write_len = (100U + 6 * NR_CPUS),
- .private = FILE_CPULIST,
- .flags = CFTYPE_NOT_ON_ROOT,
- },
- {
- .name = "mems",
- .seq_show = cpuset_common_seq_show,
- .write = cpuset_write_resmask,
- .max_write_len = (100U + 6 * MAX_NUMNODES),
- .private = FILE_MEMLIST,
- .flags = CFTYPE_NOT_ON_ROOT,
- },
- {
- .name = "cpus.effective",
- .seq_show = cpuset_common_seq_show,
- .private = FILE_EFFECTIVE_CPULIST,
- },
- {
- .name = "mems.effective",
- .seq_show = cpuset_common_seq_show,
- .private = FILE_EFFECTIVE_MEMLIST,
- },
- {
- .name = "cpus.partition",
- .seq_show = sched_partition_show,
- .write = sched_partition_write,
- .private = FILE_PARTITION_ROOT,
- .flags = CFTYPE_NOT_ON_ROOT,
- },
- {
- .name = "cpus.subpartitions",
- .seq_show = cpuset_common_seq_show,
- .private = FILE_SUBPARTS_CPULIST,
- .flags = CFTYPE_DEBUG,
- },
- { } /* terminate */
- };
- /*
- * cpuset_css_alloc - allocate a cpuset css
- * cgrp: control group that the new cpuset will be part of
- */
- static struct cgroup_subsys_state *
- cpuset_css_alloc(struct cgroup_subsys_state *parent_css)
- {
- struct cpuset *cs;
- if (!parent_css)
- return &top_cpuset.css;
- cs = kzalloc(sizeof(*cs), GFP_KERNEL);
- if (!cs)
- return ERR_PTR(-ENOMEM);
- if (alloc_cpumasks(cs, NULL)) {
- kfree(cs);
- return ERR_PTR(-ENOMEM);
- }
- set_bit(CS_SCHED_LOAD_BALANCE, &cs->flags);
- nodes_clear(cs->mems_allowed);
- nodes_clear(cs->effective_mems);
- fmeter_init(&cs->fmeter);
- cs->relax_domain_level = -1;
- return &cs->css;
- }
- static int cpuset_css_online(struct cgroup_subsys_state *css)
- {
- struct cpuset *cs = css_cs(css);
- struct cpuset *parent = parent_cs(cs);
- struct cpuset *tmp_cs;
- struct cgroup_subsys_state *pos_css;
- if (!parent)
- return 0;
- get_online_cpus();
- mutex_lock(&cpuset_mutex);
- set_bit(CS_ONLINE, &cs->flags);
- if (is_spread_page(parent))
- set_bit(CS_SPREAD_PAGE, &cs->flags);
- if (is_spread_slab(parent))
- set_bit(CS_SPREAD_SLAB, &cs->flags);
- cpuset_inc();
- spin_lock_irq(&callback_lock);
- if (is_in_v2_mode()) {
- cpumask_copy(cs->effective_cpus, parent->effective_cpus);
- cs->effective_mems = parent->effective_mems;
- cs->use_parent_ecpus = true;
- parent->child_ecpus_count++;
- }
- spin_unlock_irq(&callback_lock);
- if (!test_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags))
- goto out_unlock;
- /*
- * Clone @parent's configuration if CGRP_CPUSET_CLONE_CHILDREN is
- * set. This flag handling is implemented in cgroup core for
- * histrical reasons - the flag may be specified during mount.
- *
- * Currently, if any sibling cpusets have exclusive cpus or mem, we
- * refuse to clone the configuration - thereby refusing the task to
- * be entered, and as a result refusing the sys_unshare() or
- * clone() which initiated it. If this becomes a problem for some
- * users who wish to allow that scenario, then this could be
- * changed to grant parent->cpus_allowed-sibling_cpus_exclusive
- * (and likewise for mems) to the new cgroup.
- */
- rcu_read_lock();
- cpuset_for_each_child(tmp_cs, pos_css, parent) {
- if (is_mem_exclusive(tmp_cs) || is_cpu_exclusive(tmp_cs)) {
- rcu_read_unlock();
- goto out_unlock;
- }
- }
- rcu_read_unlock();
- spin_lock_irq(&callback_lock);
- cs->mems_allowed = parent->mems_allowed;
- cs->effective_mems = parent->mems_allowed;
- cpumask_copy(cs->cpus_allowed, parent->cpus_allowed);
- cpumask_copy(cs->cpus_requested, parent->cpus_requested);
- cpumask_copy(cs->effective_cpus, parent->cpus_allowed);
- spin_unlock_irq(&callback_lock);
- out_unlock:
- mutex_unlock(&cpuset_mutex);
- put_online_cpus();
- return 0;
- }
- /*
- * If the cpuset being removed has its flag 'sched_load_balance'
- * enabled, then simulate turning sched_load_balance off, which
- * will call rebuild_sched_domains_locked(). That is not needed
- * in the default hierarchy where only changes in partition
- * will cause repartitioning.
- *
- * If the cpuset has the 'sched.partition' flag enabled, simulate
- * turning 'sched.partition" off.
- */
- static void cpuset_css_offline(struct cgroup_subsys_state *css)
- {
- struct cpuset *cs = css_cs(css);
- get_online_cpus();
- mutex_lock(&cpuset_mutex);
- if (is_partition_root(cs))
- update_prstate(cs, 0);
- if (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) &&
- is_sched_load_balance(cs))
- update_flag(CS_SCHED_LOAD_BALANCE, cs, 0);
- if (cs->use_parent_ecpus) {
- struct cpuset *parent = parent_cs(cs);
- cs->use_parent_ecpus = false;
- parent->child_ecpus_count--;
- }
- cpuset_dec();
- clear_bit(CS_ONLINE, &cs->flags);
- mutex_unlock(&cpuset_mutex);
- put_online_cpus();
- }
- static void cpuset_css_free(struct cgroup_subsys_state *css)
- {
- struct cpuset *cs = css_cs(css);
- free_cpuset(cs);
- }
- static void cpuset_bind(struct cgroup_subsys_state *root_css)
- {
- mutex_lock(&cpuset_mutex);
- spin_lock_irq(&callback_lock);
- if (is_in_v2_mode()) {
- cpumask_copy(top_cpuset.cpus_allowed, cpu_possible_mask);
- top_cpuset.mems_allowed = node_possible_map;
- } else {
- cpumask_copy(top_cpuset.cpus_allowed,
- top_cpuset.effective_cpus);
- top_cpuset.mems_allowed = top_cpuset.effective_mems;
- }
- spin_unlock_irq(&callback_lock);
- mutex_unlock(&cpuset_mutex);
- }
- /*
- * Make sure the new task conform to the current state of its parent,
- * which could have been changed by cpuset just after it inherits the
- * state from the parent and before it sits on the cgroup's task list.
- */
- static void cpuset_fork(struct task_struct *task)
- {
- int inherit_cpus = 0;
- if (task_css_is_root(task, cpuset_cgrp_id))
- return;
- trace_android_rvh_cpuset_fork(task, &inherit_cpus);
- if (!inherit_cpus)
- set_cpus_allowed_ptr(task, current->cpus_ptr);
- task->mems_allowed = current->mems_allowed;
- }
- struct cgroup_subsys cpuset_cgrp_subsys = {
- .css_alloc = cpuset_css_alloc,
- .css_online = cpuset_css_online,
- .css_offline = cpuset_css_offline,
- .css_free = cpuset_css_free,
- .can_attach = cpuset_can_attach,
- .cancel_attach = cpuset_cancel_attach,
- .attach = cpuset_attach,
- .post_attach = cpuset_post_attach,
- .bind = cpuset_bind,
- .fork = cpuset_fork,
- .legacy_cftypes = legacy_files,
- .dfl_cftypes = dfl_files,
- .early_init = true,
- .threaded = true,
- };
- /**
- * cpuset_init - initialize cpusets at system boot
- *
- * Description: Initialize top_cpuset
- **/
- int __init cpuset_init(void)
- {
- BUG_ON(!alloc_cpumask_var(&top_cpuset.cpus_allowed, GFP_KERNEL));
- BUG_ON(!alloc_cpumask_var(&top_cpuset.effective_cpus, GFP_KERNEL));
- BUG_ON(!zalloc_cpumask_var(&top_cpuset.subparts_cpus, GFP_KERNEL));
- BUG_ON(!alloc_cpumask_var(&top_cpuset.cpus_requested, GFP_KERNEL));
- cpumask_setall(top_cpuset.cpus_allowed);
- cpumask_setall(top_cpuset.cpus_requested);
- nodes_setall(top_cpuset.mems_allowed);
- cpumask_setall(top_cpuset.effective_cpus);
- nodes_setall(top_cpuset.effective_mems);
- fmeter_init(&top_cpuset.fmeter);
- set_bit(CS_SCHED_LOAD_BALANCE, &top_cpuset.flags);
- top_cpuset.relax_domain_level = -1;
- BUG_ON(!alloc_cpumask_var(&cpus_attach, GFP_KERNEL));
- return 0;
- }
- /*
- * If CPU and/or memory hotplug handlers, below, unplug any CPUs
- * or memory nodes, we need to walk over the cpuset hierarchy,
- * removing that CPU or node from all cpusets. If this removes the
- * last CPU or node from a cpuset, then move the tasks in the empty
- * cpuset to its next-highest non-empty parent.
- */
- static void remove_tasks_in_empty_cpuset(struct cpuset *cs)
- {
- struct cpuset *parent;
- /*
- * Find its next-highest non-empty parent, (top cpuset
- * has online cpus, so can't be empty).
- */
- parent = parent_cs(cs);
- while (cpumask_empty(parent->cpus_allowed) ||
- nodes_empty(parent->mems_allowed))
- parent = parent_cs(parent);
- if (cgroup_transfer_tasks(parent->css.cgroup, cs->css.cgroup)) {
- pr_err("cpuset: failed to transfer tasks out of empty cpuset ");
- pr_cont_cgroup_name(cs->css.cgroup);
- pr_cont("\n");
- }
- }
- static void
- hotplug_update_tasks_legacy(struct cpuset *cs,
- struct cpumask *new_cpus, nodemask_t *new_mems,
- bool cpus_updated, bool mems_updated)
- {
- bool is_empty;
- spin_lock_irq(&callback_lock);
- cpumask_copy(cs->cpus_allowed, new_cpus);
- cpumask_copy(cs->effective_cpus, new_cpus);
- cs->mems_allowed = *new_mems;
- cs->effective_mems = *new_mems;
- spin_unlock_irq(&callback_lock);
- /*
- * Don't call update_tasks_cpumask() if the cpuset becomes empty,
- * as the tasks will be migratecd to an ancestor.
- */
- if (cpus_updated && !cpumask_empty(cs->cpus_allowed))
- update_tasks_cpumask(cs);
- if (mems_updated && !nodes_empty(cs->mems_allowed))
- update_tasks_nodemask(cs);
- is_empty = cpumask_empty(cs->cpus_allowed) ||
- nodes_empty(cs->mems_allowed);
- mutex_unlock(&cpuset_mutex);
- /*
- * Move tasks to the nearest ancestor with execution resources,
- * This is full cgroup operation which will also call back into
- * cpuset. Should be done outside any lock.
- */
- if (is_empty)
- remove_tasks_in_empty_cpuset(cs);
- mutex_lock(&cpuset_mutex);
- }
- static void
- hotplug_update_tasks(struct cpuset *cs,
- struct cpumask *new_cpus, nodemask_t *new_mems,
- bool cpus_updated, bool mems_updated)
- {
- if (cpumask_empty(new_cpus))
- cpumask_copy(new_cpus, parent_cs(cs)->effective_cpus);
- if (nodes_empty(*new_mems))
- *new_mems = parent_cs(cs)->effective_mems;
- spin_lock_irq(&callback_lock);
- cpumask_copy(cs->effective_cpus, new_cpus);
- cs->effective_mems = *new_mems;
- spin_unlock_irq(&callback_lock);
- if (cpus_updated)
- update_tasks_cpumask(cs);
- if (mems_updated)
- update_tasks_nodemask(cs);
- }
- static bool force_rebuild;
- void cpuset_force_rebuild(void)
- {
- force_rebuild = true;
- }
- /**
- * cpuset_hotplug_update_tasks - update tasks in a cpuset for hotunplug
- * @cs: cpuset in interest
- * @tmp: the tmpmasks structure pointer
- *
- * Compare @cs's cpu and mem masks against top_cpuset and if some have gone
- * offline, update @cs accordingly. If @cs ends up with no CPU or memory,
- * all its tasks are moved to the nearest ancestor with both resources.
- */
- static void cpuset_hotplug_update_tasks(struct cpuset *cs, struct tmpmasks *tmp)
- {
- static cpumask_t new_cpus;
- static nodemask_t new_mems;
- bool cpus_updated;
- bool mems_updated;
- struct cpuset *parent;
- retry:
- wait_event(cpuset_attach_wq, cs->attach_in_progress == 0);
- mutex_lock(&cpuset_mutex);
- /*
- * We have raced with task attaching. We wait until attaching
- * is finished, so we won't attach a task to an empty cpuset.
- */
- if (cs->attach_in_progress) {
- mutex_unlock(&cpuset_mutex);
- goto retry;
- }
- parent = parent_cs(cs);
- compute_effective_cpumask(&new_cpus, cs, parent);
- nodes_and(new_mems, cs->mems_allowed, parent->effective_mems);
- if (cs->nr_subparts_cpus)
- /*
- * Make sure that CPUs allocated to child partitions
- * do not show up in effective_cpus.
- */
- cpumask_andnot(&new_cpus, &new_cpus, cs->subparts_cpus);
- if (!tmp || !cs->partition_root_state)
- goto update_tasks;
- /*
- * In the unlikely event that a partition root has empty
- * effective_cpus or its parent becomes erroneous, we have to
- * transition it to the erroneous state.
- */
- if (is_partition_root(cs) && (cpumask_empty(&new_cpus) ||
- (parent->partition_root_state == PRS_ERROR))) {
- if (cs->nr_subparts_cpus) {
- spin_lock_irq(&callback_lock);
- cs->nr_subparts_cpus = 0;
- cpumask_clear(cs->subparts_cpus);
- spin_unlock_irq(&callback_lock);
- compute_effective_cpumask(&new_cpus, cs, parent);
- }
- /*
- * If the effective_cpus is empty because the child
- * partitions take away all the CPUs, we can keep
- * the current partition and let the child partitions
- * fight for available CPUs.
- */
- if ((parent->partition_root_state == PRS_ERROR) ||
- cpumask_empty(&new_cpus)) {
- update_parent_subparts_cpumask(cs, partcmd_disable,
- NULL, tmp);
- spin_lock_irq(&callback_lock);
- cs->partition_root_state = PRS_ERROR;
- spin_unlock_irq(&callback_lock);
- }
- cpuset_force_rebuild();
- }
- /*
- * On the other hand, an erroneous partition root may be transitioned
- * back to a regular one or a partition root with no CPU allocated
- * from the parent may change to erroneous.
- */
- if (is_partition_root(parent) &&
- ((cs->partition_root_state == PRS_ERROR) ||
- !cpumask_intersects(&new_cpus, parent->subparts_cpus)) &&
- update_parent_subparts_cpumask(cs, partcmd_update, NULL, tmp))
- cpuset_force_rebuild();
- update_tasks:
- cpus_updated = !cpumask_equal(&new_cpus, cs->effective_cpus);
- mems_updated = !nodes_equal(new_mems, cs->effective_mems);
- if (is_in_v2_mode())
- hotplug_update_tasks(cs, &new_cpus, &new_mems,
- cpus_updated, mems_updated);
- else
- hotplug_update_tasks_legacy(cs, &new_cpus, &new_mems,
- cpus_updated, mems_updated);
- mutex_unlock(&cpuset_mutex);
- }
- /**
- * cpuset_hotplug_workfn - handle CPU/memory hotunplug for a cpuset
- *
- * This function is called after either CPU or memory configuration has
- * changed and updates cpuset accordingly. The top_cpuset is always
- * synchronized to cpu_active_mask and N_MEMORY, which is necessary in
- * order to make cpusets transparent (of no affect) on systems that are
- * actively using CPU hotplug but making no active use of cpusets.
- *
- * Non-root cpusets are only affected by offlining. If any CPUs or memory
- * nodes have been taken down, cpuset_hotplug_update_tasks() is invoked on
- * all descendants.
- *
- * Note that CPU offlining during suspend is ignored. We don't modify
- * cpusets across suspend/resume cycles at all.
- */
- void cpuset_hotplug_workfn(struct work_struct *work)
- {
- static cpumask_t new_cpus;
- static nodemask_t new_mems;
- bool cpus_updated, mems_updated;
- bool on_dfl = is_in_v2_mode();
- struct tmpmasks tmp, *ptmp = NULL;
- if (on_dfl && !alloc_cpumasks(NULL, &tmp))
- ptmp = &tmp;
- mutex_lock(&cpuset_mutex);
- /* fetch the available cpus/mems and find out which changed how */
- cpumask_copy(&new_cpus, cpu_active_mask);
- new_mems = node_states[N_MEMORY];
- /*
- * If subparts_cpus is populated, it is likely that the check below
- * will produce a false positive on cpus_updated when the cpu list
- * isn't changed. It is extra work, but it is better to be safe.
- */
- cpus_updated = !cpumask_equal(top_cpuset.effective_cpus, &new_cpus);
- mems_updated = !nodes_equal(top_cpuset.effective_mems, new_mems);
- /*
- * In the rare case that hotplug removes all the cpus in subparts_cpus,
- * we assumed that cpus are updated.
- */
- if (!cpus_updated && top_cpuset.nr_subparts_cpus)
- cpus_updated = true;
- /* synchronize cpus_allowed to cpu_active_mask */
- if (cpus_updated) {
- spin_lock_irq(&callback_lock);
- if (!on_dfl)
- cpumask_copy(top_cpuset.cpus_allowed, &new_cpus);
- /*
- * Make sure that CPUs allocated to child partitions
- * do not show up in effective_cpus. If no CPU is left,
- * we clear the subparts_cpus & let the child partitions
- * fight for the CPUs again.
- */
- if (top_cpuset.nr_subparts_cpus) {
- if (cpumask_subset(&new_cpus,
- top_cpuset.subparts_cpus)) {
- top_cpuset.nr_subparts_cpus = 0;
- cpumask_clear(top_cpuset.subparts_cpus);
- } else {
- cpumask_andnot(&new_cpus, &new_cpus,
- top_cpuset.subparts_cpus);
- }
- }
- cpumask_copy(top_cpuset.effective_cpus, &new_cpus);
- spin_unlock_irq(&callback_lock);
- /* we don't mess with cpumasks of tasks in top_cpuset */
- }
- /* synchronize mems_allowed to N_MEMORY */
- if (mems_updated) {
- spin_lock_irq(&callback_lock);
- if (!on_dfl)
- top_cpuset.mems_allowed = new_mems;
- top_cpuset.effective_mems = new_mems;
- spin_unlock_irq(&callback_lock);
- update_tasks_nodemask(&top_cpuset);
- }
- mutex_unlock(&cpuset_mutex);
- /* if cpus or mems changed, we need to propagate to descendants */
- if (cpus_updated || mems_updated) {
- struct cpuset *cs;
- struct cgroup_subsys_state *pos_css;
- rcu_read_lock();
- cpuset_for_each_descendant_pre(cs, pos_css, &top_cpuset) {
- if (cs == &top_cpuset || !css_tryget_online(&cs->css))
- continue;
- rcu_read_unlock();
- cpuset_hotplug_update_tasks(cs, ptmp);
- rcu_read_lock();
- css_put(&cs->css);
- }
- rcu_read_unlock();
- }
- /* rebuild sched domains if cpus_allowed has changed */
- if (cpus_updated || force_rebuild) {
- force_rebuild = false;
- rebuild_sched_domains();
- }
- free_cpumasks(NULL, ptmp);
- }
- void cpuset_update_active_cpus(void)
- {
- /*
- * We're inside cpu hotplug critical region which usually nests
- * inside cgroup synchronization. Bounce actual hotplug processing
- * to a work item to avoid reverse locking order.
- */
- schedule_work(&cpuset_hotplug_work);
- }
- void cpuset_update_active_cpus_affine(int cpu)
- {
- schedule_work_on(cpu, &cpuset_hotplug_work);
- }
- void cpuset_wait_for_hotplug(void)
- {
- flush_work(&cpuset_hotplug_work);
- }
- /*
- * Keep top_cpuset.mems_allowed tracking node_states[N_MEMORY].
- * Call this routine anytime after node_states[N_MEMORY] changes.
- * See cpuset_update_active_cpus() for CPU hotplug handling.
- */
- static int cpuset_track_online_nodes(struct notifier_block *self,
- unsigned long action, void *arg)
- {
- schedule_work(&cpuset_hotplug_work);
- return NOTIFY_OK;
- }
- static struct notifier_block cpuset_track_online_nodes_nb = {
- .notifier_call = cpuset_track_online_nodes,
- .priority = 10, /* ??! */
- };
- /**
- * cpuset_init_smp - initialize cpus_allowed
- *
- * Description: Finish top cpuset after cpu, node maps are initialized
- */
- void __init cpuset_init_smp(void)
- {
- cpumask_copy(top_cpuset.cpus_allowed, cpu_active_mask);
- top_cpuset.mems_allowed = node_states[N_MEMORY];
- top_cpuset.old_mems_allowed = top_cpuset.mems_allowed;
- cpumask_copy(top_cpuset.effective_cpus, cpu_active_mask);
- top_cpuset.effective_mems = node_states[N_MEMORY];
- register_hotmemory_notifier(&cpuset_track_online_nodes_nb);
- cpuset_migrate_mm_wq = alloc_ordered_workqueue("cpuset_migrate_mm", 0);
- BUG_ON(!cpuset_migrate_mm_wq);
- }
- /**
- * cpuset_cpus_allowed - return cpus_allowed mask from a tasks cpuset.
- * @tsk: pointer to task_struct from which to obtain cpuset->cpus_allowed.
- * @pmask: pointer to struct cpumask variable to receive cpus_allowed set.
- *
- * Description: Returns the cpumask_var_t cpus_allowed of the cpuset
- * attached to the specified @tsk. Guaranteed to return some non-empty
- * subset of cpu_online_mask, even if this means going outside the
- * tasks cpuset.
- **/
- void cpuset_cpus_allowed(struct task_struct *tsk, struct cpumask *pmask)
- {
- unsigned long flags;
- spin_lock_irqsave(&callback_lock, flags);
- rcu_read_lock();
- guarantee_online_cpus(tsk, pmask);
- rcu_read_unlock();
- spin_unlock_irqrestore(&callback_lock, flags);
- }
- EXPORT_SYMBOL_GPL(cpuset_cpus_allowed);
- /**
- * cpuset_cpus_allowed_fallback - final fallback before complete catastrophe.
- * @tsk: pointer to task_struct with which the scheduler is struggling
- *
- * Description: In the case that the scheduler cannot find an allowed cpu in
- * tsk->cpus_allowed, we fall back to task_cs(tsk)->cpus_allowed. In legacy
- * mode however, this value is the same as task_cs(tsk)->effective_cpus,
- * which will not contain a sane cpumask during cases such as cpu hotplugging.
- * This is the absolute last resort for the scheduler and it is only used if
- * _every_ other avenue has been traveled.
- **/
- void cpuset_cpus_allowed_fallback(struct task_struct *tsk)
- {
- const struct cpumask *possible_mask = task_cpu_possible_mask(tsk);
- const struct cpumask *cs_mask;
- rcu_read_lock();
- cs_mask = task_cs(tsk)->cpus_allowed;
- if (!is_in_v2_mode() || !cpumask_subset(cs_mask, possible_mask))
- goto unlock; /* select_fallback_rq will try harder */
- do_set_cpus_allowed(tsk, cs_mask);
- unlock:
- rcu_read_unlock();
- /*
- * We own tsk->cpus_allowed, nobody can change it under us.
- *
- * But we used cs && cs->cpus_allowed lockless and thus can
- * race with cgroup_attach_task() or update_cpumask() and get
- * the wrong tsk->cpus_allowed. However, both cases imply the
- * subsequent cpuset_change_cpumask()->set_cpus_allowed_ptr()
- * which takes task_rq_lock().
- *
- * If we are called after it dropped the lock we must see all
- * changes in tsk_cs()->cpus_allowed. Otherwise we can temporary
- * set any mask even if it is not right from task_cs() pov,
- * the pending set_cpus_allowed_ptr() will fix things.
- *
- * select_fallback_rq() will fix things ups and set cpu_possible_mask
- * if required.
- */
- }
- void __init cpuset_init_current_mems_allowed(void)
- {
- nodes_setall(current->mems_allowed);
- }
- /**
- * cpuset_mems_allowed - return mems_allowed mask from a tasks cpuset.
- * @tsk: pointer to task_struct from which to obtain cpuset->mems_allowed.
- *
- * Description: Returns the nodemask_t mems_allowed of the cpuset
- * attached to the specified @tsk. Guaranteed to return some non-empty
- * subset of node_states[N_MEMORY], even if this means going outside the
- * tasks cpuset.
- **/
- nodemask_t cpuset_mems_allowed(struct task_struct *tsk)
- {
- nodemask_t mask;
- unsigned long flags;
- spin_lock_irqsave(&callback_lock, flags);
- rcu_read_lock();
- guarantee_online_mems(task_cs(tsk), &mask);
- rcu_read_unlock();
- spin_unlock_irqrestore(&callback_lock, flags);
- return mask;
- }
- /**
- * cpuset_nodemask_valid_mems_allowed - check nodemask vs. curremt mems_allowed
- * @nodemask: the nodemask to be checked
- *
- * Are any of the nodes in the nodemask allowed in current->mems_allowed?
- */
- int cpuset_nodemask_valid_mems_allowed(nodemask_t *nodemask)
- {
- return nodes_intersects(*nodemask, current->mems_allowed);
- }
- /*
- * nearest_hardwall_ancestor() - Returns the nearest mem_exclusive or
- * mem_hardwall ancestor to the specified cpuset. Call holding
- * callback_lock. If no ancestor is mem_exclusive or mem_hardwall
- * (an unusual configuration), then returns the root cpuset.
- */
- static struct cpuset *nearest_hardwall_ancestor(struct cpuset *cs)
- {
- while (!(is_mem_exclusive(cs) || is_mem_hardwall(cs)) && parent_cs(cs))
- cs = parent_cs(cs);
- return cs;
- }
- /**
- * cpuset_node_allowed - Can we allocate on a memory node?
- * @node: is this an allowed node?
- * @gfp_mask: memory allocation flags
- *
- * If we're in interrupt, yes, we can always allocate. If @node is set in
- * current's mems_allowed, yes. If it's not a __GFP_HARDWALL request and this
- * node is set in the nearest hardwalled cpuset ancestor to current's cpuset,
- * yes. If current has access to memory reserves as an oom victim, yes.
- * Otherwise, no.
- *
- * GFP_USER allocations are marked with the __GFP_HARDWALL bit,
- * and do not allow allocations outside the current tasks cpuset
- * unless the task has been OOM killed.
- * GFP_KERNEL allocations are not so marked, so can escape to the
- * nearest enclosing hardwalled ancestor cpuset.
- *
- * Scanning up parent cpusets requires callback_lock. The
- * __alloc_pages() routine only calls here with __GFP_HARDWALL bit
- * _not_ set if it's a GFP_KERNEL allocation, and all nodes in the
- * current tasks mems_allowed came up empty on the first pass over
- * the zonelist. So only GFP_KERNEL allocations, if all nodes in the
- * cpuset are short of memory, might require taking the callback_lock.
- *
- * The first call here from mm/page_alloc:get_page_from_freelist()
- * has __GFP_HARDWALL set in gfp_mask, enforcing hardwall cpusets,
- * so no allocation on a node outside the cpuset is allowed (unless
- * in interrupt, of course).
- *
- * The second pass through get_page_from_freelist() doesn't even call
- * here for GFP_ATOMIC calls. For those calls, the __alloc_pages()
- * variable 'wait' is not set, and the bit ALLOC_CPUSET is not set
- * in alloc_flags. That logic and the checks below have the combined
- * affect that:
- * in_interrupt - any node ok (current task context irrelevant)
- * GFP_ATOMIC - any node ok
- * tsk_is_oom_victim - any node ok
- * GFP_KERNEL - any node in enclosing hardwalled cpuset ok
- * GFP_USER - only nodes in current tasks mems allowed ok.
- */
- bool __cpuset_node_allowed(int node, gfp_t gfp_mask)
- {
- struct cpuset *cs; /* current cpuset ancestors */
- int allowed; /* is allocation in zone z allowed? */
- unsigned long flags;
- if (in_interrupt())
- return true;
- if (node_isset(node, current->mems_allowed))
- return true;
- /*
- * Allow tasks that have access to memory reserves because they have
- * been OOM killed to get memory anywhere.
- */
- if (unlikely(tsk_is_oom_victim(current)))
- return true;
- if (gfp_mask & __GFP_HARDWALL) /* If hardwall request, stop here */
- return false;
- if (current->flags & PF_EXITING) /* Let dying task have memory */
- return true;
- /* Not hardwall and node outside mems_allowed: scan up cpusets */
- spin_lock_irqsave(&callback_lock, flags);
- rcu_read_lock();
- cs = nearest_hardwall_ancestor(task_cs(current));
- allowed = node_isset(node, cs->mems_allowed);
- rcu_read_unlock();
- spin_unlock_irqrestore(&callback_lock, flags);
- return allowed;
- }
- /**
- * cpuset_mem_spread_node() - On which node to begin search for a file page
- * cpuset_slab_spread_node() - On which node to begin search for a slab page
- *
- * If a task is marked PF_SPREAD_PAGE or PF_SPREAD_SLAB (as for
- * tasks in a cpuset with is_spread_page or is_spread_slab set),
- * and if the memory allocation used cpuset_mem_spread_node()
- * to determine on which node to start looking, as it will for
- * certain page cache or slab cache pages such as used for file
- * system buffers and inode caches, then instead of starting on the
- * local node to look for a free page, rather spread the starting
- * node around the tasks mems_allowed nodes.
- *
- * We don't have to worry about the returned node being offline
- * because "it can't happen", and even if it did, it would be ok.
- *
- * The routines calling guarantee_online_mems() are careful to
- * only set nodes in task->mems_allowed that are online. So it
- * should not be possible for the following code to return an
- * offline node. But if it did, that would be ok, as this routine
- * is not returning the node where the allocation must be, only
- * the node where the search should start. The zonelist passed to
- * __alloc_pages() will include all nodes. If the slab allocator
- * is passed an offline node, it will fall back to the local node.
- * See kmem_cache_alloc_node().
- */
- static int cpuset_spread_node(int *rotor)
- {
- return *rotor = next_node_in(*rotor, current->mems_allowed);
- }
- int cpuset_mem_spread_node(void)
- {
- if (current->cpuset_mem_spread_rotor == NUMA_NO_NODE)
- current->cpuset_mem_spread_rotor =
- node_random(¤t->mems_allowed);
- return cpuset_spread_node(¤t->cpuset_mem_spread_rotor);
- }
- int cpuset_slab_spread_node(void)
- {
- if (current->cpuset_slab_spread_rotor == NUMA_NO_NODE)
- current->cpuset_slab_spread_rotor =
- node_random(¤t->mems_allowed);
- return cpuset_spread_node(¤t->cpuset_slab_spread_rotor);
- }
- EXPORT_SYMBOL_GPL(cpuset_mem_spread_node);
- /**
- * cpuset_mems_allowed_intersects - Does @tsk1's mems_allowed intersect @tsk2's?
- * @tsk1: pointer to task_struct of some task.
- * @tsk2: pointer to task_struct of some other task.
- *
- * Description: Return true if @tsk1's mems_allowed intersects the
- * mems_allowed of @tsk2. Used by the OOM killer to determine if
- * one of the task's memory usage might impact the memory available
- * to the other.
- **/
- int cpuset_mems_allowed_intersects(const struct task_struct *tsk1,
- const struct task_struct *tsk2)
- {
- return nodes_intersects(tsk1->mems_allowed, tsk2->mems_allowed);
- }
- /**
- * cpuset_print_current_mems_allowed - prints current's cpuset and mems_allowed
- *
- * Description: Prints current's name, cpuset name, and cached copy of its
- * mems_allowed to the kernel log.
- */
- void cpuset_print_current_mems_allowed(void)
- {
- struct cgroup *cgrp;
- rcu_read_lock();
- cgrp = task_cs(current)->css.cgroup;
- pr_cont(",cpuset=");
- pr_cont_cgroup_name(cgrp);
- pr_cont(",mems_allowed=%*pbl",
- nodemask_pr_args(¤t->mems_allowed));
- rcu_read_unlock();
- }
- /*
- * Collection of memory_pressure is suppressed unless
- * this flag is enabled by writing "1" to the special
- * cpuset file 'memory_pressure_enabled' in the root cpuset.
- */
- int cpuset_memory_pressure_enabled __read_mostly;
- /**
- * cpuset_memory_pressure_bump - keep stats of per-cpuset reclaims.
- *
- * Keep a running average of the rate of synchronous (direct)
- * page reclaim efforts initiated by tasks in each cpuset.
- *
- * This represents the rate at which some task in the cpuset
- * ran low on memory on all nodes it was allowed to use, and
- * had to enter the kernels page reclaim code in an effort to
- * create more free memory by tossing clean pages or swapping
- * or writing dirty pages.
- *
- * Display to user space in the per-cpuset read-only file
- * "memory_pressure". Value displayed is an integer
- * representing the recent rate of entry into the synchronous
- * (direct) page reclaim by any task attached to the cpuset.
- **/
- void __cpuset_memory_pressure_bump(void)
- {
- rcu_read_lock();
- fmeter_markevent(&task_cs(current)->fmeter);
- rcu_read_unlock();
- }
- #ifdef CONFIG_PROC_PID_CPUSET
- /*
- * proc_cpuset_show()
- * - Print tasks cpuset path into seq_file.
- * - Used for /proc/<pid>/cpuset.
- * - No need to task_lock(tsk) on this tsk->cpuset reference, as it
- * doesn't really matter if tsk->cpuset changes after we read it,
- * and we take cpuset_mutex, keeping cpuset_attach() from changing it
- * anyway.
- */
- int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns,
- struct pid *pid, struct task_struct *tsk)
- {
- char *buf;
- struct cgroup_subsys_state *css;
- int retval;
- retval = -ENOMEM;
- buf = kmalloc(PATH_MAX, GFP_KERNEL);
- if (!buf)
- goto out;
- css = task_get_css(tsk, cpuset_cgrp_id);
- retval = cgroup_path_ns(css->cgroup, buf, PATH_MAX,
- current->nsproxy->cgroup_ns);
- css_put(css);
- if (retval >= PATH_MAX)
- retval = -ENAMETOOLONG;
- if (retval < 0)
- goto out_free;
- seq_puts(m, buf);
- seq_putc(m, '\n');
- retval = 0;
- out_free:
- kfree(buf);
- out:
- return retval;
- }
- #endif /* CONFIG_PROC_PID_CPUSET */
- /* Display task mems_allowed in /proc/<pid>/status file. */
- void cpuset_task_status_allowed(struct seq_file *m, struct task_struct *task)
- {
- seq_printf(m, "Mems_allowed:\t%*pb\n",
- nodemask_pr_args(&task->mems_allowed));
- seq_printf(m, "Mems_allowed_list:\t%*pbl\n",
- nodemask_pr_args(&task->mems_allowed));
- }
|