123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574575576577578579580581582583584585586587588589590591592593594595596597598599600601602603604605606607608609610611612613614615616617618619620621622623624625626627628629630631632633634635636637638639640641642643644645646647648649650651652653654655656657658659660661662663664665666667668669670671672673674675676677678679680681682683684685686687688689690691692693694695696697698699700701702703704705706707708709710711712713714715716717718719720721722723724725726727728729730731732733734735736737738739740741742743744745746747748749750751752753754755756757758759760761762763764765766767768769770771772773774775776777778779780781782783784785786787788789790791792793794795796797798799800801802803804805806807808809810811812813814815816817818819820821822823824825826827828829830831832833834835836837838839840841842843844845846847848849850851852853854855856857858859860861862863864865866867868869870871872873874875876877878879880881882883884885886887888889890891892893894895896897898899900901902903904905906907908909910911912913914915916917918919920921922923924925926927928929930931932933934935936937938939940941942943944945946947948949950951952953954955956957958959960961962963964965966967968969970971972973974975976977978979980981982983984985986987988989990991992993994995996997998999100010011002100310041005100610071008100910101011101210131014101510161017101810191020102110221023102410251026102710281029103010311032103310341035103610371038103910401041104210431044104510461047104810491050105110521053105410551056105710581059106010611062106310641065106610671068106910701071107210731074107510761077107810791080108110821083108410851086108710881089109010911092109310941095109610971098109911001101110211031104110511061107110811091110111111121113111411151116111711181119112011211122112311241125112611271128112911301131113211331134113511361137113811391140114111421143114411451146114711481149115011511152115311541155115611571158115911601161116211631164116511661167116811691170117111721173117411751176117711781179118011811182118311841185118611871188118911901191119211931194119511961197119811991200120112021203120412051206120712081209121012111212121312141215121612171218121912201221122212231224122512261227122812291230123112321233123412351236123712381239124012411242124312441245124612471248124912501251125212531254125512561257125812591260126112621263126412651266126712681269127012711272127312741275127612771278127912801281128212831284128512861287128812891290129112921293129412951296129712981299130013011302130313041305130613071308130913101311131213131314131513161317131813191320132113221323132413251326132713281329133013311332133313341335133613371338133913401341134213431344134513461347134813491350135113521353135413551356135713581359136013611362136313641365136613671368136913701371137213731374137513761377137813791380138113821383138413851386138713881389139013911392139313941395139613971398139914001401140214031404140514061407140814091410141114121413141414151416141714181419142014211422142314241425142614271428142914301431143214331434143514361437143814391440144114421443144414451446144714481449145014511452145314541455145614571458145914601461146214631464146514661467146814691470147114721473147414751476147714781479148014811482148314841485148614871488148914901491149214931494149514961497149814991500150115021503150415051506150715081509151015111512151315141515151615171518151915201521152215231524152515261527152815291530153115321533153415351536153715381539154015411542154315441545154615471548154915501551155215531554155515561557155815591560156115621563156415651566156715681569157015711572157315741575157615771578157915801581158215831584158515861587158815891590159115921593159415951596159715981599160016011602160316041605160616071608160916101611161216131614161516161617161816191620162116221623162416251626162716281629163016311632163316341635163616371638163916401641164216431644164516461647164816491650165116521653165416551656165716581659166016611662166316641665166616671668166916701671167216731674167516761677167816791680168116821683168416851686168716881689169016911692169316941695169616971698169917001701170217031704170517061707170817091710171117121713171417151716171717181719172017211722172317241725172617271728172917301731173217331734173517361737173817391740174117421743174417451746174717481749175017511752175317541755175617571758175917601761176217631764176517661767176817691770177117721773177417751776177717781779178017811782178317841785178617871788178917901791179217931794179517961797179817991800180118021803180418051806180718081809181018111812181318141815181618171818181918201821182218231824182518261827182818291830183118321833183418351836183718381839184018411842184318441845184618471848184918501851185218531854185518561857185818591860186118621863186418651866186718681869187018711872187318741875187618771878187918801881188218831884188518861887188818891890189118921893189418951896189718981899190019011902190319041905190619071908190919101911191219131914191519161917191819191920192119221923192419251926192719281929193019311932193319341935193619371938193919401941194219431944194519461947194819491950195119521953195419551956195719581959196019611962196319641965196619671968196919701971197219731974197519761977197819791980198119821983198419851986198719881989199019911992199319941995199619971998199920002001200220032004200520062007200820092010201120122013201420152016201720182019202020212022202320242025202620272028202920302031203220332034203520362037203820392040204120422043204420452046204720482049205020512052205320542055205620572058205920602061206220632064206520662067206820692070207120722073207420752076207720782079208020812082208320842085208620872088208920902091209220932094209520962097209820992100210121022103210421052106210721082109211021112112211321142115211621172118211921202121212221232124212521262127212821292130213121322133213421352136213721382139214021412142214321442145214621472148214921502151215221532154215521562157215821592160216121622163216421652166216721682169217021712172217321742175217621772178217921802181218221832184218521862187218821892190219121922193219421952196219721982199220022012202220322042205220622072208220922102211221222132214221522162217221822192220222122222223222422252226222722282229223022312232223322342235223622372238 |
- /*
- * CFQ, or complete fairness queueing, disk scheduler.
- *
- * Based on ideas from a previously unfinished io
- * scheduler (round robin per-process disk scheduling) and Andrea Arcangeli.
- *
- * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk>
- */
- #include <linux/module.h>
- #include <linux/blkdev.h>
- #include <linux/elevator.h>
- #include <linux/hash.h>
- #include <linux/rbtree.h>
- #include <linux/ioprio.h>
- /*
- * tunables
- */
- static const int cfq_quantum = 4; /* max queue in one round of service */
- static const int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 };
- static const int cfq_back_max = 16 * 1024; /* maximum backwards seek, in KiB */
- static const int cfq_back_penalty = 2; /* penalty of a backwards seek */
- static const int cfq_slice_sync = HZ / 10;
- static int cfq_slice_async = HZ / 25;
- static const int cfq_slice_async_rq = 2;
- static int cfq_slice_idle = HZ / 125;
- #define CFQ_IDLE_GRACE (HZ / 10)
- #define CFQ_SLICE_SCALE (5)
- #define CFQ_KEY_ASYNC (0)
- /*
- * for the hash of cfqq inside the cfqd
- */
- #define CFQ_QHASH_SHIFT 6
- #define CFQ_QHASH_ENTRIES (1 << CFQ_QHASH_SHIFT)
- #define list_entry_qhash(entry) hlist_entry((entry), struct cfq_queue, cfq_hash)
- #define list_entry_cfqq(ptr) list_entry((ptr), struct cfq_queue, cfq_list)
- #define RQ_CIC(rq) ((struct cfq_io_context*)(rq)->elevator_private)
- #define RQ_CFQQ(rq) ((rq)->elevator_private2)
- static struct kmem_cache *cfq_pool;
- static struct kmem_cache *cfq_ioc_pool;
- static DEFINE_PER_CPU(unsigned long, ioc_count);
- static struct completion *ioc_gone;
- #define CFQ_PRIO_LISTS IOPRIO_BE_NR
- #define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE)
- #define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT)
- #define ASYNC (0)
- #define SYNC (1)
- #define cfq_cfqq_dispatched(cfqq) \
- ((cfqq)->on_dispatch[ASYNC] + (cfqq)->on_dispatch[SYNC])
- #define cfq_cfqq_class_sync(cfqq) ((cfqq)->key != CFQ_KEY_ASYNC)
- #define cfq_cfqq_sync(cfqq) \
- (cfq_cfqq_class_sync(cfqq) || (cfqq)->on_dispatch[SYNC])
- #define sample_valid(samples) ((samples) > 80)
- /*
- * Per block device queue structure
- */
- struct cfq_data {
- request_queue_t *queue;
- /*
- * rr list of queues with requests and the count of them
- */
- struct list_head rr_list[CFQ_PRIO_LISTS];
- struct list_head busy_rr;
- struct list_head cur_rr;
- struct list_head idle_rr;
- unsigned int busy_queues;
- /*
- * cfqq lookup hash
- */
- struct hlist_head *cfq_hash;
- int rq_in_driver;
- int hw_tag;
- /*
- * idle window management
- */
- struct timer_list idle_slice_timer;
- struct work_struct unplug_work;
- struct cfq_queue *active_queue;
- struct cfq_io_context *active_cic;
- int cur_prio, cur_end_prio;
- unsigned int dispatch_slice;
- struct timer_list idle_class_timer;
- sector_t last_sector;
- unsigned long last_end_request;
- /*
- * tunables, see top of file
- */
- unsigned int cfq_quantum;
- unsigned int cfq_fifo_expire[2];
- unsigned int cfq_back_penalty;
- unsigned int cfq_back_max;
- unsigned int cfq_slice[2];
- unsigned int cfq_slice_async_rq;
- unsigned int cfq_slice_idle;
- struct list_head cic_list;
- };
- /*
- * Per process-grouping structure
- */
- struct cfq_queue {
- /* reference count */
- atomic_t ref;
- /* parent cfq_data */
- struct cfq_data *cfqd;
- /* cfqq lookup hash */
- struct hlist_node cfq_hash;
- /* hash key */
- unsigned int key;
- /* member of the rr/busy/cur/idle cfqd list */
- struct list_head cfq_list;
- /* sorted list of pending requests */
- struct rb_root sort_list;
- /* if fifo isn't expired, next request to serve */
- struct request *next_rq;
- /* requests queued in sort_list */
- int queued[2];
- /* currently allocated requests */
- int allocated[2];
- /* pending metadata requests */
- int meta_pending;
- /* fifo list of requests in sort_list */
- struct list_head fifo;
- unsigned long slice_end;
- unsigned long service_last;
- long slice_resid;
- /* number of requests that are on the dispatch list */
- int on_dispatch[2];
- /* io prio of this group */
- unsigned short ioprio, org_ioprio;
- unsigned short ioprio_class, org_ioprio_class;
- /* various state flags, see below */
- unsigned int flags;
- };
- enum cfqq_state_flags {
- CFQ_CFQQ_FLAG_on_rr = 0, /* on round-robin busy list */
- CFQ_CFQQ_FLAG_wait_request, /* waiting for a request */
- CFQ_CFQQ_FLAG_must_alloc, /* must be allowed rq alloc */
- CFQ_CFQQ_FLAG_must_alloc_slice, /* per-slice must_alloc flag */
- CFQ_CFQQ_FLAG_must_dispatch, /* must dispatch, even if expired */
- CFQ_CFQQ_FLAG_fifo_expire, /* FIFO checked in this slice */
- CFQ_CFQQ_FLAG_idle_window, /* slice idling enabled */
- CFQ_CFQQ_FLAG_prio_changed, /* task priority has changed */
- CFQ_CFQQ_FLAG_queue_new, /* queue never been serviced */
- CFQ_CFQQ_FLAG_slice_new, /* no requests dispatched in slice */
- };
- #define CFQ_CFQQ_FNS(name) \
- static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \
- { \
- cfqq->flags |= (1 << CFQ_CFQQ_FLAG_##name); \
- } \
- static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \
- { \
- cfqq->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \
- } \
- static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \
- { \
- return (cfqq->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \
- }
- CFQ_CFQQ_FNS(on_rr);
- CFQ_CFQQ_FNS(wait_request);
- CFQ_CFQQ_FNS(must_alloc);
- CFQ_CFQQ_FNS(must_alloc_slice);
- CFQ_CFQQ_FNS(must_dispatch);
- CFQ_CFQQ_FNS(fifo_expire);
- CFQ_CFQQ_FNS(idle_window);
- CFQ_CFQQ_FNS(prio_changed);
- CFQ_CFQQ_FNS(queue_new);
- CFQ_CFQQ_FNS(slice_new);
- #undef CFQ_CFQQ_FNS
- static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int, unsigned short);
- static void cfq_dispatch_insert(request_queue_t *, struct request *);
- static struct cfq_queue *cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk, gfp_t gfp_mask);
- /*
- * scheduler run of queue, if there are requests pending and no one in the
- * driver that will restart queueing
- */
- static inline void cfq_schedule_dispatch(struct cfq_data *cfqd)
- {
- if (cfqd->busy_queues)
- kblockd_schedule_work(&cfqd->unplug_work);
- }
- static int cfq_queue_empty(request_queue_t *q)
- {
- struct cfq_data *cfqd = q->elevator->elevator_data;
- return !cfqd->busy_queues;
- }
- static inline pid_t cfq_queue_pid(struct task_struct *task, int rw, int is_sync)
- {
- /*
- * Use the per-process queue, for read requests and syncronous writes
- */
- if (!(rw & REQ_RW) || is_sync)
- return task->pid;
- return CFQ_KEY_ASYNC;
- }
- /*
- * Scale schedule slice based on io priority. Use the sync time slice only
- * if a queue is marked sync and has sync io queued. A sync queue with async
- * io only, should not get full sync slice length.
- */
- static inline int
- cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
- {
- const int base_slice = cfqd->cfq_slice[cfq_cfqq_sync(cfqq)];
- WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR);
- return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - cfqq->ioprio));
- }
- static inline void
- cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
- {
- cfqq->slice_end = cfq_prio_to_slice(cfqd, cfqq) + jiffies;
- cfqq->slice_end += cfqq->slice_resid;
- /*
- * Don't carry over residual for more than one slice, we only want
- * to slightly correct the fairness. Carrying over forever would
- * easily introduce oscillations.
- */
- cfqq->slice_resid = 0;
- }
- /*
- * We need to wrap this check in cfq_cfqq_slice_new(), since ->slice_end
- * isn't valid until the first request from the dispatch is activated
- * and the slice time set.
- */
- static inline int cfq_slice_used(struct cfq_queue *cfqq)
- {
- if (cfq_cfqq_slice_new(cfqq))
- return 0;
- if (time_before(jiffies, cfqq->slice_end))
- return 0;
- return 1;
- }
- /*
- * Lifted from AS - choose which of rq1 and rq2 that is best served now.
- * We choose the request that is closest to the head right now. Distance
- * behind the head is penalized and only allowed to a certain extent.
- */
- static struct request *
- cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2)
- {
- sector_t last, s1, s2, d1 = 0, d2 = 0;
- unsigned long back_max;
- #define CFQ_RQ1_WRAP 0x01 /* request 1 wraps */
- #define CFQ_RQ2_WRAP 0x02 /* request 2 wraps */
- unsigned wrap = 0; /* bit mask: requests behind the disk head? */
- if (rq1 == NULL || rq1 == rq2)
- return rq2;
- if (rq2 == NULL)
- return rq1;
- if (rq_is_sync(rq1) && !rq_is_sync(rq2))
- return rq1;
- else if (rq_is_sync(rq2) && !rq_is_sync(rq1))
- return rq2;
- if (rq_is_meta(rq1) && !rq_is_meta(rq2))
- return rq1;
- else if (rq_is_meta(rq2) && !rq_is_meta(rq1))
- return rq2;
- s1 = rq1->sector;
- s2 = rq2->sector;
- last = cfqd->last_sector;
- /*
- * by definition, 1KiB is 2 sectors
- */
- back_max = cfqd->cfq_back_max * 2;
- /*
- * Strict one way elevator _except_ in the case where we allow
- * short backward seeks which are biased as twice the cost of a
- * similar forward seek.
- */
- if (s1 >= last)
- d1 = s1 - last;
- else if (s1 + back_max >= last)
- d1 = (last - s1) * cfqd->cfq_back_penalty;
- else
- wrap |= CFQ_RQ1_WRAP;
- if (s2 >= last)
- d2 = s2 - last;
- else if (s2 + back_max >= last)
- d2 = (last - s2) * cfqd->cfq_back_penalty;
- else
- wrap |= CFQ_RQ2_WRAP;
- /* Found required data */
- /*
- * By doing switch() on the bit mask "wrap" we avoid having to
- * check two variables for all permutations: --> faster!
- */
- switch (wrap) {
- case 0: /* common case for CFQ: rq1 and rq2 not wrapped */
- if (d1 < d2)
- return rq1;
- else if (d2 < d1)
- return rq2;
- else {
- if (s1 >= s2)
- return rq1;
- else
- return rq2;
- }
- case CFQ_RQ2_WRAP:
- return rq1;
- case CFQ_RQ1_WRAP:
- return rq2;
- case (CFQ_RQ1_WRAP|CFQ_RQ2_WRAP): /* both rqs wrapped */
- default:
- /*
- * Since both rqs are wrapped,
- * start with the one that's further behind head
- * (--> only *one* back seek required),
- * since back seek takes more time than forward.
- */
- if (s1 <= s2)
- return rq1;
- else
- return rq2;
- }
- }
- /*
- * would be nice to take fifo expire time into account as well
- */
- static struct request *
- cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
- struct request *last)
- {
- struct rb_node *rbnext = rb_next(&last->rb_node);
- struct rb_node *rbprev = rb_prev(&last->rb_node);
- struct request *next = NULL, *prev = NULL;
- BUG_ON(RB_EMPTY_NODE(&last->rb_node));
- if (rbprev)
- prev = rb_entry_rq(rbprev);
- if (rbnext)
- next = rb_entry_rq(rbnext);
- else {
- rbnext = rb_first(&cfqq->sort_list);
- if (rbnext && rbnext != &last->rb_node)
- next = rb_entry_rq(rbnext);
- }
- return cfq_choose_req(cfqd, next, prev);
- }
- static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted)
- {
- struct cfq_data *cfqd = cfqq->cfqd;
- struct list_head *list, *n;
- struct cfq_queue *__cfqq;
- /*
- * Resorting requires the cfqq to be on the RR list already.
- */
- if (!cfq_cfqq_on_rr(cfqq))
- return;
- list_del(&cfqq->cfq_list);
- if (cfq_class_rt(cfqq))
- list = &cfqd->cur_rr;
- else if (cfq_class_idle(cfqq))
- list = &cfqd->idle_rr;
- else {
- /*
- * if cfqq has requests in flight, don't allow it to be
- * found in cfq_set_active_queue before it has finished them.
- * this is done to increase fairness between a process that
- * has lots of io pending vs one that only generates one
- * sporadically or synchronously
- */
- if (cfq_cfqq_dispatched(cfqq))
- list = &cfqd->busy_rr;
- else
- list = &cfqd->rr_list[cfqq->ioprio];
- }
- if (preempted || cfq_cfqq_queue_new(cfqq)) {
- /*
- * If this queue was preempted or is new (never been serviced),
- * let it be added first for fairness but beind other new
- * queues.
- */
- n = list;
- while (n->next != list) {
- __cfqq = list_entry_cfqq(n->next);
- if (!cfq_cfqq_queue_new(__cfqq))
- break;
- n = n->next;
- }
- list_add_tail(&cfqq->cfq_list, n);
- } else if (!cfq_cfqq_class_sync(cfqq)) {
- /*
- * async queue always goes to the end. this wont be overly
- * unfair to writes, as the sort of the sync queue wont be
- * allowed to pass the async queue again.
- */
- list_add_tail(&cfqq->cfq_list, list);
- } else {
- /*
- * sort by last service, but don't cross a new or async
- * queue. we don't cross a new queue because it hasn't been
- * service before, and we don't cross an async queue because
- * it gets added to the end on expire.
- */
- n = list;
- while ((n = n->prev) != list) {
- struct cfq_queue *__cfqq = list_entry_cfqq(n);
- if (!cfq_cfqq_class_sync(cfqq) || !__cfqq->service_last)
- break;
- if (time_before(__cfqq->service_last, cfqq->service_last))
- break;
- }
- list_add(&cfqq->cfq_list, n);
- }
- }
- /*
- * add to busy list of queues for service, trying to be fair in ordering
- * the pending list according to last request service
- */
- static inline void
- cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
- {
- BUG_ON(cfq_cfqq_on_rr(cfqq));
- cfq_mark_cfqq_on_rr(cfqq);
- cfqd->busy_queues++;
- cfq_resort_rr_list(cfqq, 0);
- }
- static inline void
- cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
- {
- BUG_ON(!cfq_cfqq_on_rr(cfqq));
- cfq_clear_cfqq_on_rr(cfqq);
- list_del_init(&cfqq->cfq_list);
- BUG_ON(!cfqd->busy_queues);
- cfqd->busy_queues--;
- }
- /*
- * rb tree support functions
- */
- static inline void cfq_del_rq_rb(struct request *rq)
- {
- struct cfq_queue *cfqq = RQ_CFQQ(rq);
- struct cfq_data *cfqd = cfqq->cfqd;
- const int sync = rq_is_sync(rq);
- BUG_ON(!cfqq->queued[sync]);
- cfqq->queued[sync]--;
- elv_rb_del(&cfqq->sort_list, rq);
- if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list))
- cfq_del_cfqq_rr(cfqd, cfqq);
- }
- static void cfq_add_rq_rb(struct request *rq)
- {
- struct cfq_queue *cfqq = RQ_CFQQ(rq);
- struct cfq_data *cfqd = cfqq->cfqd;
- struct request *__alias;
- cfqq->queued[rq_is_sync(rq)]++;
- /*
- * looks a little odd, but the first insert might return an alias.
- * if that happens, put the alias on the dispatch list
- */
- while ((__alias = elv_rb_add(&cfqq->sort_list, rq)) != NULL)
- cfq_dispatch_insert(cfqd->queue, __alias);
- if (!cfq_cfqq_on_rr(cfqq))
- cfq_add_cfqq_rr(cfqd, cfqq);
- /*
- * check if this request is a better next-serve candidate
- */
- cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq);
- BUG_ON(!cfqq->next_rq);
- }
- static inline void
- cfq_reposition_rq_rb(struct cfq_queue *cfqq, struct request *rq)
- {
- elv_rb_del(&cfqq->sort_list, rq);
- cfqq->queued[rq_is_sync(rq)]--;
- cfq_add_rq_rb(rq);
- }
- static struct request *
- cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio)
- {
- struct task_struct *tsk = current;
- pid_t key = cfq_queue_pid(tsk, bio_data_dir(bio), bio_sync(bio));
- struct cfq_queue *cfqq;
- cfqq = cfq_find_cfq_hash(cfqd, key, tsk->ioprio);
- if (cfqq) {
- sector_t sector = bio->bi_sector + bio_sectors(bio);
- return elv_rb_find(&cfqq->sort_list, sector);
- }
- return NULL;
- }
- static void cfq_activate_request(request_queue_t *q, struct request *rq)
- {
- struct cfq_data *cfqd = q->elevator->elevator_data;
- cfqd->rq_in_driver++;
- /*
- * If the depth is larger 1, it really could be queueing. But lets
- * make the mark a little higher - idling could still be good for
- * low queueing, and a low queueing number could also just indicate
- * a SCSI mid layer like behaviour where limit+1 is often seen.
- */
- if (!cfqd->hw_tag && cfqd->rq_in_driver > 4)
- cfqd->hw_tag = 1;
- }
- static void cfq_deactivate_request(request_queue_t *q, struct request *rq)
- {
- struct cfq_data *cfqd = q->elevator->elevator_data;
- WARN_ON(!cfqd->rq_in_driver);
- cfqd->rq_in_driver--;
- }
- static void cfq_remove_request(struct request *rq)
- {
- struct cfq_queue *cfqq = RQ_CFQQ(rq);
- if (cfqq->next_rq == rq)
- cfqq->next_rq = cfq_find_next_rq(cfqq->cfqd, cfqq, rq);
- list_del_init(&rq->queuelist);
- cfq_del_rq_rb(rq);
- if (rq_is_meta(rq)) {
- WARN_ON(!cfqq->meta_pending);
- cfqq->meta_pending--;
- }
- }
- static int
- cfq_merge(request_queue_t *q, struct request **req, struct bio *bio)
- {
- struct cfq_data *cfqd = q->elevator->elevator_data;
- struct request *__rq;
- __rq = cfq_find_rq_fmerge(cfqd, bio);
- if (__rq && elv_rq_merge_ok(__rq, bio)) {
- *req = __rq;
- return ELEVATOR_FRONT_MERGE;
- }
- return ELEVATOR_NO_MERGE;
- }
- static void cfq_merged_request(request_queue_t *q, struct request *req,
- int type)
- {
- if (type == ELEVATOR_FRONT_MERGE) {
- struct cfq_queue *cfqq = RQ_CFQQ(req);
- cfq_reposition_rq_rb(cfqq, req);
- }
- }
- static void
- cfq_merged_requests(request_queue_t *q, struct request *rq,
- struct request *next)
- {
- /*
- * reposition in fifo if next is older than rq
- */
- if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) &&
- time_before(next->start_time, rq->start_time))
- list_move(&rq->queuelist, &next->queuelist);
- cfq_remove_request(next);
- }
- static int cfq_allow_merge(request_queue_t *q, struct request *rq,
- struct bio *bio)
- {
- struct cfq_data *cfqd = q->elevator->elevator_data;
- const int rw = bio_data_dir(bio);
- struct cfq_queue *cfqq;
- pid_t key;
- /*
- * Disallow merge of a sync bio into an async request.
- */
- if ((bio_data_dir(bio) == READ || bio_sync(bio)) && !rq_is_sync(rq))
- return 0;
- /*
- * Lookup the cfqq that this bio will be queued with. Allow
- * merge only if rq is queued there.
- */
- key = cfq_queue_pid(current, rw, bio_sync(bio));
- cfqq = cfq_find_cfq_hash(cfqd, key, current->ioprio);
- if (cfqq == RQ_CFQQ(rq))
- return 1;
- return 0;
- }
- static inline void
- __cfq_set_active_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
- {
- if (cfqq) {
- /*
- * stop potential idle class queues waiting service
- */
- del_timer(&cfqd->idle_class_timer);
- cfqq->slice_end = 0;
- cfq_clear_cfqq_must_alloc_slice(cfqq);
- cfq_clear_cfqq_fifo_expire(cfqq);
- cfq_mark_cfqq_slice_new(cfqq);
- }
- cfqd->active_queue = cfqq;
- }
- /*
- * current cfqq expired its slice (or was too idle), select new one
- */
- static void
- __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
- int preempted, int timed_out)
- {
- if (cfq_cfqq_wait_request(cfqq))
- del_timer(&cfqd->idle_slice_timer);
- cfq_clear_cfqq_must_dispatch(cfqq);
- cfq_clear_cfqq_wait_request(cfqq);
- cfq_clear_cfqq_queue_new(cfqq);
- /*
- * store what was left of this slice, if the queue idled out
- * or was preempted
- */
- if (timed_out && !cfq_cfqq_slice_new(cfqq))
- cfqq->slice_resid = cfqq->slice_end - jiffies;
- cfq_resort_rr_list(cfqq, preempted);
- if (cfqq == cfqd->active_queue)
- cfqd->active_queue = NULL;
- if (cfqd->active_cic) {
- put_io_context(cfqd->active_cic->ioc);
- cfqd->active_cic = NULL;
- }
- cfqd->dispatch_slice = 0;
- }
- static inline void cfq_slice_expired(struct cfq_data *cfqd, int preempted,
- int timed_out)
- {
- struct cfq_queue *cfqq = cfqd->active_queue;
- if (cfqq)
- __cfq_slice_expired(cfqd, cfqq, preempted, timed_out);
- }
- /*
- * 0
- * 0,1
- * 0,1,2
- * 0,1,2,3
- * 0,1,2,3,4
- * 0,1,2,3,4,5
- * 0,1,2,3,4,5,6
- * 0,1,2,3,4,5,6,7
- */
- static int cfq_get_next_prio_level(struct cfq_data *cfqd)
- {
- int prio, wrap;
- prio = -1;
- wrap = 0;
- do {
- int p;
- for (p = cfqd->cur_prio; p <= cfqd->cur_end_prio; p++) {
- if (!list_empty(&cfqd->rr_list[p])) {
- prio = p;
- break;
- }
- }
- if (prio != -1)
- break;
- cfqd->cur_prio = 0;
- if (++cfqd->cur_end_prio == CFQ_PRIO_LISTS) {
- cfqd->cur_end_prio = 0;
- if (wrap)
- break;
- wrap = 1;
- }
- } while (1);
- if (unlikely(prio == -1))
- return -1;
- BUG_ON(prio >= CFQ_PRIO_LISTS);
- list_splice_init(&cfqd->rr_list[prio], &cfqd->cur_rr);
- cfqd->cur_prio = prio + 1;
- if (cfqd->cur_prio > cfqd->cur_end_prio) {
- cfqd->cur_end_prio = cfqd->cur_prio;
- cfqd->cur_prio = 0;
- }
- if (cfqd->cur_end_prio == CFQ_PRIO_LISTS) {
- cfqd->cur_prio = 0;
- cfqd->cur_end_prio = 0;
- }
- return prio;
- }
- static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd)
- {
- struct cfq_queue *cfqq = NULL;
- if (!list_empty(&cfqd->cur_rr) || cfq_get_next_prio_level(cfqd) != -1) {
- /*
- * if current list is non-empty, grab first entry. if it is
- * empty, get next prio level and grab first entry then if any
- * are spliced
- */
- cfqq = list_entry_cfqq(cfqd->cur_rr.next);
- } else if (!list_empty(&cfqd->busy_rr)) {
- /*
- * If no new queues are available, check if the busy list has
- * some before falling back to idle io.
- */
- cfqq = list_entry_cfqq(cfqd->busy_rr.next);
- } else if (!list_empty(&cfqd->idle_rr)) {
- /*
- * if we have idle queues and no rt or be queues had pending
- * requests, either allow immediate service if the grace period
- * has passed or arm the idle grace timer
- */
- unsigned long end = cfqd->last_end_request + CFQ_IDLE_GRACE;
- if (time_after_eq(jiffies, end))
- cfqq = list_entry_cfqq(cfqd->idle_rr.next);
- else
- mod_timer(&cfqd->idle_class_timer, end);
- }
- __cfq_set_active_queue(cfqd, cfqq);
- return cfqq;
- }
- #define CIC_SEEKY(cic) ((cic)->seek_mean > (128 * 1024))
- static int cfq_arm_slice_timer(struct cfq_data *cfqd)
- {
- struct cfq_queue *cfqq = cfqd->active_queue;
- struct cfq_io_context *cic;
- unsigned long sl;
- WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list));
- /*
- * idle is disabled, either manually or by past process history
- */
- if (!cfqd->cfq_slice_idle)
- return 0;
- if (!cfq_cfqq_idle_window(cfqq))
- return 0;
- /*
- * task has exited, don't wait
- */
- cic = cfqd->active_cic;
- if (!cic || !cic->ioc->task)
- return 0;
- cfq_mark_cfqq_must_dispatch(cfqq);
- cfq_mark_cfqq_wait_request(cfqq);
- sl = min(cfqq->slice_end - 1, (unsigned long) cfqd->cfq_slice_idle);
- /*
- * we don't want to idle for seeks, but we do want to allow
- * fair distribution of slice time for a process doing back-to-back
- * seeks. so allow a little bit of time for him to submit a new rq
- */
- if (sample_valid(cic->seek_samples) && CIC_SEEKY(cic))
- sl = min(sl, msecs_to_jiffies(2));
- mod_timer(&cfqd->idle_slice_timer, jiffies + sl);
- return 1;
- }
- static void cfq_dispatch_insert(request_queue_t *q, struct request *rq)
- {
- struct cfq_data *cfqd = q->elevator->elevator_data;
- struct cfq_queue *cfqq = RQ_CFQQ(rq);
- cfq_remove_request(rq);
- cfqq->on_dispatch[rq_is_sync(rq)]++;
- elv_dispatch_sort(q, rq);
- rq = list_entry(q->queue_head.prev, struct request, queuelist);
- cfqd->last_sector = rq->sector + rq->nr_sectors;
- }
- /*
- * return expired entry, or NULL to just start from scratch in rbtree
- */
- static inline struct request *cfq_check_fifo(struct cfq_queue *cfqq)
- {
- struct cfq_data *cfqd = cfqq->cfqd;
- struct request *rq;
- int fifo;
- if (cfq_cfqq_fifo_expire(cfqq))
- return NULL;
- cfq_mark_cfqq_fifo_expire(cfqq);
- if (list_empty(&cfqq->fifo))
- return NULL;
- fifo = cfq_cfqq_class_sync(cfqq);
- rq = rq_entry_fifo(cfqq->fifo.next);
- if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo]))
- return rq;
- return NULL;
- }
- static inline int
- cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
- {
- const int base_rq = cfqd->cfq_slice_async_rq;
- WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR);
- return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio));
- }
- /*
- * get next queue for service
- */
- static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd)
- {
- struct cfq_queue *cfqq;
- cfqq = cfqd->active_queue;
- if (!cfqq)
- goto new_queue;
- /*
- * slice has expired
- */
- if (!cfq_cfqq_must_dispatch(cfqq) && cfq_slice_used(cfqq))
- goto expire;
- /*
- * if queue has requests, dispatch one. if not, check if
- * enough slice is left to wait for one
- */
- if (!RB_EMPTY_ROOT(&cfqq->sort_list))
- goto keep_queue;
- else if (cfq_cfqq_slice_new(cfqq) || cfq_cfqq_dispatched(cfqq)) {
- cfqq = NULL;
- goto keep_queue;
- } else if (cfq_cfqq_class_sync(cfqq)) {
- if (cfq_arm_slice_timer(cfqd))
- return NULL;
- }
- expire:
- cfq_slice_expired(cfqd, 0, 0);
- new_queue:
- cfqq = cfq_set_active_queue(cfqd);
- keep_queue:
- return cfqq;
- }
- static int
- __cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq,
- int max_dispatch)
- {
- int dispatched = 0;
- BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list));
- do {
- struct request *rq;
- /*
- * follow expired path, else get first next available
- */
- if ((rq = cfq_check_fifo(cfqq)) == NULL)
- rq = cfqq->next_rq;
- /*
- * finally, insert request into driver dispatch list
- */
- cfq_dispatch_insert(cfqd->queue, rq);
- cfqd->dispatch_slice++;
- dispatched++;
- if (!cfqd->active_cic) {
- atomic_inc(&RQ_CIC(rq)->ioc->refcount);
- cfqd->active_cic = RQ_CIC(rq);
- }
- if (RB_EMPTY_ROOT(&cfqq->sort_list))
- break;
- } while (dispatched < max_dispatch);
- /*
- * expire an async queue immediately if it has used up its slice. idle
- * queue always expire after 1 dispatch round.
- */
- if (cfqd->busy_queues > 1 && ((!cfq_cfqq_sync(cfqq) &&
- cfqd->dispatch_slice >= cfq_prio_to_maxrq(cfqd, cfqq)) ||
- cfq_class_idle(cfqq))) {
- cfqq->slice_end = jiffies + 1;
- cfq_slice_expired(cfqd, 0, 0);
- }
- return dispatched;
- }
- static int
- cfq_forced_dispatch_cfqqs(struct list_head *list)
- {
- struct cfq_queue *cfqq, *next;
- int dispatched;
- dispatched = 0;
- list_for_each_entry_safe(cfqq, next, list, cfq_list) {
- while (cfqq->next_rq) {
- cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq);
- dispatched++;
- }
- BUG_ON(!list_empty(&cfqq->fifo));
- }
- return dispatched;
- }
- static int
- cfq_forced_dispatch(struct cfq_data *cfqd)
- {
- int i, dispatched = 0;
- for (i = 0; i < CFQ_PRIO_LISTS; i++)
- dispatched += cfq_forced_dispatch_cfqqs(&cfqd->rr_list[i]);
- dispatched += cfq_forced_dispatch_cfqqs(&cfqd->busy_rr);
- dispatched += cfq_forced_dispatch_cfqqs(&cfqd->cur_rr);
- dispatched += cfq_forced_dispatch_cfqqs(&cfqd->idle_rr);
- cfq_slice_expired(cfqd, 0, 0);
- BUG_ON(cfqd->busy_queues);
- return dispatched;
- }
- static int
- cfq_dispatch_requests(request_queue_t *q, int force)
- {
- struct cfq_data *cfqd = q->elevator->elevator_data;
- struct cfq_queue *cfqq, *prev_cfqq;
- int dispatched;
- if (!cfqd->busy_queues)
- return 0;
- if (unlikely(force))
- return cfq_forced_dispatch(cfqd);
- dispatched = 0;
- prev_cfqq = NULL;
- while ((cfqq = cfq_select_queue(cfqd)) != NULL) {
- int max_dispatch;
- if (cfqd->busy_queues > 1) {
- /*
- * Don't repeat dispatch from the previous queue.
- */
- if (prev_cfqq == cfqq)
- break;
- /*
- * So we have dispatched before in this round, if the
- * next queue has idling enabled (must be sync), don't
- * allow it service until the previous have continued.
- */
- if (cfqd->rq_in_driver && cfq_cfqq_idle_window(cfqq))
- break;
- }
- cfq_clear_cfqq_must_dispatch(cfqq);
- cfq_clear_cfqq_wait_request(cfqq);
- del_timer(&cfqd->idle_slice_timer);
- max_dispatch = cfqd->cfq_quantum;
- if (cfq_class_idle(cfqq))
- max_dispatch = 1;
- dispatched += __cfq_dispatch_requests(cfqd, cfqq, max_dispatch);
- prev_cfqq = cfqq;
- }
- return dispatched;
- }
- /*
- * task holds one reference to the queue, dropped when task exits. each rq
- * in-flight on this queue also holds a reference, dropped when rq is freed.
- *
- * queue lock must be held here.
- */
- static void cfq_put_queue(struct cfq_queue *cfqq)
- {
- struct cfq_data *cfqd = cfqq->cfqd;
- BUG_ON(atomic_read(&cfqq->ref) <= 0);
- if (!atomic_dec_and_test(&cfqq->ref))
- return;
- BUG_ON(rb_first(&cfqq->sort_list));
- BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]);
- BUG_ON(cfq_cfqq_on_rr(cfqq));
- if (unlikely(cfqd->active_queue == cfqq)) {
- __cfq_slice_expired(cfqd, cfqq, 0, 0);
- cfq_schedule_dispatch(cfqd);
- }
- /*
- * it's on the empty list and still hashed
- */
- list_del(&cfqq->cfq_list);
- hlist_del(&cfqq->cfq_hash);
- kmem_cache_free(cfq_pool, cfqq);
- }
- static struct cfq_queue *
- __cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned int prio,
- const int hashval)
- {
- struct hlist_head *hash_list = &cfqd->cfq_hash[hashval];
- struct hlist_node *entry;
- struct cfq_queue *__cfqq;
- hlist_for_each_entry(__cfqq, entry, hash_list, cfq_hash) {
- const unsigned short __p = IOPRIO_PRIO_VALUE(__cfqq->org_ioprio_class, __cfqq->org_ioprio);
- if (__cfqq->key == key && (__p == prio || !prio))
- return __cfqq;
- }
- return NULL;
- }
- static struct cfq_queue *
- cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned short prio)
- {
- return __cfq_find_cfq_hash(cfqd, key, prio, hash_long(key, CFQ_QHASH_SHIFT));
- }
- static void cfq_free_io_context(struct io_context *ioc)
- {
- struct cfq_io_context *__cic;
- struct rb_node *n;
- int freed = 0;
- while ((n = rb_first(&ioc->cic_root)) != NULL) {
- __cic = rb_entry(n, struct cfq_io_context, rb_node);
- rb_erase(&__cic->rb_node, &ioc->cic_root);
- kmem_cache_free(cfq_ioc_pool, __cic);
- freed++;
- }
- elv_ioc_count_mod(ioc_count, -freed);
- if (ioc_gone && !elv_ioc_count_read(ioc_count))
- complete(ioc_gone);
- }
- static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
- {
- if (unlikely(cfqq == cfqd->active_queue)) {
- __cfq_slice_expired(cfqd, cfqq, 0, 0);
- cfq_schedule_dispatch(cfqd);
- }
- cfq_put_queue(cfqq);
- }
- static void __cfq_exit_single_io_context(struct cfq_data *cfqd,
- struct cfq_io_context *cic)
- {
- list_del_init(&cic->queue_list);
- smp_wmb();
- cic->key = NULL;
- if (cic->cfqq[ASYNC]) {
- cfq_exit_cfqq(cfqd, cic->cfqq[ASYNC]);
- cic->cfqq[ASYNC] = NULL;
- }
- if (cic->cfqq[SYNC]) {
- cfq_exit_cfqq(cfqd, cic->cfqq[SYNC]);
- cic->cfqq[SYNC] = NULL;
- }
- }
- /*
- * Called with interrupts disabled
- */
- static void cfq_exit_single_io_context(struct cfq_io_context *cic)
- {
- struct cfq_data *cfqd = cic->key;
- if (cfqd) {
- request_queue_t *q = cfqd->queue;
- spin_lock_irq(q->queue_lock);
- __cfq_exit_single_io_context(cfqd, cic);
- spin_unlock_irq(q->queue_lock);
- }
- }
- static void cfq_exit_io_context(struct io_context *ioc)
- {
- struct cfq_io_context *__cic;
- struct rb_node *n;
- /*
- * put the reference this task is holding to the various queues
- */
- n = rb_first(&ioc->cic_root);
- while (n != NULL) {
- __cic = rb_entry(n, struct cfq_io_context, rb_node);
- cfq_exit_single_io_context(__cic);
- n = rb_next(n);
- }
- }
- static struct cfq_io_context *
- cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask)
- {
- struct cfq_io_context *cic;
- cic = kmem_cache_alloc_node(cfq_ioc_pool, gfp_mask, cfqd->queue->node);
- if (cic) {
- memset(cic, 0, sizeof(*cic));
- cic->last_end_request = jiffies;
- INIT_LIST_HEAD(&cic->queue_list);
- cic->dtor = cfq_free_io_context;
- cic->exit = cfq_exit_io_context;
- elv_ioc_count_inc(ioc_count);
- }
- return cic;
- }
- static void cfq_init_prio_data(struct cfq_queue *cfqq)
- {
- struct task_struct *tsk = current;
- int ioprio_class;
- if (!cfq_cfqq_prio_changed(cfqq))
- return;
- ioprio_class = IOPRIO_PRIO_CLASS(tsk->ioprio);
- switch (ioprio_class) {
- default:
- printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class);
- case IOPRIO_CLASS_NONE:
- /*
- * no prio set, place us in the middle of the BE classes
- */
- if (tsk->policy == SCHED_IDLE)
- goto set_class_idle;
- cfqq->ioprio = task_nice_ioprio(tsk);
- cfqq->ioprio_class = IOPRIO_CLASS_BE;
- break;
- case IOPRIO_CLASS_RT:
- cfqq->ioprio = task_ioprio(tsk);
- cfqq->ioprio_class = IOPRIO_CLASS_RT;
- break;
- case IOPRIO_CLASS_BE:
- cfqq->ioprio = task_ioprio(tsk);
- cfqq->ioprio_class = IOPRIO_CLASS_BE;
- break;
- case IOPRIO_CLASS_IDLE:
- set_class_idle:
- cfqq->ioprio_class = IOPRIO_CLASS_IDLE;
- cfqq->ioprio = 7;
- cfq_clear_cfqq_idle_window(cfqq);
- break;
- }
- /*
- * keep track of original prio settings in case we have to temporarily
- * elevate the priority of this queue
- */
- cfqq->org_ioprio = cfqq->ioprio;
- cfqq->org_ioprio_class = cfqq->ioprio_class;
- cfq_resort_rr_list(cfqq, 0);
- cfq_clear_cfqq_prio_changed(cfqq);
- }
- static inline void changed_ioprio(struct cfq_io_context *cic)
- {
- struct cfq_data *cfqd = cic->key;
- struct cfq_queue *cfqq;
- unsigned long flags;
- if (unlikely(!cfqd))
- return;
- spin_lock_irqsave(cfqd->queue->queue_lock, flags);
- cfqq = cic->cfqq[ASYNC];
- if (cfqq) {
- struct cfq_queue *new_cfqq;
- new_cfqq = cfq_get_queue(cfqd, CFQ_KEY_ASYNC, cic->ioc->task,
- GFP_ATOMIC);
- if (new_cfqq) {
- cic->cfqq[ASYNC] = new_cfqq;
- cfq_put_queue(cfqq);
- }
- }
- cfqq = cic->cfqq[SYNC];
- if (cfqq)
- cfq_mark_cfqq_prio_changed(cfqq);
- spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
- }
- static void cfq_ioc_set_ioprio(struct io_context *ioc)
- {
- struct cfq_io_context *cic;
- struct rb_node *n;
- ioc->ioprio_changed = 0;
- n = rb_first(&ioc->cic_root);
- while (n != NULL) {
- cic = rb_entry(n, struct cfq_io_context, rb_node);
- changed_ioprio(cic);
- n = rb_next(n);
- }
- }
- static struct cfq_queue *
- cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk,
- gfp_t gfp_mask)
- {
- const int hashval = hash_long(key, CFQ_QHASH_SHIFT);
- struct cfq_queue *cfqq, *new_cfqq = NULL;
- unsigned short ioprio;
- retry:
- ioprio = tsk->ioprio;
- cfqq = __cfq_find_cfq_hash(cfqd, key, ioprio, hashval);
- if (!cfqq) {
- if (new_cfqq) {
- cfqq = new_cfqq;
- new_cfqq = NULL;
- } else if (gfp_mask & __GFP_WAIT) {
- /*
- * Inform the allocator of the fact that we will
- * just repeat this allocation if it fails, to allow
- * the allocator to do whatever it needs to attempt to
- * free memory.
- */
- spin_unlock_irq(cfqd->queue->queue_lock);
- new_cfqq = kmem_cache_alloc_node(cfq_pool, gfp_mask|__GFP_NOFAIL, cfqd->queue->node);
- spin_lock_irq(cfqd->queue->queue_lock);
- goto retry;
- } else {
- cfqq = kmem_cache_alloc_node(cfq_pool, gfp_mask, cfqd->queue->node);
- if (!cfqq)
- goto out;
- }
- memset(cfqq, 0, sizeof(*cfqq));
- INIT_HLIST_NODE(&cfqq->cfq_hash);
- INIT_LIST_HEAD(&cfqq->cfq_list);
- INIT_LIST_HEAD(&cfqq->fifo);
- cfqq->key = key;
- hlist_add_head(&cfqq->cfq_hash, &cfqd->cfq_hash[hashval]);
- atomic_set(&cfqq->ref, 0);
- cfqq->cfqd = cfqd;
- if (key != CFQ_KEY_ASYNC)
- cfq_mark_cfqq_idle_window(cfqq);
- cfq_mark_cfqq_prio_changed(cfqq);
- cfq_mark_cfqq_queue_new(cfqq);
- cfq_init_prio_data(cfqq);
- }
- if (new_cfqq)
- kmem_cache_free(cfq_pool, new_cfqq);
- atomic_inc(&cfqq->ref);
- out:
- WARN_ON((gfp_mask & __GFP_WAIT) && !cfqq);
- return cfqq;
- }
- static void
- cfq_drop_dead_cic(struct io_context *ioc, struct cfq_io_context *cic)
- {
- WARN_ON(!list_empty(&cic->queue_list));
- rb_erase(&cic->rb_node, &ioc->cic_root);
- kmem_cache_free(cfq_ioc_pool, cic);
- elv_ioc_count_dec(ioc_count);
- }
- static struct cfq_io_context *
- cfq_cic_rb_lookup(struct cfq_data *cfqd, struct io_context *ioc)
- {
- struct rb_node *n;
- struct cfq_io_context *cic;
- void *k, *key = cfqd;
- restart:
- n = ioc->cic_root.rb_node;
- while (n) {
- cic = rb_entry(n, struct cfq_io_context, rb_node);
- /* ->key must be copied to avoid race with cfq_exit_queue() */
- k = cic->key;
- if (unlikely(!k)) {
- cfq_drop_dead_cic(ioc, cic);
- goto restart;
- }
- if (key < k)
- n = n->rb_left;
- else if (key > k)
- n = n->rb_right;
- else
- return cic;
- }
- return NULL;
- }
- static inline void
- cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc,
- struct cfq_io_context *cic)
- {
- struct rb_node **p;
- struct rb_node *parent;
- struct cfq_io_context *__cic;
- unsigned long flags;
- void *k;
- cic->ioc = ioc;
- cic->key = cfqd;
- restart:
- parent = NULL;
- p = &ioc->cic_root.rb_node;
- while (*p) {
- parent = *p;
- __cic = rb_entry(parent, struct cfq_io_context, rb_node);
- /* ->key must be copied to avoid race with cfq_exit_queue() */
- k = __cic->key;
- if (unlikely(!k)) {
- cfq_drop_dead_cic(ioc, __cic);
- goto restart;
- }
- if (cic->key < k)
- p = &(*p)->rb_left;
- else if (cic->key > k)
- p = &(*p)->rb_right;
- else
- BUG();
- }
- rb_link_node(&cic->rb_node, parent, p);
- rb_insert_color(&cic->rb_node, &ioc->cic_root);
- spin_lock_irqsave(cfqd->queue->queue_lock, flags);
- list_add(&cic->queue_list, &cfqd->cic_list);
- spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
- }
- /*
- * Setup general io context and cfq io context. There can be several cfq
- * io contexts per general io context, if this process is doing io to more
- * than one device managed by cfq.
- */
- static struct cfq_io_context *
- cfq_get_io_context(struct cfq_data *cfqd, gfp_t gfp_mask)
- {
- struct io_context *ioc = NULL;
- struct cfq_io_context *cic;
- might_sleep_if(gfp_mask & __GFP_WAIT);
- ioc = get_io_context(gfp_mask, cfqd->queue->node);
- if (!ioc)
- return NULL;
- cic = cfq_cic_rb_lookup(cfqd, ioc);
- if (cic)
- goto out;
- cic = cfq_alloc_io_context(cfqd, gfp_mask);
- if (cic == NULL)
- goto err;
- cfq_cic_link(cfqd, ioc, cic);
- out:
- smp_read_barrier_depends();
- if (unlikely(ioc->ioprio_changed))
- cfq_ioc_set_ioprio(ioc);
- return cic;
- err:
- put_io_context(ioc);
- return NULL;
- }
- static void
- cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic)
- {
- unsigned long elapsed = jiffies - cic->last_end_request;
- unsigned long ttime = min(elapsed, 2UL * cfqd->cfq_slice_idle);
- cic->ttime_samples = (7*cic->ttime_samples + 256) / 8;
- cic->ttime_total = (7*cic->ttime_total + 256*ttime) / 8;
- cic->ttime_mean = (cic->ttime_total + 128) / cic->ttime_samples;
- }
- static void
- cfq_update_io_seektime(struct cfq_io_context *cic, struct request *rq)
- {
- sector_t sdist;
- u64 total;
- if (cic->last_request_pos < rq->sector)
- sdist = rq->sector - cic->last_request_pos;
- else
- sdist = cic->last_request_pos - rq->sector;
- /*
- * Don't allow the seek distance to get too large from the
- * odd fragment, pagein, etc
- */
- if (cic->seek_samples <= 60) /* second&third seek */
- sdist = min(sdist, (cic->seek_mean * 4) + 2*1024*1024);
- else
- sdist = min(sdist, (cic->seek_mean * 4) + 2*1024*64);
- cic->seek_samples = (7*cic->seek_samples + 256) / 8;
- cic->seek_total = (7*cic->seek_total + (u64)256*sdist) / 8;
- total = cic->seek_total + (cic->seek_samples/2);
- do_div(total, cic->seek_samples);
- cic->seek_mean = (sector_t)total;
- }
- /*
- * Disable idle window if the process thinks too long or seeks so much that
- * it doesn't matter
- */
- static void
- cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
- struct cfq_io_context *cic)
- {
- int enable_idle = cfq_cfqq_idle_window(cfqq);
- if (!cic->ioc->task || !cfqd->cfq_slice_idle ||
- (cfqd->hw_tag && CIC_SEEKY(cic)))
- enable_idle = 0;
- else if (sample_valid(cic->ttime_samples)) {
- if (cic->ttime_mean > cfqd->cfq_slice_idle)
- enable_idle = 0;
- else
- enable_idle = 1;
- }
- if (enable_idle)
- cfq_mark_cfqq_idle_window(cfqq);
- else
- cfq_clear_cfqq_idle_window(cfqq);
- }
- /*
- * Check if new_cfqq should preempt the currently active queue. Return 0 for
- * no or if we aren't sure, a 1 will cause a preempt.
- */
- static int
- cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
- struct request *rq)
- {
- struct cfq_queue *cfqq = cfqd->active_queue;
- if (cfq_class_idle(new_cfqq))
- return 0;
- if (!cfqq)
- return 0;
- if (cfq_class_idle(cfqq))
- return 1;
- if (!cfq_cfqq_wait_request(new_cfqq))
- return 0;
- /*
- * if the new request is sync, but the currently running queue is
- * not, let the sync request have priority.
- */
- if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq))
- return 1;
- /*
- * So both queues are sync. Let the new request get disk time if
- * it's a metadata request and the current queue is doing regular IO.
- */
- if (rq_is_meta(rq) && !cfqq->meta_pending)
- return 1;
- return 0;
- }
- /*
- * cfqq preempts the active queue. if we allowed preempt with no slice left,
- * let it have half of its nominal slice.
- */
- static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
- {
- cfq_slice_expired(cfqd, 1, 1);
- /*
- * Put the new queue at the front of the of the current list,
- * so we know that it will be selected next.
- */
- BUG_ON(!cfq_cfqq_on_rr(cfqq));
- list_move(&cfqq->cfq_list, &cfqd->cur_rr);
- cfqq->slice_end = 0;
- cfq_mark_cfqq_slice_new(cfqq);
- }
- /*
- * Called when a new fs request (rq) is added (to cfqq). Check if there's
- * something we should do about it
- */
- static void
- cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
- struct request *rq)
- {
- struct cfq_io_context *cic = RQ_CIC(rq);
- if (rq_is_meta(rq))
- cfqq->meta_pending++;
- /*
- * we never wait for an async request and we don't allow preemption
- * of an async request. so just return early
- */
- if (!rq_is_sync(rq)) {
- /*
- * sync process issued an async request, if it's waiting
- * then expire it and kick rq handling.
- */
- if (cic == cfqd->active_cic &&
- del_timer(&cfqd->idle_slice_timer)) {
- cfq_slice_expired(cfqd, 0, 0);
- blk_start_queueing(cfqd->queue);
- }
- return;
- }
- cfq_update_io_thinktime(cfqd, cic);
- cfq_update_io_seektime(cic, rq);
- cfq_update_idle_window(cfqd, cfqq, cic);
- cic->last_request_pos = rq->sector + rq->nr_sectors;
- if (cfqq == cfqd->active_queue) {
- /*
- * if we are waiting for a request for this queue, let it rip
- * immediately and flag that we must not expire this queue
- * just now
- */
- if (cfq_cfqq_wait_request(cfqq)) {
- cfq_mark_cfqq_must_dispatch(cfqq);
- del_timer(&cfqd->idle_slice_timer);
- blk_start_queueing(cfqd->queue);
- }
- } else if (cfq_should_preempt(cfqd, cfqq, rq)) {
- /*
- * not the active queue - expire current slice if it is
- * idle and has expired it's mean thinktime or this new queue
- * has some old slice time left and is of higher priority
- */
- cfq_preempt_queue(cfqd, cfqq);
- cfq_mark_cfqq_must_dispatch(cfqq);
- blk_start_queueing(cfqd->queue);
- }
- }
- static void cfq_insert_request(request_queue_t *q, struct request *rq)
- {
- struct cfq_data *cfqd = q->elevator->elevator_data;
- struct cfq_queue *cfqq = RQ_CFQQ(rq);
- cfq_init_prio_data(cfqq);
- cfq_add_rq_rb(rq);
- list_add_tail(&rq->queuelist, &cfqq->fifo);
- cfq_rq_enqueued(cfqd, cfqq, rq);
- }
- static void cfq_completed_request(request_queue_t *q, struct request *rq)
- {
- struct cfq_queue *cfqq = RQ_CFQQ(rq);
- struct cfq_data *cfqd = cfqq->cfqd;
- const int sync = rq_is_sync(rq);
- unsigned long now;
- now = jiffies;
- WARN_ON(!cfqd->rq_in_driver);
- WARN_ON(!cfqq->on_dispatch[sync]);
- cfqd->rq_in_driver--;
- cfqq->on_dispatch[sync]--;
- cfqq->service_last = now;
- if (!cfq_class_idle(cfqq))
- cfqd->last_end_request = now;
- cfq_resort_rr_list(cfqq, 0);
- if (sync)
- RQ_CIC(rq)->last_end_request = now;
- /*
- * If this is the active queue, check if it needs to be expired,
- * or if we want to idle in case it has no pending requests.
- */
- if (cfqd->active_queue == cfqq) {
- if (cfq_cfqq_slice_new(cfqq)) {
- cfq_set_prio_slice(cfqd, cfqq);
- cfq_clear_cfqq_slice_new(cfqq);
- }
- if (cfq_slice_used(cfqq))
- cfq_slice_expired(cfqd, 0, 1);
- else if (sync && RB_EMPTY_ROOT(&cfqq->sort_list)) {
- if (!cfq_arm_slice_timer(cfqd))
- cfq_schedule_dispatch(cfqd);
- }
- }
- }
- /*
- * we temporarily boost lower priority queues if they are holding fs exclusive
- * resources. they are boosted to normal prio (CLASS_BE/4)
- */
- static void cfq_prio_boost(struct cfq_queue *cfqq)
- {
- const int ioprio_class = cfqq->ioprio_class;
- const int ioprio = cfqq->ioprio;
- if (has_fs_excl()) {
- /*
- * boost idle prio on transactions that would lock out other
- * users of the filesystem
- */
- if (cfq_class_idle(cfqq))
- cfqq->ioprio_class = IOPRIO_CLASS_BE;
- if (cfqq->ioprio > IOPRIO_NORM)
- cfqq->ioprio = IOPRIO_NORM;
- } else {
- /*
- * check if we need to unboost the queue
- */
- if (cfqq->ioprio_class != cfqq->org_ioprio_class)
- cfqq->ioprio_class = cfqq->org_ioprio_class;
- if (cfqq->ioprio != cfqq->org_ioprio)
- cfqq->ioprio = cfqq->org_ioprio;
- }
- /*
- * refile between round-robin lists if we moved the priority class
- */
- if ((ioprio_class != cfqq->ioprio_class || ioprio != cfqq->ioprio))
- cfq_resort_rr_list(cfqq, 0);
- }
- static inline int __cfq_may_queue(struct cfq_queue *cfqq)
- {
- if ((cfq_cfqq_wait_request(cfqq) || cfq_cfqq_must_alloc(cfqq)) &&
- !cfq_cfqq_must_alloc_slice(cfqq)) {
- cfq_mark_cfqq_must_alloc_slice(cfqq);
- return ELV_MQUEUE_MUST;
- }
- return ELV_MQUEUE_MAY;
- }
- static int cfq_may_queue(request_queue_t *q, int rw)
- {
- struct cfq_data *cfqd = q->elevator->elevator_data;
- struct task_struct *tsk = current;
- struct cfq_queue *cfqq;
- unsigned int key;
- key = cfq_queue_pid(tsk, rw, rw & REQ_RW_SYNC);
- /*
- * don't force setup of a queue from here, as a call to may_queue
- * does not necessarily imply that a request actually will be queued.
- * so just lookup a possibly existing queue, or return 'may queue'
- * if that fails
- */
- cfqq = cfq_find_cfq_hash(cfqd, key, tsk->ioprio);
- if (cfqq) {
- cfq_init_prio_data(cfqq);
- cfq_prio_boost(cfqq);
- return __cfq_may_queue(cfqq);
- }
- return ELV_MQUEUE_MAY;
- }
- /*
- * queue lock held here
- */
- static void cfq_put_request(struct request *rq)
- {
- struct cfq_queue *cfqq = RQ_CFQQ(rq);
- if (cfqq) {
- const int rw = rq_data_dir(rq);
- BUG_ON(!cfqq->allocated[rw]);
- cfqq->allocated[rw]--;
- put_io_context(RQ_CIC(rq)->ioc);
- rq->elevator_private = NULL;
- rq->elevator_private2 = NULL;
- cfq_put_queue(cfqq);
- }
- }
- /*
- * Allocate cfq data structures associated with this request.
- */
- static int
- cfq_set_request(request_queue_t *q, struct request *rq, gfp_t gfp_mask)
- {
- struct cfq_data *cfqd = q->elevator->elevator_data;
- struct task_struct *tsk = current;
- struct cfq_io_context *cic;
- const int rw = rq_data_dir(rq);
- const int is_sync = rq_is_sync(rq);
- pid_t key = cfq_queue_pid(tsk, rw, is_sync);
- struct cfq_queue *cfqq;
- unsigned long flags;
- might_sleep_if(gfp_mask & __GFP_WAIT);
- cic = cfq_get_io_context(cfqd, gfp_mask);
- spin_lock_irqsave(q->queue_lock, flags);
- if (!cic)
- goto queue_fail;
- if (!cic->cfqq[is_sync]) {
- cfqq = cfq_get_queue(cfqd, key, tsk, gfp_mask);
- if (!cfqq)
- goto queue_fail;
- cic->cfqq[is_sync] = cfqq;
- } else
- cfqq = cic->cfqq[is_sync];
- cfqq->allocated[rw]++;
- cfq_clear_cfqq_must_alloc(cfqq);
- atomic_inc(&cfqq->ref);
- spin_unlock_irqrestore(q->queue_lock, flags);
- rq->elevator_private = cic;
- rq->elevator_private2 = cfqq;
- return 0;
- queue_fail:
- if (cic)
- put_io_context(cic->ioc);
- cfq_schedule_dispatch(cfqd);
- spin_unlock_irqrestore(q->queue_lock, flags);
- return 1;
- }
- static void cfq_kick_queue(struct work_struct *work)
- {
- struct cfq_data *cfqd =
- container_of(work, struct cfq_data, unplug_work);
- request_queue_t *q = cfqd->queue;
- unsigned long flags;
- spin_lock_irqsave(q->queue_lock, flags);
- blk_start_queueing(q);
- spin_unlock_irqrestore(q->queue_lock, flags);
- }
- /*
- * Timer running if the active_queue is currently idling inside its time slice
- */
- static void cfq_idle_slice_timer(unsigned long data)
- {
- struct cfq_data *cfqd = (struct cfq_data *) data;
- struct cfq_queue *cfqq;
- unsigned long flags;
- int timed_out = 1;
- spin_lock_irqsave(cfqd->queue->queue_lock, flags);
- if ((cfqq = cfqd->active_queue) != NULL) {
- timed_out = 0;
- /*
- * expired
- */
- if (cfq_slice_used(cfqq))
- goto expire;
- /*
- * only expire and reinvoke request handler, if there are
- * other queues with pending requests
- */
- if (!cfqd->busy_queues)
- goto out_cont;
- /*
- * not expired and it has a request pending, let it dispatch
- */
- if (!RB_EMPTY_ROOT(&cfqq->sort_list)) {
- cfq_mark_cfqq_must_dispatch(cfqq);
- goto out_kick;
- }
- }
- expire:
- cfq_slice_expired(cfqd, 0, timed_out);
- out_kick:
- cfq_schedule_dispatch(cfqd);
- out_cont:
- spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
- }
- /*
- * Timer running if an idle class queue is waiting for service
- */
- static void cfq_idle_class_timer(unsigned long data)
- {
- struct cfq_data *cfqd = (struct cfq_data *) data;
- unsigned long flags, end;
- spin_lock_irqsave(cfqd->queue->queue_lock, flags);
- /*
- * race with a non-idle queue, reset timer
- */
- end = cfqd->last_end_request + CFQ_IDLE_GRACE;
- if (!time_after_eq(jiffies, end))
- mod_timer(&cfqd->idle_class_timer, end);
- else
- cfq_schedule_dispatch(cfqd);
- spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
- }
- static void cfq_shutdown_timer_wq(struct cfq_data *cfqd)
- {
- del_timer_sync(&cfqd->idle_slice_timer);
- del_timer_sync(&cfqd->idle_class_timer);
- blk_sync_queue(cfqd->queue);
- }
- static void cfq_exit_queue(elevator_t *e)
- {
- struct cfq_data *cfqd = e->elevator_data;
- request_queue_t *q = cfqd->queue;
- cfq_shutdown_timer_wq(cfqd);
- spin_lock_irq(q->queue_lock);
- if (cfqd->active_queue)
- __cfq_slice_expired(cfqd, cfqd->active_queue, 0, 0);
- while (!list_empty(&cfqd->cic_list)) {
- struct cfq_io_context *cic = list_entry(cfqd->cic_list.next,
- struct cfq_io_context,
- queue_list);
- __cfq_exit_single_io_context(cfqd, cic);
- }
- spin_unlock_irq(q->queue_lock);
- cfq_shutdown_timer_wq(cfqd);
- kfree(cfqd->cfq_hash);
- kfree(cfqd);
- }
- static void *cfq_init_queue(request_queue_t *q)
- {
- struct cfq_data *cfqd;
- int i;
- cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL, q->node);
- if (!cfqd)
- return NULL;
- memset(cfqd, 0, sizeof(*cfqd));
- for (i = 0; i < CFQ_PRIO_LISTS; i++)
- INIT_LIST_HEAD(&cfqd->rr_list[i]);
- INIT_LIST_HEAD(&cfqd->busy_rr);
- INIT_LIST_HEAD(&cfqd->cur_rr);
- INIT_LIST_HEAD(&cfqd->idle_rr);
- INIT_LIST_HEAD(&cfqd->cic_list);
- cfqd->cfq_hash = kmalloc_node(sizeof(struct hlist_head) * CFQ_QHASH_ENTRIES, GFP_KERNEL, q->node);
- if (!cfqd->cfq_hash)
- goto out_free;
- for (i = 0; i < CFQ_QHASH_ENTRIES; i++)
- INIT_HLIST_HEAD(&cfqd->cfq_hash[i]);
- cfqd->queue = q;
- init_timer(&cfqd->idle_slice_timer);
- cfqd->idle_slice_timer.function = cfq_idle_slice_timer;
- cfqd->idle_slice_timer.data = (unsigned long) cfqd;
- init_timer(&cfqd->idle_class_timer);
- cfqd->idle_class_timer.function = cfq_idle_class_timer;
- cfqd->idle_class_timer.data = (unsigned long) cfqd;
- INIT_WORK(&cfqd->unplug_work, cfq_kick_queue);
- cfqd->cfq_quantum = cfq_quantum;
- cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0];
- cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1];
- cfqd->cfq_back_max = cfq_back_max;
- cfqd->cfq_back_penalty = cfq_back_penalty;
- cfqd->cfq_slice[0] = cfq_slice_async;
- cfqd->cfq_slice[1] = cfq_slice_sync;
- cfqd->cfq_slice_async_rq = cfq_slice_async_rq;
- cfqd->cfq_slice_idle = cfq_slice_idle;
- return cfqd;
- out_free:
- kfree(cfqd);
- return NULL;
- }
- static void cfq_slab_kill(void)
- {
- if (cfq_pool)
- kmem_cache_destroy(cfq_pool);
- if (cfq_ioc_pool)
- kmem_cache_destroy(cfq_ioc_pool);
- }
- static int __init cfq_slab_setup(void)
- {
- cfq_pool = kmem_cache_create("cfq_pool", sizeof(struct cfq_queue), 0, 0,
- NULL, NULL);
- if (!cfq_pool)
- goto fail;
- cfq_ioc_pool = kmem_cache_create("cfq_ioc_pool",
- sizeof(struct cfq_io_context), 0, 0, NULL, NULL);
- if (!cfq_ioc_pool)
- goto fail;
- return 0;
- fail:
- cfq_slab_kill();
- return -ENOMEM;
- }
- /*
- * sysfs parts below -->
- */
- static ssize_t
- cfq_var_show(unsigned int var, char *page)
- {
- return sprintf(page, "%d\n", var);
- }
- static ssize_t
- cfq_var_store(unsigned int *var, const char *page, size_t count)
- {
- char *p = (char *) page;
- *var = simple_strtoul(p, &p, 10);
- return count;
- }
- #define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \
- static ssize_t __FUNC(elevator_t *e, char *page) \
- { \
- struct cfq_data *cfqd = e->elevator_data; \
- unsigned int __data = __VAR; \
- if (__CONV) \
- __data = jiffies_to_msecs(__data); \
- return cfq_var_show(__data, (page)); \
- }
- SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0);
- SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1);
- SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1);
- SHOW_FUNCTION(cfq_back_seek_max_show, cfqd->cfq_back_max, 0);
- SHOW_FUNCTION(cfq_back_seek_penalty_show, cfqd->cfq_back_penalty, 0);
- SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1);
- SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1);
- SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1);
- SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0);
- #undef SHOW_FUNCTION
- #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \
- static ssize_t __FUNC(elevator_t *e, const char *page, size_t count) \
- { \
- struct cfq_data *cfqd = e->elevator_data; \
- unsigned int __data; \
- int ret = cfq_var_store(&__data, (page), count); \
- if (__data < (MIN)) \
- __data = (MIN); \
- else if (__data > (MAX)) \
- __data = (MAX); \
- if (__CONV) \
- *(__PTR) = msecs_to_jiffies(__data); \
- else \
- *(__PTR) = __data; \
- return ret; \
- }
- STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0);
- STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, UINT_MAX, 1);
- STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, UINT_MAX, 1);
- STORE_FUNCTION(cfq_back_seek_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0);
- STORE_FUNCTION(cfq_back_seek_penalty_store, &cfqd->cfq_back_penalty, 1, UINT_MAX, 0);
- STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1);
- STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1);
- STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1);
- STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, UINT_MAX, 0);
- #undef STORE_FUNCTION
- #define CFQ_ATTR(name) \
- __ATTR(name, S_IRUGO|S_IWUSR, cfq_##name##_show, cfq_##name##_store)
- static struct elv_fs_entry cfq_attrs[] = {
- CFQ_ATTR(quantum),
- CFQ_ATTR(fifo_expire_sync),
- CFQ_ATTR(fifo_expire_async),
- CFQ_ATTR(back_seek_max),
- CFQ_ATTR(back_seek_penalty),
- CFQ_ATTR(slice_sync),
- CFQ_ATTR(slice_async),
- CFQ_ATTR(slice_async_rq),
- CFQ_ATTR(slice_idle),
- __ATTR_NULL
- };
- static struct elevator_type iosched_cfq = {
- .ops = {
- .elevator_merge_fn = cfq_merge,
- .elevator_merged_fn = cfq_merged_request,
- .elevator_merge_req_fn = cfq_merged_requests,
- .elevator_allow_merge_fn = cfq_allow_merge,
- .elevator_dispatch_fn = cfq_dispatch_requests,
- .elevator_add_req_fn = cfq_insert_request,
- .elevator_activate_req_fn = cfq_activate_request,
- .elevator_deactivate_req_fn = cfq_deactivate_request,
- .elevator_queue_empty_fn = cfq_queue_empty,
- .elevator_completed_req_fn = cfq_completed_request,
- .elevator_former_req_fn = elv_rb_former_request,
- .elevator_latter_req_fn = elv_rb_latter_request,
- .elevator_set_req_fn = cfq_set_request,
- .elevator_put_req_fn = cfq_put_request,
- .elevator_may_queue_fn = cfq_may_queue,
- .elevator_init_fn = cfq_init_queue,
- .elevator_exit_fn = cfq_exit_queue,
- .trim = cfq_free_io_context,
- },
- .elevator_attrs = cfq_attrs,
- .elevator_name = "cfq",
- .elevator_owner = THIS_MODULE,
- };
- static int __init cfq_init(void)
- {
- int ret;
- /*
- * could be 0 on HZ < 1000 setups
- */
- if (!cfq_slice_async)
- cfq_slice_async = 1;
- if (!cfq_slice_idle)
- cfq_slice_idle = 1;
- if (cfq_slab_setup())
- return -ENOMEM;
- ret = elv_register(&iosched_cfq);
- if (ret)
- cfq_slab_kill();
- return ret;
- }
- static void __exit cfq_exit(void)
- {
- DECLARE_COMPLETION_ONSTACK(all_gone);
- elv_unregister(&iosched_cfq);
- ioc_gone = &all_gone;
- /* ioc_gone's update must be visible before reading ioc_count */
- smp_wmb();
- if (elv_ioc_count_read(ioc_count))
- wait_for_completion(ioc_gone);
- synchronize_rcu();
- cfq_slab_kill();
- }
- module_init(cfq_init);
- module_exit(cfq_exit);
- MODULE_AUTHOR("Jens Axboe");
- MODULE_LICENSE("GPL");
- MODULE_DESCRIPTION("Completely Fair Queueing IO scheduler");
|