From: Jens Axboe Date: Sat, 22 Jul 2006 14:48:31 +0000 (+0200) Subject: [PATCH] cfq-iosched: cleanups, fixes, dead code removal X-Git-Tag: v2.6.19-rc1~640^2~44 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=89850f7ee905410c89f9295e89dc4c33502a34ac;p=linux-2.6-omap-h63xx.git [PATCH] cfq-iosched: cleanups, fixes, dead code removal A collection of little fixes and cleanups: - We don't use the 'queued' sysfs exported attribute, since the may_queue() logic was rewritten. So kill it. - Remove dead defines. - cfq_set_active_queue() can be rewritten cleaner with else if conditions. - Several places had cfq_exit_cfqq() like logic, abstract that out and use that. - Annotate the cfqq kmem_cache_alloc() so the allocator knows that this is a repeat allocation if it fails with __GFP_WAIT set. Allows the allocator to start freeing some memory, if needed. CFQ already loops for this condition, so might as well pass the hint down. - Remove cfqd->rq_starved logic. It's not needed anymore after we dropped the crq allocation in cfq_set_request(). - Remove uneeded parameter passing. Signed-off-by: Jens Axboe --- diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 2ac35aacbbf..ec24284e9d3 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -17,7 +17,6 @@ * tunables */ static const int cfq_quantum = 4; /* max queue in one round of service */ -static const int cfq_queued = 8; /* minimum rq allocate limit per-queue*/ 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 */ @@ -54,7 +53,6 @@ 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_be(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_BE) #define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT) #define ASYNC (0) @@ -98,9 +96,6 @@ struct cfq_data { int rq_in_driver; int hw_tag; - /* - * schedule slice state info - */ /* * idle window management */ @@ -117,13 +112,10 @@ struct cfq_data { sector_t last_sector; unsigned long last_end_request; - unsigned int rq_starved; - /* * tunables, see top of file */ unsigned int cfq_quantum; - unsigned int cfq_queued; unsigned int cfq_fifo_expire[2]; unsigned int cfq_back_penalty; unsigned int cfq_back_max; @@ -484,12 +476,14 @@ 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)); - sector_t sector = bio->bi_sector + bio_sectors(bio); struct cfq_queue *cfqq; cfqq = cfq_find_cfq_hash(cfqd, key, tsk->ioprio); - if (cfqq) + if (cfqq) { + sector_t sector = bio->bi_sector + bio_sectors(bio); + return elv_rb_find(&cfqq->sort_list, sector); + } return NULL; } @@ -699,26 +693,25 @@ static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd) { struct cfq_queue *cfqq = NULL; - /* - * 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 - */ - if (!list_empty(&cfqd->cur_rr) || cfq_get_next_prio_level(cfqd) != -1) + 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); - - /* - * If no new queues are available, check if the busy list has some - * before falling back to idle io. - */ - if (!cfqq && !list_empty(&cfqd->busy_rr)) + } 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); - - /* - * 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 - */ - if (!cfqq && !list_empty(&cfqd->idle_rr)) { + } 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)) @@ -793,18 +786,19 @@ 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; + if (list_empty(&cfqq->fifo)) + return NULL; - if (!list_empty(&cfqq->fifo)) { - int fifo = cfq_cfqq_class_sync(cfqq); + fifo = cfq_cfqq_class_sync(cfqq); + rq = rq_entry_fifo(cfqq->fifo.next); - rq = rq_entry_fifo(cfqq->fifo.next); - if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo])) { - cfq_mark_cfqq_fifo_expire(cfqq); - return rq; - } + if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo])) { + cfq_mark_cfqq_fifo_expire(cfqq); + return rq; } return NULL; @@ -1096,40 +1090,48 @@ static void cfq_trim(struct io_context *ioc) cfq_free_io_context(ioc); } -/* - * Called with interrupts disabled - */ -static void cfq_exit_single_io_context(struct cfq_io_context *cic) +static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq) { - struct cfq_data *cfqd = cic->key; - request_queue_t *q; - - if (!cfqd) - return; - - q = cfqd->queue; - - WARN_ON(!irqs_disabled()); + if (unlikely(cfqq == cfqd->active_queue)) + __cfq_slice_expired(cfqd, cfqq, 0); - spin_lock(q->queue_lock); + cfq_put_queue(cfqq); +} +static void __cfq_exit_single_io_context(struct cfq_data *cfqd, + struct cfq_io_context *cic) +{ if (cic->cfqq[ASYNC]) { - if (unlikely(cic->cfqq[ASYNC] == cfqd->active_queue)) - __cfq_slice_expired(cfqd, cic->cfqq[ASYNC], 0); - cfq_put_queue(cic->cfqq[ASYNC]); + cfq_exit_cfqq(cfqd, cic->cfqq[ASYNC]); cic->cfqq[ASYNC] = NULL; } if (cic->cfqq[SYNC]) { - if (unlikely(cic->cfqq[SYNC] == cfqd->active_queue)) - __cfq_slice_expired(cfqd, cic->cfqq[SYNC], 0); - cfq_put_queue(cic->cfqq[SYNC]); + cfq_exit_cfqq(cfqd, cic->cfqq[SYNC]); cic->cfqq[SYNC] = NULL; } cic->key = NULL; list_del_init(&cic->queue_list); - spin_unlock(q->queue_lock); +} + + +/* + * Called with interrupts disabled + */ +static void cfq_exit_single_io_context(struct cfq_io_context *cic) +{ + struct cfq_data *cfqd = cic->key; + + WARN_ON(!irqs_disabled()); + + if (cfqd) { + request_queue_t *q = cfqd->queue; + + spin_lock(q->queue_lock); + __cfq_exit_single_io_context(cfqd, cic); + spin_unlock(q->queue_lock); + } } static void cfq_exit_io_context(struct io_context *ioc) @@ -1286,8 +1288,14 @@ retry: 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(cfq_pool, gfp_mask); + new_cfqq = kmem_cache_alloc(cfq_pool, gfp_mask|__GFP_NOFAIL); spin_lock_irq(cfqd->queue->queue_lock); goto retry; } else { @@ -1739,9 +1747,7 @@ static void cfq_prio_boost(struct cfq_queue *cfqq) cfq_resort_rr_list(cfqq, 0); } -static inline int -__cfq_may_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq, - struct task_struct *task, int rw) +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)) { @@ -1769,27 +1775,12 @@ static int cfq_may_queue(request_queue_t *q, int rw) cfq_init_prio_data(cfqq); cfq_prio_boost(cfqq); - return __cfq_may_queue(cfqd, cfqq, tsk, rw); + return __cfq_may_queue(cfqq); } return ELV_MQUEUE_MAY; } -static void cfq_check_waiters(request_queue_t *q, struct cfq_queue *cfqq) -{ - struct cfq_data *cfqd = q->elevator->elevator_data; - - if (unlikely(cfqd->rq_starved)) { - struct request_list *rl = &q->rq; - - smp_mb(); - if (waitqueue_active(&rl->wait[READ])) - wake_up(&rl->wait[READ]); - if (waitqueue_active(&rl->wait[WRITE])) - wake_up(&rl->wait[WRITE]); - } -} - /* * queue lock held here */ @@ -1808,7 +1799,6 @@ static void cfq_put_request(request_queue_t *q, struct request *rq) rq->elevator_private = NULL; rq->elevator_private2 = NULL; - cfq_check_waiters(q, cfqq); cfq_put_queue(cfqq); } } @@ -1848,7 +1838,6 @@ cfq_set_request(request_queue_t *q, struct request *rq, gfp_t gfp_mask) cfqq->allocated[rw]++; cfq_clear_cfqq_must_alloc(cfqq); - cfqd->rq_starved = 0; atomic_inc(&cfqq->ref); spin_unlock_irqrestore(q->queue_lock, flags); @@ -1860,12 +1849,7 @@ cfq_set_request(request_queue_t *q, struct request *rq, gfp_t gfp_mask) queue_fail: if (cic) put_io_context(cic->ioc); - /* - * mark us rq allocation starved. we need to kickstart the process - * ourselves if there are no pending requests that can do it for us. - * that would be an extremely rare OOM situation - */ - cfqd->rq_starved = 1; + cfq_schedule_dispatch(cfqd); spin_unlock_irqrestore(q->queue_lock, flags); return 1; @@ -1874,25 +1858,9 @@ queue_fail: static void cfq_kick_queue(void *data) { request_queue_t *q = data; - struct cfq_data *cfqd = q->elevator->elevator_data; unsigned long flags; spin_lock_irqsave(q->queue_lock, flags); - - if (cfqd->rq_starved) { - struct request_list *rl = &q->rq; - - /* - * we aren't guaranteed to get a request after this, but we - * have to be opportunistic - */ - smp_mb(); - if (waitqueue_active(&rl->wait[READ])) - wake_up(&rl->wait[READ]); - if (waitqueue_active(&rl->wait[WRITE])) - wake_up(&rl->wait[WRITE]); - } - blk_remove_plug(q); q->request_fn(q); spin_unlock_irqrestore(q->queue_lock, flags); @@ -1987,16 +1955,8 @@ static void cfq_exit_queue(elevator_t *e) struct cfq_io_context *cic = list_entry(cfqd->cic_list.next, struct cfq_io_context, queue_list); - if (cic->cfqq[ASYNC]) { - cfq_put_queue(cic->cfqq[ASYNC]); - cic->cfqq[ASYNC] = NULL; - } - if (cic->cfqq[SYNC]) { - cfq_put_queue(cic->cfqq[SYNC]); - cic->cfqq[SYNC] = NULL; - } - cic->key = NULL; - list_del_init(&cic->queue_list); + + __cfq_exit_single_io_context(cfqd, cic); } spin_unlock_irq(q->queue_lock); @@ -2047,7 +2007,6 @@ static void *cfq_init_queue(request_queue_t *q, elevator_t *e) INIT_WORK(&cfqd->unplug_work, cfq_kick_queue, q); - cfqd->cfq_queued = cfq_queued; cfqd->cfq_quantum = cfq_quantum; cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0]; cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1]; @@ -2119,7 +2078,6 @@ static ssize_t __FUNC(elevator_t *e, char *page) \ return cfq_var_show(__data, (page)); \ } SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0); -SHOW_FUNCTION(cfq_queued_show, cfqd->cfq_queued, 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); @@ -2147,7 +2105,6 @@ static ssize_t __FUNC(elevator_t *e, const char *page, size_t count) \ return ret; \ } STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0); -STORE_FUNCTION(cfq_queued_store, &cfqd->cfq_queued, 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); @@ -2163,7 +2120,6 @@ STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, UINT_MAX, static struct elv_fs_entry cfq_attrs[] = { CFQ_ATTR(quantum), - CFQ_ATTR(queued), CFQ_ATTR(fifo_expire_sync), CFQ_ATTR(fifo_expire_async), CFQ_ATTR(back_seek_max),