[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 <axboe@suse.de>
This commit is contained in:
Jens Axboe
Jens Axboe
parent
e6a1c874a0
commit
89850f7ee9
1 changed files with 72 additions and 116 deletions
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@ -17,7 +17,6 @@
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* tunables
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*/
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static const int cfq_quantum = 4; /* max queue in one round of service */
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static const int cfq_queued = 8; /* minimum rq allocate limit per-queue*/
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static const int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 };
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static const int cfq_back_max = 16 * 1024; /* maximum backwards seek, in KiB */
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static const int cfq_back_penalty = 2; /* penalty of a backwards seek */
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@ -54,7 +53,6 @@ static struct completion *ioc_gone;
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#define CFQ_PRIO_LISTS IOPRIO_BE_NR
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#define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE)
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#define cfq_class_be(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_BE)
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#define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT)
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#define ASYNC (0)
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@ -98,9 +96,6 @@ struct cfq_data {
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int rq_in_driver;
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int hw_tag;
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/*
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* schedule slice state info
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*/
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/*
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* idle window management
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*/
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@ -117,13 +112,10 @@ struct cfq_data {
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sector_t last_sector;
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unsigned long last_end_request;
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unsigned int rq_starved;
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/*
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* tunables, see top of file
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*/
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unsigned int cfq_quantum;
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unsigned int cfq_queued;
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unsigned int cfq_fifo_expire[2];
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unsigned int cfq_back_penalty;
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unsigned int cfq_back_max;
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@ -484,12 +476,14 @@ cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio)
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{
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struct task_struct *tsk = current;
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pid_t key = cfq_queue_pid(tsk, bio_data_dir(bio));
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sector_t sector = bio->bi_sector + bio_sectors(bio);
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struct cfq_queue *cfqq;
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cfqq = cfq_find_cfq_hash(cfqd, key, tsk->ioprio);
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if (cfqq)
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if (cfqq) {
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sector_t sector = bio->bi_sector + bio_sectors(bio);
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return elv_rb_find(&cfqq->sort_list, sector);
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}
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return NULL;
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}
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@ -699,26 +693,25 @@ static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd)
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{
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struct cfq_queue *cfqq = NULL;
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if (!list_empty(&cfqd->cur_rr) || cfq_get_next_prio_level(cfqd) != -1) {
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/*
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* if current list is non-empty, grab first entry. if it is empty,
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* get next prio level and grab first entry then if any are spliced
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* if current list is non-empty, grab first entry. if it is
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* empty, get next prio level and grab first entry then if any
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* are spliced
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*/
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if (!list_empty(&cfqd->cur_rr) || cfq_get_next_prio_level(cfqd) != -1)
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cfqq = list_entry_cfqq(cfqd->cur_rr.next);
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} else if (!list_empty(&cfqd->busy_rr)) {
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/*
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* If no new queues are available, check if the busy list has some
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* before falling back to idle io.
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* If no new queues are available, check if the busy list has
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* some before falling back to idle io.
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*/
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if (!cfqq && !list_empty(&cfqd->busy_rr))
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cfqq = list_entry_cfqq(cfqd->busy_rr.next);
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} else if (!list_empty(&cfqd->idle_rr)) {
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/*
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* if we have idle queues and no rt or be queues had pending
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* requests, either allow immediate service if the grace period
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* has passed or arm the idle grace timer
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*/
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if (!cfqq && !list_empty(&cfqd->idle_rr)) {
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unsigned long end = cfqd->last_end_request + CFQ_IDLE_GRACE;
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if (time_after_eq(jiffies, end))
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@ -793,19 +786,20 @@ static inline struct request *cfq_check_fifo(struct cfq_queue *cfqq)
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{
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struct cfq_data *cfqd = cfqq->cfqd;
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struct request *rq;
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int fifo;
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if (cfq_cfqq_fifo_expire(cfqq))
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return NULL;
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if (list_empty(&cfqq->fifo))
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return NULL;
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if (!list_empty(&cfqq->fifo)) {
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int fifo = cfq_cfqq_class_sync(cfqq);
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fifo = cfq_cfqq_class_sync(cfqq);
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rq = rq_entry_fifo(cfqq->fifo.next);
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if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo])) {
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cfq_mark_cfqq_fifo_expire(cfqq);
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return rq;
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}
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}
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return NULL;
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}
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@ -1096,41 +1090,49 @@ static void cfq_trim(struct io_context *ioc)
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cfq_free_io_context(ioc);
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}
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static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
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{
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if (unlikely(cfqq == cfqd->active_queue))
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__cfq_slice_expired(cfqd, cfqq, 0);
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cfq_put_queue(cfqq);
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}
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static void __cfq_exit_single_io_context(struct cfq_data *cfqd,
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struct cfq_io_context *cic)
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{
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if (cic->cfqq[ASYNC]) {
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cfq_exit_cfqq(cfqd, cic->cfqq[ASYNC]);
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cic->cfqq[ASYNC] = NULL;
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}
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if (cic->cfqq[SYNC]) {
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cfq_exit_cfqq(cfqd, cic->cfqq[SYNC]);
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cic->cfqq[SYNC] = NULL;
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}
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cic->key = NULL;
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list_del_init(&cic->queue_list);
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}
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/*
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* Called with interrupts disabled
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*/
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static void cfq_exit_single_io_context(struct cfq_io_context *cic)
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{
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struct cfq_data *cfqd = cic->key;
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request_queue_t *q;
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if (!cfqd)
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return;
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q = cfqd->queue;
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WARN_ON(!irqs_disabled());
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if (cfqd) {
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request_queue_t *q = cfqd->queue;
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spin_lock(q->queue_lock);
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if (cic->cfqq[ASYNC]) {
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if (unlikely(cic->cfqq[ASYNC] == cfqd->active_queue))
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__cfq_slice_expired(cfqd, cic->cfqq[ASYNC], 0);
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cfq_put_queue(cic->cfqq[ASYNC]);
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cic->cfqq[ASYNC] = NULL;
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}
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if (cic->cfqq[SYNC]) {
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if (unlikely(cic->cfqq[SYNC] == cfqd->active_queue))
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__cfq_slice_expired(cfqd, cic->cfqq[SYNC], 0);
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cfq_put_queue(cic->cfqq[SYNC]);
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cic->cfqq[SYNC] = NULL;
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}
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cic->key = NULL;
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list_del_init(&cic->queue_list);
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__cfq_exit_single_io_context(cfqd, cic);
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spin_unlock(q->queue_lock);
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}
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}
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static void cfq_exit_io_context(struct io_context *ioc)
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{
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@ -1286,8 +1288,14 @@ cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk,
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cfqq = new_cfqq;
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new_cfqq = NULL;
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} else if (gfp_mask & __GFP_WAIT) {
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/*
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* Inform the allocator of the fact that we will
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* just repeat this allocation if it fails, to allow
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* the allocator to do whatever it needs to attempt to
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* free memory.
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*/
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spin_unlock_irq(cfqd->queue->queue_lock);
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new_cfqq = kmem_cache_alloc(cfq_pool, gfp_mask);
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new_cfqq = kmem_cache_alloc(cfq_pool, gfp_mask|__GFP_NOFAIL);
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spin_lock_irq(cfqd->queue->queue_lock);
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goto retry;
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} else {
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@ -1739,9 +1747,7 @@ static void cfq_prio_boost(struct cfq_queue *cfqq)
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cfq_resort_rr_list(cfqq, 0);
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}
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static inline int
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__cfq_may_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq,
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struct task_struct *task, int rw)
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static inline int __cfq_may_queue(struct cfq_queue *cfqq)
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{
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if ((cfq_cfqq_wait_request(cfqq) || cfq_cfqq_must_alloc(cfqq)) &&
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!cfq_cfqq_must_alloc_slice(cfqq)) {
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@ -1769,27 +1775,12 @@ static int cfq_may_queue(request_queue_t *q, int rw)
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cfq_init_prio_data(cfqq);
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cfq_prio_boost(cfqq);
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return __cfq_may_queue(cfqd, cfqq, tsk, rw);
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return __cfq_may_queue(cfqq);
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}
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return ELV_MQUEUE_MAY;
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}
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static void cfq_check_waiters(request_queue_t *q, struct cfq_queue *cfqq)
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{
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struct cfq_data *cfqd = q->elevator->elevator_data;
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if (unlikely(cfqd->rq_starved)) {
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struct request_list *rl = &q->rq;
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smp_mb();
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if (waitqueue_active(&rl->wait[READ]))
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wake_up(&rl->wait[READ]);
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if (waitqueue_active(&rl->wait[WRITE]))
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wake_up(&rl->wait[WRITE]);
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}
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}
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/*
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* queue lock held here
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*/
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@ -1808,7 +1799,6 @@ static void cfq_put_request(request_queue_t *q, struct request *rq)
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rq->elevator_private = NULL;
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rq->elevator_private2 = NULL;
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cfq_check_waiters(q, cfqq);
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cfq_put_queue(cfqq);
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}
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}
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@ -1848,7 +1838,6 @@ cfq_set_request(request_queue_t *q, struct request *rq, gfp_t gfp_mask)
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cfqq->allocated[rw]++;
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cfq_clear_cfqq_must_alloc(cfqq);
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cfqd->rq_starved = 0;
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atomic_inc(&cfqq->ref);
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spin_unlock_irqrestore(q->queue_lock, flags);
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@ -1860,12 +1849,7 @@ cfq_set_request(request_queue_t *q, struct request *rq, gfp_t gfp_mask)
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queue_fail:
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if (cic)
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put_io_context(cic->ioc);
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/*
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* mark us rq allocation starved. we need to kickstart the process
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* ourselves if there are no pending requests that can do it for us.
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* that would be an extremely rare OOM situation
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*/
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cfqd->rq_starved = 1;
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cfq_schedule_dispatch(cfqd);
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spin_unlock_irqrestore(q->queue_lock, flags);
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return 1;
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@ -1874,25 +1858,9 @@ cfq_set_request(request_queue_t *q, struct request *rq, gfp_t gfp_mask)
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static void cfq_kick_queue(void *data)
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{
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request_queue_t *q = data;
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struct cfq_data *cfqd = q->elevator->elevator_data;
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unsigned long flags;
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spin_lock_irqsave(q->queue_lock, flags);
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if (cfqd->rq_starved) {
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struct request_list *rl = &q->rq;
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/*
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* we aren't guaranteed to get a request after this, but we
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* have to be opportunistic
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*/
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smp_mb();
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if (waitqueue_active(&rl->wait[READ]))
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wake_up(&rl->wait[READ]);
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if (waitqueue_active(&rl->wait[WRITE]))
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wake_up(&rl->wait[WRITE]);
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}
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blk_remove_plug(q);
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q->request_fn(q);
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spin_unlock_irqrestore(q->queue_lock, flags);
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@ -1987,16 +1955,8 @@ static void cfq_exit_queue(elevator_t *e)
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struct cfq_io_context *cic = list_entry(cfqd->cic_list.next,
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struct cfq_io_context,
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queue_list);
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if (cic->cfqq[ASYNC]) {
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cfq_put_queue(cic->cfqq[ASYNC]);
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cic->cfqq[ASYNC] = NULL;
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}
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if (cic->cfqq[SYNC]) {
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cfq_put_queue(cic->cfqq[SYNC]);
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cic->cfqq[SYNC] = NULL;
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}
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cic->key = NULL;
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list_del_init(&cic->queue_list);
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__cfq_exit_single_io_context(cfqd, cic);
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}
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spin_unlock_irq(q->queue_lock);
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@ -2047,7 +2007,6 @@ static void *cfq_init_queue(request_queue_t *q, elevator_t *e)
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INIT_WORK(&cfqd->unplug_work, cfq_kick_queue, q);
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cfqd->cfq_queued = cfq_queued;
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cfqd->cfq_quantum = cfq_quantum;
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cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0];
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cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1];
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@ -2119,7 +2078,6 @@ static ssize_t __FUNC(elevator_t *e, char *page) \
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return cfq_var_show(__data, (page)); \
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}
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SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0);
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SHOW_FUNCTION(cfq_queued_show, cfqd->cfq_queued, 0);
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SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1);
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SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1);
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SHOW_FUNCTION(cfq_back_seek_max_show, cfqd->cfq_back_max, 0);
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@ -2147,7 +2105,6 @@ static ssize_t __FUNC(elevator_t *e, const char *page, size_t count) \
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return ret; \
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}
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STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0);
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STORE_FUNCTION(cfq_queued_store, &cfqd->cfq_queued, 1, UINT_MAX, 0);
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STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, UINT_MAX, 1);
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STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, UINT_MAX, 1);
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STORE_FUNCTION(cfq_back_seek_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0);
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@ -2163,7 +2120,6 @@ STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, UINT_MAX,
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static struct elv_fs_entry cfq_attrs[] = {
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CFQ_ATTR(quantum),
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CFQ_ATTR(queued),
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CFQ_ATTR(fifo_expire_sync),
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CFQ_ATTR(fifo_expire_async),
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CFQ_ATTR(back_seek_max),
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