dm thin: use per thin device deferred bio lists
The thin-pool previously only had a single deferred_bios list that would collect bios for all thin devices in the pool. Split this per-pool deferred_bios list out to per-thin deferred_bios_list -- doing so enables increased parallelism when processing deferred bios. And now that each thin device has it's own deferred_bios_list we can sort all bios in the list using logical sector. The requeue code in error handling path is also cleaner as a side-effect. Signed-off-by: Mike Snitzer <snitzer@redhat.com> Acked-by: Joe Thornber <ejt@redhat.com>
This commit is contained in:
Mike Snitzer
parent
760fe67e53
commit
c140e1c4e2
1 changed files with 104 additions and 61 deletions
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@ -12,6 +12,7 @@
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#include <linux/dm-io.h>
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#include <linux/dm-kcopyd.h>
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#include <linux/list.h>
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#include <linux/rculist.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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@ -178,12 +179,10 @@ struct pool {
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unsigned ref_count;
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spinlock_t lock;
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struct bio_list deferred_bios;
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struct bio_list deferred_flush_bios;
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struct list_head prepared_mappings;
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struct list_head prepared_discards;
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struct bio_list retry_on_resume_list;
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struct list_head active_thins;
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struct dm_deferred_set *shared_read_ds;
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struct dm_deferred_set *all_io_ds;
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@ -220,6 +219,7 @@ struct pool_c {
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* Target context for a thin.
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*/
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struct thin_c {
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struct list_head list;
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struct dm_dev *pool_dev;
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struct dm_dev *origin_dev;
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dm_thin_id dev_id;
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@ -227,6 +227,9 @@ struct thin_c {
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struct pool *pool;
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struct dm_thin_device *td;
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bool requeue_mode:1;
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spinlock_t lock;
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struct bio_list deferred_bio_list;
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struct bio_list retry_on_resume_list;
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};
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/*----------------------------------------------------------------*/
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@ -287,9 +290,9 @@ static void cell_defer_no_holder_no_free(struct thin_c *tc,
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struct pool *pool = tc->pool;
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unsigned long flags;
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spin_lock_irqsave(&pool->lock, flags);
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dm_cell_release_no_holder(pool->prison, cell, &pool->deferred_bios);
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spin_unlock_irqrestore(&pool->lock, flags);
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spin_lock_irqsave(&tc->lock, flags);
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dm_cell_release_no_holder(pool->prison, cell, &tc->deferred_bio_list);
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spin_unlock_irqrestore(&tc->lock, flags);
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wake_worker(pool);
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}
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@ -378,30 +381,22 @@ static void requeue_bio_list(struct thin_c *tc, struct bio_list *master)
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bio_list_init(&bios);
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spin_lock_irqsave(&tc->pool->lock, flags);
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spin_lock_irqsave(&tc->lock, flags);
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bio_list_merge(&bios, master);
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bio_list_init(master);
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spin_unlock_irqrestore(&tc->pool->lock, flags);
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spin_unlock_irqrestore(&tc->lock, flags);
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while ((bio = bio_list_pop(&bios))) {
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struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
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if (h->tc == tc)
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bio_endio(bio, DM_ENDIO_REQUEUE);
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else
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bio_list_add(master, bio);
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}
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while ((bio = bio_list_pop(&bios)))
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bio_endio(bio, DM_ENDIO_REQUEUE);
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}
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static void requeue_io(struct thin_c *tc)
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{
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struct pool *pool = tc->pool;
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requeue_bio_list(tc, &pool->deferred_bios);
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requeue_bio_list(tc, &pool->retry_on_resume_list);
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requeue_bio_list(tc, &tc->deferred_bio_list);
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requeue_bio_list(tc, &tc->retry_on_resume_list);
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}
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static void error_retry_list(struct pool *pool)
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static void error_thin_retry_list(struct thin_c *tc)
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{
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struct bio *bio;
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unsigned long flags;
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@ -409,15 +404,25 @@ static void error_retry_list(struct pool *pool)
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bio_list_init(&bios);
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spin_lock_irqsave(&pool->lock, flags);
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bio_list_merge(&bios, &pool->retry_on_resume_list);
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bio_list_init(&pool->retry_on_resume_list);
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spin_unlock_irqrestore(&pool->lock, flags);
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spin_lock_irqsave(&tc->lock, flags);
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bio_list_merge(&bios, &tc->retry_on_resume_list);
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bio_list_init(&tc->retry_on_resume_list);
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spin_unlock_irqrestore(&tc->lock, flags);
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while ((bio = bio_list_pop(&bios)))
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bio_io_error(bio);
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}
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static void error_retry_list(struct pool *pool)
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{
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struct thin_c *tc;
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rcu_read_lock();
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list_for_each_entry_rcu(tc, &pool->active_thins, list)
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error_thin_retry_list(tc);
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rcu_read_unlock();
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}
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/*
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* This section of code contains the logic for processing a thin device's IO.
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* Much of the code depends on pool object resources (lists, workqueues, etc)
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@ -608,9 +613,9 @@ static void cell_defer(struct thin_c *tc, struct dm_bio_prison_cell *cell)
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struct pool *pool = tc->pool;
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unsigned long flags;
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spin_lock_irqsave(&pool->lock, flags);
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cell_release(pool, cell, &pool->deferred_bios);
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spin_unlock_irqrestore(&tc->pool->lock, flags);
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spin_lock_irqsave(&tc->lock, flags);
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cell_release(pool, cell, &tc->deferred_bio_list);
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spin_unlock_irqrestore(&tc->lock, flags);
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wake_worker(pool);
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}
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@ -623,9 +628,9 @@ static void cell_defer_no_holder(struct thin_c *tc, struct dm_bio_prison_cell *c
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struct pool *pool = tc->pool;
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unsigned long flags;
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spin_lock_irqsave(&pool->lock, flags);
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cell_release_no_holder(pool, cell, &pool->deferred_bios);
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spin_unlock_irqrestore(&pool->lock, flags);
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spin_lock_irqsave(&tc->lock, flags);
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cell_release_no_holder(pool, cell, &tc->deferred_bio_list);
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spin_unlock_irqrestore(&tc->lock, flags);
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wake_worker(pool);
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}
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@ -1001,12 +1006,11 @@ static void retry_on_resume(struct bio *bio)
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{
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struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
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struct thin_c *tc = h->tc;
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struct pool *pool = tc->pool;
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unsigned long flags;
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spin_lock_irqsave(&pool->lock, flags);
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bio_list_add(&pool->retry_on_resume_list, bio);
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spin_unlock_irqrestore(&pool->lock, flags);
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spin_lock_irqsave(&tc->lock, flags);
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bio_list_add(&tc->retry_on_resume_list, bio);
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spin_unlock_irqrestore(&tc->lock, flags);
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}
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static bool should_error_unserviceable_bio(struct pool *pool)
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@ -1363,38 +1367,36 @@ static int need_commit_due_to_time(struct pool *pool)
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jiffies > pool->last_commit_jiffies + COMMIT_PERIOD;
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}
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static void process_deferred_bios(struct pool *pool)
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static void process_thin_deferred_bios(struct thin_c *tc)
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{
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struct pool *pool = tc->pool;
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unsigned long flags;
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struct bio *bio;
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struct bio_list bios;
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if (tc->requeue_mode) {
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requeue_bio_list(tc, &tc->deferred_bio_list);
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return;
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}
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bio_list_init(&bios);
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spin_lock_irqsave(&pool->lock, flags);
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bio_list_merge(&bios, &pool->deferred_bios);
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bio_list_init(&pool->deferred_bios);
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spin_unlock_irqrestore(&pool->lock, flags);
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spin_lock_irqsave(&tc->lock, flags);
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bio_list_merge(&bios, &tc->deferred_bio_list);
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bio_list_init(&tc->deferred_bio_list);
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spin_unlock_irqrestore(&tc->lock, flags);
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while ((bio = bio_list_pop(&bios))) {
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struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
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struct thin_c *tc = h->tc;
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if (tc->requeue_mode) {
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bio_endio(bio, DM_ENDIO_REQUEUE);
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continue;
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}
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/*
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* If we've got no free new_mapping structs, and processing
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* this bio might require one, we pause until there are some
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* prepared mappings to process.
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*/
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if (ensure_next_mapping(pool)) {
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spin_lock_irqsave(&pool->lock, flags);
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bio_list_add(&pool->deferred_bios, bio);
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bio_list_merge(&pool->deferred_bios, &bios);
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spin_unlock_irqrestore(&pool->lock, flags);
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spin_lock_irqsave(&tc->lock, flags);
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bio_list_add(&tc->deferred_bio_list, bio);
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bio_list_merge(&tc->deferred_bio_list, &bios);
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spin_unlock_irqrestore(&tc->lock, flags);
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break;
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}
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@ -1403,6 +1405,19 @@ static void process_deferred_bios(struct pool *pool)
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else
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pool->process_bio(tc, bio);
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}
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}
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static void process_deferred_bios(struct pool *pool)
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{
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unsigned long flags;
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struct bio *bio;
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struct bio_list bios;
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struct thin_c *tc;
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rcu_read_lock();
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list_for_each_entry_rcu(tc, &pool->active_thins, list)
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process_thin_deferred_bios(tc);
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rcu_read_unlock();
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/*
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* If there are any deferred flush bios, we must commit
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@ -1634,9 +1649,9 @@ static void thin_defer_bio(struct thin_c *tc, struct bio *bio)
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unsigned long flags;
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struct pool *pool = tc->pool;
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spin_lock_irqsave(&pool->lock, flags);
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bio_list_add(&pool->deferred_bios, bio);
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spin_unlock_irqrestore(&pool->lock, flags);
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spin_lock_irqsave(&tc->lock, flags);
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bio_list_add(&tc->deferred_bio_list, bio);
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spin_unlock_irqrestore(&tc->lock, flags);
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wake_worker(pool);
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}
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@ -1767,10 +1782,19 @@ static int pool_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
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return bdi_congested(&q->backing_dev_info, bdi_bits);
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}
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static void __requeue_bios(struct pool *pool)
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static void requeue_bios(struct pool *pool)
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{
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bio_list_merge(&pool->deferred_bios, &pool->retry_on_resume_list);
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bio_list_init(&pool->retry_on_resume_list);
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unsigned long flags;
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struct thin_c *tc;
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rcu_read_lock();
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list_for_each_entry_rcu(tc, &pool->active_thins, list) {
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spin_lock_irqsave(&tc->lock, flags);
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bio_list_merge(&tc->deferred_bio_list, &tc->retry_on_resume_list);
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bio_list_init(&tc->retry_on_resume_list);
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spin_unlock_irqrestore(&tc->lock, flags);
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}
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rcu_read_unlock();
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}
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/*----------------------------------------------------------------
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@ -1951,12 +1975,11 @@ static struct pool *pool_create(struct mapped_device *pool_md,
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INIT_WORK(&pool->worker, do_worker);
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INIT_DELAYED_WORK(&pool->waker, do_waker);
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spin_lock_init(&pool->lock);
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bio_list_init(&pool->deferred_bios);
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bio_list_init(&pool->deferred_flush_bios);
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INIT_LIST_HEAD(&pool->prepared_mappings);
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INIT_LIST_HEAD(&pool->prepared_discards);
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INIT_LIST_HEAD(&pool->active_thins);
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pool->low_water_triggered = false;
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bio_list_init(&pool->retry_on_resume_list);
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pool->shared_read_ds = dm_deferred_set_create();
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if (!pool->shared_read_ds) {
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@ -2501,8 +2524,8 @@ static void pool_resume(struct dm_target *ti)
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spin_lock_irqsave(&pool->lock, flags);
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pool->low_water_triggered = false;
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__requeue_bios(pool);
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spin_unlock_irqrestore(&pool->lock, flags);
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requeue_bios(pool);
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do_waker(&pool->waker.work);
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}
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@ -2962,6 +2985,12 @@ static struct target_type pool_target = {
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static void thin_dtr(struct dm_target *ti)
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{
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struct thin_c *tc = ti->private;
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unsigned long flags;
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spin_lock_irqsave(&tc->pool->lock, flags);
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list_del_rcu(&tc->list);
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spin_unlock_irqrestore(&tc->pool->lock, flags);
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synchronize_rcu();
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mutex_lock(&dm_thin_pool_table.mutex);
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@ -3008,6 +3037,9 @@ static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
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r = -ENOMEM;
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goto out_unlock;
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}
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spin_lock_init(&tc->lock);
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bio_list_init(&tc->deferred_bio_list);
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bio_list_init(&tc->retry_on_resume_list);
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if (argc == 3) {
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r = dm_get_device(ti, argv[2], FMODE_READ, &origin_dev);
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@ -3079,6 +3111,17 @@ static int thin_ctr(struct dm_target *ti, unsigned argc, char **argv)
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mutex_unlock(&dm_thin_pool_table.mutex);
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spin_lock(&tc->pool->lock);
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list_add_tail_rcu(&tc->list, &tc->pool->active_thins);
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spin_unlock(&tc->pool->lock);
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/*
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* This synchronize_rcu() call is needed here otherwise we risk a
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* wake_worker() call finding no bios to process (because the newly
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* added tc isn't yet visible). So this reduces latency since we
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* aren't then dependent on the periodic commit to wake_worker().
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*/
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synchronize_rcu();
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return 0;
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bad_target_max_io_len:
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