dm thin: throttle incoming IO (7d327fe0) · Commits · 戴 / test

drivers/md/dm-thin.c

+65 −1

Original line number	Diff line number	Diff line
		@@ -126,6 +126,53 @@ static void build_virtual_key(struct dm_thin_device *td, dm_block_t b,

		/----------------------------------------------------------------/

		#define THROTTLE_THRESHOLD (1 * HZ)

		struct throttle {
		struct rw_semaphore lock;
		unsigned long threshold;
		bool throttle_applied;
		};

		static void throttle_init(struct throttle *t)
		{
		init_rwsem(&t->lock);
		t->throttle_applied = false;
		}

		static void throttle_work_start(struct throttle *t)
		{
		t->threshold = jiffies + THROTTLE_THRESHOLD;
		}

		static void throttle_work_update(struct throttle *t)
		{
		if (!t->throttle_applied && jiffies > t->threshold) {
		down_write(&t->lock);
		t->throttle_applied = true;
		}
		}

		static void throttle_work_complete(struct throttle *t)
		{
		if (t->throttle_applied) {
		t->throttle_applied = false;
		up_write(&t->lock);
		}
		}

		static void throttle_lock(struct throttle *t)
		{
		down_read(&t->lock);
		}

		static void throttle_unlock(struct throttle *t)
		{
		up_read(&t->lock);
		}

		/----------------------------------------------------------------/

		/*
		* A pool device ties together a metadata device and a data device. It
		* also provides the interface for creating and destroying internal
		@@ -175,6 +222,7 @@ struct pool {
		struct dm_kcopyd_client *copier;

		struct workqueue_struct *wq;
		struct throttle throttle;
		struct work_struct worker;
		struct delayed_work waker;
		struct delayed_work no_space_timeout;
		@@ -1570,6 +1618,7 @@ static void process_thin_deferred_bios(struct thin_c *tc)
		pool->process_bio(tc, bio);

		if ((count++ & 127) == 0) {
		throttle_work_update(&pool->throttle);
		dm_pool_issue_prefetches(pool->pmd);
		}
		}
		@@ -1657,10 +1706,15 @@ static void do_worker(struct work_struct *ws)
		{
		struct pool *pool = container_of(ws, struct pool, worker);

		throttle_work_start(&pool->throttle);
		dm_pool_issue_prefetches(pool->pmd);
		throttle_work_update(&pool->throttle);
		process_prepared(pool, &pool->prepared_mappings, &pool->process_prepared_mapping);
		throttle_work_update(&pool->throttle);
		process_prepared(pool, &pool->prepared_discards, &pool->process_prepared_discard);
		throttle_work_update(&pool->throttle);
		process_deferred_bios(pool);
		throttle_work_complete(&pool->throttle);
		}

		/*
		@@ -1900,6 +1954,15 @@ static void thin_defer_bio(struct thin_c tc, struct bio bio)
		wake_worker(pool);
		}

		static void thin_defer_bio_with_throttle(struct thin_c tc, struct bio bio)
		{
		struct pool *pool = tc->pool;

		throttle_lock(&pool->throttle);
		thin_defer_bio(tc, bio);
		throttle_unlock(&pool->throttle);
		}

		static void thin_hook_bio(struct thin_c tc, struct bio bio)
		{
		struct dm_thin_endio_hook *h = dm_per_bio_data(bio, sizeof(struct dm_thin_endio_hook));
		@@ -1937,7 +2000,7 @@ static int thin_bio_map(struct dm_target ti, struct bio bio)
		}

		if (bio->bi_rw & (REQ_DISCARD \| REQ_FLUSH \| REQ_FUA)) {
		thin_defer_bio(tc, bio);
		thin_defer_bio_with_throttle(tc, bio);
		return DM_MAPIO_SUBMITTED;
		}

		@@ -2220,6 +2283,7 @@ static struct pool pool_create(struct mapped_device pool_md,
		goto bad_wq;
		}

		throttle_init(&pool->throttle);
		INIT_WORK(&pool->worker, do_worker);
		INIT_DELAYED_WORK(&pool->waker, do_waker);
		INIT_DELAYED_WORK(&pool->no_space_timeout, do_no_space_timeout);

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