Thread (8 messages) 8 messages, 2 authors, 2017-03-12
STALE3389d

[PATCH 3/5] blk: make the bioset rescue_workqueue optional.

From: NeilBrown <hidden>
Date: 2017-03-10 06:02:21
Also in: dm-devel, linux-raid, lkml
Subsystem: bcache (block layer cache), block layer, btrfs file system, device-mapper (lvm), drbd driver, filesystems (vfs and infrastructure), scsi target subsystem, software raid (multiple disks) support, the rest, xfs filesystem · Maintainers: Coly Li, Kent Overstreet, Jens Axboe, Chris Mason, David Sterba, Alasdair Kergon, Mike Snitzer, Mikulas Patocka, Benjamin Marzinski, Philipp Reisner, Lars Ellenberg, Christoph Böhmwalder, Alexander Viro, Christian Brauner, "Martin K. Petersen", Song Liu, Yu Kuai, Linus Torvalds, Carlos Maiolino 

This patch converts bioset_create() and bioset_create_nobvec()
to not create a workqueue so alloctions will never trigger
punt_bios_to_rescuer().
It also introduces bioset_create_rescued() and bioset_create_nobvec_rescued()
which preserve the old behaviour.

*All* callers of bioset_create() and bioset_create_nobvec() are
converted to the _rescued() version, so that no change in behaviour
is experienced.

It is hoped that most, if not all, biosets can end up being the
non-rescued version.

Signed-off-by: NeilBrown <redacted>
---
 block/bio.c                         |   30 +++++++++++++++++++++++++-----
 block/blk-core.c                    |    2 +-
 drivers/block/drbd/drbd_main.c      |    2 +-
 drivers/md/bcache/super.c           |    4 ++--
 drivers/md/dm-crypt.c               |    2 +-
 drivers/md/dm-io.c                  |    2 +-
 drivers/md/dm.c                     |    5 +++--
 drivers/md/md.c                     |    2 +-
 drivers/md/raid5-cache.c            |    2 +-
 drivers/target/target_core_iblock.c |    2 +-
 fs/block_dev.c                      |    2 +-
 fs/btrfs/extent_io.c                |    4 ++--
 fs/xfs/xfs_super.c                  |    2 +-
 include/linux/bio.h                 |    2 ++
 14 files changed, 43 insertions(+), 20 deletions(-)

diff --git a/block/bio.c b/block/bio.c
index e75878f8b14a..3790c3f376b6 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -362,6 +362,8 @@ static void punt_bios_to_rescuer(struct bio_set *bs)
 	struct bio_list punt, nopunt;
 	struct bio *bio;
 
+	if (!WARN_ON_ONCE(!bs->rescue_workqueue))
+		return;
 	/*
 	 * In order to guarantee forward progress we must punt only bios that
 	 * were allocated from this bio_set; otherwise, if there was a bio on
@@ -472,7 +474,8 @@ struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs)
 
 		if (current->bio_list &&
 		    (!bio_list_empty(&current->bio_list[0]) ||
-		     !bio_list_empty(&current->bio_list[1])))
+		     !bio_list_empty(&current->bio_list[1])) &&
+		    bs->rescue_workqueue)
 			gfp_mask &= ~__GFP_DIRECT_RECLAIM;
 
 		p = mempool_alloc(bs->bio_pool, gfp_mask);
@@ -1941,7 +1944,8 @@ EXPORT_SYMBOL(bioset_free);
 
 static struct bio_set *__bioset_create(unsigned int pool_size,
 				       unsigned int front_pad,
-				       bool create_bvec_pool)
+				       bool create_bvec_pool,
+				       bool create_rescue_workqueue)
 {
 	unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec);
 	struct bio_set *bs;
@@ -1972,6 +1976,9 @@ static struct bio_set *__bioset_create(unsigned int pool_size,
 			goto bad;
 	}
 
+	if (!create_rescue_workqueue)
+		return bs;
+
 	bs->rescue_workqueue = alloc_workqueue("bioset", WQ_MEM_RECLAIM, 0);
 	if (!bs->rescue_workqueue)
 		goto bad;
@@ -1997,10 +2004,16 @@ static struct bio_set *__bioset_create(unsigned int pool_size,
  */
 struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad)
 {
-	return __bioset_create(pool_size, front_pad, true);
+	return __bioset_create(pool_size, front_pad, true, false);
 }
 EXPORT_SYMBOL(bioset_create);
 
+struct bio_set *bioset_create_rescued(unsigned int pool_size, unsigned int front_pad)
+{
+	return __bioset_create(pool_size, front_pad, true, true);
+}
+EXPORT_SYMBOL(bioset_create_rescued);
+
 /**
  * bioset_create_nobvec  - Create a bio_set without bio_vec mempool
  * @pool_size:	Number of bio to cache in the mempool
@@ -2012,10 +2025,17 @@ EXPORT_SYMBOL(bioset_create);
  */
 struct bio_set *bioset_create_nobvec(unsigned int pool_size, unsigned int front_pad)
 {
-	return __bioset_create(pool_size, front_pad, false);
+	return __bioset_create(pool_size, front_pad, false, false);
 }
 EXPORT_SYMBOL(bioset_create_nobvec);
 
+struct bio_set *bioset_create_nobvec_rescued(unsigned int pool_size,
+					     unsigned int front_pad)
+{
+	return __bioset_create(pool_size, front_pad, false, true);
+}
+EXPORT_SYMBOL(bioset_create_nobvec_rescued);
+
 #ifdef CONFIG_BLK_CGROUP
 
 /**
@@ -2130,7 +2150,7 @@ static int __init init_bio(void)
 	bio_integrity_init();
 	biovec_init_slabs();
 
-	fs_bio_set = bioset_create(BIO_POOL_SIZE, 0);
+	fs_bio_set = bioset_create_rescued(BIO_POOL_SIZE, 0);
 	if (!fs_bio_set)
 		panic("bio: can't allocate bios\n");
 
diff --git a/block/blk-core.c b/block/blk-core.c
index fae7966e1f98..430c82f646eb 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -712,7 +712,7 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
 	if (q->id < 0)
 		goto fail_q;
 
-	q->bio_split = bioset_create(BIO_POOL_SIZE, 0);
+	q->bio_split = bioset_create_rescued(BIO_POOL_SIZE, 0);
 	if (!q->bio_split)
 		goto fail_id;
 
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 92c60cbd04ee..2c69c2ab0fff 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -2166,7 +2166,7 @@ static int drbd_create_mempools(void)
 		goto Enomem;
 
 	/* mempools */
-	drbd_md_io_bio_set = bioset_create(DRBD_MIN_POOL_PAGES, 0);
+	drbd_md_io_bio_set = bioset_create_rescued(DRBD_MIN_POOL_PAGES, 0);
 	if (drbd_md_io_bio_set == NULL)
 		goto Enomem;
 
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 85e3f21c2514..6cb30792f0ed 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -786,7 +786,7 @@ static int bcache_device_init(struct bcache_device *d, unsigned block_size,
 
 	minor *= BCACHE_MINORS;
 
-	if (!(d->bio_split = bioset_create(4, offsetof(struct bbio, bio))) ||
+	if (!(d->bio_split = bioset_create_rescued(4, offsetof(struct bbio, bio))) ||
 	    !(d->disk = alloc_disk(BCACHE_MINORS))) {
 		ida_simple_remove(&bcache_minor, minor);
 		return -ENOMEM;
@@ -1520,7 +1520,7 @@ struct cache_set *bch_cache_set_alloc(struct cache_sb *sb)
 				sizeof(struct bbio) + sizeof(struct bio_vec) *
 				bucket_pages(c))) ||
 	    !(c->fill_iter = mempool_create_kmalloc_pool(1, iter_size)) ||
-	    !(c->bio_split = bioset_create(4, offsetof(struct bbio, bio))) ||
+	    !(c->bio_split = bioset_create_rescued(4, offsetof(struct bbio, bio))) ||
 	    !(c->uuids = alloc_bucket_pages(GFP_KERNEL, c)) ||
 	    !(c->moving_gc_wq = alloc_workqueue("bcache_gc",
 						WQ_MEM_RECLAIM, 0)) ||
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 389a3637ffcc..91a2d637d44f 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -1936,7 +1936,7 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 		goto bad;
 	}
 
-	cc->bs = bioset_create(MIN_IOS, 0);
+	cc->bs = bioset_create_rescued(MIN_IOS, 0);
 	if (!cc->bs) {
 		ti->error = "Cannot allocate crypt bioset";
 		goto bad;
diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c
index 03940bf36f6c..fe1241c196b1 100644
--- a/drivers/md/dm-io.c
+++ b/drivers/md/dm-io.c
@@ -58,7 +58,7 @@ struct dm_io_client *dm_io_client_create(void)
 	if (!client->pool)
 		goto bad;
 
-	client->bios = bioset_create(min_ios, 0);
+	client->bios = bioset_create_rescued(min_ios, 0);
 	if (!client->bios)
 		goto bad;
 
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index dfb75979e455..41b1f033841f 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1002,7 +1002,8 @@ static void flush_current_bio_list(struct blk_plug_cb *cb, bool from_schedule)
 
 		while ((bio = bio_list_pop(&list))) {
 			struct bio_set *bs = bio->bi_pool;
-			if (unlikely(!bs) || bs == fs_bio_set) {
+			if (unlikely(!bs) || bs == fs_bio_set ||
+			    !bs->rescue_workqueue) {
 				bio_list_add(&current->bio_list[i], bio);
 				continue;
 			}
@@ -2577,7 +2578,7 @@ struct dm_md_mempools *dm_alloc_md_mempools(struct mapped_device *md, unsigned t
 		BUG();
 	}
 
-	pools->bs = bioset_create_nobvec(pool_size, front_pad);
+	pools->bs = bioset_create_nobvec_rescued(pool_size, front_pad);
 	if (!pools->bs)
 		goto out;
 
diff --git a/drivers/md/md.c b/drivers/md/md.c
index d7d2bb51a58d..e5f08a195837 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -5220,7 +5220,7 @@ int md_run(struct mddev *mddev)
 	}
 
 	if (mddev->bio_set == NULL) {
-		mddev->bio_set = bioset_create(BIO_POOL_SIZE, 0);
+		mddev->bio_set = bioset_create_rescued(BIO_POOL_SIZE, 0);
 		if (!mddev->bio_set)
 			return -ENOMEM;
 	}
diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c
index 3f307be01b10..c95c6c046395 100644
--- a/drivers/md/raid5-cache.c
+++ b/drivers/md/raid5-cache.c
@@ -2831,7 +2831,7 @@ int r5l_init_log(struct r5conf *conf, struct md_rdev *rdev)
 	if (!log->io_pool)
 		goto io_pool;
 
-	log->bs = bioset_create(R5L_POOL_SIZE, 0);
+	log->bs = bioset_create_rescued(R5L_POOL_SIZE, 0);
 	if (!log->bs)
 		goto io_bs;
 
diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c
index d316ed537d59..5bf3392195c6 100644
--- a/drivers/target/target_core_iblock.c
+++ b/drivers/target/target_core_iblock.c
@@ -93,7 +93,7 @@ static int iblock_configure_device(struct se_device *dev)
 		return -EINVAL;
 	}
 
-	ib_dev->ibd_bio_set = bioset_create(IBLOCK_BIO_POOL_SIZE, 0);
+	ib_dev->ibd_bio_set = bioset_create_rescued(IBLOCK_BIO_POOL_SIZE, 0);
 	if (!ib_dev->ibd_bio_set) {
 		pr_err("IBLOCK: Unable to create bioset\n");
 		goto out;
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 2eca00ec4370..c0ca5f0d0369 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -436,7 +436,7 @@ blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 
 static __init int blkdev_init(void)
 {
-	blkdev_dio_pool = bioset_create(4, offsetof(struct blkdev_dio, bio));
+	blkdev_dio_pool = bioset_create_rescued(4, offsetof(struct blkdev_dio, bio));
 	if (!blkdev_dio_pool)
 		return -ENOMEM;
 	return 0;
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 28e81922a21c..34aa8893790a 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -173,8 +173,8 @@ int __init extent_io_init(void)
 	if (!extent_buffer_cache)
 		goto free_state_cache;
 
-	btrfs_bioset = bioset_create(BIO_POOL_SIZE,
-				     offsetof(struct btrfs_io_bio, bio));
+	btrfs_bioset = bioset_create_rescued(BIO_POOL_SIZE,
+					     offsetof(struct btrfs_io_bio, bio));
 	if (!btrfs_bioset)
 		goto free_buffer_cache;
 
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 890862f2447c..f4c4d6f41d91 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -1756,7 +1756,7 @@ MODULE_ALIAS_FS("xfs");
 STATIC int __init
 xfs_init_zones(void)
 {
-	xfs_ioend_bioset = bioset_create(4 * MAX_BUF_PER_PAGE,
+	xfs_ioend_bioset = bioset_create_rescued(4 * MAX_BUF_PER_PAGE,
 			offsetof(struct xfs_ioend, io_inline_bio));
 	if (!xfs_ioend_bioset)
 		goto out;
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 8e521194f6fc..05730603fcf1 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -379,7 +379,9 @@ static inline struct bio *bio_next_split(struct bio *bio, int sectors,
 }
 
 extern struct bio_set *bioset_create(unsigned int, unsigned int);
+extern struct bio_set *bioset_create_rescued(unsigned int, unsigned int);
 extern struct bio_set *bioset_create_nobvec(unsigned int, unsigned int);
+extern struct bio_set *bioset_create_nobvec_rescued(unsigned int, unsigned int);
 extern void bioset_free(struct bio_set *);
 extern mempool_t *biovec_create_pool(int pool_entries);
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