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

NeilBrown
2017-03-10T06:00:47Z

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 <neilb@suse.com>
---
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);