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authorLinus Torvalds <torvalds@linux-foundation.org>2021-08-30 19:30:30 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-08-30 19:30:30 -0700
commit3b629f8d6dc04d3af94429c18fe17239d6fbe2c3 (patch)
treef67dd6ef5c662927ee4c6533450c7b2c5724f69e
parentc547d89a9a445f6bb757b93247de43d312e722da (diff)
parent3d5b3fbedad65088ec079a4c4d1a2f47e11ae1e7 (diff)
Merge tag 'io_uring-bio-cache.5-2021-08-30' of git://git.kernel.dk/linux-block
Pull support for struct bio recycling from Jens Axboe: "This adds bio recycling support for polled IO, allowing quick reuse of a bio for high IOPS scenarios via a percpu bio_set list. It's good for almost a 10% improvement in performance, bumping our per-core IO limit from ~3.2M IOPS to ~3.5M IOPS" * tag 'io_uring-bio-cache.5-2021-08-30' of git://git.kernel.dk/linux-block: bio: improve kerneldoc documentation for bio_alloc_kiocb() block: provide bio_clear_hipri() helper block: use the percpu bio cache in __blkdev_direct_IO io_uring: enable use of bio alloc cache block: clear BIO_PERCPU_CACHE flag if polling isn't supported bio: add allocation cache abstraction fs: add kiocb alloc cache flag bio: optimize initialization of a bio
-rw-r--r--block/bio.c169
-rw-r--r--block/blk-core.c2
-rw-r--r--block/blk-merge.c2
-rw-r--r--block/blk.h7
-rw-r--r--fs/block_dev.c6
-rw-r--r--fs/io_uring.c2
-rw-r--r--include/linux/bio.h13
-rw-r--r--include/linux/blk_types.h1
-rw-r--r--include/linux/cpuhotplug.h1
-rw-r--r--include/linux/fs.h2
10 files changed, 184 insertions, 21 deletions
diff --git a/block/bio.c b/block/bio.c
index 265bff6b549a..1319dd2aa0b8 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -25,6 +25,11 @@
#include "blk.h"
#include "blk-rq-qos.h"
+struct bio_alloc_cache {
+ struct bio_list free_list;
+ unsigned int nr;
+};
+
static struct biovec_slab {
int nr_vecs;
char *name;
@@ -246,12 +251,40 @@ static void bio_free(struct bio *bio)
void bio_init(struct bio *bio, struct bio_vec *table,
unsigned short max_vecs)
{
- memset(bio, 0, sizeof(*bio));
+ bio->bi_next = NULL;
+ bio->bi_bdev = NULL;
+ bio->bi_opf = 0;
+ bio->bi_flags = 0;
+ bio->bi_ioprio = 0;
+ bio->bi_write_hint = 0;
+ bio->bi_status = 0;
+ bio->bi_iter.bi_sector = 0;
+ bio->bi_iter.bi_size = 0;
+ bio->bi_iter.bi_idx = 0;
+ bio->bi_iter.bi_bvec_done = 0;
+ bio->bi_end_io = NULL;
+ bio->bi_private = NULL;
+#ifdef CONFIG_BLK_CGROUP
+ bio->bi_blkg = NULL;
+ bio->bi_issue.value = 0;
+#ifdef CONFIG_BLK_CGROUP_IOCOST
+ bio->bi_iocost_cost = 0;
+#endif
+#endif
+#ifdef CONFIG_BLK_INLINE_ENCRYPTION
+ bio->bi_crypt_context = NULL;
+#endif
+#ifdef CONFIG_BLK_DEV_INTEGRITY
+ bio->bi_integrity = NULL;
+#endif
+ bio->bi_vcnt = 0;
+
atomic_set(&bio->__bi_remaining, 1);
atomic_set(&bio->__bi_cnt, 1);
- bio->bi_io_vec = table;
bio->bi_max_vecs = max_vecs;
+ bio->bi_io_vec = table;
+ bio->bi_pool = NULL;
}
EXPORT_SYMBOL(bio_init);
@@ -586,6 +619,53 @@ void guard_bio_eod(struct bio *bio)
bio_truncate(bio, maxsector << 9);
}
+#define ALLOC_CACHE_MAX 512
+#define ALLOC_CACHE_SLACK 64
+
+static void bio_alloc_cache_prune(struct bio_alloc_cache *cache,
+ unsigned int nr)
+{
+ unsigned int i = 0;
+ struct bio *bio;
+
+ while ((bio = bio_list_pop(&cache->free_list)) != NULL) {
+ cache->nr--;
+ bio_free(bio);
+ if (++i == nr)
+ break;
+ }
+}
+
+static int bio_cpu_dead(unsigned int cpu, struct hlist_node *node)
+{
+ struct bio_set *bs;
+
+ bs = hlist_entry_safe(node, struct bio_set, cpuhp_dead);
+ if (bs->cache) {
+ struct bio_alloc_cache *cache = per_cpu_ptr(bs->cache, cpu);
+
+ bio_alloc_cache_prune(cache, -1U);
+ }
+ return 0;
+}
+
+static void bio_alloc_cache_destroy(struct bio_set *bs)
+{
+ int cpu;
+
+ if (!bs->cache)
+ return;
+
+ cpuhp_state_remove_instance_nocalls(CPUHP_BIO_DEAD, &bs->cpuhp_dead);
+ for_each_possible_cpu(cpu) {
+ struct bio_alloc_cache *cache;
+
+ cache = per_cpu_ptr(bs->cache, cpu);
+ bio_alloc_cache_prune(cache, -1U);
+ }
+ free_percpu(bs->cache);
+}
+
/**
* bio_put - release a reference to a bio
* @bio: bio to release reference to
@@ -596,16 +676,23 @@ void guard_bio_eod(struct bio *bio)
**/
void bio_put(struct bio *bio)
{
- if (!bio_flagged(bio, BIO_REFFED))
- bio_free(bio);
- else {
+ if (unlikely(bio_flagged(bio, BIO_REFFED))) {
BIO_BUG_ON(!atomic_read(&bio->__bi_cnt));
+ if (!atomic_dec_and_test(&bio->__bi_cnt))
+ return;
+ }
- /*
- * last put frees it
- */
- if (atomic_dec_and_test(&bio->__bi_cnt))
- bio_free(bio);
+ if (bio_flagged(bio, BIO_PERCPU_CACHE)) {
+ struct bio_alloc_cache *cache;
+
+ bio_uninit(bio);
+ cache = per_cpu_ptr(bio->bi_pool->cache, get_cpu());
+ bio_list_add_head(&cache->free_list, bio);
+ if (++cache->nr > ALLOC_CACHE_MAX + ALLOC_CACHE_SLACK)
+ bio_alloc_cache_prune(cache, ALLOC_CACHE_SLACK);
+ put_cpu();
+ } else {
+ bio_free(bio);
}
}
EXPORT_SYMBOL(bio_put);
@@ -1496,6 +1583,7 @@ int biovec_init_pool(mempool_t *pool, int pool_entries)
*/
void bioset_exit(struct bio_set *bs)
{
+ bio_alloc_cache_destroy(bs);
if (bs->rescue_workqueue)
destroy_workqueue(bs->rescue_workqueue);
bs->rescue_workqueue = NULL;
@@ -1557,12 +1645,18 @@ int bioset_init(struct bio_set *bs,
biovec_init_pool(&bs->bvec_pool, pool_size))
goto bad;
- if (!(flags & BIOSET_NEED_RESCUER))
- return 0;
-
- bs->rescue_workqueue = alloc_workqueue("bioset", WQ_MEM_RECLAIM, 0);
- if (!bs->rescue_workqueue)
- goto bad;
+ if (flags & BIOSET_NEED_RESCUER) {
+ bs->rescue_workqueue = alloc_workqueue("bioset",
+ WQ_MEM_RECLAIM, 0);
+ if (!bs->rescue_workqueue)
+ goto bad;
+ }
+ if (flags & BIOSET_PERCPU_CACHE) {
+ bs->cache = alloc_percpu(struct bio_alloc_cache);
+ if (!bs->cache)
+ goto bad;
+ cpuhp_state_add_instance_nocalls(CPUHP_BIO_DEAD, &bs->cpuhp_dead);
+ }
return 0;
bad:
@@ -1589,6 +1683,46 @@ int bioset_init_from_src(struct bio_set *bs, struct bio_set *src)
}
EXPORT_SYMBOL(bioset_init_from_src);
+/**
+ * bio_alloc_kiocb - Allocate a bio from bio_set based on kiocb
+ * @kiocb: kiocb describing the IO
+ * @nr_iovecs: number of iovecs to pre-allocate
+ * @bs: bio_set to allocate from
+ *
+ * Description:
+ * Like @bio_alloc_bioset, but pass in the kiocb. The kiocb is only
+ * used to check if we should dip into the per-cpu bio_set allocation
+ * cache. The allocation uses GFP_KERNEL internally. On return, the
+ * bio is marked BIO_PERCPU_CACHEABLE, and the final put of the bio
+ * MUST be done from process context, not hard/soft IRQ.
+ *
+ */
+struct bio *bio_alloc_kiocb(struct kiocb *kiocb, unsigned short nr_vecs,
+ struct bio_set *bs)
+{
+ struct bio_alloc_cache *cache;
+ struct bio *bio;
+
+ if (!(kiocb->ki_flags & IOCB_ALLOC_CACHE) || nr_vecs > BIO_INLINE_VECS)
+ return bio_alloc_bioset(GFP_KERNEL, nr_vecs, bs);
+
+ cache = per_cpu_ptr(bs->cache, get_cpu());
+ bio = bio_list_pop(&cache->free_list);
+ if (bio) {
+ cache->nr--;
+ put_cpu();
+ bio_init(bio, nr_vecs ? bio->bi_inline_vecs : NULL, nr_vecs);
+ bio->bi_pool = bs;
+ bio_set_flag(bio, BIO_PERCPU_CACHE);
+ return bio;
+ }
+ put_cpu();
+ bio = bio_alloc_bioset(GFP_KERNEL, nr_vecs, bs);
+ bio_set_flag(bio, BIO_PERCPU_CACHE);
+ return bio;
+}
+EXPORT_SYMBOL_GPL(bio_alloc_kiocb);
+
static int __init init_bio(void)
{
int i;
@@ -1603,6 +1737,9 @@ static int __init init_bio(void)
SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
}
+ cpuhp_setup_state_multi(CPUHP_BIO_DEAD, "block/bio:dead", NULL,
+ bio_cpu_dead);
+
if (bioset_init(&fs_bio_set, BIO_POOL_SIZE, 0, BIOSET_NEED_BVECS))
panic("bio: can't allocate bios\n");
diff --git a/block/blk-core.c b/block/blk-core.c
index b5098739f72a..5454db2fa263 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -821,7 +821,7 @@ static noinline_for_stack bool submit_bio_checks(struct bio *bio)
}
if (!test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
- bio->bi_opf &= ~REQ_HIPRI;
+ bio_clear_hipri(bio);
switch (bio_op(bio)) {
case REQ_OP_DISCARD:
diff --git a/block/blk-merge.c b/block/blk-merge.c
index eeba8422ae82..7a5c81c02c80 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -285,7 +285,7 @@ split:
* iopoll in direct IO routine. Given performance gain of iopoll for
* big IO can be trival, disable iopoll when split needed.
*/
- bio->bi_opf &= ~REQ_HIPRI;
+ bio_clear_hipri(bio);
return bio_split(bio, sectors, GFP_NOIO, bs);
}
diff --git a/block/blk.h b/block/blk.h
index 346d184c82b0..8c96b0c90c48 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -366,4 +366,11 @@ extern struct device_attribute dev_attr_events;
extern struct device_attribute dev_attr_events_async;
extern struct device_attribute dev_attr_events_poll_msecs;
+static inline void bio_clear_hipri(struct bio *bio)
+{
+ /* can't support alloc cache if we turn off polling */
+ bio_clear_flag(bio, BIO_PERCPU_CACHE);
+ bio->bi_opf &= ~REQ_HIPRI;
+}
+
#endif /* BLK_INTERNAL_H */
diff --git a/fs/block_dev.c b/fs/block_dev.c
index 1f21ac984253..45df6cbccf12 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -386,7 +386,7 @@ static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
(bdev_logical_block_size(bdev) - 1))
return -EINVAL;
- bio = bio_alloc_bioset(GFP_KERNEL, nr_pages, &blkdev_dio_pool);
+ bio = bio_alloc_kiocb(iocb, nr_pages, &blkdev_dio_pool);
dio = container_of(bio, struct blkdev_dio, bio);
dio->is_sync = is_sync = is_sync_kiocb(iocb);
@@ -514,7 +514,9 @@ blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
static __init int blkdev_init(void)
{
- return bioset_init(&blkdev_dio_pool, 4, offsetof(struct blkdev_dio, bio), BIOSET_NEED_BVECS);
+ return bioset_init(&blkdev_dio_pool, 4,
+ offsetof(struct blkdev_dio, bio),
+ BIOSET_NEED_BVECS|BIOSET_PERCPU_CACHE);
}
module_init(blkdev_init);
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 7cc458e0b636..73928d957691 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2835,7 +2835,7 @@ static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe)
!kiocb->ki_filp->f_op->iopoll)
return -EOPNOTSUPP;
- kiocb->ki_flags |= IOCB_HIPRI;
+ kiocb->ki_flags |= IOCB_HIPRI | IOCB_ALLOC_CACHE;
kiocb->ki_complete = io_complete_rw_iopoll;
req->iopoll_completed = 0;
} else {
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 7b5f65a81f2b..3d67d0fbc868 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -400,6 +400,7 @@ static inline struct bio *bio_next_split(struct bio *bio, int sectors,
enum {
BIOSET_NEED_BVECS = BIT(0),
BIOSET_NEED_RESCUER = BIT(1),
+ BIOSET_PERCPU_CACHE = BIT(2),
};
extern int bioset_init(struct bio_set *, unsigned int, unsigned int, int flags);
extern void bioset_exit(struct bio_set *);
@@ -408,6 +409,8 @@ extern int bioset_init_from_src(struct bio_set *bs, struct bio_set *src);
struct bio *bio_alloc_bioset(gfp_t gfp, unsigned short nr_iovecs,
struct bio_set *bs);
+struct bio *bio_alloc_kiocb(struct kiocb *kiocb, unsigned short nr_vecs,
+ struct bio_set *bs);
struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned short nr_iovecs);
extern void bio_put(struct bio *);
@@ -657,6 +660,11 @@ struct bio_set {
struct kmem_cache *bio_slab;
unsigned int front_pad;
+ /*
+ * per-cpu bio alloc cache
+ */
+ struct bio_alloc_cache __percpu *cache;
+
mempool_t bio_pool;
mempool_t bvec_pool;
#if defined(CONFIG_BLK_DEV_INTEGRITY)
@@ -673,6 +681,11 @@ struct bio_set {
struct bio_list rescue_list;
struct work_struct rescue_work;
struct workqueue_struct *rescue_workqueue;
+
+ /*
+ * Hot un-plug notifier for the per-cpu cache, if used
+ */
+ struct hlist_node cpuhp_dead;
};
static inline bool bioset_initialized(struct bio_set *bs)
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 1335efa8a1db..9e392daa1d7f 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -297,6 +297,7 @@ enum {
BIO_TRACKED, /* set if bio goes through the rq_qos path */
BIO_REMAPPED,
BIO_ZONE_WRITE_LOCKED, /* Owns a zoned device zone write lock */
+ BIO_PERCPU_CACHE, /* can participate in per-cpu alloc cache */
BIO_FLAG_LAST
};
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 6ac543d33b66..95f88edc8f09 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -46,6 +46,7 @@ enum cpuhp_state {
CPUHP_ARM_OMAP_WAKE_DEAD,
CPUHP_IRQ_POLL_DEAD,
CPUHP_BLOCK_SOFTIRQ_DEAD,
+ CPUHP_BIO_DEAD,
CPUHP_ACPI_CPUDRV_DEAD,
CPUHP_S390_PFAULT_DEAD,
CPUHP_BLK_MQ_DEAD,
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 7eae53fff7c5..ae29027d2ac8 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -319,6 +319,8 @@ enum rw_hint {
/* iocb->ki_waitq is valid */
#define IOCB_WAITQ (1 << 19)
#define IOCB_NOIO (1 << 20)
+/* can use bio alloc cache */
+#define IOCB_ALLOC_CACHE (1 << 21)
struct kiocb {
struct file *ki_filp;