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io_uring-bio-cache.5-2021-08-30

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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
This commit is contained in:
Linus Torvalds 2021-08-30 19:30:30 -07:00
commit 3b629f8d6d
10 changed files with 184 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

169
block/bio.c
View File

@ -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");

2
block/blk-core.c
View File

@ -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:

2
block/blk-merge.c
View File

@ -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);
}

7
block/blk.h
View File

@ -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 */

6
fs/block_dev.c
View File

@ -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);

2
fs/io_uring.c
View File

@ -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 {

13
include/linux/bio.h
View File

@ -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)

1
include/linux/blk_types.h
View File

@ -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
};

1
include/linux/cpuhotplug.h
View File

@ -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,

2
include/linux/fs.h
View File

@ -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;