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dm: improve abnormal bio processing

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Read/write/flush are the most common operations, optimize switch in
is_abnormal_io() for those cases. Follows same pattern established in
block perf-wip commit ("block: optimise blk_may_split for normal rw")

Also, push is_abnormal_io() check and blk_queue_split() down from
dm_submit_bio() to dm_split_and_process_bio() and set new
'is_abnormal_io' flag in clone_info. Optimize __split_and_process_bio
and __process_abnormal_io by leveraging ci.is_abnormal_io flag.

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
This commit is contained in:
Mike Snitzer 2022-04-17 13:00:15 -04:00
parent 9d20653fe8
commit 4edadf6dcb
1 changed files with 36 additions and 31 deletions
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57
drivers/md/dm.c
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@ -84,7 +84,8 @@ struct clone_info {
struct dm_io *io;
sector_t sector;
unsigned sector_count;
bool submit_as_polled;
bool is_abnormal_io:1;
bool submit_as_polled:1;
};
#define DM_TARGET_IO_BIO_OFFSET (offsetof(struct dm_target_io, clone))
@ -1491,21 +1492,24 @@ static void __send_changing_extent_only(struct clone_info *ci, struct dm_target
static bool is_abnormal_io(struct bio *bio)
{
bool r = false;
unsigned int op = bio_op(bio);
switch (bio_op(bio)) {
if (op != REQ_OP_READ && op != REQ_OP_WRITE && op != REQ_OP_FLUSH) {
switch (op) {
case REQ_OP_DISCARD:
case REQ_OP_SECURE_ERASE:
case REQ_OP_WRITE_ZEROES:
r = true;
return true;
default:
break;
}
}
return r;
return false;
}
static bool __process_abnormal_io(struct clone_info *ci, struct dm_target *ti,
blk_status_t *status)
static blk_status_t __process_abnormal_io(struct clone_info *ci,
struct dm_target *ti)
{
unsigned num_bios = 0;
@ -1519,8 +1523,6 @@ static bool __process_abnormal_io(struct clone_info *ci, struct dm_target *ti,
case REQ_OP_WRITE_ZEROES:
num_bios = ti->num_write_zeroes_bios;
break;
default:
return false;
}
/*
@ -1530,12 +1532,10 @@ static bool __process_abnormal_io(struct clone_info *ci, struct dm_target *ti,
* check was performed.
*/
if (unlikely(!num_bios))
*status = BLK_STS_NOTSUPP;
else {
return BLK_STS_NOTSUPP;
__send_changing_extent_only(ci, ti, num_bios);
*status = BLK_STS_OK;
}
return true;
return BLK_STS_OK;
}
/*
@ -1588,11 +1588,12 @@ static blk_status_t __split_and_process_bio(struct clone_info *ci)
struct bio *clone;
struct dm_target *ti;
unsigned len;
blk_status_t error = BLK_STS_IOERR;
ti = dm_table_find_target(ci->map, ci->sector);
if (unlikely(!ti || __process_abnormal_io(ci, ti, &error)))
return error;
if (unlikely(!ti))
return BLK_STS_IOERR;
else if (unlikely(ci->is_abnormal_io))
return __process_abnormal_io(ci, ti);
/*
* Only support bio polling for normal IO, and the target io is
@ -1612,11 +1613,12 @@ static blk_status_t __split_and_process_bio(struct clone_info *ci)
}
static void init_clone_info(struct clone_info *ci, struct mapped_device *md,
struct dm_table *map, struct bio *bio)
struct dm_table *map, struct bio *bio, bool is_abnormal)
{
ci->map = map;
ci->io = alloc_io(md, bio);
ci->bio = bio;
ci->is_abnormal_io = is_abnormal;
ci->submit_as_polled = false;
ci->sector = bio->bi_iter.bi_sector;
ci->sector_count = bio_sectors(bio);
@ -1636,8 +1638,18 @@ static void dm_split_and_process_bio(struct mapped_device *md,
struct clone_info ci;
struct dm_io *io;
blk_status_t error = BLK_STS_OK;
bool is_abnormal;
init_clone_info(&ci, md, map, bio);
is_abnormal = is_abnormal_io(bio);
if (unlikely(is_abnormal)) {
/*
* Use blk_queue_split() for abnormal IO (e.g. discard, etc)
* otherwise associated queue_limits won't be imposed.
*/
blk_queue_split(&bio);
}
init_clone_info(&ci, md, map, bio, is_abnormal);
io = ci.io;
if (bio->bi_opf & REQ_PREFLUSH) {
@ -1697,13 +1709,6 @@ static void dm_submit_bio(struct bio *bio)
goto out;
}
/*
* Use blk_queue_split() for abnormal IO (e.g. discard, writesame, etc)
* otherwise associated queue_limits won't be imposed.
*/
if (unlikely(is_abnormal_io(bio)))
blk_queue_split(&bio);
dm_split_and_process_bio(md, map, bio);
out:
dm_put_live_table_bio(md, srcu_idx, bio);