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blk-throttle: factor out code to calculate ios/bytes_allowed 

No functional changes, new apis will be used in later patches to
calculate wait time for throttled bios when new configuration is
submitted.

Noted this patch also rename tg_with_in_iops/bps_limit() to
tg_within_iops/bps_limit().

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220829022240.3348319-4-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Yu Kuai 2022-08-29 10:22:39 +08:00 committed by Jens Axboe
parent 8d6bbaada2
commit 681cd46fff
1 changed files with 37 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

63
block/blk-throttle.c
View File

@ -754,13 +754,41 @@ static inline void throtl_trim_slice(struct throtl_grp *tg, bool rw)
tg->slice_start[rw], tg->slice_end[rw], jiffies);
}
static bool tg_with_in_iops_limit(struct throtl_grp *tg, struct bio *bio,
u32 iops_limit, unsigned long *wait)
static unsigned int calculate_io_allowed(u32 iops_limit,
unsigned long jiffy_elapsed)
{
unsigned int io_allowed;
u64 tmp;
/*
* jiffy_elapsed should not be a big value as minimum iops can be
* 1 then at max jiffy elapsed should be equivalent of 1 second as we
* will allow dispatch after 1 second and after that slice should
* have been trimmed.
*/
tmp = (u64)iops_limit * jiffy_elapsed;
do_div(tmp, HZ);
if (tmp > UINT_MAX)
io_allowed = UINT_MAX;
else
io_allowed = tmp;
return io_allowed;
}
static u64 calculate_bytes_allowed(u64 bps_limit, unsigned long jiffy_elapsed)
{
return mul_u64_u64_div_u64(bps_limit, (u64)jiffy_elapsed, (u64)HZ);
}
static bool tg_within_iops_limit(struct throtl_grp *tg, struct bio *bio,
u32 iops_limit, unsigned long *wait)
{
bool rw = bio_data_dir(bio);
unsigned int io_allowed;
unsigned long jiffy_elapsed, jiffy_wait, jiffy_elapsed_rnd;
u64 tmp;
if (iops_limit == UINT_MAX) {
if (wait)
@ -772,22 +800,7 @@ static bool tg_with_in_iops_limit(struct throtl_grp *tg, struct bio *bio,
/* Round up to the next throttle slice, wait time must be nonzero */
jiffy_elapsed_rnd = roundup(jiffy_elapsed + 1, tg->td->throtl_slice);
/*
* jiffy_elapsed_rnd should not be a big value as minimum iops can be
* 1 then at max jiffy elapsed should be equivalent of 1 second as we
* will allow dispatch after 1 second and after that slice should
* have been trimmed.
*/
tmp = (u64)iops_limit * jiffy_elapsed_rnd;
do_div(tmp, HZ);
if (tmp > UINT_MAX)
io_allowed = UINT_MAX;
else
io_allowed = tmp;
io_allowed = calculate_io_allowed(iops_limit, jiffy_elapsed_rnd);
if (tg->io_disp[rw] + 1 <= io_allowed) {
if (wait)
*wait = 0;
@ -802,8 +815,8 @@ static bool tg_with_in_iops_limit(struct throtl_grp *tg, struct bio *bio,
return false;
}
static bool tg_with_in_bps_limit(struct throtl_grp *tg, struct bio *bio,
u64 bps_limit, unsigned long *wait)
static bool tg_within_bps_limit(struct throtl_grp *tg, struct bio *bio,
u64 bps_limit, unsigned long *wait)
{
bool rw = bio_data_dir(bio);
u64 bytes_allowed, extra_bytes;
@ -824,9 +837,7 @@ static bool tg_with_in_bps_limit(struct throtl_grp *tg, struct bio *bio,
jiffy_elapsed_rnd = tg->td->throtl_slice;
jiffy_elapsed_rnd = roundup(jiffy_elapsed_rnd, tg->td->throtl_slice);
bytes_allowed = mul_u64_u64_div_u64(bps_limit, (u64)jiffy_elapsed_rnd,
(u64)HZ);
bytes_allowed = calculate_bytes_allowed(bps_limit, jiffy_elapsed_rnd);
if (tg->bytes_disp[rw] + bio_size <= bytes_allowed) {
if (wait)
*wait = 0;
@ -895,8 +906,8 @@ static bool tg_may_dispatch(struct throtl_grp *tg, struct bio *bio,
jiffies + tg->td->throtl_slice);
}
if (tg_with_in_bps_limit(tg, bio, bps_limit, &bps_wait) &&
tg_with_in_iops_limit(tg, bio, iops_limit, &iops_wait)) {
if (tg_within_bps_limit(tg, bio, bps_limit, &bps_wait) &&
tg_within_iops_limit(tg, bio, iops_limit, &iops_wait)) {
if (wait)
*wait = 0;
return true;