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| author | Yu Kuai <yukuai3@huawei.com> | 2023-08-16 03:27:08 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2023-08-30 18:15:01 +0200 |
| commit | eead0056648cef49d7b15c07ae612fa217083165 (patch) | |
| tree | 5945d041f446ea086d237697ba969079d07d6082 /block | |
| parent | blk-throttle: use calculate_io/bytes_allowed() for throtl_trim_slice() (diff) | |
| download | linux-eead0056648cef49d7b15c07ae612fa217083165.tar.xz linux-eead0056648cef49d7b15c07ae612fa217083165.zip | |
blk-throttle: consider 'carryover_ios/bytes' in throtl_trim_slice()
Currently, 'carryover_ios/bytes' is not handled in throtl_trim_slice(),
for consequence, 'carryover_ios/bytes' will be used to throttle bio
multiple times, for example:
1) set iops limit to 100, and slice start is 0, slice end is 100ms;
2) current time is 0, and 10 ios are dispatched, those io won't be
throttled and io_disp is 10;
3) still at current time 0, update iops limit to 1000, carryover_ios is
updated to (0 - 10) = -10;
4) in this slice(0 - 100ms), io_allowed = 100 + (-10) = 90, which means
only 90 ios can be dispatched without waiting;
5) assume that io is throttled in slice(0 - 100ms), and
throtl_trim_slice() update silce to (100ms - 200ms). In this case,
'carryover_ios/bytes' is not cleared and still only 90 ios can be
dispatched between 100ms - 200ms.
Fix this problem by updating 'carryover_ios/bytes' in
throtl_trim_slice().
Fixes: a880ae93e5b5 ("blk-throttle: fix io hung due to configuration updates")
Reported-by: zhuxiaohui <zhuxiaohui.400@bytedance.com>
Link: https://lore.kernel.org/all/20230812072116.42321-1-zhuxiaohui.400@bytedance.com/
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20230816012708.1193747-5-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-throttle.c | 21 |
1 files changed, 13 insertions, 8 deletions
diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 69a994156772..38a881cf97d0 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -729,8 +729,9 @@ static u64 calculate_bytes_allowed(u64 bps_limit, unsigned long jiffy_elapsed) /* Trim the used slices and adjust slice start accordingly */ static inline void throtl_trim_slice(struct throtl_grp *tg, bool rw) { - unsigned long time_elapsed, io_trim; - u64 bytes_trim; + unsigned long time_elapsed; + long long bytes_trim; + int io_trim; BUG_ON(time_before(tg->slice_end[rw], tg->slice_start[rw])); @@ -758,17 +759,21 @@ static inline void throtl_trim_slice(struct throtl_grp *tg, bool rw) return; bytes_trim = calculate_bytes_allowed(tg_bps_limit(tg, rw), - time_elapsed); - io_trim = calculate_io_allowed(tg_iops_limit(tg, rw), time_elapsed); - if (!bytes_trim && !io_trim) + time_elapsed) + + tg->carryover_bytes[rw]; + io_trim = calculate_io_allowed(tg_iops_limit(tg, rw), time_elapsed) + + tg->carryover_ios[rw]; + if (bytes_trim <= 0 && io_trim <= 0) return; - if (tg->bytes_disp[rw] >= bytes_trim) + tg->carryover_bytes[rw] = 0; + if ((long long)tg->bytes_disp[rw] >= bytes_trim) tg->bytes_disp[rw] -= bytes_trim; else tg->bytes_disp[rw] = 0; - if (tg->io_disp[rw] >= io_trim) + tg->carryover_ios[rw] = 0; + if ((int)tg->io_disp[rw] >= io_trim) tg->io_disp[rw] -= io_trim; else tg->io_disp[rw] = 0; @@ -776,7 +781,7 @@ static inline void throtl_trim_slice(struct throtl_grp *tg, bool rw) tg->slice_start[rw] += time_elapsed; throtl_log(&tg->service_queue, - "[%c] trim slice nr=%lu bytes=%llu io=%lu start=%lu end=%lu jiffies=%lu", + "[%c] trim slice nr=%lu bytes=%lld io=%d start=%lu end=%lu jiffies=%lu", rw == READ ? 'R' : 'W', time_elapsed / tg->td->throtl_slice, bytes_trim, io_trim, tg->slice_start[rw], tg->slice_end[rw], jiffies); |