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| author | Kemeng Shi <shikemeng@huawei.com> | 2022-12-05 19:57:02 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-04-13 16:55:37 +0200 |
| commit | 414207ff47d12850ce9ed1186de57218b710a312 (patch) | |
| tree | aa4576df575e8f18d5891cd4963d4ed52c97cb86 /block | |
| parent | 240bb94f3510e0ced4877a786520ee47743c880d (diff) | |
| download | linux-414207ff47d12850ce9ed1186de57218b710a312.tar.gz | |
blk-throttle: Fix that bps of child could exceed bps limited in parent
commit 84aca0a7e039c8735abc0f89f3f48e9006c0dfc7 upstream. Consider situation as following (on the default hierarchy): HDD | root (bps limit: 4k) | child (bps limit :8k) | fio bs=8k Rate of fio is supposed to be 4k, but result is 8k. Reason is as following: Size of single IO from fio is larger than bytes allowed in one throtl_slice in child, so IOs are always queued in child group first. When queued IOs in child are dispatched to parent group, BIO_BPS_THROTTLED is set and these IOs will not be limited by tg_within_bps_limit anymore. Fix this by only set BIO_BPS_THROTTLED when the bio traversed the entire tree. There patch has no influence on situation which is not on the default hierarchy as each group is a single root group without parent. Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Kemeng Shi <shikemeng@huawei.com> Link: https://lore.kernel.org/r/20221205115709.251489-3-shikemeng@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk> Cc: Khazhy Kumykov <khazhy@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-throttle.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 847721dc2b2b..f1bc600c4ded 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -1066,7 +1066,6 @@ static void tg_dispatch_one_bio(struct throtl_grp *tg, bool rw) sq->nr_queued[rw]--; throtl_charge_bio(tg, bio); - bio_set_flag(bio, BIO_BPS_THROTTLED); /* * If our parent is another tg, we just need to transfer @bio to @@ -1079,6 +1078,7 @@ static void tg_dispatch_one_bio(struct throtl_grp *tg, bool rw) throtl_add_bio_tg(bio, &tg->qnode_on_parent[rw], parent_tg); start_parent_slice_with_credit(tg, parent_tg, rw); } else { + bio_set_flag(bio, BIO_BPS_THROTTLED); throtl_qnode_add_bio(bio, &tg->qnode_on_parent[rw], &parent_sq->queued[rw]); BUG_ON(tg->td->nr_queued[rw] <= 0); |