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authorKemeng Shi <shikemeng@huawei.com>2022-12-05 12:57:02 +0100
committerJens Axboe <axboe@kernel.dk>2022-12-05 21:44:27 +0100
commit84aca0a7e039c8735abc0f89f3f48e9006c0dfc7 (patch)
tree2c558db44b8ff430c08d41a8f92f3789e7eb99d6 /Kbuild
parentblk-throttle: correct stale comment in throtl_pd_init (diff)
downloadlinux-84aca0a7e039c8735abc0f89f3f48e9006c0dfc7.tar.xz
linux-84aca0a7e039c8735abc0f89f3f48e9006c0dfc7.zip
blk-throttle: Fix that bps of child could exceed bps limited in parent
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>
Diffstat (limited to 'Kbuild')
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