blk-cgroup-rwstat: add missing DISCARD counter in blkg_rwstat_total()#838
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blk-cgroup-rwstat: add missing DISCARD counter in blkg_rwstat_total()#838blktests-ci[bot] wants to merge 1 commit into
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Since commit 636620b ("blkcg: Track DISCARD statistics and output them in cgroup io.stat"), blkg_rwstat_add() routes discard IOs into BLKG_RWSTAT_DISCARD, but blkg_rwstat_total() still only sums READ and WRITE. This makes the total inconsistent with the per-type counters whenever discard IOs are present. On mixed read/write/discard workloads, the total undercounts the actual IO activity. If only discard requests are queued, the total returns 0 outright. In BFQ this causes avg_queue_size to be underestimated and the group to be incorrectly marked empty. The affected BFQ code paths are all gated by CONFIG_BFQ_CGROUP_DEBUG and used only for statistics display (bfq.sectors, bfq.avg_queue_size, bfq.empty_time). No scheduling decisions depend on these values. Signed-off-by: Tao Cui <cuitao@kylinos.cn>
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Upstream branch: 70eda68 |
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Pull request for series with
subject: blk-cgroup-rwstat: add missing DISCARD counter in blkg_rwstat_total()
version: 1
url: https://patchwork.kernel.org/project/linux-block/list/?series=1095754