Commit b9df115b authored by Chengming Zhou's avatar Chengming Zhou Committed by Zheng Zengkai
Browse files

psi: Use ONCPU state tracking machinery to detect reclaim

mainline inclusion
from mainline-v5.13-rc1
commit 7fae6c81
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I562O9
CVE: NA
backport: openEuler-22.03-LTS

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7fae6c8171d20ac55402930ee8ae760cf85dff7b



--------------------------------

Move the reclaim detection from the timer tick to the task state
tracking machinery using the recently added ONCPU state. And we
also add task psi_flags changes checking in the psi_task_switch()
optimization to update the parents properly.

In terms of performance and cost, this ONCPU task state tracking
is not cheaper than previous timer tick in aggregate. But the code is
simpler and shorter this way, so it's a maintainability win. And
Johannes did some testing with perf bench, the performace and cost
changes would be acceptable for real workloads.

Thanks to Johannes Weiner for pointing out the psi_task_switch()
optimization things and the clearer changelog.

Co-developed-by: default avatarMuchun Song <songmuchun@bytedance.com>
Signed-off-by: default avatarMuchun Song <songmuchun@bytedance.com>
Signed-off-by: default avatarChengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Link: https://lkml.kernel.org/r/20210303034659.91735-3-zhouchengming@bytedance.com


Signed-off-by: default avatarChen Wandun <chenwandun@huawei.com>
Reviewed-by: default avatarKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: default avatarZheng Zengkai <zhengzengkai@huawei.com>
parent e05cfcd6
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