Re: [PATCH v2 0/4] psi: Add PSI_CPU_FULL state and some code optimization

From: Johannes Weiner
Date: Wed Mar 03 2021 - 13:24:05 EST


On Wed, Mar 03, 2021 at 11:46:55AM +0800, Chengming Zhou wrote:
> This patch series is RESEND of the previous patches on psi subsystem. A few
> weeks passed since the last review, so I put them together and resend for
> more convenient review and merge.
>
> Patch 1 add PSI_CPU_FULL state means all non-idle tasks in a cgroup are delayed
> on the CPU resource which used by others outside of the cgroup or throttled
> by the cgroup cpu.max configuration.
>
> Patch 2 use ONCPU state and the current in_memstall flag to detect reclaim,
> remove the hook in timer tick to make code more concise and maintainable.
> And patch 3 adds unlikely() annotations to move the pressure state branches
> out of line to eliminate undesirable jumps during wakeup and sleeps.
>
> Patch 4 optimize the voluntary sleep switch by remove one call of
> psi_group_change() for every common cgroup ancestor of the two tasks.
>
> Chengming Zhou (3):
> psi: Add PSI_CPU_FULL state
> psi: Use ONCPU state tracking machinery to detect reclaim
> psi: Optimize task switch inside shared cgroups
>
> Johannes Weiner (1):
> psi: pressure states are unlikely

Peter, would you mind routing these through the sched tree for 5.13?