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

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Date:   Wed, 3 Mar 2021 09:59:11 -0500
From:   Johannes Weiner <hannes@...xchg.org>
To:     peterz@...radead.org
Cc:     Chengming Zhou <zhouchengming@...edance.com>, mingo@...hat.com,
        juri.lelli@...hat.com, vincent.guittot@...aro.org,
        dietmar.eggemann@....com, rostedt@...dmis.org,
        linux-kernel@...r.kernel.org, songmuchun@...edance.com
Subject: Re: [PATCH v2 0/4] psi: Add PSI_CPU_FULL state and some code
 optimization

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?