linux-kernel - Re: [PATCH 2/2] sched/psi: iterate through cgroups directly

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20230208172956.GF24523@blackbody.suse.cz>
Date:   Wed, 8 Feb 2023 18:29:56 +0100
From:   Michal Koutný <mkoutny@...e.com>
To:     Kairui Song <kasong@...cent.com>
Cc:     Johannes Weiner <hannes@...xchg.org>,
        Suren Baghdasaryan <surenb@...gle.com>,
        Chengming Zhou <zhouchengming@...edance.com>,
        Tejun Heo <tj@...nel.org>, Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>, cgroups@...r.kernel.org,
        linux-kernel@...r.kernel.org, Kairui Song <ryncsn@...il.com>
Subject: Re: [PATCH 2/2] sched/psi: iterate through cgroups directly

On Thu, Feb 09, 2023 at 12:16:54AM +0800, Kairui Song <ryncsn@...il.com> wrote:
> Signed-off-by: Kairui Song <kasong@...cent.com>
> Signed-off-by: Kairui Song <ryncsn@...il.com>

Typo?

> -static inline struct psi_group *task_psi_group(struct task_struct *task)
> +static inline struct psi_group *psi_iter_first(struct task_struct *task, void **iter)
>  {
>  #ifdef CONFIG_CGROUPS
> -	if (static_branch_likely(&psi_cgroups_enabled))
> -		return cgroup_psi(task_dfl_cgroup(task));
> +	if (static_branch_likely(&psi_cgroups_enabled)) {
> +		struct cgroup *cgroup = task_dfl_cgroup(task);
> +
> +		*iter = cgroup_parent(cgroup);

This seems to skip a cgroup level -- maybe that's the observed
performance gain?

> +		return cgroup_psi(cgroup);
> +	}
>  #endif
>  	return &psi_system;
>  }

Michal

Download attachment "signature.asc" of type "application/pgp-signature" (229 bytes)