linux-kernel - Re: [PATCH v3 2/3] misc_cgroup: remove error log to avoid log flood

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Date:   Thu, 16 Sep 2021 19:57:11 +0200
From:   Michal Koutný <mkoutny@...e.com>
To:     brookxu <brookxu.cn@...il.com>
Cc:     tj@...nel.org, lizefan.x@...edance.com, hannes@...xchg.org,
        vipinsh@...gle.com, corbet@....net, linux-kernel@...r.kernel.org,
        cgroups@...r.kernel.org, linux-doc@...r.kernel.org
Subject: Re: [PATCH v3 2/3] misc_cgroup: remove error log to avoid log flood

On Wed, Sep 15, 2021 at 10:18:50AM +0800, brookxu <brookxu.cn@...il.com> wrote:
> In scenarios where containers are frequently created and deleted,
> a large number of error logs maybe generated. This log provides
> less information, we can get more detailed info from misc.events.

IIUC, the log provides equal information (with persistence), no?

> diff --git a/kernel/cgroup/misc.c b/kernel/cgroup/misc.c
> index 4b2b492..fe3e8a0 100644
> --- a/kernel/cgroup/misc.c
> +++ b/kernel/cgroup/misc.c
> @@ -157,13 +157,6 @@ int misc_cg_try_charge(enum misc_res_type type, struct misc_cg *cg,
>  		new_usage = atomic_long_add_return(amount, &res->usage);
>  		if (new_usage > READ_ONCE(res->max) ||
>  		    new_usage > READ_ONCE(misc_res_capacity[type])) {
> -			if (!res->failed) {
> -				pr_info("cgroup: charge rejected by the misc controller for %s resource in ",
> -					misc_res_name[type]);
> -				pr_cont_cgroup_path(i->css.cgroup);
> -				pr_cont("\n");
> -				res->failed = true;
> -			}

As I argued previously, reporting this as "in" `i` cgroup instead
of `cg` is not that useful and equivalent to the misc.events:*.max now,
so the drop is appropriate.

The change/patch is OK,
Reviewed-by: Michal Koutný <mkoutny@...e.com>

The commit message might be fixed (if you agree with remark).