From: Hao Lee <haolee.swjtu@gmail.com>
To: tj@kernel.org
Cc: lizefan@huawei.com, hannes@cmpxchg.org, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] cgroup: Delete unnecessary if statement in css_visible()
Date: Thu, 1 Oct 2020 14:44:26 +0000 [thread overview]
Message-ID: <20201001144426.GA8928@haolee.github.io> (raw)
In-Reply-To: <20200829100202.GA855@haolee.github.io>
Hi, ping...
On Sat, Aug 29, 2020 at 10:03:16AM +0000, Hao Lee wrote:
> css_visible() is called in either cgroup_apply_control_enable()
> or cgroup_apply_control_disable().
> In cgroup_apply_control_enable(), we have checked ss_mask before calling
> css_visible(), so there is no need to do the same thing again.
> In cgroup_apply_control_disable():
> - If css->parent is not NULL, we have checked ss_mask in the
> second condition, so there is no need to do the same thing again.
> - If css->parent is NULL, dsct is root cgroup so the deleted if
> statement is always false and there is no need to keep it.
>
> Signed-off-by: Hao Lee <haolee.swjtu@gmail.com>
> ---
> kernel/cgroup/cgroup.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
> index dd247747ec14..b6714166106d 100644
> --- a/kernel/cgroup/cgroup.c
> +++ b/kernel/cgroup/cgroup.c
> @@ -3023,8 +3023,6 @@ static bool css_visible(struct cgroup_subsys_state *css)
>
> if (cgroup_control(cgrp) & (1 << ss->id))
> return true;
> - if (!(cgroup_ss_mask(cgrp) & (1 << ss->id)))
> - return false;
> return cgroup_on_dfl(cgrp) && ss->implicit_on_dfl;
> }
>
> --
> 2.24.1
>
prev parent reply other threads:[~2020-10-01 14:44 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-29 10:03 [PATCH] cgroup: Delete unnecessary if statement in css_visible() Hao Lee
2020-09-08 12:48 ` Hao Lee
2020-10-01 14:44 ` Hao Lee [this message]
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