linux-kernel - Re: [PATCH 2/2] oom_kill: change oom_kill.c to use for_each

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Message-ID: <20131204125728.GA2549@redhat.com>
Date:	Wed, 4 Dec 2013 13:57:28 +0100
From:	Oleg Nesterov <oleg@...hat.com>
To:	Sameer Nanda <snanda@...omium.org>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	David Rientjes <rientjes@...gle.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Mandeep Singh Baines <msb@...omium.org>,
	"Ma, Xindong" <xindong.ma@...el.com>,
	Michal Hocko <mhocko@...e.cz>,
	Sergey Dyasly <dserrg@...il.com>,
	"Tu, Xiaobing" <xiaobing.tu@...el.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] oom_kill: change oom_kill.c to use
	for_each_thread()

Sameer, I didn't notice this part yesterday.

On 12/03, Sameer Nanda wrote:
>
> > @@ -406,7 +409,7 @@ void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
> >  {
> >         struct task_struct *victim = p;
> >         struct task_struct *child;
> > -       struct task_struct *t = p;
> > +       struct task_struct *t;
> >         struct mm_struct *mm;
> >         unsigned int victim_points = 0;
> >         static DEFINE_RATELIMIT_STATE(oom_rs, DEFAULT_RATELIMIT_INTERVAL,
> > @@ -437,7 +440,7 @@ void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
> >          * still freeing memory.
> >          */
> >         read_lock(&tasklist_lock);
> This can be a rcu_read_lock now, I think?

No, we need tasklist for list_for_each_entry(t->children), it
is not rcu-safe.

Oleg.

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