Re: [PATCH v1] ringbuffer: Don't choose the process with adj equal OOM_SCORE_ADJ_MIN

From: Steven Rostedt <rostedt@goodmis.org>
To: Zhaoyang Huang <huangzhaoyang@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v1] ringbuffer: Don't choose the process with adj equal OOM_SCORE_ADJ_MIN
Date: Mon, 9 Apr 2018 09:49:44 -0400	[thread overview]
Message-ID: <20180409094944.6399b211@gandalf.local.home> (raw)
In-Reply-To: <CAGWkznEQbaw7HMvE1pbVDMriOL8yW74Ka5UEci4YFRdLnVbFzA@mail.gmail.com>

On Mon, 9 Apr 2018 08:56:01 +0800
Zhaoyang Huang <huangzhaoyang@gmail.com> wrote:

> >>
> >>         if (oom_task_origin(task)) {
> >>                 points = ULONG_MAX;
> >>                 goto select;
> >>         }
> >>
> >>         points = oom_badness(task, NULL, oc->nodemask, oc->totalpages);
> >>         if (!points || points < oc->chosen_points)
> >>                 goto next;  
> >
> > And what's wrong with that?
> >
> > -- Steve  
> I think the original thought of OOM is the flag 'OOM_SCORE_ADJ_MIN' is
> most likely to be set by process himself via accessing the proc file,
> if it does so, OOM can select it as the victim. except, it is
> reluctant to choose the critical process to be killed, so I suggest
> not to set such heavy flag as OOM_SCORE_ADJ_MIN on behalf of -1000
> process.

Really, I don't think tasks that are setting OOM_CORE_ADJ_MIN should be
allocating a lot of memory in the kernel (via ring buffer). It sounds
like a good way to wreck havoc on the system.

It's basically saying, "I'm going to take up all memory, but don't kill
me, just kill some random user on the system".

-- Steve