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From: Michal Hocko <mhocko@kernel.org>
To: Zhaoyang Huang <huangzhaoyang@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	Ingo Molnar <mingo@kernel.org>,
	linux-kernel@vger.kernel.org, kernel-patch-test@lists.linaro.org,
	Andrew Morton <akpm@linux-foundation.org>,
	Joel Fernandes <joelaf@google.com>,
	linux-mm@kvack.org, Vlastimil Babka <vbabka@suse.cz>
Subject: Re: [PATCH v1] kernel/trace:check the val against the available mem
Date: Wed, 4 Apr 2018 08:23:40 +0200	[thread overview]
Message-ID: <20180404062340.GD6312@dhcp22.suse.cz> (raw)
In-Reply-To: <CAGWkznH-yfAu=fMo1YWU9zo-DomHY8YP=rw447rUTgzvVH4RpQ@mail.gmail.com>

On Wed 04-04-18 10:58:39, Zhaoyang Huang wrote:
> On Tue, Apr 3, 2018 at 9:56 PM, Michal Hocko <mhocko@kernel.org> wrote:
> > On Tue 03-04-18 09:32:45, Steven Rostedt wrote:
> >> On Tue, 3 Apr 2018 14:35:14 +0200
> >> Michal Hocko <mhocko@kernel.org> wrote:
> > [...]
> >> > Being clever is OK if it doesn't add a tricky code. And relying on
> >> > si_mem_available is definitely tricky and obscure.
> >>
> >> Can we get the mm subsystem to provide a better method to know if an
> >> allocation will possibly succeed or not before trying it? It doesn't
> >> have to be free of races. Just "if I allocate this many pages right
> >> now, will it work?" If that changes from the time it asks to the time
> >> it allocates, that's fine. I'm not trying to prevent OOM to never
> >> trigger. I just don't want to to trigger consistently.
> >
> > How do you do that without an actuall allocation request? And more
> > fundamentally, what if your _particular_ request is just fine but it
> > will get us so close to the OOM edge that the next legit allocation
> > request simply goes OOM? There is simply no sane interface I can think
> > of that would satisfy a safe/sensible "will it cause OOM" semantic.
> >
> The point is the app which try to allocate the size over the line will escape
> the OOM and let other innocent to be sacrificed. However, the one which you
> mentioned above will be possibly selected by OOM that triggered by consequnce
> failed allocation.

If you are afraid of that then you can have a look at {set,clear}_current_oom_origin()
which will automatically select the current process as an oom victim and
kill it.
-- 
Michal Hocko
SUSE Labs

  reply	other threads:[~2018-04-04  6:23 UTC|newest]

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-03-29 10:41 [PATCH v1] kernel/trace:check the val against the available mem Zhaoyang Huang
2018-03-29 16:05 ` Steven Rostedt
2018-03-30  3:32   ` Zhaoyang Huang
2018-03-30 14:07     ` Steven Rostedt
2018-03-30  6:53 ` [Kernel-patch-test] " kbuild test robot
2018-03-30  6:54 ` kbuild test robot
2018-03-30 14:20 ` Steven Rostedt
2018-03-30 16:37   ` Joel Fernandes
2018-03-30 19:10     ` Steven Rostedt
2018-03-30 20:37       ` Joel Fernandes
2018-03-30 20:53   ` Matthew Wilcox
2018-03-30 21:30     ` Steven Rostedt
2018-03-30 21:42       ` Steven Rostedt
2018-03-30 23:38         ` Joel Fernandes
2018-03-31  1:41           ` Steven Rostedt
2018-03-31  2:18             ` Matthew Wilcox
2018-03-31  3:07               ` Steven Rostedt
2018-03-31  5:44                 ` Joel Fernandes
2018-04-02  0:52         ` Zhaoyang Huang
2018-04-03 11:06   ` Michal Hocko
2018-04-03 11:51     ` Steven Rostedt
2018-04-03 12:16       ` Michal Hocko
2018-04-03 12:23         ` Steven Rostedt
2018-04-03 12:35           ` Michal Hocko
2018-04-03 13:32             ` Steven Rostedt
2018-04-03 13:56               ` Michal Hocko
2018-04-03 14:17                 ` Steven Rostedt
2018-04-03 16:11                   ` Michal Hocko
2018-04-03 16:59                     ` Steven Rostedt
2018-04-03 22:56                     ` Steven Rostedt
2018-04-04  6:20                       ` Michal Hocko
2018-04-04 12:21                         ` Joel Fernandes
2018-04-04 12:59                         ` Steven Rostedt
2018-04-04 14:10                           ` Michal Hocko
2018-04-04 14:25                             ` Steven Rostedt
2018-04-04 14:42                               ` Michal Hocko
2018-04-04 15:04                                 ` Steven Rostedt
2018-04-04 15:27                                   ` Michal Hocko
2018-04-04 15:38                                     ` Steven Rostedt
2018-04-04  2:58                 ` Zhaoyang Huang
2018-04-04  6:23                   ` Michal Hocko [this message]
2018-04-04  9:29                     ` Zhaoyang Huang
2018-04-04 14:11                     ` Steven Rostedt
2018-04-04 14:23                       ` Michal Hocko
2018-04-04 14:31                         ` Steven Rostedt
2018-04-04 14:47                           ` Michal Hocko
2018-04-04 15:47                         ` Steven Rostedt
2018-04-05  2:58                           ` Matthew Wilcox
2018-04-05  4:12                             ` Joel Fernandes
2018-04-05 14:22                               ` Matthew Wilcox
2018-04-05 14:27                                 ` Michal Hocko
2018-04-05 14:34                                   ` Steven Rostedt
2018-04-05 15:13                                   ` Matthew Wilcox
2018-04-05 15:32                                     ` Michal Hocko
2018-04-05 16:15                                       ` Matthew Wilcox
2018-04-05 18:54                                         ` Michal Hocko
2018-04-05 20:15                                           ` __GFP_LOW Matthew Wilcox
2018-04-06  6:09                                             ` __GFP_LOW Michal Hocko
2018-04-08  4:27                                               ` __GFP_LOW Matthew Wilcox
2018-04-09  7:34                                                 ` __GFP_LOW Michal Hocko
2018-04-09 15:51                                                   ` __GFP_LOW Matthew Wilcox
2018-04-09 18:14                                                     ` __GFP_LOW Michal Hocko
     [not found]                                                       ` <CA+JonM0HG9kWb6-0iyDQ8UMxTeR-f=+ZL89t5DvvDULDC8Sfyw@mail.gmail.com>
2018-04-10 12:19                                                         ` __GFP_LOW Matthew Wilcox
2018-04-05 14:30                                 ` [PATCH v1] kernel/trace:check the val against the available mem Steven Rostedt

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