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From: Shawn Landden <slandden@gmail.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-mm@kvack.org, linux-api@vger.kernel.org
Subject: Re: [RFC v2] prctl: prctl(PR_SET_IDLE, PR_IDLE_MODE_KILLME), for stateless idle loops
Date: Mon, 20 Nov 2017 20:48:10 -0800	[thread overview]
Message-ID: <CA+49okomOyRy1Av_cAv38xJuX+TstVe6jWWuitmr3XCBx8mU_g@mail.gmail.com> (raw)
In-Reply-To: <20171120083548.stupram6kpi5iu7i@dhcp22.suse.cz>

On Mon, Nov 20, 2017 at 12:35 AM, Michal Hocko <mhocko@kernel.org> wrote:
> On Fri 17-11-17 20:45:03, Shawn Landden wrote:
>> On Fri, Nov 3, 2017 at 2:09 AM, Michal Hocko <mhocko@kernel.org> wrote:
>>
>> > On Thu 02-11-17 23:35:44, Shawn Landden wrote:
>> > > It is common for services to be stateless around their main event loop.
>> > > If a process sets PR_SET_IDLE to PR_IDLE_MODE_KILLME then it
>> > > signals to the kernel that epoll_wait() and friends may not complete,
>> > > and the kernel may send SIGKILL if resources get tight.
>> > >
>> > > See my systemd patch: https://github.com/shawnl/systemd/tree/prctl
>> > >
>> > > Android uses this memory model for all programs, and having it in the
>> > > kernel will enable integration with the page cache (not in this
>> > > series).
>> > >
>> > > 16 bytes per process is kinda spendy, but I want to keep
>> > > lru behavior, which mem_score_adj does not allow. When a supervisor,
>> > > like Android's user input is keeping track this can be done in
>> > user-space.
>> > > It could be pulled out of task_struct if an cross-indexing additional
>> > > red-black tree is added to support pid-based lookup.
>> >
>> > This is still an abuse and the patch is wrong. We really do have an API
>> > to use I fail to see why you do not use it.
>> >
>> When I looked at wait_queue_head_t it was 20 byes.
>
> I do not understand. What I meant to say is that we do have a proper
> user api to hint OOM killer decisions.
This is a FIFO queue, rather than a heuristic, which is all you get
with the current API.
> --
> Michal Hocko
> SUSE Labs

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  reply	other threads:[~2017-11-21  4:48 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-01  5:32 [RFC] EPOLL_KILLME: New flag to epoll_wait() that subscribes process to death row (new syscall) Shawn Landden
2017-11-01 14:04 ` Matthew Wilcox
2017-11-01 15:16 ` Colin Walters
2017-11-01 15:22   ` Colin Walters
2017-11-03  9:22     ` peter enderborg
2017-11-01 19:02   ` Shawn Landden
2017-11-01 19:37     ` Colin Walters
2017-11-01 19:43       ` Shawn Landden
2017-11-01 20:54       ` Shawn Landden
2017-11-02 15:24       ` Shawn Paul Landden
2017-11-01 19:05   ` Shawn Landden
2017-11-01 22:10 ` Tetsuo Handa
2017-11-02  7:36   ` Shawn Landden
2017-11-02 15:45 ` Michal Hocko
2017-11-03  6:35 ` [RFC v2] prctl: prctl(PR_SET_IDLE, PR_IDLE_MODE_KILLME), for stateless idle loops Shawn Landden
2017-11-03  9:09   ` Michal Hocko
2017-11-18  4:45     ` Shawn Landden
2017-11-19  4:19       ` Matthew Wilcox
2017-11-20  8:35       ` Michal Hocko
2017-11-21  4:48         ` Shawn Landden [this message]
2017-11-21  7:05           ` Michal Hocko
2017-11-18 20:33     ` Shawn Landden
2017-11-21  4:49   ` [RFC v3] It is common for services to be stateless around their main event loop. If a process sets PR_SET_IDLE to PR_IDLE_MODE_KILLME then it signals to the kernel that epoll_wait() and friends may not complete, and the kernel may send SIGKILL if resources get tight Shawn Landden
2017-11-21  4:56     ` Shawn Landden
2017-11-21  5:16     ` [RFC v4] " Shawn Landden
2017-11-21  5:26       ` Shawn Landden
2017-11-21  9:14       ` Thomas Gleixner
2017-11-22 10:29   ` [RFC v2] prctl: prctl(PR_SET_IDLE, PR_IDLE_MODE_KILLME), for stateless idle loops peter enderborg

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