From: Michal Hocko <mhocko@kernel.org>
To: Shawn Landden <slandden@gmail.com>
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: Tue, 21 Nov 2017 08:05:08 +0100 [thread overview]
Message-ID: <20171121070508.iapcp5lg3zjpfimi@dhcp22.suse.cz> (raw)
In-Reply-To: <CA+49okomOyRy1Av_cAv38xJuX+TstVe6jWWuitmr3XCBx8mU_g@mail.gmail.com>
On Mon 20-11-17 20:48:10, Shawn Landden wrote:
> 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.
Yes I can read the code. All I am saing is that we already have an API
to achieve what you want or at least very similar.
Let me be explicit.
Nacked-by: Michal Hocko <mhocko@suse.com>
until it is sufficiently explained that the oom_score_adj is not
suitable and there are no other means to achieve what you need.
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2017-11-21 7:05 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
2017-11-21 7:05 ` Michal Hocko [this message]
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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