linux-kernel - Re: [RFC v2] prctl: prctl(PR_SET_IDLE, PR_IDLE_MODE

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Date:   Wed, 15 Nov 2017 22:11:52 +0100
From:   Pavel Machek <pavel@....cz>
To:     Shawn Landden <slandden@...il.com>
Cc:     kernel list <linux-kernel@...r.kernel.org>
Subject: Re: [RFC v2] prctl: prctl(PR_SET_IDLE, PR_IDLE_MODE_KILLME), for
 stateless idle loops

Hi!

> 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.

Having android-like system for low memory killing might be
interesting... but rather than throwing around patches maybe there
should be discussion on lkml how the interface should look like,
first?

									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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