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Subject: Re: [RFC v2] prctl: prctl(PR_SET_IDLE, PR_IDLE_MODE_KILLME), for
 stateless idle loops
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>
References: <20171101053244.5218-1-slandden@gmail.com>
 <20171103063544.13383-1-slandden@gmail.com>
From: peter enderborg <peter.enderborg@sony.com>
Message-ID: <f141dd62-b962-9235-d70d-4b2b4bd508bc@sony.com>
Date: Wed, 22 Nov 2017 11:29:40 +0100
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On 11/03/2017 07:35 AM, 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.
What android version is using systemd?
In android there is a OnTrimMemory that is sent from activitymanager that
you can listen on and make a nice exit.