linux-kernel - Re: [PATCH 0/3 staging-next] android: Lowmemmorykiller task tree

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Message-ID: <5579dead-092d-2ce2-a9d4-f2b50721f0dc@sonymobile.com>
Date:   Mon, 13 Feb 2017 16:42:42 +0100
From:   peter enderborg <peter.enderborg@...ymobile.com>
To:     Michal Hocko <mhocko@...nel.org>
CC:     <devel@...verdev.osuosl.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        <linux-kernel@...r.kernel.org>,
        Arve Hjønnevåg <arve@...roid.com>,
        Riley Andrews <riandrews@...roid.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        <linux-mm@...ck.org>
Subject: Re: [PATCH 0/3 staging-next] android: Lowmemmorykiller task tree

On 02/10/2017 11:27 AM, Michal Hocko wrote:
> [I have only now see this cover - it answers some of the questions I've
>  had to specific patches. It would be really great if you could use git
>  send-email to post patch series - it just does the right thing(tm)]
>
> On Thu 09-02-17 14:21:40, peter enderborg wrote:
>> Lowmemorykiller efficiency problem and a solution.
>>
>> Lowmemorykiller in android has a severe efficiency problem. The basic
>> problem is that the registered shrinker gets called very often without
>>  anything actually happening.
> Which is an inherent problem because lkml doesn't belong to shrinkers
> infrastructure.

Not really what this patch address.  I see it as a problem with shrinker
that there no slow-path-free (scan/count) where it should belong.
This patch address a specific problem where lot of cpu are wasted
in low memory conditions.