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Date:   Tue, 7 May 2019 09:43:34 +0200
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     Sultan Alsawaf <sultan@kerneltoast.com>
Cc:     "open list:ANDROID DRIVERS" <devel@driverdev.osuosl.org>,
        Daniel Colascione <dancol@google.com>,
        Todd Kjos <tkjos@android.com>,
        Kees Cook <keescook@chromium.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Martijn Coenen <maco@android.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Tim Murray <timmurray@google.com>,
        Michal Hocko <mhocko@kernel.org>,
        Suren Baghdasaryan <surenb@google.com>,
        linux-mm <linux-mm@kvack.org>,
        Arve =?iso-8859-1?B?SGr4bm5lduVn?= <arve@android.com>,
        Ingo Molnar <mingo@redhat.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Oleg Nesterov <oleg@redhat.com>,
        Joel Fernandes <joel@joelfernandes.org>,
        Andy Lutomirski <luto@amacapital.net>,
        kernel-team <kernel-team@android.com>,
        Christian Brauner <christian@brauner.io>
Subject: Re: [RFC] simple_lmk: Introduce Simple Low Memory Killer for Android
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On Tue, May 07, 2019 at 12:27:21AM -0700, Sultan Alsawaf wrote:
> On Tue, May 07, 2019 at 09:04:30AM +0200, Greg Kroah-Hartman wrote:
> > Um, why can't "all" Android devices take the same patches that the Pixel
> > phones are using today?  They should all be in the public android-common
> > kernel repositories that all Android devices should be syncing with on a
> > weekly/monthly basis anyway, right?
> > 
> > thanks,
> > 
> > greg k-h
> 
> Hi Greg,
> 
> I only see PSI present in the android-common kernels for 4.9 and above. The vast
> majority of Android devices do not run a 4.9+ kernel. It seems unreasonable to
> expect OEMs to toil with backporting PSI themselves to get decent memory
> management.

Given that any "new" android device that gets shipped "soon" should be
using 4.9.y or newer, is this a real issue?

And if it is, I'm sure that asking for those patches to be backported to
4.4.y would be just fine, have you asked?

Note that I know of Android Go devices, running 3.18.y kernels, do NOT
use the in-kernel memory killer, but instead use the userspace solution
today.  So trying to get another in-kernel memory killer solution added
anywhere seems quite odd.

thanks,

greg k-h