From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx118.postini.com [74.125.245.118]) by kanga.kvack.org (Postfix) with SMTP id B728B6B00C3 for ; Tue, 17 Jan 2012 09:29:13 -0500 (EST) From: Subject: RE: [PATCH v2 2/2] Memory notification pseudo-device module Date: Tue, 17 Jan 2012 14:28:28 +0000 Message-ID: <84FF21A720B0874AA94B46D76DB98269045593DE@008-AM1MPN1-003.mgdnok.nokia.com> References: <5b429d6c4d0a3ad06ec01193eab7edc98a03e0de.1326803859.git.leonid.moiseichuk@nokia.com> <84FF21A720B0874AA94B46D76DB9826904559397@008-AM1MPN1-003.mgdnok.nokia.com> In-Reply-To: Content-Language: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: penberg@kernel.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, cesarb@cesarb.net, kamezawa.hiroyu@jp.fujitsu.com, emunson@mgebm.net, aarcange@redhat.com, riel@redhat.com, mel@csn.ul.ie, rientjes@google.com, dima@android.com, gregkh@suse.de, rebecca@android.com, san@google.com, akpm@linux-foundation.org, vesa.jaaskelainen@nokia.com > -----Original Message----- > From: penberg@gmail.com [mailto:penberg@gmail.com] On Behalf Of ext > Pekka Enberg > Sent: 17 January, 2012 15:59 ... > If you're serious about making this a generic thing, it must live in > mm/mem_notify.c. No ifs or buts about it. > I'm also not completely convinced we need to put memnotify policy in the > kernel. Why can't we extend Minchan's patch to report the relevant > numbers and let the userspace figure out when pressure is above some > interesting threshold? I do not insist to have it as a part mm, but if you have 1-2-3 items what s= hould be done in this or Minchan's patch I can participate. >>From my point of view Minchan's patch is not ideal due to required: 1. depends on cgroups (at least as I see it from patch in shrink_mem_cgroup= _zone()part) 2. reports only memory pressure based on relation in between free and file = pages which is means by active file IO you may get lowmem=20 3. swapping should not produce lowmem, but active swapping - must, is it c= hecked there? + if (nr[LRU_INACTIVE_ANON]) + low_mem =3D true; 4. required changes in vmscan I think, due to everyone based on his experience/working area profile has o= wn understanding what is "low memory" (or similar situation which needs to= be tracked)=20 it should be some generic or extendable API, not like ON/OFF trigger for s= omething happened inside VM. From another point of view it should not be to= o generic due=20 to tasks could be solved using memcg, ionice, OOM killer or variations of s= oft-OOM-patches. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org