Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754619Ab2EBHmI (ORCPT ); Wed, 2 May 2012 03:42:08 -0400 Received: from LGEMRELSE6Q.lge.com ([156.147.1.121]:53402 "EHLO LGEMRELSE6Q.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751278Ab2EBHmH (ORCPT ); Wed, 2 May 2012 03:42:07 -0400 X-AuditID: 9c930179-b7bfaae000006f69-4f-4fa0e531232c Message-ID: <4FA0E52B.7000907@kernel.org> Date: Wed, 02 May 2012 16:41:31 +0900 From: Minchan Kim User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:11.0) Gecko/20120410 Thunderbird/11.0.1 MIME-Version: 1.0 Newsgroups: gmane.linux.kernel.mm,gmane.linux.kernel To: Pekka Enberg CC: Anton Vorontsov , KOSAKI Motohiro , Rik van Riel , Leonid Moiseichuk , John Stultz , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linaro-kernel@lists.linaro.org, patches@linaro.org, kernel-team@android.com, Glauber Costa , kamezawa.hiroyu@jp.fujitsu.com, Suleiman Souhlal Subject: Re: [PATCH v4] vmevent: Implement greater-than attribute state and one-shot mode References: <20120418083208.GA24904@lizard> <20120418083523.GB31556@lizard> <20120418224629.GA22150@lizard> <20120419162923.GA26630@lizard> <20120501131806.GA22249@lizard> <4FA04FD5.6010900@redhat.com> <20120502002026.GA3334@lizard> <4FA08BDB.1070009@gmail.com> <20120502033136.GA14740@lizard> <4FA0C042.9010907@kernel.org> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2147 Lines: 52 On 05/02/2012 03:57 PM, Pekka Enberg wrote: > On Wed, May 2, 2012 at 8:04 AM, Minchan Kim wrote: >> I think hardest problem in low mem notification is how to define _lowmem situation_. >> We all guys (server, desktop and embedded) should reach a conclusion on define lowmem situation >> before progressing further implementation because each part can require different limits. >> Hopefully, I want it. >> >> What is the best situation we can call it as "low memory"? > > Looking at real-world scenarios, it seems to be totally dependent on > userspace policy. That's why I insist on defining low memory state in user space, not kernel. > > On Wed, May 2, 2012 at 8:04 AM, Minchan Kim wrote: >> As a matter of fact, if we can define it well, I think even we don't neead vmevent ABI. >> In my opinion, it's not easy to generalize each use-cases so we can pass it to user space and >> just export low attributes of vmstat in kernel by vmevent. >> Userspace program can determine low mem situation well on his environment with other vmstats >> when notification happens. Of course, it has a drawback that userspace couples kernel's vmstat >> but at least I think that's why we need vmevent for triggering event when we start watching carefully. > > Please keep in mind that VM events is not only about "low memory" > notification. The ABI might be useful for other kinds of VM events as > well. Fully agreed but we should prove why such event is useful in real scenario before adding more features. > > -- > 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 > -- Kind regards, Minchan Kim -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/