From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx165.postini.com [74.125.245.165]) by kanga.kvack.org (Postfix) with SMTP id 5E68E6B004D for ; Wed, 2 May 2012 03:41:45 -0400 (EDT) Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1SPUBy-0003HZ-SB for linux-mm@kvack.org; Wed, 02 May 2012 09:41:43 +0200 Received: from 121.50.20.41 ([121.50.20.41]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Wed, 02 May 2012 09:41:42 +0200 Received: from minchan by 121.50.20.41 with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Wed, 02 May 2012 09:41:42 +0200 From: Minchan Kim Subject: Re: [PATCH v4] vmevent: Implement greater-than attribute state and one-shot mode Date: Wed, 02 May 2012 16:41:31 +0900 Message-ID: <4FA0E52B.7000907@kernel.org> 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> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org 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, 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