Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753084Ab2EBG5I (ORCPT ); Wed, 2 May 2012 02:57:08 -0400 Received: from mail-gy0-f174.google.com ([209.85.160.174]:57225 "EHLO mail-gy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751672Ab2EBG5G (ORCPT ); Wed, 2 May 2012 02:57:06 -0400 MIME-Version: 1.0 In-Reply-To: <4FA0C042.9010907@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> Date: Wed, 2 May 2012 09:57:05 +0300 X-Google-Sender-Auth: NpTZ9M3sWc1V5D7LrZ1SqJT-K5M Message-ID: Subject: Re: [PATCH v4] vmevent: Implement greater-than attribute state and one-shot mode From: Pekka Enberg To: Minchan Kim 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 Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1528 Lines: 27 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. 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 need 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. -- 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/