From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx141.postini.com [74.125.245.141]) by kanga.kvack.org (Postfix) with SMTP id 1AF686B0083 for ; Mon, 7 May 2012 04:26:22 -0400 (EDT) Received: by ghbf11 with SMTP id f11so277142ghb.8 for ; Mon, 07 May 2012 01:26:20 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <20120501132409.GA22894@lizard> <20120501132620.GC24226@lizard> <4FA35A85.4070804@kernel.org> <20120504073810.GA25175@lizard> From: KOSAKI Motohiro Date: Mon, 7 May 2012 04:26:00 -0400 Message-ID: Subject: Re: [PATCH 3/3] vmevent: Implement special low-memory attribute Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: Pekka Enberg Cc: Anton Vorontsov , Minchan Kim , 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 >> If we'll give up on "1." (Pekka, ping), then we need to solve "2." >> in a sane way: we'll have to add a 'NR_FILE_PAGES - NR_SHMEM - >> ' attribute, and give it a name. > > Well, no, we can't give up on (1) completely. That'd mean that > eventually we'd need to change the ABI and break userspace. The > difference between exposing internal details and reasonable > abstractions is by no means black and white. > > AFAICT, RECLAIMABLE_CACHE_PAGES is a reasonable thing to support. Can > anyone come up with a reason why we couldn't do that in the future? It can. but the problem is, that is completely useless. Because of, 1) dirty pages writing-out is sometimes very slow and 2) libc and some important library's pages are critical important for running a system even though it is clean and reclaimable. In other word, kernel don't have an info then can't expose it. -- 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