Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933924Ab2FHIsM (ORCPT ); Fri, 8 Jun 2012 04:48:12 -0400 Received: from mail-yw0-f46.google.com ([209.85.213.46]:48112 "EHLO mail-yw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933872Ab2FHIsH convert rfc822-to-8bit (ORCPT ); Fri, 8 Jun 2012 04:48:07 -0400 MIME-Version: 1.0 In-Reply-To: <4FD1BB29.1050805@kernel.org> References: <20120601122118.GA6128@lizard> <4FCC7592.9030403@kernel.org> <20120604113811.GA4291@lizard> <4FCD14F1.1030105@gmail.com> <20120605083921.GA21745@lizard> <4FD014D7.6000605@kernel.org> <20120608074906.GA27095@lizard> <4FD1BB29.1050805@kernel.org> Date: Fri, 8 Jun 2012 11:48:06 +0300 X-Google-Sender-Auth: Y0HphNQeIAwhB8UbMX0JzQuOFiM Message-ID: Subject: Re: [PATCH 0/5] Some vmevent fixes... From: Pekka Enberg To: Minchan Kim Cc: Anton Vorontsov , KOSAKI Motohiro , 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 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1346 Lines: 29 On Fri, Jun 8, 2012 at 11:43 AM, Minchan Kim wrote: >> So, the solution would be then two-fold: >> >> 1. Use your memory pressure notifications. They must be quite fast when >> ? ?we starting to feel the high pressure. (I see the you use >> ? ?zone_page_state() and friends, which is vm_stat, and it is updated > > VM has other information like nr_reclaimed, nr_scanned, nr_congested, recent_scanned, > recent_rotated, too. I hope we can make math by them and improve as we improve > VM reclaimer. > >> ? ?very infrequently, but to get accurate notification we have to >> ? ?update it much more frequently, but this is very expensive. So >> ? ?KOSAKI and Christoph will complain. :-) > > > Reclaimer already have used that and if we need accuracy, we handled it > like zone_watermark_ok_safe. If it's very inaccurate, VM should be fixed, too. Exactly. I don't know why people think pushing vmevents to userspace is going to fix any of the hard problems. Anton, Lenoid, do you see any fundamental issues from userspace point of view with going forward what Minchan is proposing? -- 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/