From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with ESMTP id 3B5956B0047 for ; Sun, 28 Feb 2010 15:36:42 -0500 (EST) Date: Sun, 28 Feb 2010 21:36:27 +0100 From: Johannes Weiner Subject: Re: mm: used-once mapped file page detection Message-ID: <20100228203627.GA21128@cmpxchg.org> References: <1266868150-25984-1-git-send-email-hannes@cmpxchg.org> <20100224133946.a5092804.akpm@linux-foundation.org> <20100226143232.GA13001@cmpxchg.org> <4B8AAC9A.10203@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4B8AAC9A.10203@redhat.com> Sender: owner-linux-mm@kvack.org To: Rik van Riel Cc: Andrew Morton , KOSAKI Motohiro , Minchan Kim , linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: On Sun, Feb 28, 2010 at 12:49:14PM -0500, Rik van Riel wrote: > On 02/26/2010 09:32 AM, Johannes Weiner wrote: > >On Wed, Feb 24, 2010 at 01:39:46PM -0800, Andrew Morton wrote: > >>On Mon, 22 Feb 2010 20:49:07 +0100 Johannes Weiner > >>wrote: > >> > >>>This patch makes the VM be more careful about activating mapped file > >>>pages in the first place. The minimum granted lifetime without > >>>another memory access becomes an inactive list cycle instead of the > >>>full memory cycle, which is more natural given the mentioned loads. > >> > >>iirc from a long time ago, the insta-activation of mapped pages was > >>done because people were getting peeved about having their interactive > >>applications (X, browser, etc) getting paged out, and bumping the pages > >>immediately was found to help with this subjective problem. > >> > >>So it was a latency issue more than a throughput issue. I wouldn't be > >>surprised if we get some complaints from people for the same reasons as > >>a result of this patch. > > > >Agreed. Although we now have other things in place to protect them once > >they are active (VM_EXEC protection, lazy active list scanning). > > You think we'll need VM_EXEC protection on the inactive list > after your changes? So far I personally did not experience anything that would indicate the need for it. But I would consider it an option if Andrew's worries turned out to be true. -- 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/ . Don't email: email@kvack.org