From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx106.postini.com [74.125.245.106]) by kanga.kvack.org (Postfix) with SMTP id E97C26B0005 for ; Sun, 24 Feb 2013 16:25:45 -0500 (EST) Received: from /spool/local by e35.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Sun, 24 Feb 2013 14:25:45 -0700 Received: from d03relay02.boulder.ibm.com (d03relay02.boulder.ibm.com [9.17.195.227]) by d03dlp03.boulder.ibm.com (Postfix) with ESMTP id 927FE19D803D for ; Sun, 24 Feb 2013 14:25:41 -0700 (MST) Received: from d03av03.boulder.ibm.com (d03av03.boulder.ibm.com [9.17.195.169]) by d03relay02.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r1OLPgLm287580 for ; Sun, 24 Feb 2013 14:25:42 -0700 Received: from d03av03.boulder.ibm.com (loopback [127.0.0.1]) by d03av03.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r1OLPfKi003607 for ; Sun, 24 Feb 2013 14:25:41 -0700 Message-ID: <512A8550.2040200@linux.vnet.ibm.com> Date: Sun, 24 Feb 2013 13:25:36 -0800 From: Dave Hansen MIME-Version: 1.0 Subject: Re: [PATCH 1/2] mm: fadvise: fix POSIX_FADV_DONTNEED References: <1361660281-22165-1-git-send-email-psusi@ubuntu.com> <1361660281-22165-2-git-send-email-psusi@ubuntu.com> <5129710F.6060804@linux.vnet.ibm.com> <51298B0C.2020400@ubuntu.com> <512A5AC4.30808@linux.vnet.ibm.com> <512A7AC4.5000006@ubuntu.com> In-Reply-To: <512A7AC4.5000006@ubuntu.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Phillip Susi Cc: linux-mm@kvack.org On 02/24/2013 12:40 PM, Phillip Susi wrote: >> > I actually really like the concept behind your patch. It looks >> > like very useful functionality. I'm just saying that I know it >> > will break _existing_ users. > I'm not seeing how it will break anything. Which aspect of the > current behavior is the app relying on? If it is the immediate > removal of clean pages from the cache, then it should not care about > the new behavior since the pages will still be removed very soon when > under high cache pressure. Essentially, they don't want any I/O initiated except that which is initiated by the app. If you let the system get in to reclaim, it'll start doing dirty writeout for pages other than those the app is interested in. I'm also not sure how far the "just use O_DIRECT" argument is going to go: https://lkml.org/lkml/2007/1/10/233 -- 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