From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sd0208e0.au.ibm.com (d23rh904.au.ibm.com [202.81.18.202]) by ausmtp04.au.ibm.com (8.13.8/8.13.8) with ESMTP id l0P64DgM071456 for ; Thu, 25 Jan 2007 17:04:13 +1100 Received: from d23av01.au.ibm.com (d23av01.au.ibm.com [9.190.250.242]) by sd0208e0.au.ibm.com (8.13.8/8.13.8/NCO v8.2) with ESMTP id l0P5r56q222204 for ; Thu, 25 Jan 2007 16:53:07 +1100 Received: from d23av01.au.ibm.com (loopback [127.0.0.1]) by d23av01.au.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id l0P5na6b014594 for ; Thu, 25 Jan 2007 16:49:36 +1100 Message-ID: <45B844E3.4050203@linux.vnet.ibm.com> Date: Thu, 25 Jan 2007 11:19:23 +0530 From: Vaidyanathan Srinivasan MIME-Version: 1.0 Subject: Re: [RFC] Limit the size of the pagecache References: <45B75208.90208@linux.vnet.ibm.com> <45B82F41.9040705@linux.vnet.ibm.com> <45B835FE.6030107@redhat.com> In-Reply-To: <45B835FE.6030107@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Rik van Riel Cc: Christoph Lameter , Aubrey Li , Nick Piggin , Robin Getz , "Henn, erich, Michael" , linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: Rik van Riel wrote: > Vaidyanathan Srinivasan wrote: > >> In my opinion, once a >> file page is mapped by the process, then it should be treated at par >> with anon pages. Application programs generally do not mmap a file >> page if the reuse for the content is very low. > > Why not have the VM measure this, instead of making wild > assumptions about every possible workload out there? Yes, VM page aging and page replacement algorithm should decide on the relevance of anon or mmap page. However we may still need to limit total pages in memory for a given set of process. > There are a few databases out there that mmap the whole > thing. Sleepycat for one... > That is why my suggestion would be not to touch mmapped pagecache pages in the current pagecache limit code. The limit should concern only unmapped pagecache pages. When the application unmaps the pages, then instantly we would go over limit and 'now' unmapped pages can be reclaimed. This behavior has been verified with my fix on top of Christoph's patch. -- 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