From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <45C15AF0.4080406@redhat.com> Date: Wed, 31 Jan 2007 22:13:52 -0500 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [patch] not to disturb page LRU state when unmapping memory range References: <1170279811.10924.32.camel@lappy> <20070131140450.09f174e9.akpm@osdl.org> <1170282300.10924.50.camel@lappy> In-Reply-To: <1170282300.10924.50.camel@lappy> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Peter Zijlstra Cc: Andrew Morton , Hugh Dickins , Ken Chen , linux-mm@kvack.org List-ID: Peter Zijlstra wrote: > Yes, why would unmapping a range make the pages more likely to be used > in the immediate future than otherwise indicated by their individual > young bits? > > Even the opposite was suggested, that unmapping a range makes it less > likely to be used again. I agree, the VM looks at the usage of individual pages and makes decisions based on that. We can only see how often individual pages are referenced, and do not have much additional information (except from the readahead code). Making sweeping generalizations like "unmapping makes pages less likely to be needed again" is bound to cause trouble for some workloads. -- Politics is the struggle between those who want to make their country the best in the world, and those who believe it already is. Each group calls the other unpatriotic. -- 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