From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <48D17AEC.3070804@goop.org> Date: Wed, 17 Sep 2008 14:47:24 -0700 From: Jeremy Fitzhardinge MIME-Version: 1.0 Subject: Re: Populating multiple ptes at fault time References: <48D142B2.3040607@goop.org> <20080917142805.41e2b07e@bree.surriel.com> In-Reply-To: <20080917142805.41e2b07e@bree.surriel.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Rik van Riel Cc: Nick Piggin , Hugh Dickens , Linux Memory Management List , Linux Kernel Mailing List , Avi Kivity , Andrew Morton List-ID: Rik van Riel wrote: > On Wed, 17 Sep 2008 10:47:30 -0700 > Jeremy Fitzhardinge wrote: > > >> Minor faults are easier; if the page already exists in memory, we should >> just create mappings to it. If neighbouring pages are also already >> present, then we can can cheaply create mappings for them too. >> > > This is especially true for mmaped files, where we do not have to > allocate anything to create the mapping. > Yes, that was the case I particularly had in mind. > Populating multiple PTEs at a time is questionable for anonymous > memory, where we'd have to allocate extra pages. > It might be worthwhile if the memory access pattern to anonymous memory is linear. I agree that speculatively allocating pages on a random access region would be a bad idea. J -- 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