From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from d03relay04.boulder.ibm.com (d03relay04.boulder.ibm.com [9.17.195.106]) by e35.co.us.ibm.com (8.12.10/8.12.9) with ESMTP id iB8HuCQf199076 for ; Wed, 8 Dec 2004 12:56:13 -0500 Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by d03relay04.boulder.ibm.com (8.12.10/NCO/VER6.6) with ESMTP id iB8HuC2j232098 for ; Wed, 8 Dec 2004 10:56:12 -0700 Received: from d03av02.boulder.ibm.com (loopback [127.0.0.1]) by d03av02.boulder.ibm.com (8.12.11/8.12.11) with ESMTP id iB8HuC4e002637 for ; Wed, 8 Dec 2004 10:56:12 -0700 Subject: Re: Anticipatory prefaulting in the page fault handler V1 From: Dave Hansen In-Reply-To: References: <41AEB44D.2040805@pobox.com> <20041201223441.3820fbc0.akpm@osdl.org> <41AEBAB9.3050705@pobox.com> <20041201230217.1d2071a8.akpm@osdl.org> <179540000.1101972418@[10.10.2.4]> <41AEC4D7.4060507@pobox.com> <20041202101029.7fe8b303.cliffw@osdl.org> Content-Type: text/plain Message-Id: <1102528526.25546.974.camel@localhost> Mime-Version: 1.0 Date: Wed, 08 Dec 2004 09:55:26 -0800 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: Nick Piggin , Jeff Garzik , Linus Torvalds , hugh@veritas.com, Benjamin Herrenschmidt , linux-mm , linux-ia64@vger.kernel.org, Linux Kernel Mailing List List-ID: On Wed, 2004-12-08 at 09:24, Christoph Lameter wrote: > The page fault handler for anonymous pages can generate significant overhead > apart from its essential function which is to clear and setup a new page > table entry for a never accessed memory location. This overhead increases > significantly in an SMP environment. do_anonymous_page() is a relatively compact function at this point. This would probably be a lot more readable if it was broken out into at least another function or two that do_anonymous_page() calls into. That way, you also get a much cleaner separation if anyone needs to turn it off in the future. Speaking of that, have you seen this impair performance on any other workloads? -- Dave -- 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: aart@kvack.org