From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Hansen Date: Wed, 08 Dec 2004 17:55:26 +0000 Subject: Re: Anticipatory prefaulting in the page fault handler V1 Message-Id: <1102528526.25546.974.camel@localhost> List-Id: 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> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit 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 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