From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 24 May 2006 15:20:46 +0100 (BST) From: Hugh Dickins Subject: Re: tracking dirty pages patches In-Reply-To: <1148425627.10561.32.camel@lappy> Message-ID: References: <1148425627.10561.32.camel@lappy> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Peter Zijlstra Cc: Andrew Morton , Linus Torvalds , David Howells , linux-mm@kvack.org, Christoph Lameter List-ID: On Wed, 24 May 2006, Peter Zijlstra wrote: > On Mon, 2006-05-22 at 20:31 +0100, Hugh Dickins wrote: > > > I'm not convinced that optimize-follow_pages is a worthwhile optimization > > (in some cases you're adding an atomic inc and dec), and it's irrelevant > > to your tracking of dirty pages, but I don't feel strongly about it. > > Except, if it stays then it needs fixing: the flags 0 case is doing > > a put_page without having done a get_page. > > Not sure on the benefit either, I just did it to educate myself on the > subject (and blotched it on my way). Christoph kindly fixed the > offending condition. > > I guess this patch could really do with some numbers if found that the > set_page_dirty() is needed at all. Just drop that patch from the set. It's a distraction from the rest, and I believe we'll optimize it much better by removing those tests and their set_page_dirty (but not immediately). Hugh -- 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