From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 19 Nov 2007 23:58:24 +0100 From: Nick Piggin Subject: Re: [patch 0/6] lockless pagecache Message-ID: <20071119225824.GB24255@wotan.suse.de> References: <20071111084556.GC19816@wotan.suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org Return-Path: To: Hugh Dickins Cc: Andrew Morton , Linus Torvalds , Peter Zijlstra , Linux Memory Management List List-ID: On Sat, Nov 17, 2007 at 08:16:18PM +0000, Hugh Dickins wrote: > On Sun, 11 Nov 2007, Nick Piggin wrote: > > > > I wonder what everyone thinks about getting the lockless pagecache patch > > into -mm? This version uses Hugh's suggestion to avoid a smp_rmb and a load > > and branch in the lockless lookup side, and avoids some atomic ops in the > > reclaim path, and avoids using a page flag! The coolest thing about it is > > that it speeds up single-threaded pagecache lookups... > > I've liked this in the past, with the exception of PageNoNewRefs which > seemed an unnecessary ugliness. Now you've eliminated that, thank you, > I expect I should like it through and through (if I actually found time > to redigest it). A moment came up and I thought I'd give it a spin... Yeah I decided it is actually just as good or better at it's job -- neither really protects against an errant get_page() or put_page(), however at least this scheme will go bug with CONFIG_DEBUG_VM, as opposed to the current or old lockless schemes (which I guess will silently allow it). > > Patches are against latest git for RFC. > > ... but they're not. You seem to have descended into sending out > ?cleanup? patches at intervals, and recursive dependence upon them. > This set relies on there being something called __set_page_locked() > in include/linux/pagemap.h, but there isn't in latest git (nor mm). > Ah, you posted a patch earlier which introduced that, but it relies on > there being something called set_page_locked() in include/linux/pagemap.h, > but there isn't in latest git (nor mm). Ah, you posted a patch earlier > which introduced that ... I gave up at this point. > > We've all got lots of other things to do, please make it easier. Sorry, I honestly didn't pay enough attention there because I didn't think anybody would run it! I'll update it and resend. -- 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