From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nick Piggin Subject: Re: [patch] mm: fix anon_vma races Date: Tue, 21 Oct 2008 13:45:14 +1100 References: <20081016041033.GB10371@wotan.suse.de> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200810211345.14954.nickpiggin@yahoo.com.au> Sender: owner-linux-mm@kvack.org Return-Path: To: Hugh Dickins Cc: Nick Piggin , Linus Torvalds , Peter Zijlstra , Linux Memory Management List List-ID: On Monday 20 October 2008 14:26, Hugh Dickins wrote: > On Sun, 19 Oct 2008, Hugh Dickins wrote: > > On Sun, 19 Oct 2008, Nick Piggin wrote: > > > There is already a page_mapped check in there. I'm just going to > > > propose we move that down. No extra branchesin the fastpath. OK? > > > > That should be OK, yes. Looking back at the history, I believe > > I sited the page_mapped test where it is, partly for simpler flow, > > and partly to avoid overhead of taking spinlock unnecessarily. > > Arrgh! What terrible advice I gave you there, completely wrong: > that's what happens when I rush a reply instead of thinking. > > I'm three-quarters through replying to Linus on this, and going > into that detail, remember now why its placement is critical. > > Repeat the page_mapped check before returning if you wish, > but do not remove the one that's there: see other mail for > explanation. Right, thanks for that. -- 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