From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 26 Jun 2006 16:35:10 +0100 (BST) From: Hugh Dickins Subject: Re: [PATCH 0/5] mm: tracking dirty pages -v11 In-Reply-To: <20060623223103.11513.50991.sendpatchset@lappy> Message-ID: References: <20060623223103.11513.50991.sendpatchset@lappy> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Peter Zijlstra Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , David Howells , Christoph Lameter , Martin Bligh , Nick Piggin , Linus Torvalds List-ID: On Sat, 24 Jun 2006, Peter Zijlstra wrote: > > I hope to have addressed all Hugh's latest comments in this version. > Its against 2.6.17-mm1, however I wasted most of the day trying to > test it on that kernel. But due to various circumstances that failed. Looks good - I'm happy that we leave the do_wp_page test reordering (to fix up that third order ptrace poke issue) to a subsequent patch, it's better separated. > So I've tested something like this against something 2.6.17'ish and > respun against the -mm lineup. Your next (final?) spin should be against Linus' current git tree, http://ftp.kernel.org/pub/linux/kernel/v2.6/snapshots/patch-2.6.17-git10.bz2 is the latest snapshot patch if you're not using git itself. That will suit Andrew better too: he prefers patches against Linus' current tree, except when the changes are to work that's only in -mm. You ought to respin, because the vma_wants_writenotify mods in mprotect.c affect later patches in your series, giving rejects at present. It does look _much_ better with Linus' vma_wants_writenotify. I did think of asking you for that, but it seemed unfair because I knew you'd want to use it in mprotect, and then get in trouble with backing-dev.h: which you've solved by #including that now in mm.h - a pity, but an unavoidable decision. Given the reordering you had to make in mprotect_fixup to get its tests working right (a little naughty!), I'd now do away with the "mask" variable, and just work directly on "newflags" itself; but up to you. > I've taken Hugh's msync changes too, looks a lot better and does indeed > fix some boundary cases. Thanks for reviewing: please add my Signed-off-by: Hugh Dickins to that msync one. In the respin of 1/5 you enquired: > Bah Bah Bah, why didn't the page_mkwrite() patch re-protect clean pages? > And is it a Bad-Thing (tm) that that can happen now? You'll need a reply from David for the definitive answer, but I think page_mkwrite is only wanting to know about the _first_ write to the page e.g. so that it can allocate space on disk for that page. And many (most) calls to page_mkwrite won't be for that first write at all, the filesystem already has to work out the irrelevant calls: so it's no great problem that you'll be making some more such calls. 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