From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 10 Oct 2006 08:59:27 +0200 From: Nick Piggin Subject: Re: [patch] mm: bug in set_page_dirty_buffers Message-ID: <20061010065927.GA14557@wotan.suse.de> References: <20061010033412.GH15822@wotan.suse.de> <20061009205030.e247482e.akpm@osdl.org> <20061010035851.GK15822@wotan.suse.de> <20061009211404.ad112128.akpm@osdl.org> <20061010042144.GM15822@wotan.suse.de> <20061009213806.b158ea82.akpm@osdl.org> <20061010044745.GA24600@wotan.suse.de> <20061009220127.c4721d2d.akpm@osdl.org> <20061010052248.GB24600@wotan.suse.de> <1160462936.27479.4.camel@taijtu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1160462936.27479.4.camel@taijtu> Sender: owner-linux-mm@kvack.org Return-Path: To: Peter Zijlstra Cc: Andrew Morton , Linus Torvalds , Linux Memory Management List , Greg KH List-ID: On Tue, Oct 10, 2006 at 08:48:56AM +0200, Peter Zijlstra wrote: > On Tue, 2006-10-10 at 07:22 +0200, Nick Piggin wrote: > > > > I disagree because it will lead to horrible hacks because many callers > > can't sleep. If anything I would much prefer an innermost-spinlock in > > page->flags that specifically excludes truncate. Actually tree_lock can > > do that now, provided we pin mapping in all callers to set_page_dirty > > (which we should do). > > Yeah, but we're hard working to eradicate tree lock; I have ran into Well yeah, but until then the tree_lock works. > this problem before; that is, zap_pte_range and co. not being able to > lock the page. I'd really like to see that fixed. What's your problem with zap_pte_range? > In my current concurrent pagecache patches I've abused your PG_nonewrefs > and made it this page internal (bit)spinlock, but it just doesn't look > nice to have both this lock and PG_locked. Regardless of whether or not they spin, PG_locked is an outermost, and set_page_dirty is called innermost. I don't see why we'd particularly want to mush them together now, just because we're worried a filesystem writer wrote buggy code. It is all well and good to tell me I'm wrong unless I audit all filesystems, but the fact is that I'm not a filesystem expert, and if this is what it has come to then either the process has failed, or we have a large number of filesystems to cull from the tree as unmaintained. -- 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