From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 16 May 2008 01:52:03 +0200 From: Nick Piggin Subject: Re: [PATCH 08 of 11] anon-vma-rwsem Message-ID: <20080515235203.GB25305@wotan.suse.de> References: <6b384bb988786aa78ef0.1210170958@duo.random> <20080508003838.GA9878@sgi.com> <200805132206.47655.nickpiggin@yahoo.com.au> <20080513153238.GL19717@sgi.com> <20080514041122.GE24516@wotan.suse.de> <20080514112625.GY9878@sgi.com> <20080515075747.GA7177@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: Christoph Lameter Cc: Robin Holt , Nick Piggin , Linus Torvalds , Andrea Arcangeli , Andrew Morton , Jack Steiner , Peter Zijlstra , kvm-devel@lists.sourceforge.net, Kanoj Sarcar , Roland Dreier , Steve Wise , linux-kernel@vger.kernel.org, Avi Kivity , linux-mm@kvack.org, general@lists.openfabrics.org, Hugh Dickins , Rusty Russell , Anthony Liguori , Chris Wright , Marcelo Tosatti , Eric Dumazet , "Paul E. McKenney" List-ID: On Thu, May 15, 2008 at 10:33:57AM -0700, Christoph Lameter wrote: > On Thu, 15 May 2008, Nick Piggin wrote: > > > Oh, I get that confused because of the mixed up naming conventions > > there: unmap_page_range should actually be called zap_page_range. But > > at any rate, yes we can easily zap pagetables without holding mmap_sem. > > How is that synchronized with code that walks the same pagetable. These > walks may not hold mmap_sem either. I would expect that one could only > remove a portion of the pagetable where we have some sort of guarantee > that no accesses occur. So the removal of the vma prior ensures that? I don't really understand the question. If you remove the pte and invalidate the TLBS on the remote image's process (importing the page), then it can of course try to refault the page in because it's vma is still there. But you catch that refault in your driver , which can prevent the page from being faulted back in. -- 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