From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 5 Feb 2008 06:25:25 +0100 From: Andrea Arcangeli Subject: Re: [PATCH] mmu notifiers #v5 Message-ID: <20080205052525.GD7441@v2.random> References: <20080131045750.855008281@sgi.com> <20080131171806.GN7185@v2.random> <20080131234101.GS7185@v2.random> <20080201120955.GX7185@v2.random> <20080203021704.GC7185@v2.random> 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 , Avi Kivity , Izik Eidus , kvm-devel@lists.sourceforge.net, Peter Zijlstra , steiner@sgi.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, daniel.blueman@quadrics.com List-ID: On Mon, Feb 04, 2008 at 11:09:01AM -0800, Christoph Lameter wrote: > On Sun, 3 Feb 2008, Andrea Arcangeli wrote: > > > > Right but that pin requires taking a refcount which we cannot do. > > > > GRU can use my patch without the pin. XPMEM obviously can't use my > > patch as my invalidate_page[s] are under the PT lock (a feature to fit > > GRU/KVM in the simplest way), this is why an incremental patch adding > > invalidate_range_start/end would be required to support XPMEM too. > > Doesnt the kernel in some situations release the page before releasing the > pte lock? Then there will be an external pte pointing to a page that may > now have a different use. Its really bad if that pte does allow writes. Sure the kernel does that most of the time, which is for example why I had to use invalidate_page instead of invalidate_pages inside zap_pte_range. Zero problems with that (this is also the exact reason why I mentioned the tlb flushing code would need changes to convert some page in pages). -- 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