From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sat, 16 Feb 2008 11:22:18 -0800 (PST) From: Christoph Lameter Subject: Re: [patch 3/6] mmu_notifier: invalidate_page callbacks In-Reply-To: <20080215193736.9d6e7da3.akpm@linux-foundation.org> Message-ID: References: <20080215064859.384203497@sgi.com> <20080215064932.918191502@sgi.com> <20080215193736.9d6e7da3.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: Andrea Arcangeli , Robin Holt , Avi Kivity , Izik Eidus , kvm-devel@lists.sourceforge.net, Peter Zijlstra , general@lists.openfabrics.org, Steve Wise , Roland Dreier , Kanoj Sarcar , steiner@sgi.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, daniel.blueman@quadrics.com List-ID: On Fri, 15 Feb 2008, Andrew Morton wrote: > > @@ -287,7 +288,8 @@ static int page_referenced_one(struct pa > > if (vma->vm_flags & VM_LOCKED) { > > referenced++; > > *mapcount = 1; /* break early from loop */ > > - } else if (ptep_clear_flush_young(vma, address, pte)) > > + } else if (ptep_clear_flush_young(vma, address, pte) | > > + mmu_notifier_age_page(mm, address)) > > referenced++; > > The "|" is obviously deliberate. But no explanation is provided telling us > why we still call the callback if ptep_clear_flush_young() said the page > was recently referenced. People who read your code will want to understand > this. Andrea? > > flush_cache_page(vma, address, pte_pfn(*pte)); > > entry = ptep_clear_flush(vma, address, pte); > > + mmu_notifier(invalidate_page, mm, address); > > I just don't see how ths can be done if the callee has another thread in > the middle of establishing IO against this region of memory. > ->invalidate_page() _has_ to be able to block. Confused. The page lock is held and that holds off I/O? -- 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