From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758273Ab0E1KAI (ORCPT ); Fri, 28 May 2010 06:00:08 -0400 Received: from gir.skynet.ie ([193.1.99.77]:39118 "EHLO gir.skynet.ie" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757303Ab0E1KAG (ORCPT ); Fri, 28 May 2010 06:00:06 -0400 Date: Fri, 28 May 2010 10:59:47 +0100 From: Mel Gorman To: Doug Doan Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, andi@firstfloor.org, lee.schermerhorn@hp.com, rientjes@google.com, akpm@linux-foundation.org Subject: Re: [PATCH] hugetlb: call mmu notifiers on hugepage cow Message-ID: <20100528095946.GB9774@csn.ul.ie> References: <4BFED954.8060807@cray.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <4BFED954.8060807@cray.com> User-Agent: Mutt/1.5.17+20080114 (2008-01-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 27, 2010 at 01:43:00PM -0700, Doug Doan wrote: > From: Doug Doan > > When a copy-on-write occurs, we take one of two paths in handle_mm_fault: > through handle_pte_fault for normal pages, or through hugetlb_fault for > huge pages. > > In the normal page case, we eventually get to do_wp_page and call mmu > notifiers via ptep_clear_flush_notify. There is no callout to the mmmu > notifiers in the huge page case. This patch fixes that. > > Signed-off-by: Doug Doan > --- > --- mm/hugetlb.c.orig 2010-05-27 13:07:58.569546314 -0700 > +++ mm/hugetlb.c 2010-05-26 14:41:06.449296524 -0700 > @@ -2345,11 +2345,17 @@ retry_avoidcopy: > ptep = huge_pte_offset(mm, address & huge_page_mask(h)); > if (likely(pte_same(huge_ptep_get(ptep), pte))) { > /* Break COW */ > + mmu_notifier_invalidate_range_start(mm, > + address & huge_page_mask(h), > + (address & huge_page_mask(h)) + huge_page_size(h)); Should the address not already be aligned? Otherwise, I don't see any problem. > huge_ptep_clear_flush(vma, address, ptep); > set_huge_pte_at(mm, address, ptep, > make_huge_pte(vma, new_page, 1)); > /* Make the old page be freed below */ > new_page = old_page; > + mmu_notifier_invalidate_range_end(mm, > + address & huge_page_mask(h), > + (address & huge_page_mask(h)) + huge_page_size(h)); > } > page_cache_release(new_page); > page_cache_release(old_page); -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab