From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx205.postini.com [74.125.245.205]) by kanga.kvack.org (Postfix) with SMTP id 45B1C6B0062 for ; Mon, 9 Jul 2012 09:46:36 -0400 (EDT) Message-ID: <1341841593.14828.9.camel@gandalf.stny.rr.com> Subject: Re: [patch] mm, slub: ensure irqs are enabled for kmemcheck From: Steven Rostedt Date: Mon, 09 Jul 2012 09:46:33 -0400 In-Reply-To: References: <20120708040009.GA8363@localhost> Content-Type: text/plain; charset="ISO-8859-15" Content-Transfer-Encoding: 7bit Mime-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: David Rientjes Cc: Pekka Enberg , JoonSoo Kim , Fengguang Wu , Vegard Nossum , Christoph Lameter , Rus , Ben Hutchings , stable@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org On Mon, 2012-07-09 at 03:36 -0700, David Rientjes wrote: > kmemcheck_alloc_shadow() requires irqs to be enabled, so wait to disable > them until after its called for __GFP_WAIT allocations. > > This fixes a warning for such allocations: > > WARNING: at kernel/lockdep.c:2739 lockdep_trace_alloc+0x14e/0x1c0() > > Cc: stable@vger.kernel.org [3.1+] > Acked-by: Fengguang Wu > Tested-by: Fengguang Wu > Signed-off-by: David Rientjes > --- > mm/slub.c | 13 ++++++------- > 1 file changed, 6 insertions(+), 7 deletions(-) > > diff --git a/mm/slub.c b/mm/slub.c > --- a/mm/slub.c > +++ b/mm/slub.c > @@ -1314,13 +1314,7 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node) > stat(s, ORDER_FALLBACK); > } > > - if (flags & __GFP_WAIT) > - local_irq_disable(); > - > - if (!page) > - return NULL; > - > - if (kmemcheck_enabled > + if (page && kmemcheck_enabled One micro-optimization nit... If kmemcheck_enabled is mostly false, and page is mostly true, wouldn't it be better to swap the two? if (kmemcheck_enabled && page Then the first check would just short-circuit out and we don't do the double check. Otherwise it looks good. Acked-by: Steven Rostedt -- Steve > && !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) { > int pages = 1 << oo_order(oo); > > @@ -1336,6 +1330,11 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node) > kmemcheck_mark_unallocated_pages(page, pages); > } > > + if (flags & __GFP_WAIT) > + local_irq_disable(); > + if (!page) > + return NULL; > + > page->objects = oo_objects(oo); > mod_zone_page_state(page_zone(page), > (s->flags & SLAB_RECLAIM_ACCOUNT) ? -- 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