From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752578AbXLHRtS (ORCPT ); Sat, 8 Dec 2007 12:49:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751093AbXLHRtD (ORCPT ); Sat, 8 Dec 2007 12:49:03 -0500 Received: from smtp2.linux-foundation.org ([207.189.120.14]:40154 "EHLO smtp2.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751072AbXLHRtB (ORCPT ); Sat, 8 Dec 2007 12:49:01 -0500 Date: Sat, 8 Dec 2007 09:47:49 -0800 (PST) From: Linus Torvalds To: Matt Mackall cc: Ingo Molnar , "Rafael J. Wysocki" , LKML , Andrew Morton , Christoph Lameter Subject: Re: tipc_init(), WARNING: at arch/x86/mm/highmem_32.c:52, [2.6.24-rc4-git5: Reported regressions from 2.6.23] In-Reply-To: <20071208163749.GI19691@waste.org> Message-ID: References: <200712080340.49546.rjw@sisk.pl> <20071208093039.GA28054@elte.hu> <20071208163749.GI19691@waste.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 8 Dec 2007, Matt Mackall wrote: > > Avoid calling page allocator with __GFP_ZERO, as we might be in atomic > context and this will make thing unhappy on highmem systems. Instead, > manually zero allocations from the page allocator. I think this is fine, but didn't we fix the warning already? Calling page allocators with __GFP_ZERO should be fine, as long as __GFP_HIGHMEM isn't set, and slab/slub/slob/kmalloc cannot use GFP_HIGHMEM *anyway*. But I'll apply it anyway, because it looks "obviously correct" from the standpoint that the _other_ slob user already clears the end result explicitly later on, and we simply should never pass down __GFP_ZERO to the actual page allocator. On that note, shouldn't we also do this for slub.c? Christoph? Linus --- mm/slub.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index b9f37cb..9c1d9f3 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -1468,6 +1468,9 @@ static void *__slab_alloc(struct kmem_cache *s, void **object; struct page *new; + /* We handle __GFP_ZERO in the caller */ + gfpflags &= ~__GFP_ZERO; + if (!c->page) goto new_slab;