Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759226Ab0FJOoJ (ORCPT ); Thu, 10 Jun 2010 10:44:09 -0400 Received: from casper.infradead.org ([85.118.1.10]:36257 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753068Ab0FJOoH convert rfc822-to-8bit (ORCPT ); Thu, 10 Jun 2010 10:44:07 -0400 Subject: Re: [PATCH] [10/23] SCHED: Only allocate per cpu cpu mask buffer with offstack cpumasks From: Peter Zijlstra To: Andi Kleen Cc: mingo@elte.hu, akpm@linux-foundation.org, linux-kernel@vger.kernel.org In-Reply-To: <20100610111046.18EB4B1A2B@basil.firstfloor.org> References: <20100610110.764742110@firstfloor.org> <20100610111046.18EB4B1A2B@basil.firstfloor.org> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Date: Thu, 10 Jun 2010 16:43:50 +0200 Message-ID: <1276181030.2077.399.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1591 Lines: 47 On Thu, 2010-06-10 at 13:10 +0200, Andi Kleen wrote: > This will save a few bytes in the non offstack cpumask case. > > Found by gcc 4.6's new warnings. > > Cc: peterz@infradead.org > Cc: mingo@elte.hu > Signed-off-by: Andi Kleen > > --- > kernel/sched.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > Index: linux-2.6.35-rc2-gcc/kernel/sched.c > =================================================================== > --- linux-2.6.35-rc2-gcc.orig/kernel/sched.c > +++ linux-2.6.35-rc2-gcc/kernel/sched.c > @@ -7482,7 +7482,7 @@ static void init_tg_rt_entry(struct task > void __init sched_init(void) > { > int i, j; > - unsigned long alloc_size = 0, ptr; > + unsigned long alloc_size = 0; > > #ifdef CONFIG_FAIR_GROUP_SCHED > alloc_size += 2 * nr_cpu_ids * sizeof(void **); > @@ -7494,7 +7494,10 @@ void __init sched_init(void) > alloc_size += num_possible_cpus() * cpumask_size(); > #endif > if (alloc_size) { > +#ifdef CONFIG_CPUMASK_OFFSTACK > + unsigned long ptr; > ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT); > +#endif > > #ifdef CONFIG_FAIR_GROUP_SCHED > init_task_group.se = (struct sched_entity **)ptr; This patch will actually break things.. please read the code. I guess we could move the unsigned long into that block, but I really don't see the point. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/