From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx120.postini.com [74.125.245.120]) by kanga.kvack.org (Postfix) with SMTP id C02E36B004D for ; Sun, 1 Jan 2012 07:41:58 -0500 (EST) Message-ID: <4F00547A.9090204@redhat.com> Date: Sun, 01 Jan 2012 14:41:30 +0200 From: Avi Kivity MIME-Version: 1.0 Subject: Re: [PATCH v4 4/5] slub: Only IPI CPUs that have per cpu obj to flush References: <1321960128-15191-1-git-send-email-gilad@benyossef.com> <1321960128-15191-5-git-send-email-gilad@benyossef.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Pekka Enberg Cc: Gilad Ben-Yossef , linux-kernel@vger.kernel.org, Chris Metcalf , Peter Zijlstra , Frederic Weisbecker , Russell King , linux-mm@kvack.org, Matt Mackall , Sasha Levin , Rik van Riel , Andi Kleen , apkm@linux-foundation.org On 11/23/2011 08:23 AM, Pekka Enberg wrote: > On Tue, 22 Nov 2011, Gilad Ben-Yossef wrote: >> static void flush_all(struct kmem_cache *s) >> { >> - on_each_cpu(flush_cpu_slab, s, 1); >> + cpumask_var_t cpus; >> + struct kmem_cache_cpu *c; >> + int cpu; >> + >> + if (likely(zalloc_cpumask_var(&cpus, GFP_ATOMIC))) { > > __GFP_NOWARN too maybe? > >> + for_each_online_cpu(cpu) { >> + c = per_cpu_ptr(s->cpu_slab, cpu); >> + if (c->page) >> + cpumask_set_cpu(cpu, cpus); >> + } >> + on_each_cpu_mask(cpus, flush_cpu_slab, s, 1); >> + free_cpumask_var(cpus); >> + } else >> + on_each_cpu(flush_cpu_slab, s, 1); >> } > Since this seems to be a common pattern, how about: zalloc_cpumask_var_or_all_online_cpus(&cpus, GFTP_ATOMIC); ... free_cpumask_var(cpus); The long-named function at the top of the block either returns a newly allocated zeroed cpumask, or a static cpumask with all online cpus set. The code in the middle is only allowed to set bits in the cpumask (should be the common usage). free_cpumask_var() needs to check whether the freed object is the static variable. -- error compiling committee.c: too many arguments to function -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org