Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753415Ab2KUBDA (ORCPT ); Tue, 20 Nov 2012 20:03:00 -0500 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:58172 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752414Ab2KUBC6 (ORCPT ); Tue, 20 Nov 2012 20:02:58 -0500 X-SecurityPolicyCheck: OK by SHieldMailChecker v1.8.4 Message-ID: <50AC282A.4070309@jp.fujitsu.com> Date: Wed, 21 Nov 2012 10:02:34 +0900 From: Kamezawa Hiroyuki User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:16.0) Gecko/20121026 Thunderbird/16.0.2 MIME-Version: 1.0 To: Andrew Morton CC: David Rientjes , Johannes Weiner , Michal Hocko , Hugh Dickins , linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org Subject: Re: [patch] mm, memcg: avoid unnecessary function call when memcg is disabled References: <20121120134932.055bc192.akpm@linux-foundation.org> In-Reply-To: <20121120134932.055bc192.akpm@linux-foundation.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1648 Lines: 46 (2012/11/21 6:49), Andrew Morton wrote: > On Mon, 19 Nov 2012 17:44:34 -0800 (PST) > David Rientjes wrote: > >> While profiling numa/core v16 with cgroup_disable=memory on the command >> line, I noticed mem_cgroup_count_vm_event() still showed up as high as >> 0.60% in perftop. >> >> This occurs because the function is called extremely often even when memcg >> is disabled. >> >> To fix this, inline the check for mem_cgroup_disabled() so we avoid the >> unnecessary function call if memcg is disabled. >> >> ... >> >> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h >> --- a/include/linux/memcontrol.h >> +++ b/include/linux/memcontrol.h >> @@ -181,7 +181,14 @@ unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order, >> gfp_t gfp_mask, >> unsigned long *total_scanned); >> >> -void mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx); >> +void __mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx); >> +static inline void mem_cgroup_count_vm_event(struct mm_struct *mm, >> + enum vm_event_item idx) >> +{ >> + if (mem_cgroup_disabled() || !mm) >> + return; >> + __mem_cgroup_count_vm_event(mm, idx); >> +} > > Does the !mm case occur frequently enough to justify inlining it, or > should that test remain out-of-line? > I think this should be out-of-line. Thanks, -Kame -- 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/