From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1035093AbcIWSPT (ORCPT ); Fri, 23 Sep 2016 14:15:19 -0400 Received: from sender153-mail.zoho.com ([74.201.84.153]:25435 "EHLO sender153-mail.zoho.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030271AbcIWSPS (ORCPT ); Fri, 23 Sep 2016 14:15:18 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=zapps768; d=zoho.com; h=cc:to:from:subject:message-id:date:user-agent:mime-version:content-type; b=sTBvx1TiiIuFP+/cbkrJ9IpKHkArCWER304XpK+uTTDOsLx82NDBbhgc0zipIwxssbYL80h94Q6y gLzIpD+c9B72E3GtzLFWxT51K3pHx6mgwRi8EBlW6V+VAK6y/IGw Cc: zijun_hu@htc.com, linux-mm@kvack.org, "linux-kernel@vger.kernel.org" , cl@linux.com To: Tejun Heo , Andrew Morton From: zijun_hu Subject: [PATCH 1/1] mm/percpu.c: simplify grouping cpu logic in pcpu_build_alloc_info() Message-ID: <5dcf5870-67ad-97e4-518b-645d60b0a520@zoho.com> Date: Sat, 24 Sep 2016 02:15:09 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: zijun_hu simplify grouping cpu logic in pcpu_build_alloc_info() to improve readability and performance, it discards the goto statement too for every possible cpu, decide whether it can share group id of any lower index CPU, use the group id if so, otherwise a new group id is allocated to it Signed-off-by: zijun_hu --- mm/percpu.c | 28 +++++++++++++++------------- 1 file changed, 15 insertions(+), 13 deletions(-) diff --git a/mm/percpu.c b/mm/percpu.c index 9903830aaebb..fcaaac977954 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -1824,23 +1824,25 @@ static struct pcpu_alloc_info * __init pcpu_build_alloc_info( max_upa = upa; /* group cpus according to their proximity */ - for_each_possible_cpu(cpu) { - group = 0; - next_group: + group = 0; + for_each_possible_cpu(cpu) for_each_possible_cpu(tcpu) { - if (cpu == tcpu) - break; - if (group_map[tcpu] == group && cpu_distance_fn && - (cpu_distance_fn(cpu, tcpu) > LOCAL_DISTANCE || - cpu_distance_fn(tcpu, cpu) > LOCAL_DISTANCE)) { + if (tcpu == cpu) { + group_map[cpu] = group; + group_cnt[group] = 1; group++; - nr_groups = max(nr_groups, group + 1); - goto next_group; + break; + } + + if (!cpu_distance_fn || + (cpu_distance_fn(cpu, tcpu) == LOCAL_DISTANCE && + cpu_distance_fn(tcpu, cpu) == LOCAL_DISTANCE)) { + group_map[cpu] = group_map[tcpu]; + group_cnt[group_map[cpu]]++; + break; } } - group_map[cpu] = group; - group_cnt[group]++; - } + nr_groups = group; /* * Expand unit size until address space usage goes over 75% -- 1.9.1