From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9DEC6C43463 for ; Mon, 21 Sep 2020 04:07:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4F7DC2078D for ; Mon, 21 Sep 2020 04:07:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726234AbgIUEEU (ORCPT ); Mon, 21 Sep 2020 00:04:20 -0400 Received: from out30-130.freemail.mail.aliyun.com ([115.124.30.130]:56315 "EHLO out30-130.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726011AbgIUEEU (ORCPT ); Mon, 21 Sep 2020 00:04:20 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R601e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04420;MF=richard.weiyang@linux.alibaba.com;NM=1;PH=DS;RN=4;SR=0;TI=SMTPD_---0U9XRxlZ_1600661057; Received: from localhost(mailfrom:richard.weiyang@linux.alibaba.com fp:SMTPD_---0U9XRxlZ_1600661057) by smtp.aliyun-inc.com(127.0.0.1); Mon, 21 Sep 2020 12:04:17 +0800 From: Wei Yang To: akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Wei Yang Subject: [PATCH] mm/mempolicy: remove or narrow the lock on current Date: Mon, 21 Sep 2020 12:04:16 +0800 Message-Id: <20200921040416.86185-1-richard.weiyang@linux.alibaba.com> X-Mailer: git-send-email 2.20.1 (Apple Git-117) MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org It is not necessary to hold the lock of current when setting nodemask of a new policy. Signed-off-by: Wei Yang --- mm/mempolicy.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 906adc58d86f..3fde772ef5ef 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -875,13 +875,12 @@ static long do_set_mempolicy(unsigned short mode, unsigned short flags, goto out; } - task_lock(current); ret = mpol_set_nodemask(new, nodes, scratch); if (ret) { - task_unlock(current); mpol_put(new); goto out; } + task_lock(current); old = current->mempolicy; current->mempolicy = new; if (new && new->mode == MPOL_INTERLEAVE) @@ -1324,9 +1323,7 @@ static long do_mbind(unsigned long start, unsigned long len, NODEMASK_SCRATCH(scratch); if (scratch) { mmap_write_lock(mm); - task_lock(current); err = mpol_set_nodemask(new, nmask, scratch); - task_unlock(current); if (err) mmap_write_unlock(mm); } else -- 2.20.1 (Apple Git-117)