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=-6.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 E6F5EC433E7 for ; Tue, 13 Oct 2020 23:57:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9C98022247 for ; Tue, 13 Oct 2020 23:57:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602633429; bh=+f3C+XaYK4WzZOmmvwQWmVQMjkZstl/vMI9LhsloERY=; h=Date:From:To:Subject:In-Reply-To:Reply-To:List-ID:From; b=ELJEaFtbFJ6rtTDWXWS53MVqzz3TDdkUb4mBMbOE6Z0/byWG5nn4TYNL+Gwlr2ufp ioRnwJ8/7j/g0dz2FP0n/7UcUf6CQ6FAVOBXZPImXoT+w7OoA4KGL7fIA2a3izMcQJ jKbnxggpwvtXgKp1kPBOoGNIooyXYOF5SXAWiyiQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389359AbgJMX5J (ORCPT ); Tue, 13 Oct 2020 19:57:09 -0400 Received: from mail.kernel.org ([198.145.29.99]:43026 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389233AbgJMX5J (ORCPT ); Tue, 13 Oct 2020 19:57:09 -0400 Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 671952222E; Tue, 13 Oct 2020 23:57:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602633428; bh=+f3C+XaYK4WzZOmmvwQWmVQMjkZstl/vMI9LhsloERY=; h=Date:From:To:Subject:In-Reply-To:From; b=HRh04Fquznd0c4q6C7KOVxK+lmVr9H6ZknMUjNLTjMJywLUmJdi85FTVaRZXH20G/ MbUl4NJpNlFJ3b5HBo+ZtSlBi2V3bSM9AX0J3e45mjDT5Kaz02uByMElk7iopnxOU+ 9ZOIGBgLEErlkMHb4AJVB3d1l+iiHm0p4KEijE+s= Date: Tue, 13 Oct 2020 16:57:08 -0700 From: Andrew Morton To: akpm@linux-foundation.org, linux-mm@kvack.org, mm-commits@vger.kernel.org, richard.weiyang@linux.alibaba.com, torvalds@linux-foundation.org Subject: [patch 159/181] mm/mempolicy: remove or narrow the lock on current Message-ID: <20201013235708.jAS0Gx_Zg%akpm@linux-foundation.org> In-Reply-To: <20201013164658.3bfd96cc224d8923e66a9f4e@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: Wei Yang Subject: mm/mempolicy: remove or narrow the lock on current It is not necessary to hold the lock of current when setting nodemask of a new policy. Link: https://lkml.kernel.org/r/20200921040416.86185-1-richard.weiyang@linux.alibaba.com Signed-off-by: Wei Yang Reviewed-by: Andrew Morton Signed-off-by: Andrew Morton --- mm/mempolicy.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) --- a/mm/mempolicy.c~mm-mempolicy-remove-or-narrow-the-lock-on-current +++ a/mm/mempolicy.c @@ -875,13 +875,12 @@ static long do_set_mempolicy(unsigned sh 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 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 _