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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, 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 92FCEC32789 for ; Thu, 8 Nov 2018 05:10:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 663BA20857 for ; Thu, 8 Nov 2018 05:10:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 663BA20857 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=stgolabs.net Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729040AbeKHOoM (ORCPT ); Thu, 8 Nov 2018 09:44:12 -0500 Received: from smtp2.provo.novell.com ([137.65.250.81]:45488 "EHLO smtp2.provo.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726145AbeKHOoJ (ORCPT ); Thu, 8 Nov 2018 09:44:09 -0500 Received: from linux-r8p5.suse.de (prv-ext-foundry1int.gns.novell.com [137.65.251.240]) by smtp2.provo.novell.com with ESMTP (TLS encrypted); Wed, 07 Nov 2018 22:10:21 -0700 From: Davidlohr Bueso To: akpm@linux-foundation.org Cc: jbaron@akamai.com, viro@zeniv.linux.org.uk, dave@stgolabs.net, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 6/6] fs/epoll: avoid barrier after an epoll_wait(2) timeout Date: Wed, 7 Nov 2018 21:10:06 -0800 Message-Id: <20181108051006.18751-7-dave@stgolabs.net> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20181108051006.18751-1-dave@stgolabs.net> References: <20181108051006.18751-1-dave@stgolabs.net> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Upon timeout, we can just exit out of the loop, without the cost of the changing the task's state smp_store_mb call. Just exit out of the loop and be done - setting the task state afterwards will be, of course, redundant. Signed-off-by: Davidlohr Bueso --- fs/eventpoll.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/fs/eventpoll.c b/fs/eventpoll.c index f6c023f085f6..ec14e5bcdaa9 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -1820,15 +1820,18 @@ static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events, res = -EINTR; break; } - if (ep_events_available(ep) || timed_out) + + if (ep_events_available(ep)) break; if (signal_pending(current)) { res = -EINTR; break; } - if (!schedule_hrtimeout_range(to, slack, HRTIMER_MODE_ABS)) + if (!schedule_hrtimeout_range(to, slack, HRTIMER_MODE_ABS)) { timed_out = 1; + break; + } } __set_current_state(TASK_RUNNING); -- 2.16.4