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=-8.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,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 14373C43441 for ; Mon, 26 Nov 2018 14:21:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CFCE720855 for ; Mon, 26 Nov 2018 14:21:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="QcAGnhVE" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org CFCE720855 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com 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 S1726770AbeK0BQK (ORCPT ); Mon, 26 Nov 2018 20:16:10 -0500 Received: from mail-pf1-f194.google.com ([209.85.210.194]:44408 "EHLO mail-pf1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726176AbeK0BQK (ORCPT ); Mon, 26 Nov 2018 20:16:10 -0500 Received: by mail-pf1-f194.google.com with SMTP id u6so6641498pfh.11 for ; Mon, 26 Nov 2018 06:21:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=CGdMwR0sKw6CzKU4fRgtQLyppoVW56ZQjD11dAUBNw8=; b=QcAGnhVE4saiZ1NQPxaASTzEw95N2l1hScq4zJbb/8MX3eWgy5P3W+L+i6LHUK6c6w lsTYWqf/RRmHpIvZXRYTpy2iRtBuUeooivvLnBKqnOWJfQqaC30n5kA1AKrE15i4jqUq DaAZGTVioTC1IQ9ckmB/gsw/YRgM1JPv9ulZkskKAb2ay85nLtkqH4b3ygAaDkaU4y0B So0f59ATfDw3kw9JT7ohdwaRtTtR6B9MOCeOrCiBx+RgJtJ/Dk/78A2zDE91FzXe3p1I kP/aJTcWc1G5cJs7Xcv7AqFPbOte8pjhb5ryRcf2qBtxFpHK4Vzd5Orrm5Agb7wpmmhb AS3w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=CGdMwR0sKw6CzKU4fRgtQLyppoVW56ZQjD11dAUBNw8=; b=TLukMlAo5ubfh2DNp5dVnDerc8U6nlG8wT4VNhbdjw+3VgXk3iWWtMkefbKtSegwmi no9m5MgiMuM8QlVOXQQBTm5MHAimL570E6SfvWiJaAW2vnnBxNl69w2hSxGGvyXupzMF 9FLEBHJ/xCORkIHAGbh/X0pknOExfoDXWv2d6WBeHo+W6udC8dI3jBHVzulGqhR1jIkb zb13bnsmZq23GbQA0nFK2NsDzHzrsyMzYJB51ZjTUZDMpSLBT9F92i0TappYDiiVUH1P PaMzFhmF36+x0qG/Ec33rJ5yi5hUry5NKVUySeo/yL5/jXeUTwjamtadwgzzCXCaWl10 ec5Q== X-Gm-Message-State: AGRZ1gJ88ocTCxkffkQttm3/Sx9RVy3WzDokBy6DLHX15oBmfcp2Sid2 PBPXInREAnLeMZgzHgzN+QQ= X-Google-Smtp-Source: AJdET5fpTg0HAw3TNt/xlLphSR6CvBrTeSu2vTBGbMTJtgMpUmlV8Z686juNOLACghOJvnicidU/lA== X-Received: by 2002:a62:6a88:: with SMTP id f130mr28495477pfc.201.1543242113507; Mon, 26 Nov 2018 06:21:53 -0800 (PST) Received: from ubuntu.localdomain ([101.87.249.94]) by smtp.gmail.com with ESMTPSA id u70sm1000849pfa.176.2018.11.26.06.21.49 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 26 Nov 2018 06:21:52 -0800 (PST) From: Muchun Song To: mingo@kernel.org, peterz@infradead.org Cc: linux-kernel@vger.kernel.org Subject: [PATCH RESEND v2] sched/core: Remove unnecessary check for next_task in push_{rt,dl}_task() Date: Mon, 26 Nov 2018 22:21:16 +0800 Message-Id: <20181126142116.5593-1-smuchun@gmail.com> X-Mailer: git-send-email 2.17.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In push_{rt,dl}_task(), we call pick_next_pushable{_dl}_task() to pick next_task before the check. If next_task and rq->curr are equal, which will trigger BUG_ON() in pick_next_pushable{_dl}_task(). See the following code in pick_next_pushable{_dl}_task(). static struct task_struct *pick_next_pushable{_dl}_task(struct rq *rq) { BUG_ON(task_current(rq, p)); return p; } The task_current() will check if task p and rq->curr are equal. So, we can remove the unnecessary check in push_{rt,dl}_task(). Signed-off-by: Muchun Song --- kernel/sched/deadline.c | 5 ----- kernel/sched/rt.c | 5 ----- 2 files changed, 10 deletions(-) diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index 470ba6b464fe..4b0189627318 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -2042,11 +2042,6 @@ static int push_dl_task(struct rq *rq) return 0; retry: - if (unlikely(next_task == rq->curr)) { - WARN_ON(1); - return 0; - } - /* * If next_task preempts rq->curr, and rq->curr * can move away, it makes sense to just reschedule diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index f28157c8212b..efc3fbe205ac 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -1824,11 +1824,6 @@ static int push_rt_task(struct rq *rq) return 0; retry: - if (unlikely(next_task == rq->curr)) { - WARN_ON(1); - return 0; - } - /* * It's possible that the next_task slipped in of * higher priority than current. If that's the case -- 2.17.1