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 164C7C32789 for ; Sun, 4 Nov 2018 03:51:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AC9E42081D for ; Sun, 4 Nov 2018 03:51:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="bOiBGxpT" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AC9E42081D 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 S1729113AbeKDNEr (ORCPT ); Sun, 4 Nov 2018 08:04:47 -0500 Received: from mail-pf1-f196.google.com ([209.85.210.196]:37288 "EHLO mail-pf1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729000AbeKDNEr (ORCPT ); Sun, 4 Nov 2018 08:04:47 -0500 Received: by mail-pf1-f196.google.com with SMTP id u13-v6so2810743pfm.4 for ; Sat, 03 Nov 2018 20:51:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=WyXt3/RSV27qxDb1bu2HqD4MnOWv0qQF0psRZ70CdJ8=; b=bOiBGxpTj7Fm7RtK/vhAEtjMiR8HGjHW9Kl9Q2/CAoYGueBgcQM06oF2eVfDOzGFgT amayOO0Cc2ROSckbhaTbqUz9EbARAva7A7/fwlfNOvFDbicOyFAhVoxka9H7BxW3oUZb 8G0N8ucGkcztOgSwsn0VbNvJBZY1SDW3DK4qaixWJJTuZG454RihC9diZxAXMibYHUfd gzA1iFM3Aqz5mdtjLpgwgASN24UFnSH7yAHlazk58KeIAbqEnwIm9qThCpTw8fLc3TKT IaGwKsIO4UbrHcXcM07tj0lSmMUX1vs55mpdHnkJ+wWAFswpQx3GN+vjaBaMPnm0TVNk S1zg== 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=WyXt3/RSV27qxDb1bu2HqD4MnOWv0qQF0psRZ70CdJ8=; b=h5eO17VxhrjwuzWEELDkr+oLeiTkUylP8DspFydk8x5dzWXJewQUOQ9Hto8XGSh6NY FgR9j6i5mIq2kX8BMn8id1SjDB9MnM57TsYk/uKTA8K0wJaQp19s+aEZD6QGcmJtGngW zsFdOogUZ+rxNH+6NWjSWUE/O3iKHSU0Mw/sYQtK11RmuHRmOMD3xbfM79lCnjF7ZC6Q Z90lEHSPnbgFYMUcRfh0l5E+jtm+ghdzFtEWfE1caPBKbzj8fV4yivqy4ek2S5vgUGQO 4KMFN33I5S5LSfKq3JiZl/t8ys89bXEFLDJCXTaKEK69o+iJ97BrsenaK9YsyBkrJpWU T13A== X-Gm-Message-State: AGRZ1gIVwqdVgS7ZeKHNRKF57fbmoQ1xn+ntMtNJKXZ3Uec7nOjB8w4j c0gquV25U+f8GaUAecn7xeIf9BY9/84= X-Google-Smtp-Source: AJdET5e+jj7q7qMcbN/VZvS8m2BOiDZQ8BKcB5kP4/jBDiZCnAbi8xtS1ruZMivRKqD3TXP4TH1qUw== X-Received: by 2002:a62:5210:: with SMTP id g16-v6mr17405568pfb.256.1541303481098; Sat, 03 Nov 2018 20:51:21 -0700 (PDT) Received: from localhost.localdomain ([104.238.150.158]) by smtp.gmail.com with ESMTPSA id u190-v6sm98398074pgu.3.2018.11.03.20.51.17 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 03 Nov 2018 20:51:20 -0700 (PDT) From: Muchun Song To: mingo@kernel.org, peterz@infradead.org Cc: linux-kernel@vger.kernel.org Subject: [PATCH v2] sched/core: Remove unnecessary check for next_task in push_{rt,dl}_task() Date: Sun, 4 Nov 2018 11:51:01 +0800 Message-Id: <20181104035101.21805-1-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)); } 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 --- Changes in v2: -also remove unnecessary check in deadline.c -update commit message --- 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 481bb7aa25c5..ec097edea9ca 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -1813,11 +1813,6 @@ 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