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=-18.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 5FF72C433ED for ; Sat, 24 Apr 2021 01:24:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3151960C3E for ; Sat, 24 Apr 2021 01:24:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236948AbhDXBYj (ORCPT ); Fri, 23 Apr 2021 21:24:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44732 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236561AbhDXBYJ (ORCPT ); Fri, 23 Apr 2021 21:24:09 -0400 Received: from mail-qt1-x834.google.com (mail-qt1-x834.google.com [IPv6:2607:f8b0:4864:20::834]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A0CBAC061574 for ; Fri, 23 Apr 2021 18:23:04 -0700 (PDT) Received: by mail-qt1-x834.google.com with SMTP id s4so9945236qtw.3 for ; Fri, 23 Apr 2021 18:23:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=j1dtGHCCWZvvr6CUZxSFYg4ycltQtDMhB55xHyddT1U=; b=iPzgLMbqNidTWALjuay0axgZy8gCv7UEhtPJQltTbuSoObd5x9zd1vKuc8IhZgpO8p IWCLl//lvaWrBEx/ATyPLwfx5gEByi606E4QKANTfdiEyg74Y7LNZp+g5uJQ458spFTJ Bl9rmukBGpJmzdIaVwV+UhqH1onrbm2bRZnYAvUAA0m75SkbApOe/ZBH7MEupfF1/IyW iFfGFl/GSpfK/DuX8RUXf2Dlj//+T3qCp/q/wlQmIiJIncWn0qx7f7rHhRFWNFppuAK4 XqA5TxuiW3uSTMpND1F24sAX0S9XMr39yEZkPeCfNYu6mQIjSHiWL+oP1E4map+0jm05 NnLQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=j1dtGHCCWZvvr6CUZxSFYg4ycltQtDMhB55xHyddT1U=; b=BXgBnH0V4vCfejg35dqXssu8gi5zFo4bGY/QtbtNLL4ttrTmttc7GOPvs8yZ1JShvq eNxIBQP6PW25OZaBUcL9pucpPWR6lAiVK/tsyvU3x0PeRXgBl6HD4tTKGBiSgaeZjRDU oOmKIg5MEqrYmuQ8YigYJcbofxNbE/3BZ6Brurx3hN5U6K2nBBePo0TjLXCLmJathqHK e+eale7c6BRudAxQGSbw4jx5bx8wKR4P2kth+GW6ivHR7hD20Kz5BeIXLaUJw46aTlAt k+e0P5i2Fsiv2oR7tsghPeoSoSAOhPQiU+yl6TpL7L78CIJSXkHnlbQgLJJibjTeeIOI wokQ== X-Gm-Message-State: AOAM533i6zEfcB4j0eBc/IDQnDaTYelJbugGnmbuv7DDDq4ZypT9Mvjn 1N9Bx3jyB6eLl8UhC6sy39ARySY6ajqIeXj/q5tPaw== X-Google-Smtp-Source: ABdhPJx93J/4VFwNJBe7TbrHDN/vekXXuyX5e7MHnFJJ5sLxOsvTVWjFY+y+2vzfaTEJgdpjpdunXWK9g7C1/uaoy5s= X-Received: by 2002:a05:622a:3c8:: with SMTP id k8mr6422988qtx.101.1619227383594; Fri, 23 Apr 2021 18:23:03 -0700 (PDT) MIME-Version: 1.0 References: <20210422120459.447350175@infradead.org> <20210422123308.196692074@infradead.org> In-Reply-To: <20210422123308.196692074@infradead.org> From: Josh Don Date: Fri, 23 Apr 2021 18:22:52 -0700 Message-ID: Subject: Re: [PATCH 04/19] sched: Prepare for Core-wide rq->lock To: Peter Zijlstra Cc: Joel Fernandes , "Hyser,Chris" , Ingo Molnar , Vincent Guittot , Valentin Schneider , Mel Gorman , linux-kernel , Thomas Gleixner Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Peter, > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -186,12 +186,37 @@ int sysctl_sched_rt_runtime = 950000; > > void raw_spin_rq_lock_nested(struct rq *rq, int subclass) > { > - raw_spin_lock_nested(rq_lockp(rq), subclass); > + raw_spinlock_t *lock; > + > + if (sched_core_disabled()) { Nothing to stop sched_core from being enabled right here? Leading to us potentially taking the wrong lock. > + raw_spin_lock_nested(&rq->__lock, subclass); > + return; > + } > + > + for (;;) { > + lock = rq_lockp(rq); > + raw_spin_lock_nested(lock, subclass); > + if (likely(lock == rq_lockp(rq))) > + return; > + raw_spin_unlock(lock); > + } > }