From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A015D29ACED for ; Wed, 11 Jun 2025 14:15:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=216.40.44.10 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749651305; cv=none; b=PDx3Kv1M8KxmNMLgEn57eJy646s/K5uEh1ExWjyovRqPOMozkjR9lZDcxQ63pIUxAP5U1aG4+K8Iu4lnBlpUS6MAYxHHOY+S2OgC6cJkuZnRo9n3NDj9iG0JjpS+9mXtnoERqCDghf5nNoBrhZqT4QcdTMQxw+uKbWep1axeA7A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749651305; c=relaxed/simple; bh=pFxx+C/5QWV40QbrKzTdzefhgo5GIRyytsEQA9i/6/Q=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=s4FHEy+XZwSH9lI8Jc1bPBmeYf8YWFly3OKo01cy5CqPu58mQzhSkzr8HDbs8DuCRIkYgEpTE9b7GBtWCJ5eVMX2dntFYCE7a48Pbz6YcvZq3mgB/j4i76KspkPG3qon+d1KCHI0FGqug3nLQh9gS2F1ula6t+gj4zgkXmbczVg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org; spf=pass smtp.mailfrom=goodmis.org; arc=none smtp.client-ip=216.40.44.10 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=goodmis.org Received: from omf04.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id ABE241D7240; Wed, 11 Jun 2025 14:15:00 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: rostedt@goodmis.org) by omf04.hostedemail.com (Postfix) with ESMTPA id 5C6D920033; Wed, 11 Jun 2025 14:14:58 +0000 (UTC) Date: Wed, 11 Jun 2025 10:14:57 -0400 From: Steven Rostedt To: Peter Zijlstra Cc: Sebastian Andrzej Siewior , linux-kernel@vger.kernel.org, Ben Segall , Dietmar Eggemann , Ingo Molnar , Juri Lelli , Mel Gorman , Thomas Gleinxer , Valentin Schneider , Vincent Guittot Subject: Re: [PATCH v2] sched: Remove a preempt-disable section in rt_mutex_setprio() Message-ID: <20250611101457.13ea44f5@batman.local.home> In-Reply-To: <20250611090306.GA2273038@noisy.programming.kicks-ass.net> References: <20250610144700.uBK6RS95@linutronix.de> <20250611090306.GA2273038@noisy.programming.kicks-ass.net> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspamout03 X-Rspamd-Queue-Id: 5C6D920033 X-Stat-Signature: jfpkggf699s5uq3t8z8iukopfwho48gx X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX1/WvrBFQsv3gRwMyZGvufRM72PtMU2aDtY= X-HE-Tag: 1749651298-720991 X-HE-Meta: U2FsdGVkX18MuulUrPufGWjBco2mf9EefcB2MFUtAED5qZCkZckI1+jdoixvFikw+D9j4rhy+pZAeE0Osm9OzscW+0mEoVxG3ZW/44EBCVBhNTRnx76SU8EDBidHUU/y/T/oCkfb0Y8vEL3gPp8Rq0mBxG8vbH7o6y7YISHIsWxjmNAu4oCEsjvrOIlBcIC+gHJ2n9AKKX+LBeIBCZ4bECKivTQNfnjvRNj6jN68a1IYnHUBKjdVM+3u1XUwUKBp1Yz6e2XkyLUGpRQ2Xr8HENiv96uOzIl0Bp981i0bGNcjh33uFXLmWgu3ArFpTHCb13yu3XgJ4kVJGAN1TL5kCh649f0AjS9hXRvOJEJYG/lo9MUox1YwQjJ0JfZqkxIGoXS0E9Vt+kIFOd8V43wfog== On Wed, 11 Jun 2025 11:03:06 +0200 Peter Zijlstra wrote: > > --- a/kernel/sched/core.c > > +++ b/kernel/sched/core.c > > @@ -7292,14 +7292,10 @@ void rt_mutex_setprio(struct task_struct *p, struct task_struct *pi_task) > > > > check_class_changed(rq, p, prev_class, oldprio); > > out_unlock: > > - /* Avoid rq from going away on us: */ > > - preempt_disable(); > > Perhaps add: > > /* IRQs are still disabled */ > > or something to that effect such that it is obvious from reading the > code that dropping the lock will not enable preemption? Hmm, wouldn't lockdep_assert_irqs_disabled() be better than a comment. It lets people know that interrupts are disabled and when lockdep is enabled it also makes sure they are. -- Steve