From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) (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 54EED43C047 for ; Tue, 28 Apr 2026 14:29:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=216.40.44.16 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777386567; cv=none; b=VHoAkoqOw0mT/KGf8Su6DCNXcTSVKgg8c3NWwoOHdBRsS+AWZHy8rDs1KnUbmhOWYZ7TgVqzXTDuiQQHJKjoYuY8Zfn9ctfZdjhUXSr4b1m8+/s2d8W1tOFBnaAbl5CMgqesyUgnw/oSSxnG8bqvZs3a5egmYjx5WOIzIxJaJtQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777386567; c=relaxed/simple; bh=B7x9/T4SdEz77y4pLt6s73GlJ3CGvHI395I6n6BCjKU=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=LqMiG7Aicy9AE7Ucu2t7bNnNJ4vd6mVWqPsOGA/pbXYatgU3bz014fFZy1SHe4RXf5WCQuPo3AA0Iic1T/3ERwkgZXTDGxJNb/c0oHYlkdgtr2XhzLta5fSA3sig//9TaluTRX/ka61XQyLBqx0FV1f+f9QAe2BOyZo6gBGKHaI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org; spf=pass smtp.mailfrom=goodmis.org; arc=none smtp.client-ip=216.40.44.16 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=goodmis.org Received: from omf08.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 3A2FD1201DB; Tue, 28 Apr 2026 14:29:22 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: rostedt@goodmis.org) by omf08.hostedemail.com (Postfix) with ESMTPA id B886520032; Tue, 28 Apr 2026 14:29:18 +0000 (UTC) Date: Tue, 28 Apr 2026 10:29:33 -0400 From: Steven Rostedt To: Andrea Righi Cc: K Prateek Nayak , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Ben Segall , Mel Gorman , Valentin Schneider , Christian Loehle , Koba Ko , Felix Abecassis , Balbir Singh , Joel Fernandes , Shrikanth Hegde , linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/6] sched/fair: Use guard(rcu) for sched_domain RCU sections Message-ID: <20260428102933.1be5f329@gandalf.local.home> In-Reply-To: References: <20260428051720.3180182-1-arighi@nvidia.com> <20260428051720.3180182-2-arighi@nvidia.com> <0882ce78-a51f-4317-a1b4-624e39e65507@amd.com> <20260428101209.58006c27@gandalf.local.home> X-Mailer: Claws Mail 3.20.0git84 (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-Queue-Id: B886520032 X-Rspamd-Server: rspamout06 X-Stat-Signature: a1q9xznfzgt9ormeuofdfinqkptsy88g X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX1+3mVpzGLejwF4gpAjpiKZtX3fJJ14IT7o= X-HE-Tag: 1777386558-32579 X-HE-Meta: U2FsdGVkX1/QQalert7/rtA3loJ+jtxZsZzUmgfOODt8d4t5sGt6KU3NJr4YvnzK4NZK8df3avZaJD6fSZPpOaoPjH7fe165poLEv8vltOY8A5l6cxTMlavcZloAfc2nA4m9Gk2BKmn1zZuG9y1i314ECWWlnxjr6VHNj/c5W/259z1CMEUMNOs3WV/YJMlMKc9B6RrUPWoo+ivJqjXb4xx+mQ3nDtT89e618td0ZIc8YB3xKJiJq+Vq4IxgfiU+24t4FFpnPRMDgxttLfS+cthcV/TZauuPwi8hgz5Fq0cBM8CU/10mZ4kCZn7i6F0L4MXJH+VJgC34EiNmbhj1NOkbjS+pspVC On Tue, 28 Apr 2026 16:26:02 +0200 Andrea Righi wrote: > > > with IRQs disabled, we can get rid of that rcu_read_lock() entirely. > > > > Then we need to add a lockdep_assert_irqs_disabled() here too. > > Yeah, initially I suggested to add a lockdep_assert_irqs_disabled() in > nohz_balancer_kick() but what we care about here is RCU safety, if we do > something unsafe in the future we should be able to catch that with > rcu_dererference_all(), as pointed by Peter, right? Yeah, I posted this before I saw Peter's reply. -- Steve