From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 41CC330E0D5 for ; Tue, 5 May 2026 09:15:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777972531; cv=none; b=Dh/8wxwqBhYCSjijab6+rlPdsHxHhfW/6e+TZ16ZCerf5il/+4Vo/052Ihr3rSifrrDbroy4Bsm3E6vjLQ413cE1zyUD6MxkXM5qSYeNZIQu5Hkbs7W4NHIoXC5EyHt59jLG5tzJjujTp41A9ZtdVeeuamw2rbmaonwB6Wyi/Bo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777972531; c=relaxed/simple; bh=7X5HYOo3eIBbRqTycsJXp9aFXsBzoTEGkR2aBI92Ucc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=lSETljAyvGo25Q/zmZ7HIxTQPY2ivn5tiHtQ/IScaFoWE/X+t3P0EsyFY+ogFWSZ+KzqAh0sok6fgdASWJGpgxXfGsU1Dg/6j2YEudh9mevOLK+48hxaU0Makcpwan/5UmM45N7XAVRCCVPH8w9MgGjtWLZBwX9G2hHKpa50IeM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=hfnlP1kr; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="hfnlP1kr" Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 204DC2D97; Tue, 5 May 2026 02:15:17 -0700 (PDT) Received: from [192.168.178.100] (usa-sjc-mx-foss1.foss.arm.com [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 306773F836; Tue, 5 May 2026 02:15:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1777972522; bh=7X5HYOo3eIBbRqTycsJXp9aFXsBzoTEGkR2aBI92Ucc=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=hfnlP1krVr4CGN0KUvueEpFEGCFlYCxhWUkLLR76gWIXffTssVjKggUpvR1mVAWuq AI8oRT26fpotmFojJcuY8dtnqT2MG0QkmpIVaX0o01Yd8aRwZ9rTvQblBPm1bq6VjG c3RNi0838P2q7xw8iqiJXLgzkd+3kBoWNWixMzHo= Message-ID: <4b4aadb2-a159-4ed9-852e-8aeb53d798ab@arm.com> Date: Tue, 5 May 2026 11:15:12 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/5] sched/fair: Drop redundant RCU read lock in NOHZ kick path To: Andrea Righi , Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot Cc: Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , K Prateek Nayak , Christian Loehle , Koba Ko , Felix Abecassis , Balbir Singh , Joel Fernandes , Shrikanth Hegde , linux-kernel@vger.kernel.org References: <20260428144352.3575863-1-arighi@nvidia.com> <20260428144352.3575863-2-arighi@nvidia.com> From: Dietmar Eggemann Content-Language: en-GB In-Reply-To: <20260428144352.3575863-2-arighi@nvidia.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 28.04.26 16:41, Andrea Righi wrote: [...] > @@ -12799,10 +12795,10 @@ static void nohz_balancer_kick(struct rq *rq) > * > * Skip the LLC logic because it's not relevant in that case. > */ > - goto unlock; > + goto out; > } > > - sds = rcu_dereference_all(per_cpu(sd_llc_shared, cpu)); > + sds = rcu_dereference_all(per_cpu(sd_balance_shared, cpu)); nit: sd_balance_shared is only defined in 2/5. [...]