From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 93A453876C4 for ; Tue, 13 Jan 2026 10:08:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768298888; cv=none; b=ilgR4MBi27rqkN2QZ7uMeV5Lnd0gflRL8Ut4J9B73w2SN10eYcLHMW6cysET9cvavjQJYnVbmSlaevSt+f/mid4Ve2HSh8Mt8niSNTO9pAMYlFJzP2CHg/fRu8ZuIz5jNykbMZNbG/AV6iQmSLyGn7qIIHT9NcqwV54oA+C5GVM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1768298888; c=relaxed/simple; bh=Xrw0Sue8VzrW13IWdHy+QddBqiXclToYqJ5aQ8uCXU0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=e7ercqVZfKrbdKJ40VrknmPctSRyfpcE/dG/ZX4siOlxMDDLkd7yBtIMvWUEYlm1wMB5ZZv+ID0riANviTREH5NT/DMFqkz7NIeCbkA9lRVxZZEIb7WNXr0eIsbdlT6iSXxz+LEyRnTKtaUQkhe65quniJsxlQew4hEFLX/uNic= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=RXkZlGkn; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="RXkZlGkn" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=ZqZOy9HlYhsBhZMeYBHO0VVy7ivfIZIoCkMGqK31tIY=; b=RXkZlGknpgEG/MxD0E8N3sTMp+ FQs7YNWHodyPVYD/wt2m2sF67QPP5fRov4pu6jxasqov35csDIORz9dXWmItquf/ttw8DW/ptG5u/ jmT/BnkYsGQS6TCq4vBGTjR4mLwSJK8sM6/NOvnbOLa6MDWBSz4hODgmqF3yyTtIphdpE8qKQXDwo 9vBMlovYwnVoiE2/WhbGh9Uz5CcL150Z3ffcblo8DW5YzfF3qcjrfZzuVSO5XQYUpP2OYM/11Ll7B Y+4E7QqQdIej56r/pp2wy+pWoKM7sTH2eunQg+cVTWaUzhIfZnmEE8ITGYm6ZEJTNjEikXn40m29F wnqcrbqA==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1vfbJd-00000002WvL-0GrA; Tue, 13 Jan 2026 10:07:57 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 8D367301C77; Tue, 13 Jan 2026 11:07:55 +0100 (CET) Date: Tue, 13 Jan 2026 11:07:55 +0100 From: Peter Zijlstra To: Wangyang Guo Cc: K Prateek Nayak , Ingo Molnar , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , linux-kernel@vger.kernel.org, Shrikanth Hegde , Benjamin Lei , Tim Chen , Tianyou Li Subject: Re: [PATCH v2] sched/clock: Avoid false sharing for sched_clock_irqtime Message-ID: <20260113100755.GV830755@noisy.programming.kicks-ass.net> References: <20260113074807.3404180-1-wangyang.guo@intel.com> 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-Disposition: inline In-Reply-To: <20260113074807.3404180-1-wangyang.guo@intel.com> On Tue, Jan 13, 2026 at 03:48:07PM +0800, Wangyang Guo wrote: > Read-mostly sched_clock_irqtime may share the same cacheline with > frequently updated nohz struct. Mark it as __read_mostly to avoid > false sharing issue. > Is there a reason that thing can't be a static_key or so?