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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 59059C77B75 for ; Tue, 16 May 2023 09:26:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231531AbjEPJ0J (ORCPT ); Tue, 16 May 2023 05:26:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60318 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232141AbjEPJZg (ORCPT ); Tue, 16 May 2023 05:25:36 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E244C59EC for ; Tue, 16 May 2023 02:25:03 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 770C8636F5 for ; Tue, 16 May 2023 09:25:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2F3EDC433EF; Tue, 16 May 2023 09:24:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1684229102; bh=+pabQntQs5wnhpRu5Y4UyExhIZfqYNzZqCn5O3LU9Bw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=bijNI5i8oeK1xQifVY/LljPzxOceTkfZsZt94bemiIEo9A/dqFy3DC4v0yr6uXHWI psj/Uwv2vJ0q+twSEVlorzBUCOlXxVA/DuQv7eYt8w0mVfH2lvDa2ZQlvdUOzw2QEn +xCNquV6IYV6hHAI7B2Np2ahiyuf6ckL0xh+Dsv9JK8kGmSQ7c4Xe/PCoG9D3faVA/ 37El5FnfDuuXNa3iegpsn2qqNZPdYlous4LkBr+nxWc1TiT1iTEK7Voj65mDRTO+uL kL7VRQSHB8MjypTWTMEnNLsrlQBta/CZor2gb9lQgUuA3rBwmWoQQ1aCsd5WTH+PRP ZD1T5lnXI85sg== Date: Tue, 16 May 2023 11:24:51 +0200 From: Frederic Weisbecker To: Sebastian Siewior Cc: Anna-Maria Behnsen , linux-kernel@vger.kernel.org, Peter Zijlstra , John Stultz , Thomas Gleixner , Eric Dumazet , "Rafael J . Wysocki" , Arjan van de Ven , "Paul E . McKenney" , Frederic Weisbecker , Rik van Riel , Steven Rostedt , Giovanni Gherdovich , Lukasz Luba , "Gautham R . Shenoy" Subject: Re: [PATCH v6 19/21] timer: Implement the hierarchical pull model Message-ID: References: <20230510072817.116056-1-anna-maria@linutronix.de> <20230510072817.116056-20-anna-maria@linutronix.de> <20230515101936.3amAvw0T@linutronix.de> <398d7731-f5ca-a34-9e4-77da60c49d21@linutronix.de> <20230515124133.XkKOksjW@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20230515124133.XkKOksjW@linutronix.de> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Le Mon, May 15, 2023 at 02:41:33PM +0200, Sebastian Siewior a écrit : > On 2023-05-15 12:50:25 [+0200], Anna-Maria Behnsen wrote: > > As menitoned in the reply last week to Frederics objections regarding the > > locking asymmetry, I would like to keep it to make the locking region of > > timer base locks as small as possible and to prevent holding up to five > > locks during the walk. > > This looks okay. I wouldn't suggest to hold the timer_base::lock or > tmigr_cpu::lock longer than needed. Both can be acquired independently > cross CPU and have explicit locking order. So it is fine. LOCK(A) LOCK(B) UNLOCK(A) UNLOCK(B) Cross rhymes aren't pretty in locking. They don't make the review smooth but yeah it's not incorrect either. And since I don't have a better way to propose... > > > Thanks, > > > > Anna-Maria > > Sebastian