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 34E75C433F5 for ; Tue, 15 Feb 2022 09:32:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235917AbiBOJck (ORCPT ); Tue, 15 Feb 2022 04:32:40 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:34020 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235916AbiBOJcc (ORCPT ); Tue, 15 Feb 2022 04:32:32 -0500 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6F236AA007 for ; Tue, 15 Feb 2022 01:32:22 -0800 (PST) Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out1.suse.de (Postfix) with ESMTP id 2CE86210DC; Tue, 15 Feb 2022 09:32:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1644917541; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=KYdGeFsANOtOABOCKg2n5btFGKH4PKRKWZczmP67Y4c=; b=Fre+2KMos1Xt+rzKEa0yiIruHha9K585218YxzHlAprj3wPnd0UmAjNDO0DHnOvj8I85EA 8qWBQ1+65aI05croPjluXpbDyoll3bC7Hs4+mQpwSmwWUif6BvnvediTZJTFwLVB7+EflY v+3muQf3MguEBQ5s+V4KTIjsqnksXqU= Received: from suse.cz (unknown [10.100.216.66]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id 148E0A3B85; Tue, 15 Feb 2022 09:32:21 +0000 (UTC) Date: Tue, 15 Feb 2022 10:32:20 +0100 From: Petr Mladek To: Peter Zijlstra , Steven Rostedt Cc: John Ogness , Sergey Senozhatsky , Thomas Gleixner , linux-kernel@vger.kernel.org, Andrew Morton , Marco Elver , Stephen Boyd , Alexander Potapenko , Randy Dunlap , Nicholas Piggin Subject: Re: [PATCH printk v1 01/13] printk: rename cpulock functions Message-ID: References: <20220207194323.273637-1-john.ogness@linutronix.de> <20220207194323.273637-2-john.ogness@linutronix.de> <87fsopcvnj.fsf@jogness.linutronix.de> <20220211155727.49ab86f5@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 2022-02-11 22:04:48, Peter Zijlstra wrote: > On Fri, Feb 11, 2022 at 03:57:27PM -0500, Steven Rostedt wrote: > > On Fri, 11 Feb 2022 15:48:08 +0106 > > John Ogness wrote: > > > > > It is because (as in the example above), taking this "lock" does not > > > provide synchronization to data. It is only synchronizing between > > > CPUs. It was Steven's suggestion to call the thing a cpu_sync object and > > > nobody in the RT Track seemed to disagree. > > > > I love causing trouble ;-) > > > > Actually, it wasn't just my suggestion. IIRC, I believe Peter Zijlstra was > > against calling it a lock (Peter, you can use lore to see the context here). > > All I remember is that it was in a room and I was late, I can't even > remember what City we were all in at the time. Was this Lisbon? > > Anyway, as Steve said, it isn't really a strict exclusion thing, it only > avoids the most egregious inter-cpu interleaving. I'm down with > goldi-locks, something has to have that name :-) You troublemakers :-) OK, I know, I am the troublemaker here. Best Regards, Petr