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 BFC60C4332F for ; Wed, 30 Nov 2022 15:06:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229748AbiK3PGZ (ORCPT ); Wed, 30 Nov 2022 10:06:25 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60112 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229730AbiK3PGX (ORCPT ); Wed, 30 Nov 2022 10:06:23 -0500 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 408A03AC2D; Wed, 30 Nov 2022 07:06:22 -0800 (PST) Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id BBC351F37C; Wed, 30 Nov 2022 15:06:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1669820780; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=4lUys73fH/9stzM7XaBk+5X7L109u+d+RX+rmB4MkMA=; b=ufeFNCzr1hWeuBgyuNpvEF3akbEmjj6ZlUB2MGQnaTW256u+AYaByt+jq/2PL7PXALCmnm P4YESlV7RtXDqRcCgfDYGP0Kx2C1G0GAXnp4klzKgmMuqnEZfls7p9Fy634pIQcfCGgtNy foEr5JrMLKluEXnpo4dc2b+FaYd8hso= Received: from suse.cz (unknown [10.100.208.146]) (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 50D1D2C14F; Wed, 30 Nov 2022 15:06:20 +0000 (UTC) Date: Wed, 30 Nov 2022 16:06:19 +0100 From: Petr Mladek To: Thomas =?iso-8859-1?Q?Wei=DFschuh?= Cc: Joe Perches , "Rafael J. Wysocki" , Pavel Machek , Len Brown , linux-pm@vger.kernel.org, Sergey Senozhatsky , Andy Whitcroft , linux-kernel@vger.kernel.org, Steven Rostedt , Dwaipayan Ray , Lukas Bulwahn Subject: Re: [PATCH v2 3/3] power: process: use explicit levels for printk continuations Message-ID: References: <20221125190948.2062-1-linux@weissschuh.net> <20221125190948.2062-4-linux@weissschuh.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On Fri 2022-11-25 21:41:55, Thomas Weißschuh wrote: > On 2022-11-25 11:53-0800, Joe Perches wrote: > > On Fri, 2022-11-25 at 20:09 +0100, Thomas Weißschuh wrote: > >> Many of the printk messages emitted during suspend and resume are > >> emitted in fragments using pr_cont()/KERN_CONT. > >> > >> As during suspend and resume a lot of operations are happing in the > >> kernel the chances are high that the fragments are interspersed with > >> unrelated messages. > >> > >> In this case if no explicit level is specified for the fragments the > >> standard level is applied, which by default is KERN_WARNING. > >> > >> If the user is only observing KERN_WARNING and *not* KERN_INFO messages > >> they will see incomplete message fragments. > >> > >> By specifing the correct printk level also with the continuations this > >> mismatch can be avoided. > >> Also it reduces the amount of false-positive KERN_WARNING messages. > >> > >> Signed-off-by: Thomas Weißschuh > >> --- > >> kernel/power/process.c | 18 +++++++++--------- > >> 1 file changed, 9 insertions(+), 9 deletions(-) > >> > >> diff --git a/kernel/power/process.c b/kernel/power/process.c > > [] > >> @@ -82,7 +82,7 @@ static int try_to_freeze_tasks(bool user_only) > >> elapsed_msecs = ktime_to_ms(elapsed); > >> > >> if (todo) { > >> - pr_cont("\n"); > >> + pr_info_cont("\n"); > > > > I think this isn't needed because of the immediately following pr_err. Great catch. > The pr_cont() itself or the conversion to pr_info_cont() is not needed? The pr_cont() was needed before the commit 4bcc595ccd80decb42450 ("printk: reinstate KERN_CONT for printing continuation lines"). Before this commit, lines were appended even without KERN_CONT when the previous line did not end with "\n". The above commit caused that only lines with KERN_CONT will be appended. We have the code: pr_cont("\n"); pr_err("Freezing of tasks %s after %d.%03d seconds " The pr_cont() is not needed here because pr_err() does not have KERN_CONT. It will always start on a new line. > Personally I would prefer to keep the patch as is. > > If only the conversion is not needed for consistency with the rest of the file. > If the pr_cont() in general is not needed it should be changed in a dedicated > patch (by somebody who knows this code better). I agree that it should be removed in a separate patch. The commit message should mention the commit that modified the KERN_CONT handling. Best Regards, Petr