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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 19ED9C4332F for ; Mon, 5 Dec 2022 00:31:03 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1A7848E0002; Sun, 4 Dec 2022 19:31:03 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 1585C8E0001; Sun, 4 Dec 2022 19:31:03 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 01F268E0002; Sun, 4 Dec 2022 19:31:02 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id E77388E0001 for ; Sun, 4 Dec 2022 19:31:02 -0500 (EST) Received: from smtpin28.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id B1E1280335 for ; Mon, 5 Dec 2022 00:31:02 +0000 (UTC) X-FDA: 80206372764.28.8D30851 Received: from mail-pg1-f171.google.com (mail-pg1-f171.google.com [209.85.215.171]) by imf01.hostedemail.com (Postfix) with ESMTP id B0A6D40013 for ; Mon, 5 Dec 2022 00:31:00 +0000 (UTC) Authentication-Results: imf01.hostedemail.com; dkim=none; spf=pass (imf01.hostedemail.com: domain of dennisszhou@gmail.com designates 209.85.215.171 as permitted sender) smtp.mailfrom=dennisszhou@gmail.com; dmarc=fail reason="SPF not aligned (relaxed), No valid DKIM" header.from=kernel.org (policy=none) ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1670200260; a=rsa-sha256; cv=none; b=iGVr2x662iZb6SobKymv9jXS8TqpTlsjsTaI7/tjHBO/d7qk4ckQlBhrSMzMf6jFiSGi24 FPCTc3PFUNZZw8A3WBRU7K832uZKryUl/vQ+bL45QNqc0Z4mDLM3M5Y26aZjrdqNGVjr9m OpqlGG0uNPbnzosl++N7rCCihXK4lHE= ARC-Authentication-Results: i=1; imf01.hostedemail.com; dkim=none; spf=pass (imf01.hostedemail.com: domain of dennisszhou@gmail.com designates 209.85.215.171 as permitted sender) smtp.mailfrom=dennisszhou@gmail.com; dmarc=fail reason="SPF not aligned (relaxed), No valid DKIM" header.from=kernel.org (policy=none) ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1670200260; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=jKIUaFMZtVQb2ZrexpCPM8972M5z5pGrf8gX4cPJRts=; b=gC50RiePhzlEi2fm2tTlgrY6x3/0EFKoH1HxxWGnNOfigJagQk7f1/14hJOYLxRgl27S/B CCPTIpzCBsojufI+tVYKEoDDzFZ8ders176fXQK8g8HPUHCdVPVxNY6aehsZ+c08kVbSek oSH99NDb+l7F61EdcuSV9/GbZ7OsaJY= Received: by mail-pg1-f171.google.com with SMTP id v3so9090194pgh.4 for ; Sun, 04 Dec 2022 16:31:00 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=jKIUaFMZtVQb2ZrexpCPM8972M5z5pGrf8gX4cPJRts=; b=tO4axSZyVy8keAGq7Ji3ILY572k9QbLa1xbm2ZoKcaZAIprYqfztaH8pnShhFsn5wS aGga8w3ihJs4XDsF0UqdXy2pczwS0JVE7zabvXw8IqieqC7+aH9jcFIe1dyeMvOxw0N1 9c7G/LdoxuYWrqZKGhUI468SNqLAg+e4E6j5+7MQND3uZTPK1UDIA9hcr9thyhK6nQHk miKHZEhU4OoFwaWFtDHG1KCzq3SZaFLAnzPkdx1zv4bujyHZrMpMBJGTvX5wgMcR9gQM taY4W6UrtfkLGhBtnms7eIg2xu4u+jem1cCJ31u9oEEDdZA5Ie8l6KT45d05ipE9EvoP EKgg== X-Gm-Message-State: ANoB5pmoptYG396WOYNviY52bG0DU6JDXonRqC2UpgAw4vrUWsmXGgQk hs2UlypknJsx5fLSqYmgi/c= X-Google-Smtp-Source: AA0mqf6atU2USi/6KyHpJKwAfHY/t/b9TTPZAbJf+Bvt392DcA95YAJGJL7GZhM06aGuPDh9HUVXsg== X-Received: by 2002:a62:be08:0:b0:574:26df:aac2 with SMTP id l8-20020a62be08000000b0057426dfaac2mr59183772pff.46.1670200259383; Sun, 04 Dec 2022 16:30:59 -0800 (PST) Received: from fedora ([2607:f598:b99a:26e1:80d8:4540:2de3:c7d6]) by smtp.gmail.com with ESMTPSA id 123-20020a620581000000b005747b59fc54sm8843666pff.172.2022.12.04.16.30.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 04 Dec 2022 16:30:58 -0800 (PST) Date: Sun, 4 Dec 2022 16:30:56 -0800 From: Dennis Zhou To: Baoquan He , Wupeng Ma Cc: akpm@linux-foundation.org, tj@kernel.org, cl@linux.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH -next 1/1] percpu: cleanup invalid assignment to err in pcpu_alloc Message-ID: References: <20221204031430.662169-1-mawupeng1@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Spamd-Result: default: False [-0.74 / 9.00]; BAYES_HAM(-5.74)[99.44%]; SORBS_IRL_BL(3.00)[209.85.215.171:from]; SUBJECT_HAS_UNDERSCORES(1.00)[]; MID_RHS_NOT_FQDN(0.50)[]; FORGED_SENDER(0.30)[dennis@kernel.org,dennisszhou@gmail.com]; DMARC_POLICY_SOFTFAIL(0.10)[kernel.org : SPF not aligned (relaxed), No valid DKIM,none]; RCVD_NO_TLS_LAST(0.10)[]; MIME_GOOD(-0.10)[text/plain]; BAD_REP_POLICIES(0.10)[]; ARC_SIGNED(0.00)[hostedemail.com:s=arc-20220608:i=1]; R_DKIM_NA(0.00)[]; FROM_HAS_DN(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; FROM_NEQ_ENVFROM(0.00)[dennis@kernel.org,dennisszhou@gmail.com]; PREVIOUSLY_DELIVERED(0.00)[linux-mm@kvack.org]; TO_DN_SOME(0.00)[]; RCPT_COUNT_SEVEN(0.00)[7]; R_SPF_ALLOW(0.00)[+ip4:209.85.128.0/17:c]; MIME_TRACE(0.00)[0:+]; RCVD_COUNT_THREE(0.00)[3]; TO_MATCH_ENVRCPT_SOME(0.00)[]; ARC_NA(0.00)[] X-Rspamd-Queue-Id: B0A6D40013 X-Rspamd-Server: rspam01 X-Stat-Signature: fwqts71fdjskgu8h4c9j6j11f4a1xyk3 X-HE-Tag: 1670200260-290233 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Hi Baoquan and Wupeng, On Sun, Dec 04, 2022 at 08:11:23PM +0800, Baoquan He wrote: > On 12/04/22 at 11:14am, Wupeng Ma wrote: > > From: Ma Wupeng > > > > Assignment to err if is_atomic is true will never be used since warn > > message can only be shown if is_atomic is false after label fail. So drop > > it. > > > > Signed-off-by: Ma Wupeng > > --- > > mm/percpu.c | 4 +--- > > 1 file changed, 1 insertion(+), 3 deletions(-) > > > > diff --git a/mm/percpu.c b/mm/percpu.c > > index acd78da0493b..df86d79325b2 100644 > > --- a/mm/percpu.c > > +++ b/mm/percpu.c > > @@ -1817,10 +1817,8 @@ static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved, > > > > spin_unlock_irqrestore(&pcpu_lock, flags); > > > > - if (is_atomic) { > > - err = "atomic alloc failed, no space left"; > > + if (is_atomic) > > goto fail; > > - } > > This is good catch. But I think Dennis may not like this way because he > added the message intentionally in commit 11df02bf9bc1 ("percpu: resolve > err may not be initialized in pcpu_alloc"). > You're right Baoquan haha. I agree with Christoph as well we should surface atomic. Though I don't think below is quite right either. We should likely have a separate warn_limit for atomic and I need to think about dump_stack() if there are any requirements there. Thanks, Dennis > Can we change the conditional checking in fail part as below? > > diff --git a/mm/percpu.c b/mm/percpu.c > index 27697b2429c2..0ac55500fad9 100644 > --- a/mm/percpu.c > +++ b/mm/percpu.c > @@ -1897,7 +1897,7 @@ static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved, > fail: > trace_percpu_alloc_percpu_fail(reserved, is_atomic, size, align); > > - if (!is_atomic && do_warn && warn_limit) { > + if (do_warn && warn_limit) { > pr_warn("allocation failed, size=%zu align=%zu atomic=%d, %s\n", > size, align, is_atomic, err); > dump_stack(); >