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 X-Spam-Level: X-Spam-Status: No, score=-3.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9FCF5C433B4 for ; Wed, 7 Apr 2021 23:28:02 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D0E18611C9 for ; Wed, 7 Apr 2021 23:28:01 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D0E18611C9 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=e16-tech.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 61BF66B0080; Wed, 7 Apr 2021 19:28:01 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 5CB296B0081; Wed, 7 Apr 2021 19:28:01 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 493E06B0082; Wed, 7 Apr 2021 19:28:01 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0106.hostedemail.com [216.40.44.106]) by kanga.kvack.org (Postfix) with ESMTP id 2CD986B0080 for ; Wed, 7 Apr 2021 19:28:01 -0400 (EDT) Received: from smtpin03.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id CF259181CC1B6 for ; Wed, 7 Apr 2021 23:28:00 +0000 (UTC) X-FDA: 78007161120.03.EB90121 Received: from out20-3.mail.aliyun.com (out20-3.mail.aliyun.com [115.124.20.3]) by imf14.hostedemail.com (Postfix) with ESMTP id 65BD8C0001FA for ; Wed, 7 Apr 2021 23:27:53 +0000 (UTC) X-Alimail-AntiSpam:AC=CONTINUE;BC=0.1162082|-1;CH=green;DM=|CONTINUE|false|;DS=CONTINUE|ham_social|0.36726-0.00326118-0.629478;FP=0|0|0|0|0|-1|-1|-1;HT=ay29a033018047209;MF=wangyugui@e16-tech.com;NM=1;PH=DS;RN=4;RT=4;SR=0;TI=SMTPD_---.JwZxs4d_1617838075; Received: from 192.168.2.112(mailfrom:wangyugui@e16-tech.com fp:SMTPD_---.JwZxs4d_1617838075) by smtp.aliyun-inc.com(10.147.42.197); Thu, 08 Apr 2021 07:27:55 +0800 Date: Thu, 08 Apr 2021 07:28:01 +0800 From: Wang Yugui To: Dennis Zhou Subject: Re: unexpected -ENOMEM from percpu_counter_init() Cc: Vlastimil Babka , linux-mm@kvack.org, linux-btrfs@vger.kernel.org In-Reply-To: References: <20210407210905.F790.409509F4@e16-tech.com> Message-Id: <20210408072800.6C1F.409509F4@e16-tech.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.75.03 [en] X-Rspamd-Queue-Id: 65BD8C0001FA X-Stat-Signature: 3bixzu7qqq91kg33twjkrhf6cxqhndwo X-Rspamd-Server: rspam02 Received-SPF: none (e16-tech.com>: No applicable sender policy available) receiver=imf14; identity=mailfrom; envelope-from=""; helo=out20-3.mail.aliyun.com; client-ip=115.124.20.3 X-HE-DKIM-Result: none/none X-HE-Tag: 1617838073-189944 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000368, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Hi, > > > > upper caller: > > > > nofs_flag = memalloc_nofs_save(); > > > > ret = btrfs_drew_lock_init(&root->snapshot_lock); > > > > memalloc_nofs_restore(nofs_flag); > > The issue is here. nofs is set which means percpu attempts an atomic > allocation. If it cannot find anything already allocated it isn't happy. > This was done before memalloc_nofs_{save/restore}() were pervasive. > > Percpu should probably try to allocate some pages if possible even if > nofs is set. Thanks. I will wait for the patch, and then test it. Best Regards Wang Yugui (wangyugui@e16-tech.com) 2021/04/08