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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_SANE_1 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 B2ACFC5DF63 for ; Wed, 6 Nov 2019 16:13:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 83D572075C for ; Wed, 6 Nov 2019 16:13:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="Z/MxUDsb" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728373AbfKFQNZ (ORCPT ); Wed, 6 Nov 2019 11:13:25 -0500 Received: from userp2130.oracle.com ([156.151.31.86]:41980 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727275AbfKFQNY (ORCPT ); Wed, 6 Nov 2019 11:13:24 -0500 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.27/8.16.0.27) with SMTP id xA6GBn6n112923; Wed, 6 Nov 2019 16:13:14 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : in-reply-to; s=corp-2019-08-05; bh=I0DJWno1AIe+k5abobaMoeRn9tVqWR0gId8YXBLkfLU=; b=Z/MxUDsbCUmW5zQ2T/RfJyCzyM0BeSDW3UJsAxGkPJFljV9zNpvrMWBZVSdOpLWuHRIQ 5ljA/IXWHREzUmFCsWejP9lOp5QGWBRCfyLtmyaPsZUukRue2g4EqEa0G3UPkAjEeTSm BugzEkF06N3MUL9PUbhm7su/VxW/C9Ls7JT+d9IU+BWcdc2hF3haBHygQCBcCZof4NBB nGYsrE8q9HsKSuaCFs9o8nruCwVOngerCQlR+KHViO1nVYDs6NcL5iWcX1OsxmCiWe/N vYGTkpZvUBiXGvP//FxbgnvJEJWrEa0CqDcOxY8VI9X+r72eMVhuBCrtuPhely5INPii EQ== Received: from userp3030.oracle.com (userp3030.oracle.com [156.151.31.80]) by userp2130.oracle.com with ESMTP id 2w117u7vwc-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 06 Nov 2019 16:13:14 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id xA6G8GqG181508; Wed, 6 Nov 2019 16:13:14 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by userp3030.oracle.com with ESMTP id 2w3xc2x3ab-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 06 Nov 2019 16:13:14 +0000 Received: from abhmp0018.oracle.com (abhmp0018.oracle.com [141.146.116.24]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id xA6GDDQv027261; Wed, 6 Nov 2019 16:13:13 GMT Received: from localhost (/67.169.218.210) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 06 Nov 2019 08:13:13 -0800 Date: Wed, 6 Nov 2019 08:13:12 -0800 From: "Darrick J. Wong" To: Christoph Hellwig Cc: Christoph Hellwig , linux-xfs@vger.kernel.org Subject: Re: [PATCH 2/2] xfs: periodically yield scrub threads to the scheduler Message-ID: <20191106161312.GL4153244@magnolia> References: <157301537390.678524.16085197974806955970.stgit@magnolia> <157301538629.678524.5328247190031479757.stgit@magnolia> <20191106144446.GB17196@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191106144446.GB17196@lst.de> User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9433 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1908290000 definitions=main-1911060155 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9433 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1908290000 definitions=main-1911060155 Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Wed, Nov 06, 2019 at 03:44:46PM +0100, Christoph Hellwig wrote: > On Tue, Nov 05, 2019 at 08:43:06PM -0800, Darrick J. Wong wrote: > > +++ b/fs/xfs/scrub/common.h > > @@ -14,8 +14,20 @@ > > static inline bool > > xchk_should_terminate( > > struct xfs_scrub *sc, > > - int *error) > > + int *error) > > { > > +#if !IS_ENABLED(CONFIG_PREEMPT) > > + /* > > + * If preemption is disabled, we need to yield to the scheduler every > > + * few seconds so that we don't run afoul of the soft lockup watchdog > > + * or RCU stall detector. > > + */ > > + if (sc->next_yield != 0 && time_after(jiffies, sc->next_yield)) > > + return false; > > + schedule(); > > + sc->next_yield = jiffies + msecs_to_jiffies(5000); > > +#endif > > This looks weird. Can't we just do a cond_resched() here? DOH. Yes, probably. Dave even suggested it a few nights ago to fix a similar problem and apparently I forgot. Will fix. :( --D