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=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY autolearn=ham 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 C3E89C433DF for ; Wed, 3 Jun 2020 17:26:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 983B420679 for ; Wed, 3 Jun 2020 17:26:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="g95sZCkO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725961AbgFCR0C (ORCPT ); Wed, 3 Jun 2020 13:26:02 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:43698 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725956AbgFCR0B (ORCPT ); Wed, 3 Jun 2020 13:26:01 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 053HM7Zp125336; Wed, 3 Jun 2020 17:25:59 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-2020-01-29; bh=DAK8xqjYoqvyLl8RllK8jz1RxH67VFbtYjP30D9qyDQ=; b=g95sZCkOLiYWePktsc+rJXdbmnq7Ixoz/WCYCJrpZ0+ZgwA4iEMxr1w5xptrjvQq8Lkx 6Czn67Kcd8MgVz2elJ+gcCvRQAHOMWZ2JIBecRRRlnNrl/CJCJmdFXnyZH1GFchpiXmQ rOLh/SwTBanew7dcUzfX9hXJquqcljVPkyiTTEbZF9niFT+e1UTdjThtusBIcVDo3xqS lGsS1/4fDJHibdQNdcmyNNvdF+vvQLlT5Fk65ePg/gTDuSevm9+ZBtoGSvOs2cJtYWrZ AnWcnMosAjCyK5xbgDHGqCXyI7vFcraV7Fztc9KFhoR4LOVJ+yIWYJWI1uT0w3B+UzU4 7w== Received: from aserp3020.oracle.com (aserp3020.oracle.com [141.146.126.70]) by userp2120.oracle.com with ESMTP id 31ef1ngcyr-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 03 Jun 2020 17:25:59 +0000 Received: from pps.filterd (aserp3020.oracle.com [127.0.0.1]) by aserp3020.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 053HI0Js006201; Wed, 3 Jun 2020 17:23:58 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserp3020.oracle.com with ESMTP id 31c25sp90e-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 03 Jun 2020 17:23:58 +0000 Received: from abhmp0004.oracle.com (abhmp0004.oracle.com [141.146.116.10]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 053HNv3e029907; Wed, 3 Jun 2020 17:23:57 GMT Received: from localhost (/10.159.239.239) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 03 Jun 2020 10:23:57 -0700 Date: Wed, 3 Jun 2020 10:23:55 -0700 From: "Darrick J. Wong" To: Yafang Shao Cc: linux-xfs@vger.kernel.org Subject: Re: [RFC PATCH] xfs: avoid deadlock when tigger memory reclam in xfs_map_blocks() Message-ID: <20200603172355.GP2162697@magnolia> References: <1591179035-9270-1-git-send-email-laoar.shao@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1591179035-9270-1-git-send-email-laoar.shao@gmail.com> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9641 signatures=668686 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 adultscore=0 suspectscore=5 spamscore=0 malwarescore=0 bulkscore=0 mlxscore=0 phishscore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2006030134 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9641 signatures=668686 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxlogscore=999 clxscore=1011 malwarescore=0 priorityscore=1501 impostorscore=0 spamscore=0 suspectscore=5 bulkscore=0 phishscore=0 adultscore=0 lowpriorityscore=0 mlxscore=0 cotscore=-2147483648 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2006030134 Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Wed, Jun 03, 2020 at 06:10:35AM -0400, Yafang Shao wrote: > Recently there is an XFS deadlock on our server with an old kernel. > The deadlock is caused by allocating memory xfs_map_blocks() while doing > writeback on behalf of memroy reclaim. Although this deadlock happens on an > old kernel, I think it could happen on the newest kernel as well. This > issue only happence once and can't be reproduced, so I haven't tried to > produce it on the newesr kernel. > > Bellow is the call trace of this deadlock. Note that > xfs_iomap_write_allocate() is replaced by xfs_convert_blocks() in > commit 4ad765edb02a ("xfs: move xfs_iomap_write_allocate to xfs_aops.c"). > > [480594.790087] INFO: task redis-server:16212 blocked for more than 120 seconds. > [480594.790087] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > [480594.790088] redis-server D ffffffff8168bd60 0 16212 14347 0x00000004 > [480594.790090] ffff880da128f070 0000000000000082 ffff880f94a2eeb0 ffff880da128ffd8 > [480594.790092] ffff880da128ffd8 ffff880da128ffd8 ffff880f94a2eeb0 ffff88103f9d6c40 > [480594.790094] 0000000000000000 7fffffffffffffff ffff88207ffc0ee8 ffffffff8168bd60 > [480594.790096] Call Trace: > [480594.790101] [] schedule+0x29/0x70 > [480594.790103] [] schedule_timeout+0x239/0x2c0 > [480594.790111] [] io_schedule_timeout+0xae/0x130 > [480594.790114] [] io_schedule+0x18/0x20 > [480594.790116] [] bit_wait_io+0x11/0x50 > [480594.790118] [] __wait_on_bit+0x65/0x90 > [480594.790121] [] wait_on_page_bit+0x81/0xa0 > [480594.790125] [] shrink_page_list+0x6d2/0xaf0 > [480594.790130] [] shrink_inactive_list+0x223/0x710 > [480594.790135] [] shrink_lruvec+0x3b5/0x810 > [480594.790139] [] shrink_zone+0xba/0x1e0 > [480594.790141] [] do_try_to_free_pages+0x100/0x510 > [480594.790143] [] try_to_free_mem_cgroup_pages+0xdd/0x170 > [480594.790145] [] mem_cgroup_reclaim+0x4e/0x120 > [480594.790147] [] __mem_cgroup_try_charge+0x41c/0x670 > [480594.790153] [] __memcg_kmem_newpage_charge+0xf6/0x180 > [480594.790157] [] __alloc_pages_nodemask+0x22d/0x420 > [480594.790162] [] alloc_pages_current+0xaa/0x170 > [480594.790165] [] new_slab+0x30c/0x320 > [480594.790168] [] ___slab_alloc+0x3ac/0x4f0 > [480594.790204] [] __slab_alloc+0x40/0x5c > [480594.790206] [] kmem_cache_alloc+0x193/0x1e0 > [480594.790233] [] kmem_zone_alloc+0x97/0x130 [xfs] > [480594.790247] [] _xfs_trans_alloc+0x3a/0xa0 [xfs] > [480594.790261] [] xfs_trans_alloc+0x3c/0x50 [xfs] > [480594.790276] [] xfs_iomap_write_allocate+0x1cb/0x390 [xfs] > [480594.790299] [] xfs_map_blocks+0x1a6/0x210 [xfs] > [480594.790312] [] xfs_do_writepage+0x17b/0x550 [xfs] xfs_do_writepages doesn't exist anymore. Does upstream have this problem? What kernel is this patch targeting? --D > [480594.790314] [] write_cache_pages+0x251/0x4d0 [xfs] > [480594.790338] [] xfs_vm_writepages+0xc5/0xe0 [xfs] > [480594.790341] [] do_writepages+0x1e/0x40 > [480594.790343] [] __filemap_fdatawrite_range+0x65/0x80 > [480594.790346] [] filemap_write_and_wait_range+0x41/0x90 > [480594.790360] [] xfs_file_fsync+0x66/0x1e0 [xfs] > [480594.790363] [] do_fsync+0x65/0xa0 > [480594.790365] [] SyS_fdatasync+0x13/0x20 > [480594.790367] [] system_call_fastpath+0x16/0x1b > > Signed-off-by: Yafang Shao > --- > fs/xfs/xfs_aops.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c > index 1fd4fb7..3f60766 100644 > --- a/fs/xfs/xfs_aops.c > +++ b/fs/xfs/xfs_aops.c > @@ -352,6 +352,7 @@ static inline bool xfs_ioend_needs_workqueue(struct iomap_ioend *ioend) > struct xfs_iext_cursor icur; > int retries = 0; > int error = 0; > + unsigned int nofs_flag; > > if (XFS_FORCED_SHUTDOWN(mp)) > return -EIO; > @@ -445,8 +446,16 @@ static inline bool xfs_ioend_needs_workqueue(struct iomap_ioend *ioend) > xfs_bmbt_to_iomap(ip, &wpc->iomap, &imap, 0); > trace_xfs_map_blocks_found(ip, offset, count, whichfork, &imap); > return 0; > + > allocate_blocks: > + /* > + * We can allocate memory here while doing writeback on behalf of > + * memory reclaim. To avoid memory allocation deadlocks set the > + * task-wide nofs context for the following operations. > + */ > + nofs_flag = memalloc_nofs_save(); > error = xfs_convert_blocks(wpc, ip, whichfork, offset); > + memalloc_nofs_restore(nofs_flag); > if (error) { > /* > * If we failed to find the extent in the COW fork we might have > -- > 1.8.3.1 >