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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT 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 36DA0C47409 for ; Thu, 5 Dec 2019 06:46:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1747222525 for ; Thu, 5 Dec 2019 06:46:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726108AbfLEGqh (ORCPT ); Thu, 5 Dec 2019 01:46:37 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:44032 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725974AbfLEGqg (ORCPT ); Thu, 5 Dec 2019 01:46:36 -0500 Received: from pps.filterd (m0098420.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id xB56hN3o152468 for ; Thu, 5 Dec 2019 01:46:35 -0500 Received: from e06smtp07.uk.ibm.com (e06smtp07.uk.ibm.com [195.75.94.103]) by mx0b-001b2d01.pphosted.com with ESMTP id 2wpuhv39yc-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Thu, 05 Dec 2019 01:46:35 -0500 Received: from localhost by e06smtp07.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! 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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Thu, 5 Dec 2019 06:46:31 -0000 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06avi18878370.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id xB56kUiC46268802 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 5 Dec 2019 06:46:30 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id AFF7CA4040; Thu, 5 Dec 2019 06:46:30 +0000 (GMT) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 039D9A4051; Thu, 5 Dec 2019 06:46:29 +0000 (GMT) Received: from dhcp-9-199-159-163.in.ibm.com (unknown [9.199.159.163]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTP; Thu, 5 Dec 2019 06:46:28 +0000 (GMT) From: Ritesh Harjani To: jack@suse.cz, tytso@mit.edu, linux-ext4@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, mbobrowski@mbobrowski.org, riteshh@linux.ibm.com, joseph.qi@linux.alibaba.com Subject: [PATCHv4 1/3] ext4: fix ext4_dax_read/write inode locking sequence for IOCB_NOWAIT Date: Thu, 5 Dec 2019 12:16:22 +0530 X-Mailer: git-send-email 2.21.0 In-Reply-To: <20191205064624.13419-1-riteshh@linux.ibm.com> References: <20191205064624.13419-1-riteshh@linux.ibm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 19120506-0028-0000-0000-000003C52B07 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19120506-0029-0000-0000-000024884BE9 Message-Id: <20191205064624.13419-2-riteshh@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.95,18.0.572 definitions=2019-12-05_01:2019-12-04,2019-12-05 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 clxscore=1015 priorityscore=1501 malwarescore=0 mlxlogscore=928 phishscore=0 adultscore=0 lowpriorityscore=0 bulkscore=0 impostorscore=0 suspectscore=3 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1910280000 definitions=main-1912050052 Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org Apparently our current rwsem code doesn't like doing the trylock, then lock for real scheme. So change our dax read/write methods to just do the trylock for the RWF_NOWAIT case. This seems to fix AIM7 regression in some scalable filesystems upto ~25% in some cases. Claimed in commit 942491c9e6d6 ("xfs: fix AIM7 regression") Reviewed-by: Jan Kara Reviewed-by: Matthew Bobrowski Signed-off-by: Ritesh Harjani --- fs/ext4/file.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/fs/ext4/file.c b/fs/ext4/file.c index 6a7293a5cda2..977ac58dc718 100644 --- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -88,9 +88,10 @@ static ssize_t ext4_dax_read_iter(struct kiocb *iocb, struct iov_iter *to) struct inode *inode = file_inode(iocb->ki_filp); ssize_t ret; - if (!inode_trylock_shared(inode)) { - if (iocb->ki_flags & IOCB_NOWAIT) + if (iocb->ki_flags & IOCB_NOWAIT) { + if (!inode_trylock_shared(inode)) return -EAGAIN; + } else { inode_lock_shared(inode); } /* @@ -487,9 +488,10 @@ ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from) bool extend = false; struct inode *inode = file_inode(iocb->ki_filp); - if (!inode_trylock(inode)) { - if (iocb->ki_flags & IOCB_NOWAIT) + if (iocb->ki_flags & IOCB_NOWAIT) { + if (!inode_trylock(inode)) return -EAGAIN; + } else { inode_lock(inode); } -- 2.21.0