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 47896C43215 for ; Wed, 20 Nov 2019 05:00:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 298732245F for ; Wed, 20 Nov 2019 05:00:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725854AbfKTFAi (ORCPT ); Wed, 20 Nov 2019 00:00:38 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:6168 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725554AbfKTFAi (ORCPT ); Wed, 20 Nov 2019 00:00:38 -0500 Received: from pps.filterd (m0098394.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id xAK4vVZ7050041 for ; Wed, 20 Nov 2019 00:00:37 -0500 Received: from e06smtp03.uk.ibm.com (e06smtp03.uk.ibm.com [195.75.94.99]) by mx0a-001b2d01.pphosted.com with ESMTP id 2wcf56yj4f-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Wed, 20 Nov 2019 00:00:36 -0500 Received: from localhost by e06smtp03.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) Wed, 20 Nov 2019 05:00:32 -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 xAK50VcQ42009006 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 20 Nov 2019 05:00:31 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 1258CA405D; Wed, 20 Nov 2019 05:00:31 +0000 (GMT) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id AB35FA405F; Wed, 20 Nov 2019 05:00:29 +0000 (GMT) Received: from localhost.localdomain.com (unknown [9.199.63.56]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 20 Nov 2019 05:00:29 +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 Subject: [RFCv3 1/4] ext4: fix ext4_dax_read/write inode locking sequence for IOCB_NOWAIT Date: Wed, 20 Nov 2019 10:30:21 +0530 X-Mailer: git-send-email 2.21.0 In-Reply-To: <20191120050024.11161-1-riteshh@linux.ibm.com> References: <20191120050024.11161-1-riteshh@linux.ibm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 19112005-0012-0000-0000-0000036956A2 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19112005-0013-0000-0000-000021A4E34A Message-Id: <20191120050024.11161-2-riteshh@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.95,18.0.572 definitions=2019-11-19_08:2019-11-15,2019-11-19 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 mlxscore=0 phishscore=0 adultscore=0 lowpriorityscore=0 mlxlogscore=999 priorityscore=1501 suspectscore=0 spamscore=0 impostorscore=0 clxscore=1015 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1910280000 definitions=main-1911200045 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") 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