From: Ritesh Harjani <riteshh@linux.ibm.com>
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 [thread overview]
Message-ID: <20191120050024.11161-2-riteshh@linux.ibm.com> (raw)
In-Reply-To: <20191120050024.11161-1-riteshh@linux.ibm.com>
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 <riteshh@linux.ibm.com>
---
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
next prev parent reply other threads:[~2019-11-20 5:00 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-20 5:00 [RFCv3 0/4] ext4: Introducing ilock wrapper APIs & fixing i_rwsem scalablity prob. in DIO mixed-rw Ritesh Harjani
2019-11-20 5:00 ` Ritesh Harjani [this message]
2019-11-20 12:51 ` [RFCv3 1/4] ext4: fix ext4_dax_read/write inode locking sequence for IOCB_NOWAIT Jan Kara
2019-11-22 5:53 ` Matthew Bobrowski
2019-11-20 5:00 ` [RFCv3 2/4] ext4: Add ext4_ilock & ext4_iunlock API Ritesh Harjani
2019-11-20 11:23 ` Matthew Bobrowski
2019-11-20 12:18 ` Ritesh Harjani
2019-11-20 16:35 ` Matthew Wilcox
2019-11-23 11:51 ` Ritesh Harjani
2019-11-20 13:11 ` Jan Kara
2019-11-20 16:06 ` Darrick J. Wong
2019-11-20 5:00 ` [RFCv3 3/4] ext4: start with shared iolock in case of DIO instead of excl. iolock Ritesh Harjani
2019-11-20 13:55 ` Jan Kara
2019-11-23 13:17 ` Ritesh Harjani
2019-11-20 5:00 ` [RFCv3 4/4] ext4: Move to shared iolock even without dioread_nolock mount opt Ritesh Harjani
2019-11-20 14:32 ` Jan Kara
2019-11-26 10:51 ` Ritesh Harjani
2019-11-26 12:45 ` Ritesh Harjani
2019-11-29 17:23 ` Jan Kara
2019-11-29 17:18 ` Jan Kara
2019-12-03 11:54 ` Ritesh Harjani
2019-12-03 12:39 ` Jan Kara
2019-12-03 13:10 ` Ritesh Harjani
2019-12-03 13:48 ` Jan Kara
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