From: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
To: linux-xfs@vger.kernel.org
Cc: Dave Chinner <david@fromorbit.com>,
"Darrick J . Wong" <djwong@kernel.org>,
Christoph Hellwig <hch@infradead.org>,
Ojaswin Mujoo <ojaswin@linux.ibm.com>,
Ritesh Harjani <ritesh.list@gmail.com>
Subject: [PATCHv3 0/1] xfs: soft lockups in unmapping and reflink remapping path
Date: Tue, 7 May 2024 10:43:06 +0530 [thread overview]
Message-ID: <cover.1715057896.git.ritesh.list@gmail.com> (raw)
Hello,
In one of the testcases, parallel async dio writes to a file generates
large no. of extents (upto 2M or more), and then this file is cleaned up for
running other I/O tests. In the process of deleting this file, soft lockup
messages are observed. We believe this is happening due to kernel being busy
in unmapping/freeing those extents as part of the transaction processing.
This is similar observation with the same call stack which was also reported
here [1]. I also tried the qemu-img bench testcase shared in [1], and I was
able to reproduce the soft lockup with that on Power.
Similarly another instance was reported where xfs reflink remapping path also
saw a similar softlockup problem while iterating over deferrd work items
in xfs_trans_commit() -> xfs_defer_finish_noroll().
So as I understood from that discussion [1], that kernel is moving towards a new
preemption model, but IIUC, it is still an ongoing work.
Also IMHO, this is still a problem in upstream and in older stable kernels
which we still do support and such a fix might still be necessary for them.
This patch fixes the softlockup warning for both of the callstacks.
v2 -> v3:
Move cond_resched within xfs_defer_finish_noroll() loop
[v2]: https://lore.kernel.org/linux-xfs/cover.1714033516.git.ritesh.list@gmail.com/
Ritesh Harjani (IBM) (1):
xfs: Add cond_resched to xfs_defer_finish_noroll
fs/xfs/libxfs/xfs_defer.c | 1 +
1 file changed, 1 insertion(+)
--
2.44.0
next reply other threads:[~2024-05-07 5:13 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-07 5:13 Ritesh Harjani (IBM) [this message]
2024-05-07 5:13 ` [PATCHv3 1/1] xfs: Add cond_resched to xfs_defer_finish_noroll Ritesh Harjani (IBM)
2024-05-07 6:06 ` Dave Chinner
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