From: Ojaswin Mujoo <ojaswin@linux.ibm.com>
To: linux-ext4@vger.kernel.org, "Theodore Ts'o" <tytso@mit.edu>
Cc: Ritesh Harjani <ritesh.list@gmail.com>,
linux-kernel@vger.kernel.org, Jan Kara <jack@suse.cz>,
glandvador@yahoo.com, bugzilla@eyal.emu.id.au
Subject: [PATCH 0/1] Fix for recent bugzilla reports related to long halts during block allocation
Date: Fri, 15 Dec 2023 16:49:49 +0530 [thread overview]
Message-ID: <cover.1702455010.git.ojaswin@linux.ibm.com> (raw)
This patch intends to fix the recent bugzilla [1] report where the
kworker flush thread seemed to be taking 100% CPU utilizationa and was
slowing down the whole system. The backtrace indicated that we were
stuck in mballoc allocation path. The issue was only seen kernel 6.5+
and when ext4 was mounted with -o stripe (or stripe option was
implicitly added due us mkfs flags used).
Although I was not able to fully replicate this issue, from the perf
probe logs collected I have a possible root cause which I have explained
in the patch commit message.
Now, the one thing I'm still skeptical about is why this was only seen
in kernel 6.5+. We added a new mballoc criteria in kernel 6.5 but I was
not able to find a satisfactory explanation as to why that would have
any effect here. Furter, the issue still persisted when I asked one of
the reporters to disable the it using sysfs file and rerun the test.
Maybe there are some more factors at play?
Anyways, I would appreciate if the people experiencing this issue can
help test this patch and see if it fixes the regression.
[1] https://bugzilla.kernel.org/show_bug.cgi?id=217965
Regards,
ojaswin
Ojaswin Mujoo (1):
ext4: fallback to complex scan if aligned scan doesn't work
fs/ext4/mballoc.c | 21 +++++++++++++--------
1 file changed, 13 insertions(+), 8 deletions(-)
--
2.39.3
next reply other threads:[~2023-12-15 11:20 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-15 11:19 Ojaswin Mujoo [this message]
2023-12-15 11:19 ` [PATCH 1/1] ext4: fallback to complex scan if aligned scan doesn't work Ojaswin Mujoo
2024-01-04 15:27 ` Jan Kara
2024-01-09 9:40 ` Ojaswin Mujoo
2024-01-09 2:53 ` [PATCH 0/1] Fix for recent bugzilla reports related to long halts during block allocation Theodore Ts'o
2024-03-20 16:52 ` Frederick Lawler
2024-03-22 8:31 ` Ojaswin Mujoo
2024-03-25 18:12 ` Frederick Lawler
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