From: Dongli Zhang <dongli.zhang@oracle.com>
To: <linux-ext4@vger.kernel.org>
Cc: Joe Jin <joe.jin@oracle.com>, Junxiao Bi <junxiao.bi@oracle.com>
Subject: Why jbd2 might freeze in kjournald2()
Date: Wed, 23 Jan 2019 06:32:12 -0800 (PST) [thread overview]
Message-ID: <73b3ad85-9d29-40a1-b94f-80be35e6c26b@default> (raw)
Hi,
I am writing to ask why jbd2 might freeze in kjournald2()?
I am asking this because since blk-mq commit bc27c01b5c46 (blk-mq: Do not
invoke .queue_rq() for a stopped queue), the I/O request will be queued
when the queue is stopped, that is, when OS is frozen (e.g., during xen
live migration or "echo freeze > /sys/power/state" in kvm guest). I think
it should be fine to not freeze jbd2.
Why would kjournald2() freeze to avoid submitting I/O?
Is it because of what is mentioned in code that "The simpler the better",
or there is any other reason?
Thank you very much!
Dongli Zhang
reply other threads:[~2019-01-23 14:32 UTC|newest]
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