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From: Joseph Qi <joseph.qi@huawei.com>
To: ocfs2-devel@oss.oracle.com
Subject: [Ocfs2-devel] Long io response time doubt
Date: Thu, 12 Nov 2015 11:05:44 +0800	[thread overview]
Message-ID: <56440208.7070809@huawei.com> (raw)

Hi Eric,
You reported an issue about sometime io response time may be long.

From your test case information, I think it was caused by downconvert.
And it seemed reasonable because it had to.

Node 1 wrote file, and node 2 read it. Since you used buffer io, that
was after node 1 had finished written, it might be still in page cache.
So node 1 should downconvert first then node 2 read could continue.
That was why you said it seemed ocfs2_inode_lock_with_page spent most
time. More specifically, it was ocfs2_inode_lock after trying nonblock
lock and returning -EAGAIN.

And this also explained why direct io didn't have the issue, but took
more time.

I am not sure if your test case is the same as what the customer has
reported. I think you should recheck the operations in each node.

And we have reported an case before about DLM handling issue. I am not
sure if it has relations.
https://oss.oracle.com/pipermail/ocfs2-devel/2015-August/011045.html

             reply	other threads:[~2015-11-12  3:05 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-12  3:05 Joseph Qi [this message]
2015-11-12  7:23 ` [Ocfs2-devel] Long io response time doubt Eric Ren
2015-11-12  8:00   ` Joseph Qi
2015-11-12  9:48     ` Eric Ren
2015-11-13  3:31       ` Joseph Qi
2015-11-14  5:23         ` Eric Ren
2015-11-16  1:40           ` Joseph Qi
2015-11-24 10:02             ` Eric Ren
2015-11-24 10:05               ` Eric Ren
2015-11-26  1:34                 ` Joseph Qi
2015-11-26  1:49                   ` Eric Ren

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