From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joseph Qi Date: Thu, 12 Nov 2015 11:05:44 +0800 Subject: [Ocfs2-devel] Long io response time doubt Message-ID: <56440208.7070809@huawei.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ocfs2-devel@oss.oracle.com 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