https://jira.whamcloud.com This file is an XML representation of an issue en-us 9.4.14 940014 05-12-2023 https://jira.whamcloud.com/browse/LU-6433 Lustre <p>With new quota code MDS obtains quota credits via ptlrpc requests.<br/> All quota operation takes place after obtaining ldlm lock. <br/> So, with single MDS it can happen that we are run out of mdt threads to process quota request while all other mdt threads are waiting for a lock conflicting with a lock taken by a thread which is sending quota request.</p> <p>The possible solution is to serve quota requests in a HP queue. It looks like quota lock doesn't conflicts, so quota intends can be processed in a HP queue also. </p> LU-6433

MDS deadlock in qouta

Bug Minor Resolved Fixed Niu Yawei Andriy Skulysh patch Mon, 6 Apr 2015 13:01:59 +0000 Thu, 9 Feb 2017 17:12:40 +0000 Fri, 10 Jul 2015 12:03:01 +0000 Lustre 2.8.0 0 9 <p>Andriy Skulysh (andriy.skulysh@seagate.com) uploaded a new patch: <a href="http://review.whamcloud.com/14369" class="external-link" target="_blank" rel="nofollow noopener">http://review.whamcloud.com/14369</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-6433" title="MDS deadlock in qouta " class="issue-link" data-issue-key="LU-6433"><del>LU-6433</del></a> quota: handle QUOTA_DQACQ in hp queue<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: 1<br/> Commit: a4fde3781061b33d660dccb6499469cac6ca1d25</p> <p>patch: <a href="http://review.whamcloud.com/14369" class="external-link" target="_blank" rel="nofollow noopener">http://review.whamcloud.com/14369</a></p> <p>This looks like a livelock problem to me, I don't quite see why adding the quota request to HP list is helpful. I think we usually use different portal (and thread set) to handle such problem, probably we'd introduce a new portal for quota requests?</p> <p>The patch helps because there is always an free HP thread to handle quota request even if all other MDS threads are waiting for a lock. Different portal is more general and complex solution. Is it needed in this case ?</p> <p>Using different portal looks simpler and cleaner to me, actually, I think we can just reuse the READPAGE portal for dqacq request. (or only redirect the synchronous dqacq to the readpage portal).</p> <p>Code review (and landing) of <a href="http://review.whamcloud.com/14369" class="external-link" target="_blank" rel="nofollow noopener">http://review.whamcloud.com/14369</a> was raised to the OpenSFS LWG on 7/1. What blocks this patch from landing?</p> <p>Oleg Drokin (oleg.drokin@intel.com) merged in patch <a href="http://review.whamcloud.com/14369/" class="external-link" target="_blank" rel="nofollow noopener">http://review.whamcloud.com/14369/</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-6433" title="MDS deadlock in qouta " class="issue-link" data-issue-key="LU-6433"><del>LU-6433</del></a> quota: handle QUOTA_DQACQ in READPAGE portal<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: <br/> Commit: 471ad1f679ad7c0193785f82abf6f249ffeb1e79</p> <p>Landed for 2.8</p> Related LU-7926 Development Rank 1|hzxa73: Rank (Obsolete) 9223372036854775807 Severity