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| Who | When | What | Removed | Added |
|---|---|---|---|---|
| Red Hat One Jira (issues.redhat.com) | 2023-01-05 03:31:23 UTC | Link ID | Red Hat Issue Tracker RHCEPH-5885 | |
| Xiubo Li | 2023-01-05 03:48:17 UTC | Link ID | Ceph Project Bug Tracker 58000 | |
| Xiubo Li | 2023-01-05 03:49:29 UTC | Severity | unspecified | low |
| Xiubo Li | 2023-01-05 03:51:29 UTC | Status | NEW | ASSIGNED |
| Greg Farnum | 2023-01-05 14:57:12 UTC | Assignee | nobody | xiubli |
| CC | gfarnum | |||
| Red Hat Bugzilla | 2023-01-09 08:29:49 UTC | CC | ceph-eng-bugs | |
| Alasdair Kergon | 2023-01-09 19:43:36 UTC | CC | ceph-eng-bugs | |
| Xiubo Li | 2023-04-10 13:40:29 UTC | Status | ASSIGNED | MODIFIED |
| Keywords | Rebase | |||
| Hemanth Kumar | 2023-04-12 07:10:33 UTC | CC | hyelloji | |
| Hemanth Kumar | 2023-04-12 07:10:51 UTC | QA Contact | hyelloji | |
| errata-xmlrpc | 2023-07-11 20:46:38 UTC | Fixed In Version | ceph-17.2.6-84.el9cp | |
| CC | tserlin | |||
| Status | MODIFIED | ON_QA | ||
| Akash Raj | 2023-07-13 17:36:52 UTC | CC | akraj | |
| Flags | needinfo?(xiubli) | |||
| Blocks | 2221020 | |||
| Docs Contact | akraj | |||
| Hemanth Kumar | 2023-07-13 18:09:56 UTC | Status | ON_QA | VERIFIED |
| Xiubo Li | 2023-07-14 00:51:54 UTC | Flags | needinfo?(xiubli) | |
| Doc Text | Feature: Switch the unfair Mutex lock to fair mutex. Reason: The implementations of the Mutex (e.g. std::mutex in C++) do not guarantee fairness, they do not guarantee that the lock will be acquired by threads in the order that they called the lock(). In most case this works well, but in overload case the client requests handling thread and _submit_thread could always successfully acquire the submit_mutex in a long time, which could make the MDLog::trim() get stuck. That means the MDS daemons will fill journal logs into the metadata pool, but couldn't trim the expired segments in time. This will switch the submit_mutex to fair mutex and it could make sure that the all the submit_mutex waiters are in FIFO order and could get a change to be excuted in time. Result: All the waiters will be woke up one by one in FIFO mode. | |||
| Doc Type | If docs needed, set a value | Enhancement | ||
| Akash Raj | 2023-07-14 10:58:33 UTC | Doc Text | Feature: Switch the unfair Mutex lock to fair mutex. Reason: The implementations of the Mutex (e.g. std::mutex in C++) do not guarantee fairness, they do not guarantee that the lock will be acquired by threads in the order that they called the lock(). In most case this works well, but in overload case the client requests handling thread and _submit_thread could always successfully acquire the submit_mutex in a long time, which could make the MDLog::trim() get stuck. That means the MDS daemons will fill journal logs into the metadata pool, but couldn't trim the expired segments in time. This will switch the submit_mutex to fair mutex and it could make sure that the all the submit_mutex waiters are in FIFO order and could get a change to be excuted in time. Result: All the waiters will be woke up one by one in FIFO mode. | .Switch the unfair Mutex lock to fair mutex Previously, the implementations of the _Mutex_, for example, `std::mutex` in _C++_, would not guarantee fairness and would not guarantee that the lock would be acquired by threads in the order called `lock()`. In most cases, this worked well but in an overloaded case, the client requests handling thread and _submit_ thread would always successfully acquire the _submit_mutex_ in a long time, causing `MDLog::trim()` to get stuck. That meant the MDS daemons would fill journal logs into the metadata pool, but could not trim the expired segments in time. With this enhancement, the unfair Mutex lock is switched to fair mutex and all the _submit_mutex_ waiters are woken up one by one in FIFO mode. |
| errata-xmlrpc | 2023-08-03 16:32:17 UTC | Status | VERIFIED | RELEASE_PENDING |
| errata-xmlrpc | 2023-08-03 16:45:09 UTC | Resolution | --- | ERRATA |
| Status | RELEASE_PENDING | CLOSED | ||
| Last Closed | 2023-08-03 16:45:09 UTC | |||
| errata-xmlrpc | 2023-08-03 16:46:06 UTC | Link ID | Red Hat Product Errata RHBA-2023:4473 |
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