[LU-14756] Single use LDLM locks for lockahed Created: 10/Jun/21 Updated: 10/Jun/21 |
|
| Status: | Open |
| Project: | Lustre |
| Component/s: | None |
| Affects Version/s: | None |
| Fix Version/s: | None |
| Type: | Improvement | Priority: | Minor |
| Reporter: | Patrick Farrell | Assignee: | Patrick Farrell |
| Resolution: | Unresolved | Votes: | 0 |
| Labels: | None | ||
| Rank (Obsolete): | 9223372036854775807 |
| Description |
|
Today, all LDLM locks created by lockahead are cached after use. In many situations, this is not desirable - The application or library using them only expects to use them once. The main negative side effect of this caching is that the locks pile up, and then may all need to be flushed rapidly, such as when a file is deleted, or if data is ready from a different node where it was written. This can induce significant delays. It would be much better to create the option of locks which remain in cache until used once, then do not return to cache. This can be done fairly easily with a new LDLM flag, accessible via the flags on ladvise requests. |
| Comments |
| Comment by Gerrit Updater [ 10/Jun/21 ] |
|
Patrick Farrell (farr0186@gmail.com) uploaded a new patch: https://review.whamcloud.com/43975 |
| Comment by Patrick Farrell [ 10/Jun/21 ] |
|
This is a generic improvement to lockahead, but this also has some potential applications for some ideas I have for improving unusual i/o patterns. Those ideas may never actually happen, but this improvement is relatively simple & should be beneficial to users of lockahead, so it's still worth having. |