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  1. Lustre
  2. LU-11509

LDLM: replace client lock LRU with improved cache algorithm

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Details

    • Improvement
    • Resolution: Unresolved
    • Major
    • Lustre 2.17.0
    • None
    • 9223372036854775807

    Description

      The LDLM LRU algorithm is sub-optimal for managing locks on the client, since it can flush often-used locks when there are a large number of files accessed in a short time (e.g. filesystem scanning). It would be better to implement a more sophisticated cache mechanism, such as ARC, LFRU, or similar (see https://en.wikipedia.org/wiki/Cache_replacement_policies) that includes a frequency count on the lock in addition to only the age of the lock. That will ensure that more important top-level locks are more likely to stay on the client instead of getting flushed.

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        Issue Links

          is related to

          Bug - A problem which impairs or prevents the functions of the product. LU-7266 Fix LDLM pool to make LRUR working properly

          • Critical - Crashes, loss of data, severe memory leak.
          • Open

          New Feature - A new feature of the product, which has yet to be developed. LU-10602 Add file heat support for Persistent Client Cache

          • Minor - Minor loss of function, or other problem where easy workaround is present.
          • Open

          New Feature - A new feature of the product, which has yet to be developed. LU-17329 Relaxed POSIX Consistency for Lustre

          • Minor - Minor loss of function, or other problem where easy workaround is present.
          • Open

          Improvement - An improvement or enhancement to an existing feature or task. LU-17493 restore LDLM cancel on blocking callback

          • Major - Major loss of function.
          • Open

          Improvement - An improvement or enhancement to an existing feature or task. LU-14517 Decrease default lru_max_age value

          • Minor - Minor loss of function, or other problem where easy workaround is present.
          • Resolved
          is related to

          Bug - A problem which impairs or prevents the functions of the product. LU-6529 Server side lock limits to avoid unnecessary memory exhaustion

          • Critical - Crashes, loss of data, severe memory leak.
          • Closed

          Bug - A problem which impairs or prevents the functions of the product. LU-14221 Client hangs when using DoM with a fixed mdc lru_size

          • Major - Major loss of function.
          • Closed

          Improvement - An improvement or enhancement to an existing feature or task. LU-17428 reduce default value for lru_max_age to 300s

          • Minor - Minor loss of function, or other problem where easy workaround is present.
          • Resolved

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              dekisugi Kiet Tuan Pham
              adilger Andreas Dilger
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              Dates

                Created:
                Updated: