Currently, opr_cache_init requires that opts->n_buckets is a power of
2 (since our underlying opr_dict requires this). However, callers may
want to pick a number of buckets based on some other value. Requiring
each caller to calculate the nearest power-of-2 is annoying, so
instead just have opr_cache_init itself calculate a nearby power of 2.
That is, with this commit, opts->n_buckets is allowed to not be a
power of 2; when it's not a power of 2, opr_cache_init will calculate
the next highest power of 2 and use that as the number of buckets.
Change-Id: Icd3c56c1fe0733e3dac964ea9a98ff7b436254e6
Reviewed-on: https://gerrit.openafs.org/14122
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Marcio Brito Barbosa <mbarbosa@sinenomine.net>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
Add a simple general-purpose in-memory cache implementation, called
opr_cache. Keys and values are simple flat opaque buffers (no complex
nested structures allowed), hashing is done with jhash, and cache
eviction is mostly random with some LRU bias.
Partly based off a different implementation by
mbarbosa@sinenomine.net.
Change-Id: I16b5988947ff603dfe31613cd7be3908a69264e5
Reviewed-on: https://gerrit.openafs.org/13884
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
