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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
commit | ace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch) | |
tree | b2d64bc10158fdd5497876388cd68142ca374ed3 /tools/perf/util/sharded_mutex.h | |
parent | Initial commit. (diff) | |
download | linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.tar.xz linux-ace9429bb58fd418f0c81d4c2835699bddf6bde6.zip |
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'tools/perf/util/sharded_mutex.h')
-rw-r--r-- | tools/perf/util/sharded_mutex.h | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/tools/perf/util/sharded_mutex.h b/tools/perf/util/sharded_mutex.h new file mode 100644 index 0000000000..7325e969ee --- /dev/null +++ b/tools/perf/util/sharded_mutex.h @@ -0,0 +1,29 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef PERF_SHARDED_MUTEX_H +#define PERF_SHARDED_MUTEX_H + +#include "mutex.h" +#include "hashmap.h" + +/* + * In a situation where a lock is needed per object, having a mutex can be + * relatively memory expensive (40 bytes on x86-64). If the object can be + * constantly hashed, a sharded mutex is an alternative global pool of mutexes + * where the mutex is looked up from a hash value. This can lead to collisions + * if the number of shards isn't large enough. + */ +struct sharded_mutex { + /* mutexes array is 1<<cap_bits in size. */ + unsigned int cap_bits; + struct mutex mutexes[]; +}; + +struct sharded_mutex *sharded_mutex__new(size_t num_shards); +void sharded_mutex__delete(struct sharded_mutex *sm); + +static inline struct mutex *sharded_mutex__get_mutex(struct sharded_mutex *sm, size_t hash) +{ + return &sm->mutexes[hash_bits(hash, sm->cap_bits)]; +} + +#endif /* PERF_SHARDED_MUTEX_H */ |