Refactor git_cache to use an rwlock

This significantly reduces contention when many threads are trying to
read from the cache simultaneously.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/cache.h b/src/cache.h
index 53fbcf4e9..697123739 100644
--- a/src/cache.h
+++ b/src/cache.h
@@ -30,7 +30,7 @@ typedef struct {
 
 typedef struct {
 	git_oidmap *map;
-	git_mutex   lock;
+	git_rwlock  lock;
 	ssize_t     used_memory;
 } git_cache;