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Diffstat (limited to 'libglusterfs/src/gidcache.h')
| -rw-r--r-- | libglusterfs/src/gidcache.h | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/libglusterfs/src/gidcache.h b/libglusterfs/src/gidcache.h new file mode 100644 index 000000000..f904f26eb --- /dev/null +++ b/libglusterfs/src/gidcache.h @@ -0,0 +1,52 @@ +/* + Copyright (c) 2008-2012 Red Hat, Inc. <http://www.redhat.com> + This file is part of GlusterFS. + + This file is licensed to you under your choice of the GNU Lesser + General Public License, version 3 or any later version (LGPLv3 or + later), or the GNU General Public License, version 2 (GPLv2), in all + cases as published by the Free Software Foundation. +*/ + +#ifndef __GIDCACHE_H__ +#define __GIDCACHE_H__ + +#include "glusterfs.h" +#include "locking.h" + +/* + * TBD: make the cache size tunable + * + * The current size represents a pretty trivial amount of memory, and should + * provide good hit rates even for quite busy systems. If we ever want to + * support really large cache sizes, we'll need to do dynamic allocation + * instead of just defining an array within a private structure. It doesn't make + * a whole lot of sense to change the associativity, because it won't improve + * hit rates all that much and will increase the maintenance cost as we have + * to scan more entries with every lookup/update. + */ + +#define AUX_GID_CACHE_ASSOC 4 +#define AUX_GID_CACHE_BUCKETS 256 +#define AUX_GID_CACHE_SIZE (AUX_GID_CACHE_ASSOC * AUX_GID_CACHE_BUCKETS) + +typedef struct { + uint64_t gl_id; + int gl_count; + gid_t *gl_list; + time_t gl_deadline; +} gid_list_t; + +typedef struct { + gf_lock_t gc_lock; + uint32_t gc_max_age; + unsigned int gc_nbuckets; + gid_list_t gc_cache[AUX_GID_CACHE_SIZE]; +} gid_cache_t; + +int gid_cache_init(gid_cache_t *, uint32_t); +const gid_list_t *gid_cache_lookup(gid_cache_t *, uint64_t); +void gid_cache_release(gid_cache_t *, const gid_list_t *); +int gid_cache_add(gid_cache_t *, gid_list_t *); + +#endif /* __GIDCACHE_H__ */ |