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cosmetic: comment describing negative lookup caching

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/* negative lookup caching
 *
 * by caching lookups that result in NOENT, we can avoid sending subsequent
 * lookups over the wire.  a name cache entry is negative when its attributes
 * pointer is NULL.  negative entries are created by three functions:
 * nfs41_name_cache_remove(), _insert() when called with NULL for the fh and
 * attributes, and _rename() for the source entry
 */

Signed-off-by: Casey Bodley <cbodley@umich.edu>
This commit is contained in:
Casey Bodley 2010-10-11 16:08:21 -04:00
parent 794dfeca49
commit 7db2d60c3b
1 changed files with 10 additions and 0 deletions
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10
daemon/name_cache.c
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@ -38,11 +38,21 @@ enum {
NCLVL2 NCLVL2
}; };
#define NAME_CACHE_EXPIRATION 20 /* TODO: get from configuration */ #define NAME_CACHE_EXPIRATION 20 /* TODO: get from configuration */
/* allow up to 128K of memory for name and attribute cache entries */ /* allow up to 128K of memory for name and attribute cache entries */
#define NAME_CACHE_MAX_SIZE 131072 #define NAME_CACHE_MAX_SIZE 131072
/* negative lookup caching
*
* by caching lookups that result in NOENT, we can avoid sending subsequent
* lookups over the wire. a name cache entry is negative when its attributes
* pointer is NULL. negative entries are created by three functions:
* nfs41_name_cache_remove(), _insert() when called with NULL for the fh and
* attributes, and _rename() for the source entry
*/
/* attribute cache */ /* attribute cache */
struct attr_cache_entry { struct attr_cache_entry {