LU-5108 osc: Performance tune for LRU

[fs/lustre-release.git] / lustre / include / obd.h

diff --git a/lustre/include/obd.h b/lustre/include/obd.h
index 37987ca..19e6544 100644 (file)
--- a/lustre/include/obd.h
+++ b/lustre/include/obd.h
@@ -244,16 +244,38 @@ struct client_obd {
        struct obd_histogram    cl_read_offset_hist;
        struct obd_histogram    cl_write_offset_hist;
 
-       /* lru for osc caching pages */
-       struct cl_client_cache  *cl_cache;
-       struct list_head         cl_lru_osc; /* member of cl_cache->ccc_lru */
-       atomic_long_t           *cl_lru_left;
-       atomic_long_t            cl_lru_busy;
-       atomic_long_t            cl_lru_in_list;
-       atomic_long_t            cl_unstable_count;
-       struct list_head         cl_lru_list; /* lru page list */
-       spinlock_t               cl_lru_list_lock; /* page list protector */
-       atomic_t                 cl_lru_shrinkers;
+       /** LRU for osc caching pages */
+       struct cl_client_cache  *cl_cache;
+       /** member of cl_cache->ccc_lru */
+       struct list_head         cl_lru_osc;
+       /** # of available LRU slots left in the per-OSC cache.
+        * Available LRU slots are shared by all OSCs of the same file system,
+        * therefore this is a pointer to cl_client_cache::ccc_lru_left. */
+       atomic_long_t           *cl_lru_left;
+       /** # of busy LRU pages. A page is considered busy if it's in writeback
+        * queue, or in transfer. Busy pages can't be discarded so they are not
+        * in LRU cache. */
+       atomic_long_t            cl_lru_busy;
+       /** # of LRU pages in the cache for this client_obd */
+       atomic_long_t            cl_lru_in_list;
+       /** # of threads are shrinking LRU cache. To avoid contention, it's not
+        * allowed to have multiple threads shrinking LRU cache. */
+       atomic_t                 cl_lru_shrinkers;
+       /** The time when this LRU cache was last used. */
+       time_t                   cl_lru_last_used;
+       /** stats: how many reclaims have happened for this client_obd.
+        * reclaim and shrink - shrink is async, voluntarily rebalancing;
+        * reclaim is sync, initiated by IO thread when the LRU slots are
+        * in shortage. */
+       __u64                    cl_lru_reclaim;
+       /** List of LRU pages for this client_obd */
+       struct list_head         cl_lru_list;
+       /** Lock for LRU page list */
+       spinlock_t               cl_lru_list_lock;
+       /** # of unstable pages in this client_obd.
+        * An unstable page is a page state that WRITE RPC has finished but
+        * the transaction has NOT yet committed. */
+       atomic_long_t            cl_unstable_count;
 
        /* number of in flight destroy rpcs is limited to max_rpcs_in_flight */
        atomic_t                 cl_destroy_in_flight;