staging/lustre/obdclass: convert lu_object shrinker to count/scan API

convert lu_object shrinker to new count/scan API.

Signed-off-by: Peng Tao <tao.peng@emc.com>
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/drivers/staging/lustre/lustre/obdclass/lu_object.c b/drivers/staging/lustre/lustre/obdclass/lu_object.c
index fdf0ed3676939bc1fbc8755704c7eccf37047909..1b88a747242d2cc129fef02c8198b611d43c2009 100644 (file)
--- a/drivers/staging/lustre/lustre/obdclass/lu_object.c
+++ b/drivers/staging/lustre/lustre/obdclass/lu_object.c
@@ -1783,7 +1783,6 @@ int lu_env_refill_by_tags(struct lu_env *env, __u32 ctags,
 }
 EXPORT_SYMBOL(lu_env_refill_by_tags);
 
-static struct shrinker *lu_site_shrinker = NULL;
 
 typedef struct lu_site_stats{
        unsigned        lss_populated;
@@ -1839,61 +1838,68 @@ static void lu_site_stats_get(cfs_hash_t *hs,
  * objects without taking the  lu_sites_guard lock, but this is not
  * possible in the current implementation.
  */
-static int lu_cache_shrink(SHRINKER_ARGS(sc, nr_to_scan, gfp_mask))
+static unsigned long lu_cache_shrink_count(struct shrinker *sk,
+                                          struct shrink_control *sc)
 {
        lu_site_stats_t stats;
        struct lu_site *s;
        struct lu_site *tmp;
-       int cached = 0;
-       int remain = shrink_param(sc, nr_to_scan);
-       LIST_HEAD(splice);
-
-       if (!(shrink_param(sc, gfp_mask) & __GFP_FS)) {
-               if (remain != 0)
-                       return -1;
-               else
-                       /* We must not take the lu_sites_guard lock when
-                        * __GFP_FS is *not* set because of the deadlock
-                        * possibility detailed above. Additionally,
-                        * since we cannot determine the number of
-                        * objects in the cache without taking this
-                        * lock, we're in a particularly tough spot. As
-                        * a result, we'll just lie and say our cache is
-                        * empty. This _should_ be ok, as we can't
-                        * reclaim objects when __GFP_FS is *not* set
-                        * anyways.
-                        */
-                       return 0;
-       }
+       unsigned long cached = 0;
 
-       CDEBUG(D_INODE, "Shrink %d objects\n", remain);
+       if (!sc->gfp_mask & __GFP_FS)
+               return 0;
 
        mutex_lock(&lu_sites_guard);
        list_for_each_entry_safe(s, tmp, &lu_sites, ls_linkage) {
-               if (shrink_param(sc, nr_to_scan) != 0) {
-                       remain = lu_site_purge(&lu_shrink_env, s, remain);
-                       /*
-                        * Move just shrunk site to the tail of site list to
-                        * assure shrinking fairness.
-                        */
-                       list_move_tail(&s->ls_linkage, &splice);
-               }
-
                memset(&stats, 0, sizeof(stats));
                lu_site_stats_get(s->ls_obj_hash, &stats, 0);
                cached += stats.lss_total - stats.lss_busy;
-               if (shrink_param(sc, nr_to_scan) && remain <= 0)
-                       break;
        }
-       list_splice(&splice, lu_sites.prev);
        mutex_unlock(&lu_sites_guard);
 
        cached = (cached / 100) * sysctl_vfs_cache_pressure;
-       if (shrink_param(sc, nr_to_scan) == 0)
-               CDEBUG(D_INODE, "%d objects cached\n", cached);
+       CDEBUG(D_INODE, "%ld objects cached\n", cached);
        return cached;
 }
 
+static unsigned long lu_cache_shrink_scan(struct shrinker *sk,
+                                         struct shrink_control *sc)
+{
+       struct lu_site *s;
+       struct lu_site *tmp;
+       unsigned long remain = sc->nr_to_scan, freed = 0;
+       LIST_HEAD(splice);
+
+       if (!sc->gfp_mask & __GFP_FS)
+               /* We must not take the lu_sites_guard lock when
+                * __GFP_FS is *not* set because of the deadlock
+                * possibility detailed above. Additionally,
+                * since we cannot determine the number of
+                * objects in the cache without taking this
+                * lock, we're in a particularly tough spot. As
+                * a result, we'll just lie and say our cache is
+                * empty. This _should_ be ok, as we can't
+                * reclaim objects when __GFP_FS is *not* set
+                * anyways.
+                */
+               return SHRINK_STOP;
+
+       mutex_lock(&lu_sites_guard);
+       list_for_each_entry_safe(s, tmp, &lu_sites, ls_linkage) {
+               freed = lu_site_purge(&lu_shrink_env, s, remain);
+               remain -= freed;
+               /*
+                * Move just shrunk site to the tail of site list to
+                * assure shrinking fairness.
+                */
+               list_move_tail(&s->ls_linkage, &splice);
+       }
+       list_splice(&splice, lu_sites.prev);
+       mutex_unlock(&lu_sites_guard);
+
+       return sc->nr_to_scan - remain;
+}
+
 /*
  * Debugging stuff.
  */
@@ -1917,6 +1923,12 @@ int lu_printk_printer(const struct lu_env *env,
        return 0;
 }
 
+static struct shrinker lu_site_shrinker = {
+       .count_objects  = lu_cache_shrink_count,
+       .scan_objects   = lu_cache_shrink_scan,
+       .seeks          = DEFAULT_SEEKS,
+};
+
 /**
  * Initialization of global lu_* data.
  */
@@ -1951,9 +1963,7 @@ int lu_global_init(void)
         * inode, one for ea. Unfortunately setting this high value results in
         * lu_object/inode cache consuming all the memory.
         */
-       lu_site_shrinker = set_shrinker(DEFAULT_SEEKS, lu_cache_shrink);
-       if (lu_site_shrinker == NULL)
-               return -ENOMEM;
+       register_shrinker(&lu_site_shrinker);
 
        return result;
 }
@@ -1963,11 +1973,7 @@ int lu_global_init(void)
  */
 void lu_global_fini(void)
 {
-       if (lu_site_shrinker != NULL) {
-               remove_shrinker(lu_site_shrinker);
-               lu_site_shrinker = NULL;
-       }
-
+       unregister_shrinker(&lu_site_shrinker);
        lu_context_key_degister(&lu_global_key);
 
        /*