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>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 52 insertions, 46 deletions

diff --git a/drivers/staging/lustre/lustre/obdclass/lu_object.c b/drivers/staging/lustre/lustre/obdclass/lu_object.c
index c29ac1c2defd..3a3d5bc5a628 100644
--- a/drivers/staging/lustre/lustre/obdclass/lu_object.c
+++ b/drivers/staging/lustre/lustre/obdclass/lu_object.c
@@ -1779,7 +1779,6 @@ 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;
@@ -1835,61 +1834,68 @@ 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.
  */
@@ -1913,6 +1919,12 @@ 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.
  */
@@ -1947,9 +1959,7 @@ 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;
 }
@@ -1959,11 +1969,7 @@ 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);
 
         /*