[PATCH-v2 2/4] staging/lustre/obdclass: convert lu_object shrinker to count/scan API

From: mail-agent-noreply
Date: Wed Jul 24 2013 - 06:25:03 EST


From: Peng Tao <bergwolf@xxxxxxxxx>

convert lu_object shrinker to new count/scan API.

Signed-off-by: Peng Tao <tao.peng@xxxxxxx>
Signed-off-by: Andreas Dilger <andreas.dilger@xxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Cc: Dave Chinner <dchinner@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/staging/lustre/lustre/obdclass/lu_object.c | 98 ++++++++++---------
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 ce0444f..a57d8fb 100644
--- a/drivers/staging/lustre/lustre/obdclass/lu_object.c
+++ b/drivers/staging/lustre/lustre/obdclass/lu_object.c
@@ -1780,7 +1780,6 @@ 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;
@@ -1836,61 +1835,68 @@ 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.
*/
@@ -1914,6 +1920,12 @@ 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.
*/
@@ -1948,9 +1960,7 @@ 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;
}
@@ -1960,11 +1970,7 @@ 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);

/*
--
1.7.1

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