staging/lustre: convert to new shrinker API

index 101af4b..9ac7e4d 100644
@@ -524,7 +524,7 @@ static int ldlm_cli_pool_shrink(struct ldlm_pool *pl,
 				int nr, unsigned int gfp_mask)
 {
 	struct ldlm_namespace *ns;
-	int canceled = 0, unused;
+	int unused;
 
 	ns = ldlm_pl2ns(pl);
 

@@ -543,14 +543,10 @@ static int ldlm_cli_pool_shrink(struct ldlm_pool *pl,
 	unused = ns->ns_nr_unused;
 	spin_unlock(&ns->ns_lock);
 
-	if (nr) {
-		canceled = ldlm_cancel_lru(ns, nr, LCF_ASYNC,
-					   LDLM_CANCEL_SHRINK);
-	}
-	/*
-	 * Return the number of potentially reclaimable locks.
-	 */
-	return ((unused - canceled) / 100) * sysctl_vfs_cache_pressure;
+	if (nr == 0)
+		return (unused / 100) * sysctl_vfs_cache_pressure;
+	else
+		return ldlm_cancel_lru(ns, nr, LCF_ASYNC, LDLM_CANCEL_SHRINK);
 }
 
 struct ldlm_pool_ops ldlm_srv_pool_ops = {

@@ -604,9 +600,10 @@ int ldlm_pool_recalc(struct ldlm_pool *pl)
 	return recalc_interval_sec;
 }
 
-/**
+/*
  * Pool shrink wrapper. Will call either client or server pool recalc callback
- * depending what pool \a pl is used.
+ * depending what pool pl is used. When nr == 0, just return the number of
+ * freeable locks. Otherwise, return the number of canceled locks.
  */
 int ldlm_pool_shrink(struct ldlm_pool *pl, int nr,
 		     unsigned int gfp_mask)

@@ -1025,29 +1022,24 @@ static int ldlm_pool_granted(struct ldlm_pool *pl)
 }
 
 static struct ptlrpc_thread *ldlm_pools_thread;
-static struct shrinker *ldlm_pools_srv_shrinker;
-static struct shrinker *ldlm_pools_cli_shrinker;
 static struct completion ldlm_pools_comp;
 
 /*
- * Cancel \a nr locks from all namespaces (if possible). Returns number of
- * cached locks after shrink is finished. All namespaces are asked to
- * cancel approximately equal amount of locks to keep balancing.
+ * count locks from all namespaces (if possible). Returns number of
+ * cached locks.
  */
-static int ldlm_pools_shrink(ldlm_side_t client, int nr,
-			     unsigned int gfp_mask)
+static unsigned long ldlm_pools_count(ldlm_side_t client, unsigned int gfp_mask)
 {
-	int total = 0, cached = 0, nr_ns;
+	int total = 0, nr_ns;
 	struct ldlm_namespace *ns;
 	struct ldlm_namespace *ns_old = NULL; /* loop detection */
 	void *cookie;
 
-	if (client == LDLM_NAMESPACE_CLIENT && nr != 0 &&
-	    !(gfp_mask & __GFP_FS))
-		return -1;
+	if (client == LDLM_NAMESPACE_CLIENT && !(gfp_mask & __GFP_FS))
+		return 0;
 
-	CDEBUG(D_DLMTRACE, "Request to shrink %d %s locks from all pools\n",
-	       nr, client == LDLM_NAMESPACE_CLIENT ? "client" : "server");
+	CDEBUG(D_DLMTRACE, "Request to count %s locks from all pools\n",
+	       client == LDLM_NAMESPACE_CLIENT ? "client" : "server");
 
 	cookie = cl_env_reenter();
 

@@ -1055,8 +1047,7 @@ static int ldlm_pools_shrink(ldlm_side_t client, int nr,
 	 * Find out how many resources we may release.
 	 */
 	for (nr_ns = ldlm_namespace_nr_read(client);
-	     nr_ns > 0; nr_ns--)
-	{
+	     nr_ns > 0; nr_ns--) {
 		mutex_lock(ldlm_namespace_lock(client));
 		if (list_empty(ldlm_namespace_list(client))) {
 			mutex_unlock(ldlm_namespace_lock(client));

@@ -1086,17 +1077,27 @@ static int ldlm_pools_shrink(ldlm_side_t client, int nr,
 		ldlm_namespace_put(ns);
 	}
 
-	if (nr == 0 || total == 0) {
-		cl_env_reexit(cookie);
-		return total;
-	}
+	cl_env_reexit(cookie);
+	return total;
+}
+
+static unsigned long ldlm_pools_scan(ldlm_side_t client, int nr, unsigned int gfp_mask)
+{
+	unsigned long freed = 0;
+	int tmp, nr_ns;
+	struct ldlm_namespace *ns;
+	void *cookie;
+
+	if (client == LDLM_NAMESPACE_CLIENT && !(gfp_mask & __GFP_FS))
+		return -1;
+
+	cookie = cl_env_reenter();
 
 	/*
-	 * Shrink at least ldlm_namespace_nr(client) namespaces.
+	 * Shrink at least ldlm_namespace_nr_read(client) namespaces.
 	 */
-	for (nr_ns = ldlm_namespace_nr_read(client) - nr_ns;
-	     nr_ns > 0; nr_ns--)
-	{
+	for (tmp = nr_ns = ldlm_namespace_nr_read(client);
+	     tmp > 0; tmp--) {
 		int cancel, nr_locks;
 
 		/*

@@ -1105,12 +1106,6 @@ static int ldlm_pools_shrink(ldlm_side_t client, int nr,
 		mutex_lock(ldlm_namespace_lock(client));
 		if (list_empty(ldlm_namespace_list(client))) {
 			mutex_unlock(ldlm_namespace_lock(client));
-			/*
-			 * If list is empty, we can't return any @cached > 0,
-			 * that probably would cause needless shrinker
-			 * call.
-			 */
-			cached = 0;
 			break;
 		}
 		ns = ldlm_namespace_first_locked(client);

@@ -1119,29 +1114,42 @@ static int ldlm_pools_shrink(ldlm_side_t client, int nr,
 		mutex_unlock(ldlm_namespace_lock(client));
 
 		nr_locks = ldlm_pool_granted(&ns->ns_pool);
-		cancel = 1 + nr_locks * nr / total;
-		ldlm_pool_shrink(&ns->ns_pool, cancel, gfp_mask);
-		cached += ldlm_pool_granted(&ns->ns_pool);
+		/*
+		 * We use to shrink propotionally but with new shrinker API,
+		 * we lost the total number of freeable locks.
+		 */
+		cancel = 1 + min_t(int, nr_locks, nr / nr_ns);
+		freed += ldlm_pool_shrink(&ns->ns_pool, cancel, gfp_mask);
 		ldlm_namespace_put(ns);
 	}
 	cl_env_reexit(cookie);
-	/* we only decrease the SLV in server pools shrinker, return -1 to
-	 * kernel to avoid needless loop. LU-1128 */
-	return (client == LDLM_NAMESPACE_SERVER) ? -1 : cached;
+	/*
+	 * we only decrease the SLV in server pools shrinker, return
+	 * SHRINK_STOP to kernel to avoid needless loop. LU-1128
+	 */
+	return (client == LDLM_NAMESPACE_SERVER) ? SHRINK_STOP : freed;
+}
+
+static unsigned long ldlm_pools_srv_count(struct shrinker *s, struct shrink_control *sc)
+{
+	return ldlm_pools_count(LDLM_NAMESPACE_SERVER, sc->gfp_mask);
 }
 
-static int ldlm_pools_srv_shrink(SHRINKER_ARGS(sc, nr_to_scan, gfp_mask))
+static unsigned long ldlm_pools_srv_scan(struct shrinker *s, struct shrink_control *sc)
 {
-	return ldlm_pools_shrink(LDLM_NAMESPACE_SERVER,
-				 shrink_param(sc, nr_to_scan),
-				 shrink_param(sc, gfp_mask));
+	return ldlm_pools_scan(LDLM_NAMESPACE_SERVER, sc->nr_to_scan,
+			       sc->gfp_mask);
 }
 
-static int ldlm_pools_cli_shrink(SHRINKER_ARGS(sc, nr_to_scan, gfp_mask))
+static unsigned long ldlm_pools_cli_count(struct shrinker *s, struct shrink_control *sc)
 {
-	return ldlm_pools_shrink(LDLM_NAMESPACE_CLIENT,
-				 shrink_param(sc, nr_to_scan),
-				 shrink_param(sc, gfp_mask));
+	return ldlm_pools_count(LDLM_NAMESPACE_CLIENT, sc->gfp_mask);
+}
+
+static unsigned long ldlm_pools_cli_scan(struct shrinker *s, struct shrink_control *sc)
+{
+	return ldlm_pools_scan(LDLM_NAMESPACE_CLIENT, sc->nr_to_scan,
+			       sc->gfp_mask);
 }
 
 int ldlm_pools_recalc(ldlm_side_t client)

@@ -1224,7 +1232,7 @@ int ldlm_pools_recalc(ldlm_side_t client)
 	}
 
 	/*
-	 * Recalc at least ldlm_namespace_nr(client) namespaces.
+	 * Recalc at least ldlm_namespace_nr_read(client) namespaces.
 	 */
 	for (nr = ldlm_namespace_nr_read(client); nr > 0; nr--) {
 		int     skip;

@@ -1397,6 +1405,18 @@ static void ldlm_pools_thread_stop(void)
 	EXIT;
 }
 
+static struct shrinker ldlm_pools_srv_shrinker = {
+	.count_objects	= ldlm_pools_srv_count,
+	.scan_objects	= ldlm_pools_srv_scan,
+	.seeks		= DEFAULT_SEEKS,
+};
+
+static struct shrinker ldlm_pools_cli_shrinker = {
+	.count_objects	= ldlm_pools_cli_count,
+	.scan_objects	= ldlm_pools_cli_scan,
+	.seeks		= DEFAULT_SEEKS,
+};
+
 int ldlm_pools_init(void)
 {
 	int rc;

@@ -1404,12 +1424,8 @@ int ldlm_pools_init(void)
 
 	rc = ldlm_pools_thread_start();
 	if (rc == 0) {
-		ldlm_pools_srv_shrinker =
-			set_shrinker(DEFAULT_SEEKS,
-					 ldlm_pools_srv_shrink);
-		ldlm_pools_cli_shrinker =
-			set_shrinker(DEFAULT_SEEKS,
-					 ldlm_pools_cli_shrink);
+		register_shrinker(&ldlm_pools_srv_shrinker);
+		register_shrinker(&ldlm_pools_cli_shrinker);
 	}
 	RETURN(rc);
 }

@@ -1417,14 +1433,8 @@ EXPORT_SYMBOL(ldlm_pools_init);
 
 void ldlm_pools_fini(void)
 {
-	if (ldlm_pools_srv_shrinker != NULL) {
-		remove_shrinker(ldlm_pools_srv_shrinker);
-		ldlm_pools_srv_shrinker = NULL;
-	}
-	if (ldlm_pools_cli_shrinker != NULL) {
-		remove_shrinker(ldlm_pools_cli_shrinker);
-		ldlm_pools_cli_shrinker = NULL;
-	}
+	unregister_shrinker(&ldlm_pools_srv_shrinker);
+	unregister_shrinker(&ldlm_pools_cli_shrinker);
 	ldlm_pools_thread_stop();
 }
 EXPORT_SYMBOL(ldlm_pools_fini);

index ce0444f..a57d8fb 100644
@@ -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);
 
 	/*

index 9013745..e90c8fb 100644
@@ -121,13 +121,6 @@ static struct ptlrpc_enc_page_pool {
 } page_pools;
 
 /*
- * memory shrinker
- */
-const int pools_shrinker_seeks = DEFAULT_SEEKS;
-static struct shrinker *pools_shrinker = NULL;
-
-
-/*
  * /proc/fs/lustre/sptlrpc/encrypt_page_pools
  */
 int sptlrpc_proc_enc_pool_seq_show(struct seq_file *m, void *v)

@@ -226,30 +219,46 @@ static void enc_pools_release_free_pages(long npages)
 }
 
 /*
- * could be called frequently for query (@nr_to_scan == 0).
  * we try to keep at least PTLRPC_MAX_BRW_PAGES pages in the pool.
  */
-static int enc_pools_shrink(SHRINKER_ARGS(sc, nr_to_scan, gfp_mask))
+static unsigned long enc_pools_shrink_count(struct shrinker *s,
+					    struct shrink_control *sc)
 {
-	if (unlikely(shrink_param(sc, nr_to_scan) != 0)) {
+	/*
+	 * if no pool access for a long time, we consider it's fully idle.
+	 * a little race here is fine.
+	 */
+	if (unlikely(cfs_time_current_sec() - page_pools.epp_last_access >
+		     CACHE_QUIESCENT_PERIOD)) {
 		spin_lock(&page_pools.epp_lock);
-		shrink_param(sc, nr_to_scan) = min_t(unsigned long,
-						   shrink_param(sc, nr_to_scan),
-						   page_pools.epp_free_pages -
-						   PTLRPC_MAX_BRW_PAGES);
-		if (shrink_param(sc, nr_to_scan) > 0) {
-			enc_pools_release_free_pages(shrink_param(sc,
-								  nr_to_scan));
-			CDEBUG(D_SEC, "released %ld pages, %ld left\n",
-			       (long)shrink_param(sc, nr_to_scan),
-			       page_pools.epp_free_pages);
-
-			page_pools.epp_st_shrinks++;
-			page_pools.epp_last_shrink = cfs_time_current_sec();
-		}
+		page_pools.epp_idle_idx = IDLE_IDX_MAX;
 		spin_unlock(&page_pools.epp_lock);
 	}
 
+	LASSERT(page_pools.epp_idle_idx <= IDLE_IDX_MAX);
+	return max((int)page_pools.epp_free_pages - PTLRPC_MAX_BRW_PAGES, 0) *
+		(IDLE_IDX_MAX - page_pools.epp_idle_idx) / IDLE_IDX_MAX;
+}
+
+/*
+ * we try to keep at least PTLRPC_MAX_BRW_PAGES pages in the pool.
+ */
+static unsigned long enc_pools_shrink_scan(struct shrinker *s,
+					   struct shrink_control *sc)
+{
+	spin_lock(&page_pools.epp_lock);
+	sc->nr_to_scan = min_t(unsigned long, sc->nr_to_scan,
+			      page_pools.epp_free_pages - PTLRPC_MAX_BRW_PAGES);
+	if (sc->nr_to_scan > 0) {
+		enc_pools_release_free_pages(sc->nr_to_scan);
+		CDEBUG(D_SEC, "released %ld pages, %ld left\n",
+		       (long)sc->nr_to_scan, page_pools.epp_free_pages);
+
+		page_pools.epp_st_shrinks++;
+		page_pools.epp_last_shrink = cfs_time_current_sec();
+	}
+	spin_unlock(&page_pools.epp_lock);
+
 	/*
 	 * if no pool access for a long time, we consider it's fully idle.
 	 * a little race here is fine.

@@ -262,8 +271,7 @@ static int enc_pools_shrink(SHRINKER_ARGS(sc, nr_to_scan, gfp_mask))
 	}
 
 	LASSERT(page_pools.epp_idle_idx <= IDLE_IDX_MAX);
-	return max((int)page_pools.epp_free_pages - PTLRPC_MAX_BRW_PAGES, 0) *
-		(IDLE_IDX_MAX - page_pools.epp_idle_idx) / IDLE_IDX_MAX;
+	return sc->nr_to_scan;
 }
 
 static inline

@@ -699,6 +707,12 @@ static inline void enc_pools_free(void)
 		       sizeof(*page_pools.epp_pools));
 }
 
+static struct shrinker pools_shrinker = {
+	.count_objects	= enc_pools_shrink_count,
+	.scan_objects	= enc_pools_shrink_scan,
+	.seeks		= DEFAULT_SEEKS,
+};
+
 int sptlrpc_enc_pool_init(void)
 {
 	/*

@@ -736,12 +750,7 @@ int sptlrpc_enc_pool_init(void)
 	if (page_pools.epp_pools == NULL)
 		return -ENOMEM;
 
-	pools_shrinker = set_shrinker(pools_shrinker_seeks,
-					  enc_pools_shrink);
-	if (pools_shrinker == NULL) {
-		enc_pools_free();
-		return -ENOMEM;
-	}
+	register_shrinker(&pools_shrinker);
 
 	return 0;
 }

@@ -750,11 +759,10 @@ void sptlrpc_enc_pool_fini(void)
 {
 	unsigned long cleaned, npools;
 
-	LASSERT(pools_shrinker);
 	LASSERT(page_pools.epp_pools);
 	LASSERT(page_pools.epp_total_pages == page_pools.epp_free_pages);
 
-	remove_shrinker(pools_shrinker);
+	unregister_shrinker(&pools_shrinker);
 
 	npools = npages_to_npools(page_pools.epp_total_pages);
 	cleaned = enc_pools_cleanup(page_pools.epp_pools, npools);

index 63efb7b..2af15d4 100644
@@ -79,42 +79,4 @@
 	do { __oldfs = get_fs(); set_fs(get_ds());} while(0)
 #define MMSPACE_CLOSE	       set_fs(__oldfs)
 
-/*
- * Shrinker
- */
-
-# define SHRINKER_ARGS(sc, nr_to_scan, gfp_mask)  \
-		       struct shrinker *shrinker, \
-		       struct shrink_control *sc
-# define shrink_param(sc, var) ((sc)->var)
-
-typedef int (*shrinker_t)(SHRINKER_ARGS(sc, nr_to_scan, gfp_mask));
-
-static inline
-struct shrinker *set_shrinker(int seek, shrinker_t func)
-{
-	struct shrinker *s;
-
-	s = kmalloc(sizeof(*s), GFP_KERNEL);
-	if (s == NULL)
-		return (NULL);
-
-	s->shrink = func;
-	s->seeks = seek;
-
-	register_shrinker(s);
-
-	return s;
-}
-
-static inline
-void remove_shrinker(struct shrinker *shrinker)
-{
-	if (shrinker == NULL)
-		return;
-
-	unregister_shrinker(shrinker);
-	kfree(shrinker);
-}
-
 #endif /* __LINUX_CFS_MEM_H__ */