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Subject[PATCH-v2 1/4] staging/lustre/ldlm: convert to shrinkers to count/scan API
Date
From: Peng Tao <bergwolf@gmail.com>

convert ldlm 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>
---
drivers/staging/lustre/lustre/ldlm/ldlm_pool.c | 148 +++++++++++++-----------
1 files changed, 79 insertions(+), 69 deletions(-)

diff --git a/drivers/staging/lustre/lustre/ldlm/ldlm_pool.c b/drivers/staging/lustre/lustre/ldlm/ldlm_pool.c
index 101af4b..9ac7e4d 100644
--- a/drivers/staging/lustre/lustre/ldlm/ldlm_pool.c
+++ b/drivers/staging/lustre/lustre/ldlm/ldlm_pool.c
@@ -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);
--
1.7.1


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