* [Cluster-devel] [PATCH 1/2] rhashtable: Add rhashtable_lookup_get_insert_fast
2017-02-22 15:14 [Cluster-devel] [PATCH 0/2] GFS2 rhashtable cleanup Andreas Gruenbacher
@ 2017-02-22 15:14 ` Andreas Gruenbacher
2017-02-24 14:22 ` Herbert Xu
2017-02-22 15:14 ` [Cluster-devel] [PATCH 2/2] gfs2: Switch to rhashtable_lookup_get_insert_fast Andreas Gruenbacher
2017-02-22 15:21 ` [Cluster-devel] [PATCH 0/2] GFS2 rhashtable cleanup Steven Whitehouse
2 siblings, 1 reply; 5+ messages in thread
From: Andreas Gruenbacher @ 2017-02-22 15:14 UTC (permalink / raw)
To: cluster-devel.redhat.com
Add rhashtable_lookup_get_insert_fast for fixed keys, similar to
rhashtable_lookup_get_insert_key for explicit keys.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Pablo Neira Ayuso <pablo@netfilter.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Thomas Graf <tgraf@suug.ch>
---
include/linux/rhashtable.h | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
diff --git a/include/linux/rhashtable.h b/include/linux/rhashtable.h
index 5c132d3..a85c14f 100644
--- a/include/linux/rhashtable.h
+++ b/include/linux/rhashtable.h
@@ -882,6 +882,28 @@ static inline int rhashtable_lookup_insert_fast(
}
/**
+ * rhashtable_lookup_get_insert_fast - lookup and insert object into hash table
+ * @ht: hash table
+ * @obj: pointer to hash head inside object
+ * @params: hash table parameters
+ *
+ * Just like rhashtable_lookup_insert_fast(), but this function returns the
+ * object if it exists, NULL if it did not and the insertion was successful,
+ * and an ERR_PTR otherwise.
+ */
+static inline void *rhashtable_lookup_get_insert_fast(
+ struct rhashtable *ht, struct rhash_head *obj,
+ const struct rhashtable_params params)
+{
+ const char *key = rht_obj(ht, obj);
+
+ BUG_ON(ht->p.obj_hashfn);
+
+ return __rhashtable_insert_fast(ht, key + ht->p.key_offset, obj, params,
+ false);
+}
+
+/**
* rhashtable_lookup_insert_key - search and insert object to hash table
* with explicit key
* @ht: hash table
--
2.7.4
^ permalink raw reply related [flat|nested] 5+ messages in thread* [Cluster-devel] [PATCH 2/2] gfs2: Switch to rhashtable_lookup_get_insert_fast
2017-02-22 15:14 [Cluster-devel] [PATCH 0/2] GFS2 rhashtable cleanup Andreas Gruenbacher
2017-02-22 15:14 ` [Cluster-devel] [PATCH 1/2] rhashtable: Add rhashtable_lookup_get_insert_fast Andreas Gruenbacher
@ 2017-02-22 15:14 ` Andreas Gruenbacher
2017-02-22 15:21 ` [Cluster-devel] [PATCH 0/2] GFS2 rhashtable cleanup Steven Whitehouse
2 siblings, 0 replies; 5+ messages in thread
From: Andreas Gruenbacher @ 2017-02-22 15:14 UTC (permalink / raw)
To: cluster-devel.redhat.com
Switch from rhashtable_lookup_insert_fast + rhashtable_lookup_fast to
rhashtable_lookup_get_insert_fast, which is cleaner and avoids an extra
rhashtable lookup.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
fs/gfs2/glock.c | 45 +++++++++++++++++++++------------------------
1 file changed, 21 insertions(+), 24 deletions(-)
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 1d60f5f..6dd834e4 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -653,10 +653,10 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
struct lm_lockname name = { .ln_number = number,
.ln_type = glops->go_type,
.ln_sbd = sdp };
- struct gfs2_glock *gl, *tmp = NULL;
+ struct gfs2_glock *gl, *tmp;
struct address_space *mapping;
struct kmem_cache *cachep;
- int ret, tries = 0;
+ int ret = 0;
rcu_read_lock();
gl = rhashtable_lookup_fast(&gl_hash_table, &name, ht_parms);
@@ -721,35 +721,32 @@ int gfs2_glock_get(struct gfs2_sbd *sdp, u64 number,
}
again:
- ret = rhashtable_lookup_insert_fast(&gl_hash_table, &gl->gl_node,
- ht_parms);
- if (ret == 0) {
+ rcu_read_lock();
+ tmp = rhashtable_lookup_get_insert_fast(&gl_hash_table, &gl->gl_node,
+ ht_parms);
+ if (!tmp) {
*glp = gl;
- return 0;
+ goto out;
}
-
- if (ret == -EEXIST) {
- ret = 0;
- rcu_read_lock();
- tmp = rhashtable_lookup_fast(&gl_hash_table, &name, ht_parms);
- if (tmp == NULL || !lockref_get_not_dead(&tmp->gl_lockref)) {
- if (++tries < 100) {
- rcu_read_unlock();
- cond_resched();
- goto again;
- }
- tmp = NULL;
- ret = -ENOMEM;
- }
- rcu_read_unlock();
- } else {
- WARN_ON_ONCE(ret);
+ if (IS_ERR(tmp)) {
+ ret = PTR_ERR(tmp);
+ goto out_free;
+ }
+ if (lockref_get_not_dead(&tmp->gl_lockref)) {
+ *glp = tmp;
+ goto out_free;
}
+ rcu_read_unlock();
+ cond_resched();
+ goto again;
+
+out_free:
kfree(gl->gl_lksb.sb_lvbptr);
kmem_cache_free(cachep, gl);
atomic_dec(&sdp->sd_glock_disposal);
- *glp = tmp;
+out:
+ rcu_read_unlock();
return ret;
}
--
2.7.4
^ permalink raw reply related [flat|nested] 5+ messages in thread