Changed rbthash_table_init() to take a mem-pool argument.

Changes in libglusterfs/rbthash:

rbthash_table_init() now takes a mem-pool argument.
The mem-pool argument would be mutually exclusive to expected_entries.
If expected_entries is provided, mem-pool would be ignored and vice-versa.

Changes in io-cache:
1) Moved rbthash creation to readv.
2) rbthash makes use of 1 rbt instead of 4096
3) A global mem-pool is being used in place of a mem-pool per rbt.

Signed-off-by: Vijay Bellur <vijay@gluster.com>
Signed-off-by: Anand V. Avati <avati@dev.gluster.com>

BUG: 335 (Io-cache optimization)
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=335

2 files changed, 49 insertions, 11 deletions

diff --git a/libglusterfs/src/rbthash.c b/libglusterfs/src/rbthash.c
index c2cbf99b4..63d083858 100644
--- a/libglusterfs/src/rbthash.c
+++ b/libglusterfs/src/rbthash.c
@@ -79,9 +79,21 @@ err:
 }
 
 
+/*
+ * rbthash_table_init - Initialize a RBT based hash table
+ * @buckets - Number of buckets in the hash table
+ * @hfunc   - hashing function
+ * @dfunc   - destroyer for data in the RBT
+ * @expected_entries - Number of entries expected in RBT. Mutually exclusive
+ * with entrypool.
+ * @entrypool -  Memory pool in lieu of expected_entries.
+ */
+
 rbthash_table_t *
-rbthash_table_init (int buckets, rbt_hasher_t hfunc, rbt_data_destroyer_t dfunc,
-                    unsigned long expected_entries)
+rbthash_table_init (int buckets, rbt_hasher_t hfunc,
+                    rbt_data_destroyer_t dfunc,
+                    unsigned long expected_entries,
+                    struct mem_pool *entrypool)
 {
         rbthash_table_t         *newtab = NULL;
         int                     ret = -1;
@@ -91,6 +103,19 @@ rbthash_table_init (int buckets, rbt_hasher_t hfunc, rbt_data_destroyer_t dfunc,
                 return NULL;
         }
 
+        if (!entrypool && !expected_entries) {
+                gf_log (GF_RBTHASH, GF_LOG_ERROR,
+                        "Both mem-pool and expected entries not provided");
+                return NULL;
+        }
+
+        if (entrypool && expected_entries) {
+                gf_log (GF_RBTHASH, GF_LOG_ERROR,
+                        "Both mem-pool and expected entries are provided");
+                return NULL;
+        }
+
+
         newtab = CALLOC (1, sizeof (*newtab));
         if (!newtab)
                 return NULL;
@@ -101,10 +126,17 @@ rbthash_table_init (int buckets, rbt_hasher_t hfunc, rbt_data_destroyer_t dfunc,
                 goto free_newtab;
         }
 
-        newtab->entrypool =  mem_pool_new (rbthash_entry_t, expected_entries);
-        if (!newtab->entrypool) {
-                gf_log (GF_RBTHASH, GF_LOG_ERROR,"Failed to allocate mem-pool");
-                goto free_buckets;
+        if (expected_entries) {
+                newtab->entrypool =
+                        mem_pool_new (rbthash_entry_t, expected_entries);
+                if (!newtab->entrypool) {
+                        gf_log (GF_RBTHASH, GF_LOG_ERROR,
+                                "Failed to allocate mem-pool");
+                        goto free_buckets;
+                }
+                newtab->pool_alloced = _gf_true;
+        } else {
+                newtab->entrypool = entrypool;
         }
 
         LOCK_INIT (&newtab->tablelock);
@@ -113,13 +145,16 @@ rbthash_table_init (int buckets, rbt_hasher_t hfunc, rbt_data_destroyer_t dfunc,
 
         if (ret == -1) {
                 gf_log (GF_RBTHASH, GF_LOG_ERROR, "Failed to init buckets");
-                mem_pool_destroy (newtab->entrypool);
-        } else
+                if (newtab->pool_alloced)
+                        mem_pool_destroy (newtab->entrypool);
+        } else {
                 gf_log (GF_RBTHASH, GF_LOG_TRACE, "Inited hash table: buckets:"
                         " %d", buckets);
+        }
 
         newtab->hashfunc = hfunc;
         newtab->dfunc = dfunc;
+
 free_buckets:
         if (ret == -1)
                 FREE (newtab->buckets);
@@ -133,7 +168,6 @@ free_newtab:
         return newtab;
 }
 
-
 rbthash_entry_t *
 rbthash_init_entry (rbthash_table_t *tbl, void *data, void *key, int keylen)
 {
@@ -381,7 +415,8 @@ rbthash_table_destroy (rbthash_table_t *tbl)
                 return;
 
         rbthash_table_destroy_buckets (tbl);
-        mem_pool_destroy (tbl->entrypool);
+        if (tbl->pool_alloced)
+                mem_pool_destroy (tbl->entrypool);
 
         FREE (tbl->buckets);
         FREE (tbl);
diff --git a/libglusterfs/src/rbthash.h b/libglusterfs/src/rbthash.h
index f2200f895..535dccad9 100644
--- a/libglusterfs/src/rbthash.h
+++ b/libglusterfs/src/rbthash.h
@@ -23,6 +23,7 @@
 #include "locking.h"
 #include "mem-pool.h"
 #include "logging.h"
+#include "common-utils.h"
 
 #include <pthread.h>
 
@@ -52,11 +53,13 @@ typedef struct rbthash_table {
         struct rbthash_bucket   *buckets;
         rbt_hasher_t            hashfunc;
         rbt_data_destroyer_t    dfunc;
+        gf_boolean_t            pool_alloced;
 } rbthash_table_t;
 
 extern rbthash_table_t *
 rbthash_table_init (int buckets, rbt_hasher_t hfunc,
-                    rbt_data_destroyer_t dfunc, unsigned long expected_entries);
+                    rbt_data_destroyer_t dfunc, unsigned long expected_entries,
+                    struct mem_pool *entrypool);
 
 extern int
 rbthash_insert (rbthash_table_t *tbl, void *data, void *key, int keylen);