Use slab cache for memory allocation. mucho speed improvements.

diff --git a/kernel/common/dm-snapshot.c b/kernel/common/dm-snapshot.c
index f3bfcc0747b8c48fa1cf37fc832cc883605dcbaa..9a9df702bf269baa6dd4edc64be08eb8227c2cee 100644 (file)
--- a/kernel/common/dm-snapshot.c
+++ b/kernel/common/dm-snapshot.c
@@ -192,7 +192,7 @@ struct snap_disk_header {
 };
 
 static int write_metadata(struct snapshot_c *lc);
-
+static int write_header(struct snapshot_c *lc);
 /*
  * Size of the hash table for origin volumes. If we make this
  * the size of the minors list then it should be nearly perfect
@@ -206,7 +206,8 @@ static int write_metadata(struct snapshot_c *lc);
  */
 static struct list_head *snapshot_origins = NULL;
 static struct rw_semaphore origin_hash_lock;
-
+static kmem_cache_t *exception_cachep;
+static kmem_cache_t *inflight_cachep;
 /*
  * Hash functions
  */
@@ -353,7 +354,7 @@ static struct exception *add_exception(struct snapshot_c *sc, unsigned long org,
        struct list_head *l = &sc->hash_table[exception_hash(org, sc)];
        struct exception *new_ex;
 
-       new_ex = kmalloc(sizeof(struct exception), GFP_KERNEL);
+       new_ex = kmem_cache_alloc(exception_cachep, GFP_NOIO);
        if (!new_ex) return NULL;
 
        new_ex->rsector_org = org;
@@ -389,7 +390,7 @@ static void copy_callback(copy_cb_reason_t reason, void *context, long arg)
                bh = iex->bh;
                iex->bh = NULL;
                up_write(&iex->snap->origin->lock);
-               kfree(iex);
+               kmem_cache_free(inflight_cachep, iex);
 
                while (bh) {
                        struct buffer_head *nextbh = bh->b_reqnext;
@@ -407,7 +408,7 @@ static void copy_callback(copy_cb_reason_t reason, void *context, long arg)
                if (iex->snap->persistent)
                        write_header(iex->snap);
                list_del(&iex->list);
-               kfree(iex);
+               kmem_cache_free(inflight_cachep, iex);
        }
 }
 
@@ -495,7 +496,7 @@ static struct inflight_exception *add_inflight_exception(struct snapshot_c *sc,
        struct list_head *l = &sc->inflight_hash_table[inflight_exception_hash(org, sc)];
        struct inflight_exception *new_ex;
 
-       new_ex = kmalloc(sizeof(struct inflight_exception), GFP_KERNEL);
+       new_ex = kmem_cache_alloc(inflight_cachep, GFP_NOIO);
        if (!new_ex) return NULL;
 
        new_ex->rsector_org = org;
@@ -647,7 +648,7 @@ static void free_exception_table(struct snapshot_c *lc)
                                struct exception *ex;
                                ex = list_entry(entry, struct exception, list);
                                list_del(&ex->list);
-                               kfree(ex);
+                               kmem_cache_free(exception_cachep, ex);
                        }
                }
        }
@@ -884,7 +885,6 @@ static int write_metadata(struct snapshot_c *lc)
                DMERR("Error writing COW block");
                return -1;
        }
-
        return 0;
 }
 
@@ -1380,6 +1380,26 @@ int __init dm_snapshot_init(void)
                        init_rwsem(&origin_hash_lock);
                }
        }
+       exception_cachep = kmem_cache_create("dm-snapshot-ex",
+                                            sizeof(struct exception),
+                                            __alignof__(struct exception),
+                                            0, NULL, NULL);
+       if (!exception_cachep) {
+               kfree(snapshot_origins);
+               return -1;
+       }
+
+
+       inflight_cachep = kmem_cache_create("dm-snapshot-in",
+                                           sizeof(struct inflight_exception),
+                                           __alignof__(struct inflight_exception),
+                                           0, NULL, NULL);
+       if (!inflight_cachep) {
+               kfree(snapshot_origins);
+               kmem_cache_destroy(exception_cachep);
+               return -1;
+       }
+
 
        return r;
 }
@@ -1393,6 +1413,9 @@ void dm_snapshot_exit(void)
 
        if (snapshot_origins)
                kfree(snapshot_origins);
+
+       kmem_cache_destroy(inflight_cachep);
+       kmem_cache_destroy(exception_cachep);
 }
 
 /*