libceph: allocate ceph message data with a slab allocator

Create a slab cache to manage ceph_msg_data structure allocation.

This is part of:
    http://tracker.ceph.com/issues/3926

Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index bc1ba4c..eb0a46a 100644 (file)
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -155,6 +155,7 @@ static bool con_flag_test_and_set(struct ceph_connection *con,
 /* Slab caches for frequently-allocated structures */
 
 static struct kmem_cache       *ceph_msg_cache;
+static struct kmem_cache       *ceph_msg_data_cache;
 
 /* static tag bytes (protocol control messages) */
 static char tag_msg = CEPH_MSGR_TAG_MSG;
@@ -236,11 +237,30 @@ static int ceph_msgr_slab_init(void)
        ceph_msg_cache = kmem_cache_create("ceph_msg",
                                        sizeof (struct ceph_msg),
                                        __alignof__(struct ceph_msg), 0, NULL);
-       return ceph_msg_cache ? 0 : -ENOMEM;
+
+       if (!ceph_msg_cache)
+               return -ENOMEM;
+
+       BUG_ON(ceph_msg_data_cache);
+       ceph_msg_data_cache = kmem_cache_create("ceph_msg_data",
+                                       sizeof (struct ceph_msg_data),
+                                       __alignof__(struct ceph_msg_data),
+                                       0, NULL);
+       if (ceph_msg_data_cache)
+               return 0;
+
+       kmem_cache_destroy(ceph_msg_cache);
+       ceph_msg_cache = NULL;
+
+       return -ENOMEM;
 }
 
 static void ceph_msgr_slab_exit(void)
 {
+       BUG_ON(!ceph_msg_data_cache);
+       kmem_cache_destroy(ceph_msg_data_cache);
+       ceph_msg_data_cache = NULL;
+
        BUG_ON(!ceph_msg_cache);
        kmem_cache_destroy(ceph_msg_cache);
        ceph_msg_cache = NULL;
@@ -3008,7 +3028,7 @@ static struct ceph_msg_data *ceph_msg_data_create(enum ceph_msg_data_type type)
        if (WARN_ON(!ceph_msg_data_type_valid(type)))
                return NULL;
 
-       data = kzalloc(sizeof (*data), GFP_NOFS);
+       data = kmem_cache_zalloc(ceph_msg_data_cache, GFP_NOFS);
        if (data)
                data->type = type;
        INIT_LIST_HEAD(&data->links);
@@ -3026,7 +3046,7 @@ static void ceph_msg_data_destroy(struct ceph_msg_data *data)
                ceph_pagelist_release(data->pagelist);
                kfree(data->pagelist);
        }
-       kfree(data);
+       kmem_cache_free(ceph_msg_data_cache, data);
 }
 
 void ceph_msg_data_add_pages(struct ceph_msg *msg, struct page **pages,