libceph: use slab cache for osd client requests

Create a slab cache to manage allocation of ceph_osdc_request
structures.

This resolves:
    http://tracker.ceph.com/issues/3926

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

2 files changed, 32 insertions, 2 deletions

diff --git a/net/ceph/ceph_common.c b/net/ceph/ceph_common.c
index e65e6e4be38b..34b11ee8124e 100644
--- a/net/ceph/ceph_common.c
+++ b/net/ceph/ceph_common.c
@@ -606,11 +606,17 @@ static int __init init_ceph_lib(void)
         if (ret < 0)
                 goto out_crypto;
 
+        ret = ceph_osdc_setup();
+        if (ret < 0)
+                goto out_msgr;
+
         pr_info("loaded (mon/osd proto %d/%d)\n",
                 CEPH_MONC_PROTOCOL, CEPH_OSDC_PROTOCOL);
 
         return 0;
 
+out_msgr:
+        ceph_msgr_exit();
 out_crypto:
         ceph_crypto_shutdown();
 out_debugfs:
@@ -622,6 +628,7 @@ out:
 static void __exit exit_ceph_lib(void)
 {
         dout("exit_ceph_lib\n");
+        ceph_osdc_cleanup();
         ceph_msgr_exit();
         ceph_crypto_shutdown();
         ceph_debugfs_cleanup();
diff --git a/net/ceph/osd_client.c b/net/ceph/osd_client.c
index 57d8db5b055a..a3395fdfbd4f 100644
--- a/net/ceph/osd_client.c
+++ b/net/ceph/osd_client.c
@@ -22,6 +22,8 @@
 #define OSD_OP_FRONT_LEN        4096
 #define OSD_OPREPLY_FRONT_LEN   512
 
+static struct kmem_cache        *ceph_osd_request_cache;
+
 static const struct ceph_connection_operations osd_con_ops;
 
 static void __send_queued(struct ceph_osd_client *osdc);
@@ -315,7 +317,8 @@ void ceph_osdc_release_request(struct kref *kref)
         if (req->r_mempool)
                 mempool_free(req, req->r_osdc->req_mempool);
         else
-                kfree(req);
+                kmem_cache_free(ceph_osd_request_cache, req);
+
 }
 EXPORT_SYMBOL(ceph_osdc_release_request);
 
@@ -346,7 +349,7 @@ struct ceph_osd_request *ceph_osdc_alloc_request(struct ceph_osd_client *osdc,
                 req = mempool_alloc(osdc->req_mempool, gfp_flags);
                 memset(req, 0, sizeof(*req));
         } else {
-                req = kzalloc(sizeof(*req), gfp_flags);
+                req = kmem_cache_zalloc(ceph_osd_request_cache, gfp_flags);
         }
         if (req == NULL)
                 return NULL;
@@ -2365,6 +2368,26 @@ int ceph_osdc_writepages(struct ceph_osd_client *osdc, struct ceph_vino vino,
 }
 EXPORT_SYMBOL(ceph_osdc_writepages);
 
+int ceph_osdc_setup(void)
+{
+        BUG_ON(ceph_osd_request_cache);
+        ceph_osd_request_cache = kmem_cache_create("ceph_osd_request",
+                                        sizeof (struct ceph_osd_request),
+                                        __alignof__(struct ceph_osd_request),
+                                        0, NULL);
+
+        return ceph_osd_request_cache ? 0 : -ENOMEM;
+}
+EXPORT_SYMBOL(ceph_osdc_setup);
+
+void ceph_osdc_cleanup(void)
+{
+        BUG_ON(!ceph_osd_request_cache);
+        kmem_cache_destroy(ceph_osd_request_cache);
+        ceph_osd_request_cache = NULL;
+}
+EXPORT_SYMBOL(ceph_osdc_cleanup);
+
 /*
  * handle incoming message
  */