ceph: move to a dedicated slabcache for mds requests

On my machine (x86_64) this struct is 952 bytes, which gets rounded up
to 1024 by kmalloc. Move this to a dedicated slabcache, so we can
allocate them without the extra 72 bytes of overhead per.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Ilya Dryomov <idryomov@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index 2980e57..fab9d64 100644 (file)
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -736,7 +736,7 @@ void ceph_mdsc_release_request(struct kref *kref)
        put_request_session(req);
        ceph_unreserve_caps(req->r_mdsc, &req->r_caps_reservation);
        WARN_ON_ONCE(!list_empty(&req->r_wait));
-       kfree(req);
+       kmem_cache_free(ceph_mds_request_cachep, req);
 }
 
 DEFINE_RB_FUNCS(request, struct ceph_mds_request, r_tid, r_node)
@@ -2094,8 +2094,9 @@ int ceph_alloc_readdir_reply_buffer(struct ceph_mds_request *req,
 struct ceph_mds_request *
 ceph_mdsc_create_request(struct ceph_mds_client *mdsc, int op, int mode)
 {
-       struct ceph_mds_request *req = kzalloc(sizeof(*req), GFP_NOFS);
+       struct ceph_mds_request *req;
 
+       req = kmem_cache_zalloc(ceph_mds_request_cachep, GFP_NOFS);
        if (!req)
                return ERR_PTR(-ENOMEM);
 

diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index c7f1506..b1329cd 100644 (file)
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -729,6 +729,7 @@ struct kmem_cache *ceph_cap_flush_cachep;
 struct kmem_cache *ceph_dentry_cachep;
 struct kmem_cache *ceph_file_cachep;
 struct kmem_cache *ceph_dir_file_cachep;
+struct kmem_cache *ceph_mds_request_cachep;
 
 static void ceph_inode_init_once(void *foo)
 {
@@ -769,6 +770,10 @@ static int __init init_caches(void)
        if (!ceph_dir_file_cachep)
                goto bad_dir_file;
 
+       ceph_mds_request_cachep = KMEM_CACHE(ceph_mds_request, SLAB_MEM_SPREAD);
+       if (!ceph_mds_request_cachep)
+               goto bad_mds_req;
+
        error = ceph_fscache_register();
        if (error)
                goto bad_fscache;
@@ -776,6 +781,8 @@ static int __init init_caches(void)
        return 0;
 
 bad_fscache:
+       kmem_cache_destroy(ceph_mds_request_cachep);
+bad_mds_req:
        kmem_cache_destroy(ceph_dir_file_cachep);
 bad_dir_file:
        kmem_cache_destroy(ceph_file_cachep);
@@ -804,6 +811,7 @@ static void destroy_caches(void)
        kmem_cache_destroy(ceph_dentry_cachep);
        kmem_cache_destroy(ceph_file_cachep);
        kmem_cache_destroy(ceph_dir_file_cachep);
+       kmem_cache_destroy(ceph_mds_request_cachep);
 
        ceph_fscache_unregister();
 }

diff --git a/include/linux/ceph/libceph.h b/include/linux/ceph/libceph.h
index ec73ebc..525b7c3 100644 (file)
--- a/include/linux/ceph/libceph.h
+++ b/include/linux/ceph/libceph.h
@@ -272,6 +272,7 @@ extern struct kmem_cache *ceph_cap_flush_cachep;
 extern struct kmem_cache *ceph_dentry_cachep;
 extern struct kmem_cache *ceph_file_cachep;
 extern struct kmem_cache *ceph_dir_file_cachep;
+extern struct kmem_cache *ceph_mds_request_cachep;
 
 /* ceph_common.c */
 extern bool libceph_compatible(void *data);