Commit db2993a4 authored by Christophe JAILLET's avatar Christophe JAILLET Committed by Ilya Dryomov
Browse files

ceph: reorder fields in 'struct ceph_snapid_map' 



Group some variables based on their sizes to reduce holes.
On x86_64, this shrinks the size of 'struct ceph_snapid_map' from 72 to 64
bytes.

When such a structure is allocated, because of the way memory allocation
works, when 72 bytes were requested, 96 bytes were allocated.

So, on x86_64, this change saves 32 bytes per allocation and has the
structure fit in a single cacheline.

Signed-off-by: default avatarChristophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: default avatarJeff Layton <jlayton@kernel.org>
Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
parent a5ffd7b6

fs/ceph/mds_client.h

+1 −1
Original line number Diff line number Diff line
@@ -355,8 +355,8 @@ struct ceph_snapid_map { 
	struct rb_node node;

	struct list_head lru;

	atomic_t ref;

	u64 snap;

	dev_t dev;

	u64 snap;

	unsigned long last_used;

};