This patch set aims to reduce the memory usage of the Ceph filesystems
by optimizing the layout of structs, most importantly struct
ceph_inode_info:
- use `bool` instead of `int` for booelans
- use `u32` instead of `u64` where possible
- reorder fields to eliminate padding holes
- eliminate redundant fields
Without this patch set, ceph_inode_info looks like this with pahole:
/* size: 1456, cachelines: 23, members: 79 */
/* sum members: 1424, holes: 8, sum holes: 32 */
/* member types with holes: 3, total: 3 */
With this patch set, struct ceph_inode_info got smaller by 96 bytes:
/* size: 1360, cachelines: 22, members: 76 */
/* member types with holes: 1, total: 1 */
struct ceph_cap shrinks by 24 bytes:
/* size: 120, cachelines: 2, members: 12 */
/* size: 96, cachelines: 2, members: 10 */
struct ceph_snap_realm shrinks by 24 bytes, too:
/* size: 232, cachelines: 4, members: 21 */
/* sum members: 216, holes: 3, sum holes: 12 */
/* size: 208, cachelines: 4, members: 20 */
---
v1->v2:
- fix CONFIG_FS_ENCRYPTION check in "i_truncate_pagecache_size" patch
- add patches to shrink ceph_cap and ceph_snap_realm
v2->v3:
- rebase on latest master
v3->v4:
- drop the buggy ceph_in_snap() change from ceph_d_prune()
- fix -Wunused-variable on BITS_PER_LONG<64
Max Kellermann (12):
fs/ceph/super: remove unused field `i_cap_migration_resv`
fs/ceph/super: make field `i_truncate_pagecache_size` optional
include/ceph/ceph_fs.h: convert `pool_id` to u32
fs/ceph/super.h: convert ceph_inode_xattr fields to `bool`
fs/ceph/super.h: convert ceph_cap_snap.writing fields to `bool`
fs/ceph: consistently use `u32` for `time_warp_seq`
fs/ceph/super: reorder fields to eliminate padding holes
fs/ceph: remove i_truncate_mutex, use i_fragtree_mutex for both
fs/ceph/super.h: add `const` to helpers
fs/ceph/super.h: add helper ceph_in_snap()
fs/ceph: use ceph_vino() etc. instead of accessing i_vino directly
fs/ceph: remove redundant inode number from ceph_inode_info
fs/ceph/acl.c | 2 +-
fs/ceph/addr.c | 23 ++++----
fs/ceph/cache.c | 4 +-
fs/ceph/caps.c | 8 +--
fs/ceph/dir.c | 20 +++----
fs/ceph/export.c | 8 +--
fs/ceph/file.c | 28 +++++-----
fs/ceph/inode.c | 40 +++++++++-----
fs/ceph/mds_client.c | 12 ++---
fs/ceph/mds_client.h | 2 +-
fs/ceph/quota.c | 6 +--
fs/ceph/snap.c | 8 +--
fs/ceph/super.h | 102 +++++++++++++++++++++++++----------
fs/ceph/util.c | 8 +--
fs/ceph/xattr.c | 18 +++----
include/linux/ceph/ceph_fs.h | 2 +-
16 files changed, 173 insertions(+), 118 deletions(-)
--
2.47.3