From: Alexey Dobriyan This makes in-core superblock fit into one cacheline here. Before: struct dentry * xattr_root; /* 124 4 */ /* --- cacheline 1 boundary (128 bytes) --- */ struct rw_semaphore xattr_dir_sem; /* 128 12 */ int j_errno; /* 140 4 */ }; /* size: 144, cachelines: 2 */ /* sum members: 142, holes: 1, sum holes: 2 */ /* last cacheline: 16 bytes */ After: int j_errno; /* 124 4 */ /* --- cacheline 1 boundary (128 bytes) --- */ }; /* size: 128, cachelines: 1 */ /* sum members: 126, holes: 1, sum holes: 2 */ Signed-off-by: Alexey Dobriyan Cc: Signed-off-by: Andrew Morton --- fs/reiserfs/super.c | 6 ++++-- include/linux/reiserfs_fs_sb.h | 3 ++- 2 files changed, 6 insertions(+), 3 deletions(-) diff -puN fs/reiserfs/super.c~reiserfs-shrink-superblock-if-no-xattrs fs/reiserfs/super.c --- a/fs/reiserfs/super.c~reiserfs-shrink-superblock-if-no-xattrs +++ a/fs/reiserfs/super.c @@ -433,12 +433,13 @@ int remove_save_link(struct inode *inode static void reiserfs_kill_sb(struct super_block *s) { if (REISERFS_SB(s)) { +#ifdef CONFIG_REISERFS_FS_XATTR if (REISERFS_SB(s)->xattr_root) { d_invalidate(REISERFS_SB(s)->xattr_root); dput(REISERFS_SB(s)->xattr_root); REISERFS_SB(s)->xattr_root = NULL; } - +#endif if (REISERFS_SB(s)->priv_root) { d_invalidate(REISERFS_SB(s)->priv_root); dput(REISERFS_SB(s)->priv_root); @@ -1564,9 +1565,10 @@ static int reiserfs_fill_super(struct su REISERFS_SB(s)->s_alloc_options.preallocmin = 0; /* Preallocate by 16 blocks (17-1) at once */ REISERFS_SB(s)->s_alloc_options.preallocsize = 17; +#ifdef CONFIG_REISERFS_FS_XATTR /* Initialize the rwsem for xattr dir */ init_rwsem(&REISERFS_SB(s)->xattr_dir_sem); - +#endif /* setup default block allocator options */ reiserfs_init_alloc_options(s); diff -puN include/linux/reiserfs_fs_sb.h~reiserfs-shrink-superblock-if-no-xattrs include/linux/reiserfs_fs_sb.h --- a/include/linux/reiserfs_fs_sb.h~reiserfs-shrink-superblock-if-no-xattrs +++ a/include/linux/reiserfs_fs_sb.h @@ -401,9 +401,10 @@ struct reiserfs_sb_info { int reserved_blocks; /* amount of blocks reserved for further allocations */ spinlock_t bitmap_lock; /* this lock on now only used to protect reserved_blocks variable */ struct dentry *priv_root; /* root of /.reiserfs_priv */ +#ifdef CONFIG_REISERFS_FS_XATTR struct dentry *xattr_root; /* root of /.reiserfs_priv/.xa */ struct rw_semaphore xattr_dir_sem; - +#endif int j_errno; #ifdef CONFIG_QUOTA char *s_qf_names[MAXQUOTAS]; _