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ext4: drop i_state_flags on architectures with 64-bit longs

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We can store the dynamic inode state flags in the high bits of
EXT4_I(inode)->i_flags, and eliminate i_state_flags.  This saves 8
bytes from the size of ext4_inode_info structure, which when
multiplied by the number of the number of in the inode cache, can save
a lot of memory.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Theodore Ts'o 2011-01-10 12:18:25 -05:00
parent 8a2005d3f8
commit 353eb83c14
3 changed files with 25 additions and 9 deletions
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28
fs/ext4/ext4.h
View File

@ -764,7 +764,9 @@ struct ext4_inode_info {
*/
ext4_group_t i_block_group;
ext4_lblk_t i_dir_start_lookup;
#if (BITS_PER_LONG < 64)
unsigned long i_state_flags; /* Dynamic state flags */
#endif
unsigned long i_flags;
#ifdef CONFIG_EXT4_FS_XATTR
@ -1239,22 +1241,36 @@ enum {
EXT4_STATE_DELALLOC_RESERVED, /* blks already reserved for delalloc */
};
#define EXT4_INODE_BIT_FNS(name, field) \
#define EXT4_INODE_BIT_FNS(name, field, offset) \
static inline int ext4_test_inode_##name(struct inode *inode, int bit) \
{ \
return test_bit(bit, &EXT4_I(inode)->i_##field); \
return test_bit(bit + (offset), &EXT4_I(inode)->i_##field); \
} \
static inline void ext4_set_inode_##name(struct inode *inode, int bit) \
{ \
set_bit(bit, &EXT4_I(inode)->i_##field); \
set_bit(bit + (offset), &EXT4_I(inode)->i_##field); \
} \
static inline void ext4_clear_inode_##name(struct inode *inode, int bit) \
{ \
clear_bit(bit, &EXT4_I(inode)->i_##field); \
clear_bit(bit + (offset), &EXT4_I(inode)->i_##field); \
}
EXT4_INODE_BIT_FNS(flag, flags)
EXT4_INODE_BIT_FNS(state, state_flags)
EXT4_INODE_BIT_FNS(flag, flags, 0)
#if (BITS_PER_LONG < 64)
EXT4_INODE_BIT_FNS(state, state_flags, 0)
static inline void ext4_clear_state_flags(struct ext4_inode_info *ei)
{
(ei)->i_state_flags = 0;
}
#else
EXT4_INODE_BIT_FNS(state, flags, 32)
static inline void ext4_clear_state_flags(struct ext4_inode_info *ei)
{
/* We depend on the fact that callers will set i_flags */
}
#endif
#else
/* Assume that user mode programs are passing in an ext4fs superblock, not
* a kernel struct super_block. This will allow us to call the feature-test

2
fs/ext4/ialloc.c
View File

@ -1027,7 +1027,7 @@ got:
inode->i_generation = sbi->s_next_generation++;
spin_unlock(&sbi->s_next_gen_lock);
ei->i_state_flags = 0;
ext4_clear_state_flags(ei); /* Only relevant on 32-bit archs */
ext4_set_inode_state(inode, EXT4_STATE_NEW);
ei->i_extra_isize = EXT4_SB(sb)->s_want_extra_isize;

4
fs/ext4/inode.c
View File

@ -4868,7 +4868,7 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
}
inode->i_nlink = le16_to_cpu(raw_inode->i_links_count);
ei->i_state_flags = 0;
ext4_clear_state_flags(ei); /* Only relevant on 32-bit archs */
ei->i_dir_start_lookup = 0;
ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
/* We now have enough fields to check if the inode was active or not.
@ -5127,7 +5127,7 @@ static int ext4_do_update_inode(handle_t *handle,
if (ext4_inode_blocks_set(handle, raw_inode, ei))
goto out_brelse;
raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
raw_inode->i_flags = cpu_to_le32(ei->i_flags);
raw_inode->i_flags = cpu_to_le32(ei->i_flags & 0xFFFFFFFF);
if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
cpu_to_le32(EXT4_OS_HURD))
raw_inode->i_file_acl_high =