Commit 353eb83c authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

ext4: drop i_state_flags on architectures with 64-bit longs 



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: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 8a2005d3

fs/ext4/ext4.h

+22 −6
Original line number Diff line number Diff line
@@ -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

fs/ext4/ialloc.c

+1 −1
Original line number Diff line number Diff line
@@ -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;

fs/ext4/inode.c

+2 −2
Original line number Diff line number Diff line
@@ -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 =

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