Hi,
On Thu, 2011-11-10 at 18:34 +0800, Zheng Liu wrote:
> From: Zheng Liu <wenqing.lz@xxxxxxxxxx>
>
> A per-cpu counter is defined to store io types in ext4. We define 10 io types
> in ext4, which includes 9 metadata types and 1 data type. Read and write
> operations are counted separately. When checks 'Issue' flag, filesystem needs
> to lock buffer.
>
> Signed-off-by: Zheng Liu <wenqing.lz@xxxxxxxxxx>
> Signed-off-by: Wang Shaoyan <wangshaoyan.pt@xxxxxxxxxx>
> ---
> fs/ext4/ext4.h | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> fs/ext4/super.c | 19 +++++++++++++++++++
> 2 files changed, 72 insertions(+), 0 deletions(-)
>
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index 5b0e26a..39a1495 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -1108,6 +1108,23 @@ struct ext4_super_block {
> #define EXT4_MF_FS_ABORTED 0x0002 /* Fatal error detected */
>
> /*
> + * ext4 io types
> + */
> +enum {
> + EXT4_IOS_SUPER_BLOCK = 0,
> + EXT4_IOS_GROUP_DESC,
> + EXT4_IOS_INODE_BITMAP,
> + EXT4_IOS_BLOCK_BITMAP,
> + EXT4_IOS_INODE_TABLE,
> + EXT4_IOS_EXTENT_BLOCK,
> + EXT4_IOS_INDIRECT_BLOCK,
> + EXT4_IOS_DIR_ENTRY,
> + EXT4_IOS_EXTENDED_ATTR,
> + EXT4_IOS_REGULAR_DATA,
> + EXT4_IOS_TYPE_END,
> +};
> +
> +/*
> * fourth extended-fs super-block data in memory
> */
> struct ext4_sb_info {
> @@ -1284,6 +1301,11 @@ static inline void ext4_set_io_unwritten_flag(struct inode *inode,
> }
> }
>
> +static inline unsigned ext4_blocks_per_page(struct inode *inode)
> +{
> + return PAGE_CACHE_SIZE >> inode->i_blkbits;
> +}
> +
> /*
> * Inode dynamic state flags
> */
> @@ -1926,6 +1948,37 @@ extern int ext4_group_extend(struct super_block *sb,
> ext4_fsblk_t n_blocks_count);
>
> /* super.c */
> +extern void __ext4_io_stat(int, int, unsigned long);
> +#define ext4_ios_read(bh, type, count) \
> + do { \
> + if (!bh) \
> + break; \
> + lock_buffer(bh); \
> + if (buffer_issue(bh)) { \
> + clear_buffer_issue(bh); \
> + __ext4_io_stat(READ, type, count); \
> + } \
> + unlock_buffer(bh); \
> + } while (0)
Why not just test_and_clear_bit(BH_Issue) ? I don't follow why the
buffer needs to be locked and unlocked,
Steve.
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