On Mon, Feb 20, 2017 at 01:03:45PM +0300, Artem Blagodarenko wrote:
> From: Alexey Lyashkov <alexey.lyashkov@xxxxxxxxxxx>
>
> There are ~37k of random IOs with meta_bg option on 300T target.
Yikes, 300TB ext4! :)
(Is that really 2.2 million blockgroups?)
> Debugfs requires 20 minutes to be started. Enabling readahead for
> group blocks metadata save time dramatically. Only 12s to start.
>
> Signed-off-by: Alexey Lyashkov <alexey.lyashkov@xxxxxxxxxxx>
Looks good,
Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
--D
> ---
> lib/ext2fs/openfs.c | 6 ++++++
> 1 files changed, 6 insertions(+), 0 deletions(-)
>
> diff --git a/lib/ext2fs/openfs.c b/lib/ext2fs/openfs.c
> index ba501e6..f158b0a 100644
> --- a/lib/ext2fs/openfs.c
> +++ b/lib/ext2fs/openfs.c
> @@ -399,6 +399,12 @@ errcode_t ext2fs_open2(const char *name, const char *io_options,
> #endif
> dest += fs->blocksize*first_meta_bg;
> }
> +
> + for (i = first_meta_bg ; i < fs->desc_blocks; i++) {
> + blk = ext2fs_descriptor_block_loc2(fs, group_block, i);
> + io_channel_cache_readahead(fs->io, blk, 1);
> + }
> +
> for (i=first_meta_bg ; i < fs->desc_blocks; i++) {
> blk = ext2fs_descriptor_block_loc2(fs, group_block, i);
> retval = io_channel_read_blk64(fs->io, blk, 1, dest);
> --
> 1.7.1
>
