[Ocfs2-devel] [PATCH v2] ocfs2: improve recovery performance

[Joseph Qi <joseph.qi@huawei.com>]

On 2016/6/17 17:28, Junxiao Bi wrote:
> Journal replay will be run when do recovery for a dead node,
> to avoid the stale cache impact, all blocks of dead node's
> journal inode were reload from disk. This hurts the performance,
> check whether one block is cached before reload it can improve
> a lot performance. In my test env, the time doing recovery was
> improved from 120s to 1s.
> 
> Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com>
Looks good to me. And it indeed has performance improvement from my
test.
Reviewed-by: Joseph Qi <joseph.qi@huawei.com>

> ---
>  fs/ocfs2/journal.c |   41 ++++++++++++++++++++++-------------------
>  1 file changed, 22 insertions(+), 19 deletions(-)
> 
> diff --git a/fs/ocfs2/journal.c b/fs/ocfs2/journal.c
> index e607419cdfa4..bc0e21e8a674 100644
> --- a/fs/ocfs2/journal.c
> +++ b/fs/ocfs2/journal.c
> @@ -1159,10 +1159,8 @@ static int ocfs2_force_read_journal(struct inode *inode)
>  	int status = 0;
>  	int i;
>  	u64 v_blkno, p_blkno, p_blocks, num_blocks;
> -#define CONCURRENT_JOURNAL_FILL 32ULL
> -	struct buffer_head *bhs[CONCURRENT_JOURNAL_FILL];
> -
> -	memset(bhs, 0, sizeof(struct buffer_head *) * CONCURRENT_JOURNAL_FILL);
> +	struct buffer_head *bh = NULL;
> +	struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
>  
>  	num_blocks = ocfs2_blocks_for_bytes(inode->i_sb, i_size_read(inode));
>  	v_blkno = 0;
> @@ -1174,29 +1172,34 @@ static int ocfs2_force_read_journal(struct inode *inode)
>  			goto bail;
>  		}
>  
> -		if (p_blocks > CONCURRENT_JOURNAL_FILL)
> -			p_blocks = CONCURRENT_JOURNAL_FILL;
> +		for (i = 0; i < p_blocks; i++) {
> +			bh = __find_get_block(osb->sb->s_bdev, p_blkno,
> +					osb->sb->s_blocksize);
> +			/* block not cached. */
> +			if (!bh) {
> +				p_blkno++;
> +				continue;
> +			}
>  
> -		/* We are reading journal data which should not
> -		 * be put in the uptodate cache */
> -		status = ocfs2_read_blocks_sync(OCFS2_SB(inode->i_sb),
> -						p_blkno, p_blocks, bhs);
> -		if (status < 0) {
> -			mlog_errno(status);
> -			goto bail;
> -		}
> +			brelse(bh);
> +			bh = NULL;
> +			/* We are reading journal data which should not
> +			 * be put in the uptodate cache.
> +			 */
> +			status = ocfs2_read_blocks_sync(osb, p_blkno, 1, &bh);
> +			if (status < 0) {
> +				mlog_errno(status);
> +				goto bail;
> +			}
>  
> -		for(i = 0; i < p_blocks; i++) {
> -			brelse(bhs[i]);
> -			bhs[i] = NULL;
> +			brelse(bh);
> +			bh = NULL;
>  		}
>  
>  		v_blkno += p_blocks;
>  	}
>  
>  bail:
> -	for(i = 0; i < CONCURRENT_JOURNAL_FILL; i++)
> -		brelse(bhs[i]);
>  	return status;
>  }
>  
>