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Go Back   Linux Archive > Redhat > Cluster Development

 
 
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Old 08-08-2012, 08:10 PM
Bob Peterson
 
Default GFS2: Reduce number of log flushes

Hi,

This patch reduces the number of log flushes.

Regards,

Bob Peterson
Red Hat File Systems

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
---
diff --git a/fs/gfs2/glops.c b/fs/gfs2/glops.c
index 4bdcf37..7d795e7 100644
--- a/fs/gfs2/glops.c
+++ b/fs/gfs2/glops.c
@@ -118,7 +118,13 @@ void gfs2_ail_flush(struct gfs2_glock *gl, bool fsync)
return;
__gfs2_ail_flush(gl, fsync);
gfs2_trans_end(sdp);
- gfs2_log_flush(sdp, NULL);
+ /* if fsync is true, we were called from gfs2_fsync, which means
+ we just called sync_inode_metadata, which calls sync_inode,
+ which calls writeback_single_inode, which calls write_inode,
+ which calls write_inode which calls gfs2_log_flush. So the call
+ is redundant. */
+ if (!fsync)
+ gfs2_log_flush(sdp, NULL);
}

/**
diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c
index 3cbac68..5904ce0 100644
--- a/fs/gfs2/super.c
+++ b/fs/gfs2/super.c
@@ -1542,7 +1542,11 @@ static void gfs2_evict_inode(struct inode *inode)
goto out_unlock;

out_truncate:
- gfs2_log_flush(sdp, ip->i_gl);
+ /* write_inode_now calls writeback_single_inode, which calls
+ gfs2_write_inode. gfs2_write_inode calls gfs2_log_flush if
+ (wbc->sync_mode == WB_SYNC_ALL), which it is since we pass 1.
+ therefore, this call to gfs2_log_flush is redundant:
+ gfs2_log_flush(sdp, ip->i_gl); */
write_inode_now(inode, 1);
gfs2_ail_flush(ip->i_gl, 0);
 
Old 08-09-2012, 09:04 AM
Steven Whitehouse
 
Default GFS2: Reduce number of log flushes

Hi,

On Wed, 2012-08-08 at 16:10 -0400, Bob Peterson wrote:
> Hi,
>
> This patch reduces the number of log flushes.
>
> Regards,
>
> Bob Peterson
> Red Hat File Systems
>
> Signed-off-by: Bob Peterson <rpeterso@redhat.com>
> ---
> diff --git a/fs/gfs2/glops.c b/fs/gfs2/glops.c
> index 4bdcf37..7d795e7 100644
> --- a/fs/gfs2/glops.c
> +++ b/fs/gfs2/glops.c
> @@ -118,7 +118,13 @@ void gfs2_ail_flush(struct gfs2_glock *gl, bool fsync)
> return;
> __gfs2_ail_flush(gl, fsync);
> gfs2_trans_end(sdp);
> - gfs2_log_flush(sdp, NULL);
> + /* if fsync is true, we were called from gfs2_fsync, which means
> + we just called sync_inode_metadata, which calls sync_inode,
> + which calls writeback_single_inode, which calls write_inode,
> + which calls write_inode which calls gfs2_log_flush. So the call
> + is redundant. */
> + if (!fsync)
> + gfs2_log_flush(sdp, NULL);
> }
What ensures that the revokes are on disk?

>
> /**
> diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c
> index 3cbac68..5904ce0 100644
> --- a/fs/gfs2/super.c
> +++ b/fs/gfs2/super.c
> @@ -1542,7 +1542,11 @@ static void gfs2_evict_inode(struct inode *inode)
> goto out_unlock;
>
> out_truncate:
> - gfs2_log_flush(sdp, ip->i_gl);
> + /* write_inode_now calls writeback_single_inode, which calls
> + gfs2_write_inode. gfs2_write_inode calls gfs2_log_flush if
> + (wbc->sync_mode == WB_SYNC_ALL), which it is since we pass 1.
> + therefore, this call to gfs2_log_flush is redundant:
> + gfs2_log_flush(sdp, ip->i_gl); */
> write_inode_now(inode, 1);
> gfs2_ail_flush(ip->i_gl, 0);
>
>
This one looks like it is probably correct, however there is no point in
adding a comment to refer to code that has just been removed. Just
remove that call and put the explanation in the patch description, or
maybe include just a short comment so say that there is a log flush
implicit in the write_inode_now() call,

Steve.
 

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