[Cluster-devel] [GFS2 PATCH v3 10/14] GFS2: Change from tr_touched to tr_bufs

[Steven Whitehouse <swhiteho@redhat.com>]

Hi,

On 22/10/15 20:30, Bob Peterson wrote:
> This patch changes the GFS2 transaction processing so that it keeps
> track of how many buffers are associated with a transaction rather
> than whether or not it's been touched. That way, if a buffer is
> added, then revoked, then removed entirely, it can avoid some work.
How does this relate to the issue of fixing the unlink/delete code path? 
It looks like this is something that should be a separate patch and not 
part of this series,

Steve.

> Signed-off-by: Bob Peterson <rpeterso@redhat.com>
> ---
>   fs/gfs2/incore.h  |  5 ++++-
>   fs/gfs2/meta_io.c |  6 +++---
>   fs/gfs2/trans.c   | 13 +++++++------
>   3 files changed, 14 insertions(+), 10 deletions(-)
>
> diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
> index 5065e0c..c8f9bb9 100644
> --- a/fs/gfs2/incore.h
> +++ b/fs/gfs2/incore.h
> @@ -473,10 +473,13 @@ struct gfs2_trans {
>   	unsigned int tr_blocks;
>   	unsigned int tr_revokes;
>   	unsigned int tr_reserved;
> -	unsigned int tr_touched:1;
>   	unsigned int tr_attached:1;
>   	unsigned int tr_alloced:1;
>   
> +	struct gfs2_holder tr_t_gh;
> +
> +	int tr_bufs;
> +
>   	unsigned int tr_num_buf_new;
>   	unsigned int tr_num_databuf_new;
>   	unsigned int tr_num_buf_rm;
> diff --git a/fs/gfs2/meta_io.c b/fs/gfs2/meta_io.c
> index 0e1d4be..c20d7ca 100644
> --- a/fs/gfs2/meta_io.c
> +++ b/fs/gfs2/meta_io.c
> @@ -224,7 +224,7 @@ int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags,
>   	wait_on_buffer(bh);
>   	if (unlikely(!buffer_uptodate(bh))) {
>   		struct gfs2_trans *tr = current->journal_info;
> -		if (tr && tr->tr_touched)
> +		if (tr && tr->tr_bufs)
>   			gfs2_io_error_bh(sdp, bh);
>   		brelse(bh);
>   		*bhp = NULL;
> @@ -251,7 +251,7 @@ int gfs2_meta_wait(struct gfs2_sbd *sdp, struct buffer_head *bh)
>   
>   	if (!buffer_uptodate(bh)) {
>   		struct gfs2_trans *tr = current->journal_info;
> -		if (tr && tr->tr_touched)
> +		if (tr && tr->tr_bufs)
>   			gfs2_io_error_bh(sdp, bh);
>   		return -EIO;
>   	}
> @@ -276,7 +276,7 @@ void gfs2_remove_from_journal(struct buffer_head *bh, struct gfs2_trans *tr, int
>   			tr->tr_num_buf_rm++;
>   		else
>   			tr->tr_num_databuf_rm++;
> -		tr->tr_touched = 1;
> +		tr->tr_bufs--;
>   		was_pinned = 1;
>   		brelse(bh);
>   	}
> diff --git a/fs/gfs2/trans.c b/fs/gfs2/trans.c
> index 0c1bde3..25ca935 100644
> --- a/fs/gfs2/trans.c
> +++ b/fs/gfs2/trans.c
> @@ -77,8 +77,8 @@ fail:
>   static void gfs2_print_trans(const struct gfs2_trans *tr)
>   {
>   	pr_warn("Transaction created at: %pSR\n", (void *)tr->tr_ip);
> -	pr_warn("blocks=%u revokes=%u reserved=%u touched=%u\n",
> -		tr->tr_blocks, tr->tr_revokes, tr->tr_reserved, tr->tr_touched);
> +	pr_warn("blocks=%u revokes=%u reserved=%u bufs=%d\n",
> +		tr->tr_blocks, tr->tr_revokes, tr->tr_reserved, tr->tr_bufs);
>   	pr_warn("Buf %u/%u Databuf %u/%u Revoke %u/%u\n",
>   		tr->tr_num_buf_new, tr->tr_num_buf_rm,
>   		tr->tr_num_databuf_new, tr->tr_num_databuf_rm,
> @@ -94,7 +94,7 @@ void gfs2_trans_end(struct gfs2_sbd *sdp)
>   	BUG_ON(!tr);
>   	current->journal_info = NULL;
>   
> -	if (!tr->tr_touched) {
> +	if (tr->tr_bufs == 0) {
>   		gfs2_log_release(sdp, tr->tr_reserved);
>   		if (alloced) {
>   			kfree(tr);
> @@ -182,7 +182,7 @@ void gfs2_trans_add_data(struct gfs2_glock *gl, struct buffer_head *bh)
>   		gfs2_log_lock(sdp);
>   	}
>   	gfs2_assert(sdp, bd->bd_gl == gl);
> -	tr->tr_touched = 1;
> +	tr->tr_bufs++;
>   	if (list_empty(&bd->bd_list)) {
>   		set_bit(GLF_LFLUSH, &bd->bd_gl->gl_flags);
>   		set_bit(GLF_DIRTY, &bd->bd_gl->gl_flags);
> @@ -201,7 +201,7 @@ static void meta_lo_add(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)
>   	enum gfs2_freeze_state state = atomic_read(&sdp->sd_freeze_state);
>   
>   	tr = current->journal_info;
> -	tr->tr_touched = 1;
> +	tr->tr_bufs++;
>   	if (!list_empty(&bd->bd_list))
>   		return;
>   	set_bit(GLF_LFLUSH, &bd->bd_gl->gl_flags);
> @@ -256,7 +256,7 @@ void gfs2_trans_add_revoke(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)
>   
>   	BUG_ON(!list_empty(&bd->bd_list));
>   	gfs2_add_revoke(sdp, bd);
> -	tr->tr_touched = 1;
> +	tr->tr_bufs++;
>   	tr->tr_num_revoke++;
>   }
>   
> @@ -272,6 +272,7 @@ void gfs2_trans_add_unrevoke(struct gfs2_sbd *sdp, u64 blkno, unsigned int len)
>   			list_del_init(&bd->bd_list);
>   			gfs2_assert_withdraw(sdp, sdp->sd_log_num_revoke);
>   			sdp->sd_log_num_revoke--;
> +			tr->tr_bufs--;
>   			kmem_cache_free(gfs2_bufdata_cachep, bd);
>   			tr->tr_num_revoke_rm++;
>   			if (--n == 0)