Re: [PATCH 2/2] btrfs: Add trace point for qgroup reserved space

[Goldwyn Rodrigues <rgoldwyn@suse.de>]

On 09/29/2016 08:15 PM, Qu Wenruo wrote:
> Introduce the following trace points:
> qgroup_update_reserve
> qgroup_meta_reserve
> 
> And modify the timing of btrfs_qgroup_free_delayed_ref() and
> btrfs_qgroup_release_data() events, to work with qgroup_update_reserve()
> event.
> 
> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>

Reviewed-by: Goldwyn Rodrigues <rgoldwyn@suse.com>


> ---
>  fs/btrfs/qgroup.c            | 21 ++++++++++++++++++---
>  fs/btrfs/qgroup.h            |  2 +-
>  include/trace/events/btrfs.h | 43 +++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 62 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
> index 8532587..593a519 100644
> --- a/fs/btrfs/qgroup.c
> +++ b/fs/btrfs/qgroup.c
> @@ -1062,6 +1062,8 @@ static int __qgroup_excl_accounting(struct btrfs_fs_info *fs_info,
>  	qgroup->excl += sign * num_bytes;
>  	qgroup->excl_cmpr += sign * num_bytes;
>  	if (sign > 0) {
> +		trace_qgroup_update_reserve(fs_info, qgroup->qgroupid,
> +					    qgroup->reserved, (s64)-num_bytes);
>  		if (WARN_ON(qgroup->reserved < num_bytes))
>  			qgroup->reserved = 0;
>  		else
> @@ -1087,6 +1089,9 @@ static int __qgroup_excl_accounting(struct btrfs_fs_info *fs_info,
>  		WARN_ON(sign < 0 && qgroup->excl < num_bytes);
>  		qgroup->excl += sign * num_bytes;
>  		if (sign > 0) {
> +			trace_qgroup_update_reserve(fs_info, qgroup->qgroupid,
> +						    qgroup->reserved,
> +						    (s64)-num_bytes);
>  			if (WARN_ON(qgroup->reserved < num_bytes))
>  				qgroup->reserved = 0;
>  			else
> @@ -2164,6 +2169,8 @@ static int qgroup_reserve(struct btrfs_root *root, u64 num_bytes)
>  
>  		qg = u64_to_ptr(unode->aux);
>  
> +		trace_qgroup_update_reserve(fs_info, qg->qgroupid,
> +					    qg->reserved, num_bytes);
>  		qg->reserved += num_bytes;
>  	}
>  
> @@ -2209,6 +2216,8 @@ void btrfs_qgroup_free_refroot(struct btrfs_fs_info *fs_info,
>  
>  		qg = u64_to_ptr(unode->aux);
>  
> +		trace_qgroup_update_reserve(fs_info, qg->qgroupid,
> +					    qg->reserved, (s64)-num_bytes);
>  		if (WARN_ON(qgroup->reserved < num_bytes))
>  			qgroup->reserved = 0;
>  		else
> @@ -2637,12 +2646,12 @@ static int __btrfs_qgroup_release_data(struct inode *inode, u64 start, u64 len,
>  	if (ret < 0)
>  		goto out;
>  
> -	if (free) {
> -		qgroup_free(BTRFS_I(inode)->root, changeset.bytes_changed);
> +	if (free)
>  		trace_op = QGROUP_FREE;
> -	}
>  	trace_btrfs_qgroup_release_data(inode, start, len,
>  					changeset.bytes_changed, trace_op);
> +	if (free)
> +		qgroup_free(BTRFS_I(inode)->root, changeset.bytes_changed);
>  out:
>  	ulist_free(changeset.range_changed);
>  	return ret;
> @@ -2692,6 +2701,8 @@ int btrfs_qgroup_reserve_meta(struct btrfs_root *root, int num_bytes)
>  		return 0;
>  
>  	BUG_ON(num_bytes != round_down(num_bytes, root->nodesize));
> +	trace_qgroup_meta_reserve(root->fs_info, root->objectid,
> +				  (s64)num_bytes);
>  	ret = qgroup_reserve(root, num_bytes);
>  	if (ret < 0)
>  		return ret;
> @@ -2709,6 +2720,8 @@ void btrfs_qgroup_free_meta_all(struct btrfs_root *root)
>  	reserved = atomic_xchg(&root->qgroup_meta_rsv, 0);
>  	if (reserved == 0)
>  		return;
> +	trace_qgroup_meta_reserve(root->fs_info, root->objectid,
> +				  (s64)-reserved);
>  	qgroup_free(root, reserved);
>  }
>  
> @@ -2720,6 +2733,8 @@ void btrfs_qgroup_free_meta(struct btrfs_root *root, int num_bytes)
>  	BUG_ON(num_bytes != round_down(num_bytes, root->nodesize));
>  	WARN_ON(atomic_read(&root->qgroup_meta_rsv) < num_bytes);
>  	atomic_sub(num_bytes, &root->qgroup_meta_rsv);
> +	trace_qgroup_meta_reserve(root->fs_info, root->objectid,
> +				  (s64)-num_bytes);
>  	qgroup_free(root, num_bytes);
>  }
>  
> diff --git a/fs/btrfs/qgroup.h b/fs/btrfs/qgroup.h
> index 1bc64c8..6b6756c 100644
> --- a/fs/btrfs/qgroup.h
> +++ b/fs/btrfs/qgroup.h
> @@ -114,8 +114,8 @@ void btrfs_qgroup_free_refroot(struct btrfs_fs_info *fs_info,
>  static inline void btrfs_qgroup_free_delayed_ref(struct btrfs_fs_info *fs_info,
>  						 u64 ref_root, u64 num_bytes)
>  {
> -	btrfs_qgroup_free_refroot(fs_info, ref_root, num_bytes);
>  	trace_btrfs_qgroup_free_delayed_ref(fs_info, ref_root, num_bytes);
> +	btrfs_qgroup_free_refroot(fs_info, ref_root, num_bytes);
>  }
>  void assert_qgroups_uptodate(struct btrfs_trans_handle *trans);
>  
> diff --git a/include/trace/events/btrfs.h b/include/trace/events/btrfs.h
> index e030d6f..fb3cb6c 100644
> --- a/include/trace/events/btrfs.h
> +++ b/include/trace/events/btrfs.h
> @@ -1468,6 +1468,49 @@ TRACE_EVENT(qgroup_update_counters,
>  		  __entry->cur_new_count)
>  );
>  
> +TRACE_EVENT(qgroup_update_reserve,
> +
> +	TP_PROTO(struct btrfs_fs_info *fs_info, u64 qgid, u64 cur_reserved,
> +		 s64 diff),
> +
> +	TP_ARGS(fs_info, qgid, cur_reserved, diff),
> +
> +	TP_STRUCT__entry_btrfs(
> +		__field(	u64,	qgid			)
> +		__field(	u64,	cur_reserved		)
> +		__field(	s64,	diff			)
> +	),
> +
> +	TP_fast_assign_btrfs(fs_info,
> +		__entry->qgid		= qgid;
> +		__entry->cur_reserved	= cur_reserved;
> +		__entry->diff		= diff;
> +	),
> +
> +	TP_printk_btrfs("qgid = %llu, cur_reserved = %llu, diff = %lld",
> +		__entry->qgid, __entry->cur_reserved, __entry->diff)
> +);
> +
> +TRACE_EVENT(qgroup_meta_reserve,
> +
> +	TP_PROTO(struct btrfs_fs_info *fs_info, u64 refroot, s64 diff),
> +
> +	TP_ARGS(fs_info, refroot, diff),
> +
> +	TP_STRUCT__entry_btrfs(
> +		__field(	u64,	refroot			)
> +		__field(	u64,	diff			)
> +	),
> +
> +	TP_fast_assign_btrfs(fs_info,
> +		__entry->refroot	= refroot;
> +		__entry->diff		= diff;
> +	),
> +
> +	TP_printk_btrfs("refroot = %llu, diff = %lld",
> +		__entry->refroot, __entry->diff)
> +);
> +
>  #endif /* _TRACE_BTRFS_H */
>  
>  /* This part must be outside protection */
> 

-- 
Goldwyn