Commit 480b9b4d authored by Qu Wenruo's avatar Qu Wenruo Committed by David Sterba
Browse files

btrfs: extent-tree: Add trace events for space info numbers update 



Add trace event for update_bytes_pinned() and update_bytes_may_use() to
detect underflow better.

The output would be something like (only showing data part):

  ## Buffered write start, 16K total ##
  2255.954 xfs_io/860 btrfs:update_bytes_may_use:(nil)U: type=DATA old=0 diff=4096
  2257.169 sudo/860 btrfs:update_bytes_may_use:(nil)U: type=DATA old=4096 diff=4096
  2257.346 sudo/860 btrfs:update_bytes_may_use:(nil)U: type=DATA old=8192 diff=4096
  2257.542 sudo/860 btrfs:update_bytes_may_use:(nil)U: type=DATA old=12288 diff=4096

  ## Delalloc start ##
  3727.853 kworker/u8:3-e/700 btrfs:update_bytes_may_use:(nil)U: type=DATA old=16384 diff=-16384

  ## Space cache update ##
  3733.132 sudo/862 btrfs:update_bytes_may_use:(nil)U: type=DATA old=0 diff=65536
  3733.169 sudo/862 btrfs:update_bytes_may_use:(nil)U: type=DATA old=65536 diff=-65536
  3739.868 sudo/862 btrfs:update_bytes_may_use:(nil)U: type=DATA old=0 diff=65536
  3739.891 sudo/862 btrfs:update_bytes_may_use:(nil)U: type=DATA old=65536 diff=-65536

These two trace events will allow bcc tool to probe btrfs_space_info
changes and detect underflow with more details (e.g. backtrace for each
update).

Signed-off-by: default avatarQu Wenruo <wqu@suse.com>
Reviewed-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 0185f364

fs/btrfs/extent-tree.c

+20 −16
Original line number Diff line number Diff line
@@ -55,10 +55,12 @@ enum { 
 * Declare a helper function to detect underflow of various space info members

 */

#define DECLARE_SPACE_INFO_UPDATE(name)					\

static inline void update_##name(struct btrfs_space_info *sinfo,	\

static inline void update_##name(struct btrfs_fs_info *fs_info,		\

				 struct btrfs_space_info *sinfo,	\

				 s64 bytes)				\

{									\

	lockdep_assert_held(&sinfo->lock);				\

	trace_update_##name(fs_info, sinfo, sinfo->name, bytes);	\

	if (bytes < 0 && sinfo->name < -bytes) {			\

		WARN_ON(1);						\

		sinfo->name = 0;					\
@@ -4209,7 +4211,7 @@ commit_trans: 
					      data_sinfo->flags, bytes, 1);

		return -ENOSPC;

	}

	update_bytes_may_use(data_sinfo, bytes);

	update_bytes_may_use(fs_info, data_sinfo, bytes);

	trace_btrfs_space_reservation(fs_info, "space_info",

				      data_sinfo->flags, bytes, 1);

	spin_unlock(&data_sinfo->lock);
@@ -4262,7 +4264,7 @@ void btrfs_free_reserved_data_space_noquota(struct inode *inode, u64 start, 


	data_sinfo = fs_info->data_sinfo;

	spin_lock(&data_sinfo->lock);

	update_bytes_may_use(data_sinfo, -len);

	update_bytes_may_use(fs_info, data_sinfo, -len);

	trace_btrfs_space_reservation(fs_info, "space_info",

				      data_sinfo->flags, len, 0);

	spin_unlock(&data_sinfo->lock);
@@ -5169,13 +5171,13 @@ static int __reserve_metadata_bytes(struct btrfs_fs_info *fs_info, 
	 * If not things get more complicated.

	 */

	if (used + orig_bytes <= space_info->total_bytes) {

		update_bytes_may_use(space_info, orig_bytes);

		update_bytes_may_use(fs_info, space_info, orig_bytes);

		trace_btrfs_space_reservation(fs_info, "space_info",

					      space_info->flags, orig_bytes, 1);

		ret = 0;

	} else if (can_overcommit(fs_info, space_info, orig_bytes, flush,

				  system_chunk)) {

		update_bytes_may_use(space_info, orig_bytes);

		update_bytes_may_use(fs_info, space_info, orig_bytes);

		trace_btrfs_space_reservation(fs_info, "space_info",

					      space_info->flags, orig_bytes, 1);

		ret = 0;
@@ -5503,7 +5505,7 @@ again: 
		flush = BTRFS_RESERVE_FLUSH_ALL;

		goto again;

	}

	update_bytes_may_use(space_info, -num_bytes);

	update_bytes_may_use(fs_info, space_info, -num_bytes);

	trace_btrfs_space_reservation(fs_info, "space_info",

				      space_info->flags, num_bytes, 0);

	spin_unlock(&space_info->lock);
@@ -5531,7 +5533,8 @@ again: 
						      ticket->bytes, 1);

			list_del_init(&ticket->list);

			num_bytes -= ticket->bytes;

			update_bytes_may_use(space_info, ticket->bytes);

			update_bytes_may_use(fs_info, space_info,

					     ticket->bytes);

			ticket->bytes = 0;

			space_info->tickets_id++;

			wake_up(&ticket->wait);
@@ -5539,7 +5542,7 @@ again: 
			trace_btrfs_space_reservation(fs_info, "space_info",

						      space_info->flags,

						      num_bytes, 1);

			update_bytes_may_use(space_info, num_bytes);

			update_bytes_may_use(fs_info, space_info, num_bytes);

			ticket->bytes -= num_bytes;

			num_bytes = 0;

		}
@@ -5832,14 +5835,14 @@ static void update_global_block_rsv(struct btrfs_fs_info *fs_info) 
			num_bytes = min(num_bytes,

					block_rsv->size - block_rsv->reserved);

			block_rsv->reserved += num_bytes;

			update_bytes_may_use(sinfo, num_bytes);

			update_bytes_may_use(fs_info, sinfo, num_bytes);

			trace_btrfs_space_reservation(fs_info, "space_info",

						      sinfo->flags, num_bytes,

						      1);

		}

	} else if (block_rsv->reserved > block_rsv->size) {

		num_bytes = block_rsv->reserved - block_rsv->size;

		update_bytes_may_use(sinfo, -num_bytes);

		update_bytes_may_use(fs_info, sinfo, -num_bytes);

		trace_btrfs_space_reservation(fs_info, "space_info",

				      sinfo->flags, num_bytes, 0);

		block_rsv->reserved = block_rsv->size;
@@ -6302,7 +6305,7 @@ static int update_block_group(struct btrfs_trans_handle *trans, 
			old_val -= num_bytes;

			btrfs_set_block_group_used(&cache->item, old_val);

			cache->pinned += num_bytes;

			update_bytes_pinned(cache->space_info, num_bytes);

			update_bytes_pinned(info, cache->space_info, num_bytes);

			cache->space_info->bytes_used -= num_bytes;

			cache->space_info->disk_used -= num_bytes * factor;

			spin_unlock(&cache->lock);
@@ -6377,7 +6380,7 @@ static int pin_down_extent(struct btrfs_block_group_cache *cache, 
	spin_lock(&cache->space_info->lock);

	spin_lock(&cache->lock);

	cache->pinned += num_bytes;

	update_bytes_pinned(cache->space_info, num_bytes);

	update_bytes_pinned(fs_info, cache->space_info, num_bytes);

	if (reserved) {

		cache->reserved -= num_bytes;

		cache->space_info->bytes_reserved -= num_bytes;
@@ -6586,7 +6589,7 @@ static int btrfs_add_reserved_bytes(struct btrfs_block_group_cache *cache, 
	} else {

		cache->reserved += num_bytes;

		space_info->bytes_reserved += num_bytes;

		update_bytes_may_use(space_info, -ram_bytes);

		update_bytes_may_use(cache->fs_info, space_info, -ram_bytes);

		if (delalloc)

			cache->delalloc_bytes += num_bytes;

	}
@@ -6742,7 +6745,7 @@ static int unpin_extent_range(struct btrfs_fs_info *fs_info, 
		spin_lock(&space_info->lock);

		spin_lock(&cache->lock);

		cache->pinned -= len;

		update_bytes_pinned(space_info, -len);

		update_bytes_pinned(fs_info, space_info, -len);



		trace_btrfs_space_reservation(fs_info, "pinned",

					      space_info->flags, len, 0);
@@ -6763,7 +6766,8 @@ static int unpin_extent_range(struct btrfs_fs_info *fs_info, 
				to_add = min(len, global_rsv->size -

					     global_rsv->reserved);

				global_rsv->reserved += to_add;

				update_bytes_may_use(space_info, to_add);

				update_bytes_may_use(fs_info, space_info,

						     to_add);

				if (global_rsv->reserved >= global_rsv->size)

					global_rsv->full = 1;

				trace_btrfs_space_reservation(fs_info,
@@ -11024,7 +11028,7 @@ void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info) 
		spin_lock(&space_info->lock);

		spin_lock(&block_group->lock);



		update_bytes_pinned(space_info, -block_group->pinned);

		update_bytes_pinned(fs_info, space_info, -block_group->pinned);

		space_info->bytes_readonly += block_group->pinned;

		percpu_counter_add_batch(&space_info->total_bytes_pinned,

				   -block_group->pinned,

include/trace/events/btrfs.h

+40 −0
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ struct btrfs_qgroup_extent_record; 
struct btrfs_qgroup;

struct extent_io_tree;

struct prelim_ref;

struct btrfs_space_info;



TRACE_DEFINE_ENUM(FLUSH_DELAYED_ITEMS_NR);

TRACE_DEFINE_ENUM(FLUSH_DELAYED_ITEMS);
@@ -2091,6 +2092,45 @@ DEFINE_BTRFS_LOCK_EVENT(btrfs_try_tree_read_lock); 
DEFINE_BTRFS_LOCK_EVENT(btrfs_try_tree_write_lock);

DEFINE_BTRFS_LOCK_EVENT(btrfs_tree_read_lock_atomic);



DECLARE_EVENT_CLASS(btrfs__space_info_update,



	TP_PROTO(struct btrfs_fs_info *fs_info,

		 struct btrfs_space_info *sinfo, u64 old, s64 diff),



	TP_ARGS(fs_info, sinfo, old, diff),



	TP_STRUCT__entry_btrfs(

		__field(	u64,	type		)

		__field(	u64,	old		)

		__field(	s64,	diff		)

	),



	TP_fast_assign_btrfs(fs_info,

		__entry->type	= sinfo->flags;

		__entry->old	= old;

		__entry->diff	= diff;

	),

	TP_printk_btrfs("type=%s old=%llu diff=%lld",

		__print_flags(__entry->type, "|", BTRFS_GROUP_FLAGS),

		__entry->old, __entry->diff)

);



DEFINE_EVENT(btrfs__space_info_update, update_bytes_may_use,



	TP_PROTO(struct btrfs_fs_info *fs_info,

		 struct btrfs_space_info *sinfo, u64 old, s64 diff),



	TP_ARGS(fs_info, sinfo, old, diff)

);



DEFINE_EVENT(btrfs__space_info_update, update_bytes_pinned,



	TP_PROTO(struct btrfs_fs_info *fs_info,

		 struct btrfs_space_info *sinfo, u64 old, s64 diff),



	TP_ARGS(fs_info, sinfo, old, diff)

);



#endif /* _TRACE_BTRFS_H */



/* This part must be outside protection */

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