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: Qu Wenruo <w...@suse.com>
---
fs/btrfs/extent-tree.c | 36 ++++++++++++++++++---------------
include/trace/events/btrfs.h | 39 ++++++++++++++++++++++++++++++++++++
2 files changed, 59 insertions(+), 16 deletions(-)
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 54c853ea0585..edaecf755bb7 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -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; \
@@ -4283,7 +4285,7 @@ int btrfs_alloc_data_chunk_ondemand(struct btrfs_inode
*inode, u64 bytes)
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);
@@ -4336,7 +4338,7 @@ 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);
@@ -5238,13 +5240,13 @@ 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;
@@ -5572,7 +5574,7 @@ static void space_info_add_old_bytes(struct btrfs_fs_info
*fs_info,
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);
@@ -5600,7 +5602,8 @@ static void space_info_add_new_bytes(struct btrfs_fs_info
*fs_info,
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);
@@ -5608,7 +5611,7 @@ static void space_info_add_new_bytes(struct btrfs_fs_info
*fs_info,
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;
}
@@ -5980,14 +5983,14 @@ 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;
@@ -6411,7 +6414,7 @@ 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);
@@ -6485,7 +6488,7 @@ static int pin_down_extent(struct btrfs_fs_info *fs_info,
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;
@@ -6694,7 +6697,7 @@ 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;
}
@@ -6850,7 +6853,7 @@ 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);
@@ -6871,7 +6874,8 @@ 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,
@@ -11144,7 +11148,7 @@ 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,
diff --git a/include/trace/events/btrfs.h b/include/trace/events/btrfs.h
index 8b12753fee78..81544342f89a 100644
--- a/include/trace/events/btrfs.h
+++ b/include/trace/events/btrfs.h
@@ -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);
@@ -2005,6 +2006,44 @@ TRACE_EVENT(btrfs_convert_extent_bit,
__print_flags(__entry->clear_bits, "|", EXTENT_FLAGS))
);
+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 */
--
2.21.0
