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| author | Qu Wenruo | 2019-03-01 03:48:00 +0100 |
|---|---|---|
| committer | David Sterba | 2019-04-29 19:02:19 +0200 |
| commit | a1d198478e92cc8f05c26be746edd1c58f756c0f (patch) | |
| tree | 19df7d94bb047bfa6b239704c9868b82448daa54 /fs/btrfs/extent_io.c | |
| parent | btrfs: Introduce extent_io_tree::owner to distinguish different io_trees (diff) | |
| download | kernel-qcow2-linux-a1d198478e92cc8f05c26be746edd1c58f756c0f.tar.gz kernel-qcow2-linux-a1d198478e92cc8f05c26be746edd1c58f756c0f.tar.xz kernel-qcow2-linux-a1d198478e92cc8f05c26be746edd1c58f756c0f.zip | |
btrfs: tracepoints: Add trace events for extent_io_tree
Although btrfs heavily relies on extent_io_tree, we don't really have
any good trace events for them.
This patch will add the folowing trace events:
- trace_btrfs_set_extent_bit()
- trace_btrfs_clear_extent_bit()
- trace_btrfs_convert_extent_bit()
Since selftests could create temporary extent_io_tree without fs_info,
modify TP_fast_assign_fsid() to accept NULL as fs_info. NULL fs_info
will lead to all zero fsid.
The output would be:
btrfs_set_extent_bit: <FDID>: io_tree=INODE_IO ino=1 root=1 start=22036480 len=4096 set_bits=LOCKED
btrfs_set_extent_bit: <FSID>: io_tree=INODE_IO ino=1 root=1 start=22040576 len=4096 set_bits=LOCKED
btrfs_set_extent_bit: <FSID>: io_tree=INODE_IO ino=1 root=1 start=22044672 len=4096 set_bits=LOCKED
btrfs_set_extent_bit: <FSID>: io_tree=INODE_IO ino=1 root=1 start=22048768 len=4096 set_bits=LOCKED
btrfs_clear_extent_bit: <FSID>: io_tree=INODE_IO ino=1 root=1 start=22036480 len=16384 clear_bits=LOCKED
^^^ Extent buffer 22036480 read from disk, the locking progress
btrfs_set_extent_bit: <FSID>: io_tree=TRANS_DIRTY_PAGES ino=1 root=1 start=30425088 len=16384 set_bits=DIRTY
btrfs_set_extent_bit: <FSID>: io_tree=TRANS_DIRTY_PAGES ino=1 root=1 start=30441472 len=16384 set_bits=DIRTY
^^^ 2 new tree blocks allocated in one transaction
btrfs_set_extent_bit: <FSID>: io_tree=FREED_EXTENTS0 ino=0 root=0 start=30523392 len=16384 set_bits=DIRTY
btrfs_set_extent_bit: <FSID>: io_tree=FREED_EXTENTS0 ino=0 root=0 start=30556160 len=16384 set_bits=DIRTY
^^^ 2 old tree blocks get pinned down
There is one point which need attention:
1) Those trace events can be pretty heavy:
The following workload would generate over 400 trace events.
mkfs.btrfs -f $dev
start_trace
mount $dev $mnt -o enospc_debug
sync
touch $mnt/file1
touch $mnt/file2
touch $mnt/file3
xfs_io -f -c "pwrite 0 16k" $mnt/file4
umount $mnt
end_trace
It's not recommended to use them in real world environment.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ rename enums ]
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs/extent_io.c')
| -rw-r--r-- | fs/btrfs/extent_io.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index cfd2b237fd66..ee246a7e14c5 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -614,6 +614,7 @@ int __clear_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, int clear = 0; btrfs_debug_check_extent_io_range(tree, start, end); + trace_btrfs_clear_extent_bit(tree, start, end - start + 1, bits); if (bits & EXTENT_DELALLOC) bits |= EXTENT_NORESERVE; @@ -883,6 +884,7 @@ __set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, u64 last_end; btrfs_debug_check_extent_io_range(tree, start, end); + trace_btrfs_set_extent_bit(tree, start, end - start + 1, bits); again: if (!prealloc && gfpflags_allow_blocking(mask)) { @@ -1115,6 +1117,8 @@ int convert_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, bool first_iteration = true; btrfs_debug_check_extent_io_range(tree, start, end); + trace_btrfs_convert_extent_bit(tree, start, end - start + 1, bits, + clear_bits); again: if (!prealloc) { |