Qu Wenruo a1d198478e 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>		2019-04-29 19:02:19 +02:00
..
events	btrfs: tracepoints: Add trace events for extent_io_tree	2019-04-29 19:02:19 +02:00
bpf_probe.h	bpf: introduce BPF_RAW_TRACEPOINT	2018-03-28 22:55:19 +02:00
define_trace.h	bpf: introduce BPF_RAW_TRACEPOINT	2018-03-28 22:55:19 +02:00
perf.h
syscall.h
trace_events.h	tracing: Prevent further users of zero size static arrays in trace events	2018-05-29 08:29:13 -04:00