linux/include
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
..
acpi ACPI: use different default debug value than ACPICA 2019-03-25 10:45:59 +01:00
asm-generic syscalls: Remove start and number from syscall_set_arguments() args 2019-04-05 09:27:23 -04:00
clocksource
crypto
drm drm/ttm: fix re-init of global structures 2019-04-19 11:11:20 -05:00
dt-bindings dt-bindings: clock: sifive: add FU540-C000 PRCI clock constants 2019-04-09 20:36:40 -07:00
keys KEYS: trusted: fix -Wvarags warning 2019-04-08 15:58:54 -07:00
kvm ARM: some cleanups, direct physical timer assignment, cache sanitization 2019-03-15 15:00:28 -07:00
linux There tracing fixes: 2019-04-26 11:09:55 -07:00
math-emu
media
memory
misc auxdisplay: charlcd: Introduce charlcd_free() helper 2019-03-17 08:48:16 +01:00
net netfilter: ctnetlink: don't use conntrack/expect object addresses as id 2019-04-15 07:31:44 +02:00
pcmcia
ras
rdma
scsi
soc IOMMU Updates for Linux v5.1 2019-03-10 12:29:52 -07:00
sound ASoC: core: conditionally increase module refcount on component open 2019-04-08 14:15:44 +07:00
target
trace btrfs: tracepoints: Add trace events for extent_io_tree 2019-04-29 19:02:19 +02:00
uapi 5.1 Third RC pull request 2019-04-28 10:00:45 -07:00
video media updates for v5.1-rc1 2019-03-09 14:45:54 -08:00
xen