On Fri, Mar 01, 2019 at 10:47:57AM +0800, Qu Wenruo wrote: > - Allow NULL fs_info for TP_fast_assign_fsid() > There is extent bits operation in selftest which is too deep to pass > fs_info. And since it's in selftest, it shouldn't trigger trace > events. > But to be safe, we still need to check fs_indo in > TP_fast_assign_fsid(), for NULL fs_info, just keep fsid filled with > zero.
Ok, better be safe here. I'd still like to remove the conditional, as the tests typically access only a single filesystem we could export the fs_info globally, avoiding the need to pass it around. > There is one point which need extra attention: > 1) Those trace events are pretty heavy > The following workload would generate over 400 trace events. I'm not sure if 400 is considered a lot, I'd say 400.000 would be a lot for the steps below. > 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. > > Changelog: > v2: > - Introduce fs_info to distinguish different btrfs filesystems > - Code style change to make trace code more elegant > - Minor IO_TREE_* naming change. > - Use btrfs_ino() to replace raw inode number. > - Change extent_io_tree::owner declaration to avoid affecting spinlock. v2 looks good to me, thanks. I'll add it to the 5.2 queue.
