http://bugzilla.suse.com/show_bug.cgi?id=1013598 Bug ID: 1013598 Summary: btrfs: kworker taking 100% cpu while copying large file (500GB) Classification: openSUSE Product: openSUSE Distribution Version: Leap 42.2 Hardware: x86-64 OS: Other Status: NEW Severity: Major Priority: P5 - None Component: Kernel Assignee: kernel-maintainers@forge.provo.novell.com Reporter: s.priebe@profihost.ag QA Contact: qa-bugs@suse.de Found By: --- Blocker: --- Kernel: is opensuse 42.2 build yesterday from commit b46b94732783a4f82c5562a0202d9c1dcc91395a from top: 27332 root 20 0 0 0 0 R 100,0 0,0 30:28.50 [kworker/u24:3] mount options: rw,noatime,compress-force=zlib,nossd,noacl,space_cache,skip_balance,subvolid=5,subvol=/ perf top shows: 49,96% [kernel] [k] rb_next 6,92% [kernel] [k] btrfs_find_space_for_alloc 6,49% [kernel] [k] longest_match 5,16% [kernel] [k] tree_search_offset.isra.25 4,23% [kernel] [k] deflate_fast 3,77% [kernel] [k] pqdownheap 2,89% [kernel] [k] fill_window 1,82% [kernel] [k] compress_block But there's plenty of free space so there's no need to hardly search for it: # btrfs filesystem usage /vmbackup/ Overall: Device size: 36.38TiB Device allocated: 10.05TiB Device unallocated: 26.32TiB Device missing: 0.00B Used: 9.71TiB Free (estimated): 26.66TiB (min: 26.66TiB) Data ratio: 1.00 Metadata ratio: 1.00 Global reserve: 512.00MiB (used: 0.00B) Data,single: Size:10.01TiB, Used:9.67TiB /dev/mapper/stripe0-vmbackup 10.01TiB Metadata,single: Size:44.00GiB, Used:37.87GiB /dev/mapper/stripe0-vmbackup 44.00GiB System,single: Size:32.00MiB, Used:1.61MiB /dev/mapper/stripe0-vmbackup 32.00MiB Unallocated: /dev/mapper/stripe0-vmbackup 26.32TiB Greets, Stefan -- You are receiving this mail because: You are on the CC list for the bug.