Hello,
next-20190125
kcompactd0 is spinning on something, burning CPUs in the meantime:
%CPU TIME+ COMMAND
100.0 0.0 34:04.20 R [kcompactd0]
Not sure I know how to reproduce it; so am probably not going to
be a very helpful tester.
I tried to ftrace kcompactd0 PID, and I see the same path all over
the tracing file:
2) 0.119 us | unlock_page();
2) 0.109 us | unlock_page();
2) 0.096 us | compaction_free();
2) 0.104 us | ___might_sleep();
2) 0.121 us | compaction_alloc();
2) 0.111 us | page_mapped();
2) 0.105 us | page_mapped();
2) | move_to_new_page() {
2) 0.102 us | page_mapping();
2) | buffer_migrate_page_norefs() {
2) | __buffer_migrate_page() {
2) | expected_page_refs() {
2) 0.118 us | page_mapping();
2) 0.321 us | }
2) | __might_sleep() {
2) 0.122 us | ___might_sleep();
2) 0.332 us | }
2) | _raw_spin_lock() {
2) 0.115 us | preempt_count_add();
2) 0.321 us | }
2) | _raw_spin_unlock() {
2) 0.114 us | preempt_count_sub();
2) 0.321 us | }
2) | invalidate_bh_lrus() {
2) | on_each_cpu_cond() {
2) | on_each_cpu_cond_mask() {
2) | __might_sleep() {
2) 0.114 us | ___might_sleep();
2) 0.316 us | }
2) 0.109 us | preempt_count_add();
2) 0.128 us | has_bh_in_lru();
2) 0.105 us | has_bh_in_lru();
2) 0.124 us | has_bh_in_lru();
2) 0.103 us | has_bh_in_lru();
2) 0.125 us | has_bh_in_lru();
2) 0.105 us | has_bh_in_lru();
2) 0.123 us | has_bh_in_lru();
2) 0.107 us | has_bh_in_lru();
2) | on_each_cpu_mask() {
2) 0.104 us | preempt_count_add();
2) 0.110 us | smp_call_function_many();
2) 0.105 us | preempt_count_sub();
2) 0.764 us | }
2) 0.116 us | preempt_count_sub();
2) 3.676 us | }
2) 3.889 us | }
2) 4.087 us | }
2) | _raw_spin_lock() {
2) 0.112 us | preempt_count_add();
2) 0.315 us | }
2) | _raw_spin_unlock() {
2) 0.108 us | preempt_count_sub();
2) 0.309 us | }
2) | unlock_buffer() {
2) | wake_up_bit() {
2) 0.118 us | __wake_up_bit();
2) 0.317 us | }
2) 0.513 us | }
2) 7.440 us | }
2) 7.643 us | }
2) 8.070 us | }
PG migration fails a lot:
pgmigrate_success 111063
pgmigrate_fail 269841559
compact_migrate_scanned 536253365
compact_free_scanned 360889
compact_isolated 270072733
compact_stall 0
compact_fail 0
compact_success 0
compact_daemon_wake 56
compact_daemon_migrate_scanned 536253365
compact_daemon_free_scanned 360889
Let me know if I can help with anything else. I'll keep the the box alive
for a while, but will have to power it off eventually.
-ss
