Comment 1 for bug 1817628

Also verified this with stress-ng's memory stressor class.

The system gets under memory pressure to the point of
calling shrink_slab() 10s to 100s thousand times a second
(verified with ftrace; function tracer; shrink_slab filter).

$ sudo stress-ng --class memory --all -1 &

# echo shrink_slab > /sys/kernel/debug/tracing/set_ftrace_filter
# echo function > /sys/kernel/debug/tracing/current_tracer
# cat /sys/kernel/debug/tracing/trace_pipe | awk '{print $4}' | cut -d. -f1 | uniq -c
  24384 998
  38792 999
      1 EVENTS]
  22883 999
      1 EVENTS]
   1450 999
 113849 1000
 117025 1001
  67285 1002
  75768 1003
      1 EVENTS]
  14496 1003
 170817 1004
  98136 1005