in a tree.
run: write 0 to disable ksm, read 0 while ksm is disabled.
- write 1 to run ksm, read 1 while ksm is running.
- write 2 to disable ksm and unmerge all its pages.
+
+ - write 1 to run ksm, read 1 while ksm is running.
+ - write 2 to disable ksm and unmerge all its pages.
sleep_millisecs: how many milliseconds ksm should sleep between
scans.