occurs only once every 10 minutes, or whenever the disk is forced to spin up by
a cache miss. The disk can then be spun down in the periods of inactivity.
-If you want to find out which process caused the disk to spin up, you can
-gather information by setting the flag /proc/sys/vm/block_dump. When this flag
-is set, Linux reports all disk read and write operations that take place, and
-all block dirtyings done to files. This makes it possible to debug why a disk
-needs to spin up, and to increase battery life even more. The output of
-block_dump is written to the kernel output, and it can be retrieved using
-"dmesg". When you use block_dump and your kernel logging level also includes
-kernel debugging messages, you probably want to turn off klogd, otherwise
-the output of block_dump will be logged, causing disk activity that is not
-normally there.
-
Configuration
-------------
Currently, these files are in /proc/sys/vm:
- admin_reserve_kbytes
-- block_dump
- compact_memory
- compaction_proactiveness
- compact_unevictable_allowed
Changing this takes effect whenever an application requests memory.
-block_dump
-==========
-
-block_dump enables block I/O debugging when set to a nonzero value. More
-information on block I/O debugging is in Documentation/admin-guide/laptops/laptop-mode.rst.
-
-
compact_memory
==============