[PATCHSET v4 0/4] Split iowait into two states

[Jens Axboe <axboe@kernel.dk>]

Hi,

This is v3 of the patchset where the current in_iowait state is split
into two parts:

1) The "task is sleeping waiting on IO", and would like cpufreq goodness
   in terms of sleep and wakeup latencies.
2) The above, and also accounted as such in the iowait stats.

The current ->in_iowait covers both, this series splits it into two types
of state so that each can be controlled seperately.

Patches 1..3 are prep patches, changing the type of
task_struct->nr_iowait and adding helpers to manipulate the iowait counts.

Patch 4 does the actual splitting.

Comments welcome! Peter, CC'ing you since I did on the previous posting,
feel free to ignore.

Since v3:
- Move to an atomic_long_t and drop the locking required by encoding
  both the iowait and iowait_acct state in the same variable. Suggested
  by Thomas.

-- 
Jens Axboe