Asynchronous I/O latency to a solid-state disk greatly increased

between the 2.6.32 and 3.0 kernels. By removing the plug from
do_io_submit(), we observed a 34% improvement in the I/O latency.

Unfortunately, at this level, we don't know if the request is to
a rotating disk or not.

Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Cc: linux-aio@kvack.org
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
cpufreq: Add cpu utilization statistics to aid decisions made by userspace.
Understanding system load as seen by cpufreq can help userspace
algorithms make better decisions to improve system responsiveness.
One such example would be the MP decision algorithm which mines
various system info to make decisions on hotplugging in/out
the additional cores.

Change-Id: I277db7e1a7803a3822b61e7befa25131487cfe17
Signed-off-by: Anitha Anand <anithas@codeaurora.org>
rwsem: steal writing sem for better performance
rwsem-spinlock: let rwsem write lock stealable
Revert "cpufreq: Add cpu utilization statistics to aid decisions made by userspace."

This reverts commit b544a503d7c06667d6e54810e9d7296863c09b20.
Revert "rwsem-spinlock: let rwsem write lock stealable"

This reverts commit 12bb2d9bbf5829c97c8420258dfd8019692fcd46.
Revert "rwsem: steal writing sem for better performance"

This reverts commit e6b199f8f128ca7573009a73a73e6f0bdcafe1a0.
mp fix up
derp