[RFC] fence, sa allocator, ib pool, semaphore rework

[j.glisse at gmail.com]

First chunk rework fence to use uin64_t, unlike previous patch,
we only emit the lower 32 bits with the hw. The upper 32bits is
handled in the fence process function where a lenghty comment
discuss all the possible things that can go wrong and why it
doesn't matter.

Then taking advantage of faster fence querying, the sa allocator
is simplified and improved. The commit message describe the
algorithm used. Taking advantage of that ib & semaphore is simplified
to use the same temporary ring related manager.

To finish all this, more code is axed and simplified.


It all need the previous 17 patches and the various other small fixes.
To make it easier i regrouped all the patch needed at :
http://people.freedesktop.org/~glisse/reset5/base/

Those patch should hit next soon.

The whole patchset can also be found at :
http://people.freedesktop.org/~glisse/reset5/


It all got limited testing so far, but i tried hard to make sure that
each step is working and thus bisectable. I split the fence rework
in 2 part so one can bisect if either the move to 64bits fence or
the complete change in fence handling logic is causing trouble.

Cheers,
Jerome