[PATCH RFC 00/12] xen-block: indirect descriptors

[Roger Pau Monne <roger.pau@citrix.com>]

This series contains the initial implementation of indirect 
descriptors for Linux blkback/blkfront.

Patches 1, 2, 3, 4 and 5 are bug fixes and minor optimizations.

Patch 6 contains a LRU implementation for blkback that will be needed 
when using indirect descriptors (since we are no longer able to map 
all possible grants blkfront might use).

Patch 7 is an addition to the print stats function in blkback in order 
to print information regarding persistent grant usage.

Patches 8, 9, 10 and 11 are preparatory work for indirect descriptors 
implementation, mainly make blkback use dynamic memory and remove the 
shared blkbk structure, so each blkback instance has it's own list of 
free requests, pages, handles and so on.

Finally patch 12 contains the indirect descriptors implementation.

I've also pushed this series to the following git repository:

git://xenbits.xen.org/people/royger/linux.git xen-block-indirect

Performance benefit of this series can be seen in the following graph:

http://xenbits.xen.org/people/royger/plot_indirect.png

Thanks for the review, Roger.