On 09/11/2018 03:39, Eric Farman wrote:
Hi Connie, Pierre,
This is a first round of rework to vfio-ccw that I've been cooking to
make the channel program handler easier to understand. My apologies
for the number of patches; as there are some intersections within them
I couldn't break them up without forcing them to be applied in a
particular order. I imagine that since there will probably need to be
some discussion, an RFC tag makes sense and one giant series will be
fine for now. I can break them up for later versions if desired.
(Sidebar: I'm leaving next Thursday for an early start on the US
Thanksgiving holiday. So if you are busy and can't get to this,
no problem! Now where did I leave Pierre's rework patches... :)
Patch summary:
1-2: Fixes for cleanup on error paths
3: Code simplication
I am absolutely OK with these three first patches.
4-6: Simplify the ccwchain processing
7-10: Simplify the pfn_array processing
I still need some investigation on the last 7 ones.
On a first view, it looks generally good but I developed some ideas on
the subject you address that you may want to study and may be implement
as part of this memory optimization series:
- avoiding the multiples CCW chain alloc/free (already discussed in the
dedicated patch)
- optimize the allocations of CCW chain metadata using kmem_caches
or
- dedicate a pre-allocated page to handle CCW chains in a single copy
per subchain.
we would certainly never need more than a single page.
Regards,
Pierre
--
Pierre Morel
Linux/KVM/QEMU in Böblingen - Germany
