MFC r341095:
Use busdma unconditionally in iflib
- Remove the complex mechanism to choose between using busdma
and raw pmap_kextract at runtime. The reduced complexity makes
the code easier to read and maintain.
- Fix a bug in the small packet receive path where clusters were
repeatedly mapped but never unmapped. We now store the cluster's
bus address and avoid re-mapping the cluster each time a small
packet is received.
This patch fixes bugs I've seen where ixl(4) will not even
respond to ping without seeing DMAR faults.
I see a small improvement (14%) on packet forwarding tests using
a Haswell based Xeon E5-2697 v3. Olivier sees a small
regression (-3% to -6%) with lower end hardware.
Reviewed by: mmacy
Sponsored by: Netflix, Inc
Differential Revision: https://reviews.freebsd.org/D17901
UnifiedSplitRaw
