Merge branch 'x86-uv-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86/uv changes from Ingo Molnar:
"UV2 BAU productization fixes.
The BAU (Broadcast Assist Unit) is SGI's fancy out of line way on UV
hardware to do TLB flushes, instead of the normal APIC IPI methods.
The commits here fix / work around hangs in their latest hardware
iteration (UV2).
My understanding is that the main purpose of the out of line
signalling channel is to improve scalability: the UV APIC hardware
glue does not handle broadcasting to many CPUs very well, and this
matters most for TLB shootdowns.
[ I don't agree with all aspects of the current approach: in hindsight
it would have been better to link the BAU at the IPI/APIC driver
level instead of the TLB shootdown level, where TLB flushes are
really just one of the uses of broadcast SMP messages. Doing that
would improve scalability in some other ways and it would also
remove a few uglies from the TLB path. It would also be nice to
push more is_uv_system() tests into proper x86_init or x86_platform
callbacks. Cliff? ]"
* 'x86-uv-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/uv: Work around UV2 BAU hangs
x86/uv: Implement UV BAU runtime enable and disable control via /proc/sgi_uv/
x86/uv: Fix the UV BAU destination timeout period
