[PATCH] Enable haltpoll for arm64

[Mihai Carabas]

This patchset enables the usage of haltpoll governer on arm64. This is
specifically interesting for KVM guests.

Here are some benchmarks without/with haltpoll for a KVM guest:

a) without haltpoll:
perf bench sched pipe
# Running 'sched/pipe' benchmark:
# Executed 1000000 pipe operations between two processes

     Total time: 8.410 [sec]

       8.410882 usecs/op
         118893 ops/sec

b) with haltpoll:
perf bench sched pipe
# Running 'sched/pipe' benchmark:
# Executed 1000000 pipe operations between two processes
     Total time: 5.183 [sec]
       5.183491 usecs/op
         192920 ops/sec

Joao Martins (7):
  cpuidle-haltpoll: Make boot_option_idle_override check X86 specific
  x86: Move ARCH_HAS_CPU_RELAX to arch
  x86/kvm: Move haltpoll_want() to be arch defined
  governors/haltpoll: Drop kvm_para_available() check
  arm64: Select ARCH_HAS_CPU_RELAX
  arm64: Define TIF_POLLING_NRFLAG
  cpuidle-haltpoll: ARM64 support

 arch/Kconfig                            | 3 +++
 arch/arm64/Kconfig                      | 1 +
 arch/arm64/include/asm/thread_info.h    | 6 ++++++
 arch/x86/Kconfig                        | 1 +
 arch/x86/include/asm/cpuidle_haltpoll.h | 1 +
 arch/x86/kernel/kvm.c                   | 6 ++++++
 drivers/cpuidle/Kconfig                 | 4 ++--
 drivers/cpuidle/cpuidle-haltpoll.c      | 6 ++++--
 drivers/cpuidle/governors/haltpoll.c    | 5 +----
 include/linux/cpuidle_haltpoll.h        | 5 +++++
 10 files changed, 30 insertions(+), 8 deletions(-)

-- 
1.8.3.1