linux-kernel - [PATCH v4 0/3] KVM: Introduce dedicated vCPUs hint KVM_HINTS

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Date:   Tue, 13 Feb 2018 09:05:39 +0800
From:   Wanpeng Li <kernellwp@...il.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        Eduardo Habkost <ehabkost@...hat.com>
Subject: [PATCH v4 0/3] KVM: Introduce dedicated vCPUs hint KVM_HINTS_DEDICATED

This patchset introduces dedicated vCPUs(vCPU pinning, and there is no 
vCPU over-commitment) hint KVM_HINTS_DEDICATED, it has two users now:

1) Waiman Long mentioned that:

    Generally speaking, unfair lock performs well for VMs with a small
    number of vCPUs. Native qspinlock may perform better than pvqspinlock
    if there is vCPU pinning and there is no vCPU over-commitment.

2) vCPUs are very unlikely to get preempted when they are the only task 
   running on a CPU. PV TLB flush is slower that the native flush in that 
   case.

v3 -> v4:
 * update feature bit document
v2 -> v3:
 * a separate table for CPUID[0x40000001].EDX bits
 * a new kvm_hint_has_feature macro
v1 -> v2:
 * update to KVM_HINTS_DEDICATED

Wanpeng Li (3):
  KVM: Introduce dedicated vCPUs hint KVM_HINTS_DEDICATED
  KVM: X86: Choose qspinlock when dedicated vCPUs available
  KVM: X86: Don't use PV TLB flush with dedicated vCPUs and steal time disabled

 Documentation/virtual/kvm/cpuid.txt  | 15 +++++++++++++--
 arch/mips/include/asm/kvm_para.h     |  5 +++++
 arch/powerpc/include/asm/kvm_para.h  |  5 +++++
 arch/s390/include/asm/kvm_para.h     |  5 +++++
 arch/x86/include/asm/kvm_para.h      |  6 ++++++
 arch/x86/include/uapi/asm/kvm_para.h |  8 ++++++--
 arch/x86/kernel/kvm.c                | 18 ++++++++++++++++--
 include/asm-generic/kvm_para.h       |  5 +++++
 include/linux/kvm_para.h             |  5 +++++
 9 files changed, 66 insertions(+), 6 deletions(-)

-- 
2.7.4