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authorPan Xinhui <xinhui.pan@linux.vnet.ibm.com>2016-11-02 10:08:35 +0100
committerIngo Molnar <mingo@kernel.org>2016-11-22 12:48:08 +0100
commit0b9f6c4615c993d2b552e0d2bd1ade49b56e5beb (patch)
treead86293bc792f8035ff78421370793da8c786868 /arch/x86/include/uapi
parentkvm: Introduce kvm_write_guest_offset_cached() (diff)
downloadlinux-0b9f6c4615c993d2b552e0d2bd1ade49b56e5beb.tar.xz
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x86/kvm: Support the vCPU preemption check
Support the vcpu_is_preempted() functionality under KVM. This will enhance lock performance on overcommitted hosts (more runnable vCPUs than physical CPUs in the system) as doing busy waits for preempted vCPUs will hurt system performance far worse than early yielding. Use struct kvm_steal_time::preempted to indicate that if a vCPU is running or not. Signed-off-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Cc: David.Laight@ACULAB.COM Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: benh@kernel.crashing.org Cc: boqun.feng@gmail.com Cc: borntraeger@de.ibm.com Cc: bsingharora@gmail.com Cc: dave@stgolabs.net Cc: jgross@suse.com Cc: kernellwp@gmail.com Cc: konrad.wilk@oracle.com Cc: linuxppc-dev@lists.ozlabs.org Cc: mpe@ellerman.id.au Cc: paulmck@linux.vnet.ibm.com Cc: paulus@samba.org Cc: rkrcmar@redhat.com Cc: virtualization@lists.linux-foundation.org Cc: will.deacon@arm.com Cc: xen-devel-request@lists.xenproject.org Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/1478077718-37424-9-git-send-email-xinhui.pan@linux.vnet.ibm.com [ Typo fixes. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/include/uapi')
-rw-r--r--arch/x86/include/uapi/asm/kvm_para.h4
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/x86/include/uapi/asm/kvm_para.h b/arch/x86/include/uapi/asm/kvm_para.h
index 94dc8ca434e0..1421a6585126 100644
--- a/arch/x86/include/uapi/asm/kvm_para.h
+++ b/arch/x86/include/uapi/asm/kvm_para.h
@@ -45,7 +45,9 @@ struct kvm_steal_time {
__u64 steal;
__u32 version;
__u32 flags;
- __u32 pad[12];
+ __u8 preempted;
+ __u8 u8_pad[3];
+ __u32 pad[11];
};
#define KVM_STEAL_ALIGNMENT_BITS 5