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authorPan Xinhui <xinhui.pan@linux.vnet.ibm.com>2016-11-02 05:08:33 -0400
committerIngo Molnar <mingo@kernel.org>2016-11-22 12:48:07 +0100
commit446f3dc8cc0af59259c6c8b898726fae7ed2c055 (patch)
tree29d9eae964ff972bcac9fa24d20034cb220c64dc /arch/x86/kernel/paravirt-spinlocks.c
parent760928c0dafc7d0faf0c0248e28e16d4c8dc7ad6 (diff)
downloadlinux-446f3dc8cc0af59259c6c8b898726fae7ed2c055.tar.bz2
locking/core, x86/paravirt: Implement vcpu_is_preempted(cpu) for KVM and Xen guests
Optimize spinlock and mutex busy-loops by providing a vcpu_is_preempted(cpu) function on KVM and Xen platforms. Extend the pv_lock_ops interface accordingly and implement the callbacks on KVM and Xen. Signed-off-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> [ Translated to English. ] 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/1478077718-37424-7-git-send-email-xinhui.pan@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/paravirt-spinlocks.c')
-rw-r--r--arch/x86/kernel/paravirt-spinlocks.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/x86/kernel/paravirt-spinlocks.c b/arch/x86/kernel/paravirt-spinlocks.c
index 2c55a003b793..2f204dd552a4 100644
--- a/arch/x86/kernel/paravirt-spinlocks.c
+++ b/arch/x86/kernel/paravirt-spinlocks.c
@@ -21,12 +21,18 @@ bool pv_is_native_spin_unlock(void)
__raw_callee_save___native_queued_spin_unlock;
}
+static bool native_vcpu_is_preempted(int cpu)
+{
+ return 0;
+}
+
struct pv_lock_ops pv_lock_ops = {
#ifdef CONFIG_SMP
.queued_spin_lock_slowpath = native_queued_spin_lock_slowpath,
.queued_spin_unlock = PV_CALLEE_SAVE(__native_queued_spin_unlock),
.wait = paravirt_nop,
.kick = paravirt_nop,
+ .vcpu_is_preempted = native_vcpu_is_preempted,
#endif /* SMP */
};
EXPORT_SYMBOL(pv_lock_ops);