diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2016-11-15 16:47:06 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-11-22 12:48:11 +0100 |
| commit | 3cded41794818d788aa1dc028ede4a1c1222d937 (patch) | |
| tree | b38f7540e28ee21ccec1e2fb850ff4235041984e /arch/x86/include/asm/paravirt.h | |
| parent | 05ffc951392df57edecc2519327b169210c3df75 (diff) | |
| download | linux-0-day-3cded41794818d788aa1dc028ede4a1c1222d937.tar.gz linux-0-day-3cded41794818d788aa1dc028ede4a1c1222d937.tar.xz | |
x86/paravirt: Optimize native pv_lock_ops.vcpu_is_preempted()
Avoid the pointless function call to pv_lock_ops.vcpu_is_preempted()
when a paravirt spinlock enabled kernel is ran on native hardware.
Do this by patching out the CALL instruction with "XOR %RAX,%RAX"
which has the same effect (0 return value).
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
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: mpe@ellerman.id.au
Cc: paulmck@linux.vnet.ibm.com
Cc: paulus@samba.org
Cc: pbonzini@redhat.com
Cc: rkrcmar@redhat.com
Cc: will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/include/asm/paravirt.h')
| -rw-r--r-- | arch/x86/include/asm/paravirt.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h index ce932812f142a..6108b1fada2bf 100644 --- a/arch/x86/include/asm/paravirt.h +++ b/arch/x86/include/asm/paravirt.h @@ -678,6 +678,11 @@ static __always_inline void pv_kick(int cpu) PVOP_VCALL1(pv_lock_ops.kick, cpu); } +static __always_inline bool pv_vcpu_is_preempted(int cpu) +{ + return PVOP_CALLEE1(bool, pv_lock_ops.vcpu_is_preempted, cpu); +} + #endif /* SMP && PARAVIRT_SPINLOCKS */ #ifdef CONFIG_X86_32 |