From c6338ce494456ed9c92ef10f63c0a8408bfeac6d Mon Sep 17 00:00:00 2001 From: Tiejun Chen Date: Fri, 26 Sep 2014 14:00:04 +0800 Subject: [PATCH] kvm: kvmclock: use get_cpu() and put_cpu() We can use get_cpu() and put_cpu() to replace preempt_disable()/cpu = smp_processor_id() and preempt_enable() for slightly better code. Signed-off-by: Tiejun Chen Signed-off-by: Paolo Bonzini --- arch/x86/kernel/kvmclock.c | 19 ++++++++----------- 1 file changed, 8 insertions(+), 11 deletions(-) diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c index d9156ce..0bf3467 100644 --- a/arch/x86/kernel/kvmclock.c +++ b/arch/x86/kernel/kvmclock.c @@ -59,13 +59,12 @@ static void kvm_get_wallclock(struct timespec *now) native_write_msr(msr_kvm_wall_clock, low, high); - preempt_disable(); - cpu = smp_processor_id(); + cpu = get_cpu(); vcpu_time = &hv_clock[cpu].pvti; pvclock_read_wallclock(&wall_clock, vcpu_time, now); - preempt_enable(); + put_cpu(); } static int kvm_set_wallclock(const struct timespec *now) @@ -107,11 +106,10 @@ static unsigned long kvm_get_tsc_khz(void) int cpu; unsigned long tsc_khz; - preempt_disable(); - cpu = smp_processor_id(); + cpu = get_cpu(); src = &hv_clock[cpu].pvti; tsc_khz = pvclock_tsc_khz(src); - preempt_enable(); + put_cpu(); return tsc_khz; } @@ -284,23 +282,22 @@ int __init kvm_setup_vsyscall_timeinfo(void) size = PAGE_ALIGN(sizeof(struct pvclock_vsyscall_time_info)*NR_CPUS); - preempt_disable(); - cpu = smp_processor_id(); + cpu = get_cpu(); vcpu_time = &hv_clock[cpu].pvti; flags = pvclock_read_flags(vcpu_time); if (!(flags & PVCLOCK_TSC_STABLE_BIT)) { - preempt_enable(); + put_cpu(); return 1; } if ((ret = pvclock_init_vsyscall(hv_clock, size))) { - preempt_enable(); + put_cpu(); return ret; } - preempt_enable(); + put_cpu(); kvm_clock.archdata.vclock_mode = VCLOCK_PVCLOCK; #endif -- 2.7.4