4.14-stable review patch. If anyone has any objections, please let me know.
------------------ From: Joao Martins <[email protected]> commit b888808093113ae7d63d213272d01fea4b8329ed upstream. Specifically check for PVCLOCK_TSC_STABLE_BIT and if this bit is set, then set it too on pvclock flags. This allows Xen clocksource to use it and thus speeding up xen_clocksource_read() callers (i.e. sched_clock()) Signed-off-by: Joao Martins <[email protected]> Reviewed-by: Boris Ostrovsky <[email protected]> Signed-off-by: Boris Ostrovsky <[email protected]> Signed-off-by: Juergen Gross <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/x86/xen/time.c | 9 +++++++++ 1 file changed, 9 insertions(+) --- a/arch/x86/xen/time.c +++ b/arch/x86/xen/time.c @@ -373,6 +373,7 @@ static const struct pv_time_ops xen_time static void __init xen_time_init(void) { + struct pvclock_vcpu_time_info *pvti; int cpu = smp_processor_id(); struct timespec tp; @@ -396,6 +397,14 @@ static void __init xen_time_init(void) setup_force_cpu_cap(X86_FEATURE_TSC); + /* + * We check ahead on the primary time info if this + * bit is supported hence speeding up Xen clocksource. + */ + pvti = &__this_cpu_read(xen_vcpu)->time; + if (pvti->flags & PVCLOCK_TSC_STABLE_BIT) + pvclock_set_flags(PVCLOCK_TSC_STABLE_BIT); + xen_setup_runstate_info(cpu); xen_setup_timer(cpu); xen_setup_cpu_clockevents();
