| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.14 62/68] x86/xen/time: set pvclock flags on xen_time_init() | Date | Tue, 29 Jan 2019 12:36:24 +0100 |
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4.14-stable review patch. If anyone has any objections, please let me know.
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From: Joao Martins <joao.m.martins@oracle.com>
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 <joao.m.martins@oracle.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- 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();
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