Re: [Xen-devel] [PATCH v4] xen: add steal_clock support on x86

2016-06-21 Thread David Vrabel 
On 20/05/16 08:26, Juergen Gross wrote:
> The pv_time_ops structure contains a function pointer for the
> "steal_clock" functionality used only by KVM and Xen on ARM. Xen on x86
> uses its own mechanism to account for the "stolen" time a thread wasn't
> able to run due to hypervisor scheduling.
> 
> Add support in Xen arch independent time handling for this feature by
> moving it out of the arm arch into drivers/xen and remove the x86 Xen
> hack.

Applied for-linus-4.8, thanks.

David

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Re: [Xen-devel] [PATCH v4] xen: add steal_clock support on x86

2016-05-20 Thread Stefano Stabellini 
On Fri, 20 May 2016, Juergen Gross wrote:
> The pv_time_ops structure contains a function pointer for the
> "steal_clock" functionality used only by KVM and Xen on ARM. Xen on x86
> uses its own mechanism to account for the "stolen" time a thread wasn't
> able to run due to hypervisor scheduling.
> 
> Add support in Xen arch independent time handling for this feature by
> moving it out of the arm arch into drivers/xen and remove the x86 Xen
> hack.
> 
> Signed-off-by: Juergen Gross 
> Reviewed-by: Boris Ostrovsky 

Reviewed-by: Stefano Stabellini 


> V4: minor adjustments as requested by Stefano Stabellini (remove
> no longer needed #include, remove __init from header)
> V3: add #include  to avoid build error on arm
> V2: remove the x86 do_stolen_accounting() hack
> ---
>  arch/arm/xen/enlighten.c| 18 ++
>  arch/x86/xen/time.c | 44 ++--
>  drivers/xen/time.c  | 20 
>  include/linux/kernel_stat.h |  1 -
>  include/xen/xen-ops.h   |  1 +
>  kernel/sched/cputime.c  | 10 --
>  6 files changed, 25 insertions(+), 69 deletions(-)
> 
> diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
> index 75cd734..71db30c 100644
> --- a/arch/arm/xen/enlighten.c
> +++ b/arch/arm/xen/enlighten.c
> @@ -12,7 +12,6 @@
>  #include 
>  #include 
>  #include 
> -#include 
>  #include 
>  #include 
>  #include 
> @@ -84,19 +83,6 @@ int xen_unmap_domain_gfn_range(struct vm_area_struct *vma,
>  }
>  EXPORT_SYMBOL_GPL(xen_unmap_domain_gfn_range);
>  
> -static unsigned long long xen_stolen_accounting(int cpu)
> -{
> - struct vcpu_runstate_info state;
> -
> - BUG_ON(cpu != smp_processor_id());
> -
> - xen_get_runstate_snapshot();
> -
> - WARN_ON(state.state != RUNSTATE_running);
> -
> - return state.time[RUNSTATE_runnable] + state.time[RUNSTATE_offline];
> -}
> -
>  static void xen_read_wallclock(struct timespec64 *ts)
>  {
>   u32 version;
> @@ -355,8 +341,8 @@ static int __init xen_guest_init(void)
>  
>   register_cpu_notifier(_cpu_notifier);
>  
> - pv_time_ops.steal_clock = xen_stolen_accounting;
> - static_key_slow_inc(_steal_enabled);
> + xen_time_setup_guest();
> +
>   if (xen_initial_domain())
>   pvclock_gtod_register_notifier(_pvclock_gtod_notifier);
>  
> diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
> index a0a4e55..6be31df 100644
> --- a/arch/x86/xen/time.c
> +++ b/arch/x86/xen/time.c
> @@ -11,8 +11,6 @@
>  #include 
>  #include 
>  #include 
> -#include 
> -#include 
>  #include 
>  #include 
>  #include 
> @@ -31,44 +29,6 @@
>  
>  /* Xen may fire a timer up to this many ns early */
>  #define TIMER_SLOP   10
> -#define NS_PER_TICK  (10LL / HZ)
> -
> -/* snapshots of runstate info */
> -static DEFINE_PER_CPU(struct vcpu_runstate_info, xen_runstate_snapshot);
> -
> -/* unused ns of stolen time */
> -static DEFINE_PER_CPU(u64, xen_residual_stolen);
> -
> -static void do_stolen_accounting(void)
> -{
> - struct vcpu_runstate_info state;
> - struct vcpu_runstate_info *snap;
> - s64 runnable, offline, stolen;
> - cputime_t ticks;
> -
> - xen_get_runstate_snapshot();
> -
> - WARN_ON(state.state != RUNSTATE_running);
> -
> - snap = this_cpu_ptr(_runstate_snapshot);
> -
> - /* work out how much time the VCPU has not been runn*ing*  */
> - runnable = state.time[RUNSTATE_runnable] - 
> snap->time[RUNSTATE_runnable];
> - offline = state.time[RUNSTATE_offline] - snap->time[RUNSTATE_offline];
> -
> - *snap = state;
> -
> - /* Add the appropriate number of ticks of stolen time,
> -including any left-overs from last time. */
> - stolen = runnable + offline + __this_cpu_read(xen_residual_stolen);
> -
> - if (stolen < 0)
> - stolen = 0;
> -
> - ticks = iter_div_u64_rem(stolen, NS_PER_TICK, );
> - __this_cpu_write(xen_residual_stolen, stolen);
> - account_steal_ticks(ticks);
> -}
>  
>  /* Get the TSC speed from Xen */
>  static unsigned long xen_tsc_khz(void)
> @@ -335,8 +295,6 @@ static irqreturn_t xen_timer_interrupt(int irq, void 
> *dev_id)
>   ret = IRQ_HANDLED;
>   }
>  
> - do_stolen_accounting();
> -
>   return ret;
>  }
>  
> @@ -431,6 +389,8 @@ static void __init xen_time_init(void)
>   xen_setup_timer(cpu);
>   xen_setup_cpu_clockevents();
>  
> + xen_time_setup_guest();
> +
>   if (xen_initial_domain())
>   pvclock_gtod_register_notifier(_pvclock_gtod_notifier);
>  }
> diff --git a/drivers/xen/time.c b/drivers/xen/time.c
> index 7107842..2257b66 100644
> --- a/drivers/xen/time.c
> +++ b/drivers/xen/time.c
> @@ -6,6 +6,7 @@
>  #include 
>  #include 
>  
> +#include 
>  #include 
>  #include 
>  
> @@ -75,6 +76,15 @@ bool xen_vcpu_stolen(int vcpu)
>   return per_cpu(xen_runstate, vcpu).state == RUNSTATE_runnable;
>

[Xen-devel] [PATCH v4] xen: add steal_clock support on x86

2016-05-20 Thread Juergen Gross 
The pv_time_ops structure contains a function pointer for the
"steal_clock" functionality used only by KVM and Xen on ARM. Xen on x86
uses its own mechanism to account for the "stolen" time a thread wasn't
able to run due to hypervisor scheduling.

Add support in Xen arch independent time handling for this feature by
moving it out of the arm arch into drivers/xen and remove the x86 Xen
hack.

Signed-off-by: Juergen Gross 
Reviewed-by: Boris Ostrovsky 
---
V4: minor adjustments as requested by Stefano Stabellini (remove
no longer needed #include, remove __init from header)
V3: add #include  to avoid build error on arm
V2: remove the x86 do_stolen_accounting() hack
---
 arch/arm/xen/enlighten.c| 18 ++
 arch/x86/xen/time.c | 44 ++--
 drivers/xen/time.c  | 20 
 include/linux/kernel_stat.h |  1 -
 include/xen/xen-ops.h   |  1 +
 kernel/sched/cputime.c  | 10 --
 6 files changed, 25 insertions(+), 69 deletions(-)

diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index 75cd734..71db30c 100644
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -12,7 +12,6 @@
 #include 
 #include 
 #include 
-#include 
 #include 
 #include 
 #include 
@@ -84,19 +83,6 @@ int xen_unmap_domain_gfn_range(struct vm_area_struct *vma,
 }
 EXPORT_SYMBOL_GPL(xen_unmap_domain_gfn_range);
 
-static unsigned long long xen_stolen_accounting(int cpu)
-{
-   struct vcpu_runstate_info state;
-
-   BUG_ON(cpu != smp_processor_id());
-
-   xen_get_runstate_snapshot();
-
-   WARN_ON(state.state != RUNSTATE_running);
-
-   return state.time[RUNSTATE_runnable] + state.time[RUNSTATE_offline];
-}
-
 static void xen_read_wallclock(struct timespec64 *ts)
 {
u32 version;
@@ -355,8 +341,8 @@ static int __init xen_guest_init(void)
 
register_cpu_notifier(_cpu_notifier);
 
-   pv_time_ops.steal_clock = xen_stolen_accounting;
-   static_key_slow_inc(_steal_enabled);
+   xen_time_setup_guest();
+
if (xen_initial_domain())
pvclock_gtod_register_notifier(_pvclock_gtod_notifier);
 
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index a0a4e55..6be31df 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -11,8 +11,6 @@
 #include 
 #include 
 #include 
-#include 
-#include 
 #include 
 #include 
 #include 
@@ -31,44 +29,6 @@
 
 /* Xen may fire a timer up to this many ns early */
 #define TIMER_SLOP 10
-#define NS_PER_TICK(10LL / HZ)
-
-/* snapshots of runstate info */
-static DEFINE_PER_CPU(struct vcpu_runstate_info, xen_runstate_snapshot);
-
-/* unused ns of stolen time */
-static DEFINE_PER_CPU(u64, xen_residual_stolen);
-
-static void do_stolen_accounting(void)
-{
-   struct vcpu_runstate_info state;
-   struct vcpu_runstate_info *snap;
-   s64 runnable, offline, stolen;
-   cputime_t ticks;
-
-   xen_get_runstate_snapshot();
-
-   WARN_ON(state.state != RUNSTATE_running);
-
-   snap = this_cpu_ptr(_runstate_snapshot);
-
-   /* work out how much time the VCPU has not been runn*ing*  */
-   runnable = state.time[RUNSTATE_runnable] - 
snap->time[RUNSTATE_runnable];
-   offline = state.time[RUNSTATE_offline] - snap->time[RUNSTATE_offline];
-
-   *snap = state;
-
-   /* Add the appropriate number of ticks of stolen time,
-  including any left-overs from last time. */
-   stolen = runnable + offline + __this_cpu_read(xen_residual_stolen);
-
-   if (stolen < 0)
-   stolen = 0;
-
-   ticks = iter_div_u64_rem(stolen, NS_PER_TICK, );
-   __this_cpu_write(xen_residual_stolen, stolen);
-   account_steal_ticks(ticks);
-}
 
 /* Get the TSC speed from Xen */
 static unsigned long xen_tsc_khz(void)
@@ -335,8 +295,6 @@ static irqreturn_t xen_timer_interrupt(int irq, void 
*dev_id)
ret = IRQ_HANDLED;
}
 
-   do_stolen_accounting();
-
return ret;
 }
 
@@ -431,6 +389,8 @@ static void __init xen_time_init(void)
xen_setup_timer(cpu);
xen_setup_cpu_clockevents();
 
+   xen_time_setup_guest();
+
if (xen_initial_domain())
pvclock_gtod_register_notifier(_pvclock_gtod_notifier);
 }
diff --git a/drivers/xen/time.c b/drivers/xen/time.c
index 7107842..2257b66 100644
--- a/drivers/xen/time.c
+++ b/drivers/xen/time.c
@@ -6,6 +6,7 @@
 #include 
 #include 
 
+#include 
 #include 
 #include 
 
@@ -75,6 +76,15 @@ bool xen_vcpu_stolen(int vcpu)
return per_cpu(xen_runstate, vcpu).state == RUNSTATE_runnable;
 }
 
+static u64 xen_steal_clock(int cpu)
+{
+   struct vcpu_runstate_info state;
+
+   BUG_ON(cpu != smp_processor_id());
+   xen_get_runstate_snapshot();
+   return state.time[RUNSTATE_runnable] + state.time[RUNSTATE_offline];
+}
+
 void xen_setup_runstate_info(int cpu)
 {
struct