[PATCH v4 1/4] xen: move xen_setup_runstate_info and get_runstate_snapshot to drivers/xen/time.c
Konrad Rzeszutek Wilk
konrad.wilk at oracle.com
Tue May 28 14:15:15 EDT 2013
On Tue, May 28, 2013 at 06:54:29PM +0100, Stefano Stabellini wrote:
> Signed-off-by: Stefano Stabellini <stefano.stabellini at eu.citrix.com>
> Acked-by: Ian Campbell <ian.campbell at citrix.com>
> CC: konrad.wilk at oracle.com
>
> Changes in v2:
> - leave do_stolen_accounting in arch/x86/xen/time.c;
> - use the new common functions in arch/ia64/xen/time.c.
So you also modify the function.
> ---
> arch/ia64/xen/time.c | 48 +++----------------------
> arch/x86/xen/time.c | 76 +----------------------------------------
> drivers/xen/Makefile | 2 +-
> drivers/xen/time.c | 91 +++++++++++++++++++++++++++++++++++++++++++++++++
> include/xen/xen-ops.h | 5 +++
> 5 files changed, 104 insertions(+), 118 deletions(-)
> create mode 100644 drivers/xen/time.c
>
> diff --git a/arch/ia64/xen/time.c b/arch/ia64/xen/time.c
> index 1f8244a..79a0b8c 100644
> --- a/arch/ia64/xen/time.c
> +++ b/arch/ia64/xen/time.c
> @@ -34,53 +34,17 @@
>
> #include "../kernel/fsyscall_gtod_data.h"
>
> -static DEFINE_PER_CPU(struct vcpu_runstate_info, xen_runstate);
> static DEFINE_PER_CPU(unsigned long, xen_stolen_time);
> static DEFINE_PER_CPU(unsigned long, xen_blocked_time);
>
> /* taken from i386/kernel/time-xen.c */
> static void xen_init_missing_ticks_accounting(int cpu)
> {
> - struct vcpu_register_runstate_memory_area area;
> - struct vcpu_runstate_info *runstate = &per_cpu(xen_runstate, cpu);
> - int rc;
> + xen_setup_runstate_info(&runstate);
>
> - memset(runstate, 0, sizeof(*runstate));
> -
> - area.addr.v = runstate;
> - rc = HYPERVISOR_vcpu_op(VCPUOP_register_runstate_memory_area, cpu,
> - &area);
> - WARN_ON(rc && rc != -ENOSYS);
> -
> - per_cpu(xen_blocked_time, cpu) = runstate->time[RUNSTATE_blocked];
> - per_cpu(xen_stolen_time, cpu) = runstate->time[RUNSTATE_runnable]
> - + runstate->time[RUNSTATE_offline];
> -}
> -
> -/*
> - * Runstate accounting
> - */
> -/* stolen from arch/x86/xen/time.c */
> -static void get_runstate_snapshot(struct vcpu_runstate_info *res)
> -{
> - u64 state_time;
> - struct vcpu_runstate_info *state;
> -
> - BUG_ON(preemptible());
> -
> - state = &__get_cpu_var(xen_runstate);
> -
> - /*
> - * The runstate info is always updated by the hypervisor on
> - * the current CPU, so there's no need to use anything
> - * stronger than a compiler barrier when fetching it.
> - */
> - do {
> - state_time = state->state_entry_time;
> - rmb();
> - *res = *state;
> - rmb();
> - } while (state->state_entry_time != state_time);
> + per_cpu(xen_blocked_time, cpu) = runstate.time[RUNSTATE_blocked];
> + per_cpu(xen_stolen_time, cpu) = runstate.time[RUNSTATE_runnable]
> + + runstate.time[RUNSTATE_offline];
> }
>
> #define NS_PER_TICK (1000000000LL/HZ)
> @@ -94,7 +58,7 @@ consider_steal_time(unsigned long new_itm)
> struct vcpu_runstate_info runstate;
> struct task_struct *p = current;
>
> - get_runstate_snapshot(&runstate);
> + xen_get_runstate_snapshot(&runstate);
>
> /*
> * Check for vcpu migration effect
> @@ -202,7 +166,7 @@ static unsigned long long xen_sched_clock(void)
> */
> now = ia64_native_sched_clock();
>
> - get_runstate_snapshot(&runstate);
> + xen_get_runstate_snapshot(&runstate);
>
> WARN_ON(runstate.state != RUNSTATE_running);
>
> diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
> index 3d88bfd..c0ca15e 100644
> --- a/arch/x86/xen/time.c
> +++ b/arch/x86/xen/time.c
> @@ -30,9 +30,6 @@
> #define TIMER_SLOP 100000
> #define NS_PER_TICK (1000000000LL / HZ)
>
> -/* runstate info updated by Xen */
> -static DEFINE_PER_CPU(struct vcpu_runstate_info, xen_runstate);
> -
> /* snapshots of runstate info */
> static DEFINE_PER_CPU(struct vcpu_runstate_info, xen_runstate_snapshot);
>
> @@ -40,77 +37,6 @@ static DEFINE_PER_CPU(struct vcpu_runstate_info, xen_runstate_snapshot);
> static DEFINE_PER_CPU(u64, xen_residual_stolen);
> static DEFINE_PER_CPU(u64, xen_residual_blocked);
>
> -/* return an consistent snapshot of 64-bit time/counter value */
> -static u64 get64(const u64 *p)
> -{
> - u64 ret;
> -
> - if (BITS_PER_LONG < 64) {
> - u32 *p32 = (u32 *)p;
> - u32 h, l;
> -
> - /*
> - * Read high then low, and then make sure high is
> - * still the same; this will only loop if low wraps
> - * and carries into high.
> - * XXX some clean way to make this endian-proof?
> - */
> - do {
> - h = p32[1];
> - barrier();
> - l = p32[0];
> - barrier();
> - } while (p32[1] != h);
> -
> - ret = (((u64)h) << 32) | l;
> - } else
> - ret = *p;
> -
> - return ret;
> -}
> -
> -/*
> - * Runstate accounting
> - */
> -static void get_runstate_snapshot(struct vcpu_runstate_info *res)
> -{
> - u64 state_time;
> - struct vcpu_runstate_info *state;
> -
> - BUG_ON(preemptible());
> -
> - state = &__get_cpu_var(xen_runstate);
> -
> - /*
> - * The runstate info is always updated by the hypervisor on
> - * the current CPU, so there's no need to use anything
> - * stronger than a compiler barrier when fetching it.
> - */
> - do {
> - state_time = get64(&state->state_entry_time);
> - barrier();
> - *res = *state;
> - barrier();
> - } while (get64(&state->state_entry_time) != state_time);
> -}
> -
> -/* return true when a vcpu could run but has no real cpu to run on */
> -bool xen_vcpu_stolen(int vcpu)
> -{
> - return per_cpu(xen_runstate, vcpu).state == RUNSTATE_runnable;
> -}
> -
> -void xen_setup_runstate_info(int cpu)
> -{
> - struct vcpu_register_runstate_memory_area area;
> -
> - area.addr.v = &per_cpu(xen_runstate, cpu);
> -
> - if (HYPERVISOR_vcpu_op(VCPUOP_register_runstate_memory_area,
> - cpu, &area))
> - BUG();
> -}
> -
> static void do_stolen_accounting(void)
> {
> struct vcpu_runstate_info state;
> @@ -118,7 +44,7 @@ static void do_stolen_accounting(void)
> s64 blocked, runnable, offline, stolen;
> cputime_t ticks;
>
> - get_runstate_snapshot(&state);
> + xen_get_runstate_snapshot(&state);
>
> WARN_ON(state.state != RUNSTATE_running);
>
> diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
> index eabd0ee..2bf461a 100644
> --- a/drivers/xen/Makefile
> +++ b/drivers/xen/Makefile
> @@ -3,7 +3,7 @@ obj-y += manage.o
> obj-$(CONFIG_HOTPLUG_CPU) += cpu_hotplug.o
> endif
> obj-$(CONFIG_X86) += fallback.o
> -obj-y += grant-table.o features.o events.o balloon.o
> +obj-y += grant-table.o features.o events.o balloon.o time.o
> obj-y += xenbus/
>
> nostackp := $(call cc-option, -fno-stack-protector)
> diff --git a/drivers/xen/time.c b/drivers/xen/time.c
> new file mode 100644
> index 0000000..c2e39d3
> --- /dev/null
> +++ b/drivers/xen/time.c
> @@ -0,0 +1,91 @@
> +/*
> + * Xen stolen ticks accounting.
> + */
> +#include <linux/kernel.h>
> +#include <linux/kernel_stat.h>
> +#include <linux/math64.h>
> +#include <linux/gfp.h>
> +
> +#include <asm/xen/hypervisor.h>
> +#include <asm/xen/hypercall.h>
> +
> +#include <xen/events.h>
> +#include <xen/features.h>
> +#include <xen/interface/xen.h>
> +#include <xen/interface/vcpu.h>
> +#include <xen/xen-ops.h>
> +
> +/* runstate info updated by Xen */
> +static DEFINE_PER_CPU(struct vcpu_runstate_info, xen_runstate);
> +
> +/* return an consistent snapshot of 64-bit time/counter value */
> +static u64 get64(const u64 *p)
> +{
> + u64 ret;
> +
> + if (BITS_PER_LONG < 64) {
> + u32 *p32 = (u32 *)p;
> + u32 h, l;
> +
> + /*
> + * Read high then low, and then make sure high is
> + * still the same; this will only loop if low wraps
> + * and carries into high.
> + * XXX some clean way to make this endian-proof?
> + */
> + do {
> + h = p32[1];
> + barrier();
> + l = p32[0];
> + barrier();
> + } while (p32[1] != h);
> +
> + ret = (((u64)h) << 32) | l;
> + } else
> + ret = *p;
> +
> + return ret;
> +}
> +
> +/*
> + * Runstate accounting
> + */
> +void xen_get_runstate_snapshot(struct vcpu_runstate_info *res)
> +{
> + u64 state_time;
> + struct vcpu_runstate_info *state;
> +
> + BUG_ON(preemptible());
> +
> + state = &__get_cpu_var(xen_runstate);
> +
> + /*
> + * The runstate info is always updated by the hypervisor on
> + * the current CPU, so there's no need to use anything
> + * stronger than a compiler barrier when fetching it.
> + */
> + do {
> + state_time = get64(&state->state_entry_time);
> + barrier();
> + *res = *state;
> + barrier();
> + } while (get64(&state->state_entry_time) != state_time);
> +}
> +
> +/* return true when a vcpu could run but has no real cpu to run on */
> +bool xen_vcpu_stolen(int vcpu)
> +{
> + return per_cpu(xen_runstate, vcpu).state == RUNSTATE_runnable;
> +}
> +
> +void xen_setup_runstate_info(int cpu)
> +{
> + struct vcpu_register_runstate_memory_area area;
> +
> + area.addr.v = &per_cpu(xen_runstate, cpu);
> +
> + if (HYPERVISOR_vcpu_op(VCPUOP_register_runstate_memory_area,
> + cpu, &area))
> + BUG();
The original code did:
- rc = HYPERVISOR_vcpu_op(VCPUOP_register_runstate_memory_area, cpu,
- &area);
- WARN_ON(rc && rc != -ENOSYS);
-
Any reason not to do this?
> +}
> +
> diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h
> index d6fe062..4fd4e47 100644
> --- a/include/xen/xen-ops.h
> +++ b/include/xen/xen-ops.h
> @@ -3,6 +3,7 @@
>
> #include <linux/percpu.h>
> #include <asm/xen/interface.h>
> +#include <xen/interface/vcpu.h>
>
> DECLARE_PER_CPU(struct vcpu_info *, xen_vcpu);
>
> @@ -16,6 +17,10 @@ void xen_mm_unpin_all(void);
> void xen_timer_resume(void);
> void xen_arch_resume(void);
>
> +bool xen_vcpu_stolen(int vcpu);
> +void xen_setup_runstate_info(int cpu);
> +void xen_get_runstate_snapshot(struct vcpu_runstate_info *res);
> +
> int xen_setup_shutdown_event(void);
>
> extern unsigned long *xen_contiguous_bitmap;
> --
> 1.7.2.5
>
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