aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorJuergen Gross <jgross@suse.com>2016-05-20 03:26:48 -0400
committerDavid Vrabel <david.vrabel@citrix.com>2016-07-06 05:34:48 -0400
commitecb23dc6f2eff0ce64dd60351a81f376f13b12cc (patch)
tree09536e5db2dc00af9dd5209fef72a1e1222f6cf2
parentc7ebf9d9c6b4e9402b978da0b0785db4129c1f79 (diff)
xen: add steal_clock support on x86
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 <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Diffstat
-rw-r--r--arch/arm/xen/enlighten.c18
-rw-r--r--arch/x86/xen/time.c44
-rw-r--r--drivers/xen/time.c20
-rw-r--r--include/linux/kernel_stat.h1
-rw-r--r--include/xen/xen-ops.h1
-rw-r--r--kernel/sched/cputime.c10
6 files changed, 25 insertions, 69 deletions
diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
index d4f36eba3499..47acb3613f40 100644
--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -12,7 +12,6 @@
12#include <xen/page.h> 12#include <xen/page.h>
13#include <xen/interface/sched.h> 13#include <xen/interface/sched.h>
14#include <xen/xen-ops.h> 14#include <xen/xen-ops.h>
15#include <asm/paravirt.h>
16#include <asm/xen/hypervisor.h> 15#include <asm/xen/hypervisor.h>
17#include <asm/xen/hypercall.h> 16#include <asm/xen/hypercall.h>
18#include <asm/xen/xen-ops.h> 17#include <asm/xen/xen-ops.h>
@@ -86,19 +85,6 @@ int xen_unmap_domain_gfn_range(struct vm_area_struct *vma,
86} 85}
87EXPORT_SYMBOL_GPL(xen_unmap_domain_gfn_range); 86EXPORT_SYMBOL_GPL(xen_unmap_domain_gfn_range);
88 87
89static unsigned long long xen_stolen_accounting(int cpu)
90{
91 struct vcpu_runstate_info state;
92
93 BUG_ON(cpu != smp_processor_id());
94
95 xen_get_runstate_snapshot(&state);
96
97 WARN_ON(state.state != RUNSTATE_running);
98
99 return state.time[RUNSTATE_runnable] + state.time[RUNSTATE_offline];
100}
101
102static void xen_read_wallclock(struct timespec64 *ts) 88static void xen_read_wallclock(struct timespec64 *ts)
103{ 89{
104 u32 version; 90 u32 version;
@@ -432,8 +418,8 @@ static int __init xen_guest_init(void)
432 418
433 register_cpu_notifier(&xen_cpu_notifier); 419 register_cpu_notifier(&xen_cpu_notifier);
434 420
435 pv_time_ops.steal_clock = xen_stolen_accounting; 421 xen_time_setup_guest();
436 static_key_slow_inc(&paravirt_steal_enabled); 422
437 if (xen_initial_domain()) 423 if (xen_initial_domain())
438 pvclock_gtod_register_notifier(&xen_pvclock_gtod_notifier); 424 pvclock_gtod_register_notifier(&xen_pvclock_gtod_notifier);
439 425
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index 6deba5bc7e34..c31006f0f37f 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -11,8 +11,6 @@
11#include <linux/interrupt.h> 11#include <linux/interrupt.h>
12#include <linux/clocksource.h> 12#include <linux/clocksource.h>
13#include <linux/clockchips.h> 13#include <linux/clockchips.h>
14#include <linux/kernel_stat.h>
15#include <linux/math64.h>
16#include <linux/gfp.h> 14#include <linux/gfp.h>
17#include <linux/slab.h> 15#include <linux/slab.h>
18#include <linux/pvclock_gtod.h> 16#include <linux/pvclock_gtod.h>
@@ -31,44 +29,6 @@
31 29
32/* Xen may fire a timer up to this many ns early */ 30/* Xen may fire a timer up to this many ns early */
33#define TIMER_SLOP 100000 31#define TIMER_SLOP 100000
34#define NS_PER_TICK (1000000000LL / HZ)
35
36/* snapshots of runstate info */
37static DEFINE_PER_CPU(struct vcpu_runstate_info, xen_runstate_snapshot);
38
39/* unused ns of stolen time */
40static DEFINE_PER_CPU(u64, xen_residual_stolen);
41
42static void do_stolen_accounting(void)
43{
44 struct vcpu_runstate_info state;
45 struct vcpu_runstate_info *snap;
46 s64 runnable, offline, stolen;
47 cputime_t ticks;
48
49 xen_get_runstate_snapshot(&state);
50
51 WARN_ON(state.state != RUNSTATE_running);
52
53 snap = this_cpu_ptr(&xen_runstate_snapshot);
54
55 /* work out how much time the VCPU has not been runn*ing* */
56 runnable = state.time[RUNSTATE_runnable] - snap->time[RUNSTATE_runnable];
57 offline = state.time[RUNSTATE_offline] - snap->time[RUNSTATE_offline];
58
59 *snap = state;
60
61 /* Add the appropriate number of ticks of stolen time,
62 including any left-overs from last time. */
63 stolen = runnable + offline + __this_cpu_read(xen_residual_stolen);
64
65 if (stolen < 0)
66 stolen = 0;
67
68 ticks = iter_div_u64_rem(stolen, NS_PER_TICK, &stolen);
69 __this_cpu_write(xen_residual_stolen, stolen);
70 account_steal_ticks(ticks);
71}
72 32
73/* Get the TSC speed from Xen */ 33/* Get the TSC speed from Xen */
74static unsigned long xen_tsc_khz(void) 34static unsigned long xen_tsc_khz(void)
@@ -335,8 +295,6 @@ static irqreturn_t xen_timer_interrupt(int irq, void *dev_id)
335 ret = IRQ_HANDLED; 295 ret = IRQ_HANDLED;
336 } 296 }
337 297
338 do_stolen_accounting();
339
340 return ret; 298 return ret;
341} 299}
342 300
@@ -431,6 +389,8 @@ static void __init xen_time_init(void)
431 xen_setup_timer(cpu); 389 xen_setup_timer(cpu);
432 xen_setup_cpu_clockevents(); 390 xen_setup_cpu_clockevents();
433 391
392 xen_time_setup_guest();
393
434 if (xen_initial_domain()) 394 if (xen_initial_domain())
435 pvclock_gtod_register_notifier(&xen_pvclock_gtod_notifier); 395 pvclock_gtod_register_notifier(&xen_pvclock_gtod_notifier);
436} 396}
diff --git a/drivers/xen/time.c b/drivers/xen/time.c
index 71078425c9ea..2257b6663766 100644
--- a/drivers/xen/time.c
+++ b/drivers/xen/time.c
@@ -6,6 +6,7 @@
6#include <linux/math64.h> 6#include <linux/math64.h>
7#include <linux/gfp.h> 7#include <linux/gfp.h>
8 8
9#include <asm/paravirt.h>
9#include <asm/xen/hypervisor.h> 10#include <asm/xen/hypervisor.h>
10#include <asm/xen/hypercall.h> 11#include <asm/xen/hypercall.h>
11 12
@@ -75,6 +76,15 @@ bool xen_vcpu_stolen(int vcpu)
75 return per_cpu(xen_runstate, vcpu).state == RUNSTATE_runnable; 76 return per_cpu(xen_runstate, vcpu).state == RUNSTATE_runnable;
76} 77}
77 78
79static u64 xen_steal_clock(int cpu)
80{
81 struct vcpu_runstate_info state;
82
83 BUG_ON(cpu != smp_processor_id());
84 xen_get_runstate_snapshot(&state);
85 return state.time[RUNSTATE_runnable] + state.time[RUNSTATE_offline];
86}
87
78void xen_setup_runstate_info(int cpu) 88void xen_setup_runstate_info(int cpu)
79{ 89{
80 struct vcpu_register_runstate_memory_area area; 90 struct vcpu_register_runstate_memory_area area;
@@ -86,3 +96,13 @@ void xen_setup_runstate_info(int cpu)
86 BUG(); 96 BUG();
87} 97}
88 98
99void __init xen_time_setup_guest(void)
100{
101 pv_time_ops.steal_clock = xen_steal_clock;
102
103 static_key_slow_inc(&paravirt_steal_enabled);
104 /*
105 * We can't set paravirt_steal_rq_enabled as this would require the
106 * capability to read another cpu's runstate info.
107 */
108}
diff --git a/include/linux/kernel_stat.h b/include/linux/kernel_stat.h
index 25a822f6f000..44fda64ad434 100644
--- a/include/linux/kernel_stat.h
+++ b/include/linux/kernel_stat.h
@@ -92,7 +92,6 @@ static inline void account_process_tick(struct task_struct *tsk, int user)
92extern void account_process_tick(struct task_struct *, int user); 92extern void account_process_tick(struct task_struct *, int user);
93#endif 93#endif
94 94
95extern void account_steal_ticks(unsigned long ticks);
96extern void account_idle_ticks(unsigned long ticks); 95extern void account_idle_ticks(unsigned long ticks);
97 96
98#endif /* _LINUX_KERNEL_STAT_H */ 97#endif /* _LINUX_KERNEL_STAT_H */
diff --git a/include/xen/xen-ops.h b/include/xen/xen-ops.h
index 3491582bf50a..355275bad2cf 100644
--- a/include/xen/xen-ops.h
+++ b/include/xen/xen-ops.h
@@ -21,6 +21,7 @@ void xen_resume_notifier_unregister(struct notifier_block *nb);
21 21
22bool xen_vcpu_stolen(int vcpu); 22bool xen_vcpu_stolen(int vcpu);
23void xen_setup_runstate_info(int cpu); 23void xen_setup_runstate_info(int cpu);
24void xen_time_setup_guest(void);
24void xen_get_runstate_snapshot(struct vcpu_runstate_info *res); 25void xen_get_runstate_snapshot(struct vcpu_runstate_info *res);
25 26
26int xen_setup_shutdown_event(void); 27int xen_setup_shutdown_event(void);
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index 75f98c5498d5..8c4c6dcc052c 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -490,16 +490,6 @@ void account_process_tick(struct task_struct *p, int user_tick)
490} 490}
491 491
492/* 492/*
493 * Account multiple ticks of steal time.
494 * @p: the process from which the cpu time has been stolen
495 * @ticks: number of stolen ticks
496 */
497void account_steal_ticks(unsigned long ticks)
498{
499 account_steal_time(jiffies_to_cputime(ticks));
500}
501
502/*
503 * Account multiple ticks of idle time. 493 * Account multiple ticks of idle time.
504 * @ticks: number of stolen ticks 494 * @ticks: number of stolen ticks
505 */ 495 */
generated by cgit v1.2.2 (git 2.25.0) at 2025-04-02 19:06:45 -0400