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authorIsaku Yamahata <yamahata@valinux.co.jp>2008-10-16 22:18:08 -0400
committerTony Luck <tony.luck@intel.com>2008-10-17 13:08:02 -0400
commitdcbbecdad53bd6273891ad018f9c6bb8f2b7813c (patch)
tree1db1a5ac692428c6ec258c39593647ee78e0d690 /arch/ia64/xen/time.c
parent7477de989faffd4be4adfa3d3e1bf35bdf2e0f75 (diff)
ia64/pv_ops/xen: implement xen pv_time_ops.
implement xen pv_time_ops to account steal time. Cc: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Alex Williamson <alex.williamson@hp.com> Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp> Signed-off-by: Tony Luck <tony.luck@intel.com>
Diffstat (limited to 'arch/ia64/xen/time.c')
-rw-r--r--arch/ia64/xen/time.c180
1 files changed, 180 insertions, 0 deletions
diff --git a/arch/ia64/xen/time.c b/arch/ia64/xen/time.c
new file mode 100644
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+++ b/arch/ia64/xen/time.c
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1/******************************************************************************
2 * arch/ia64/xen/time.c
3 *
4 * Copyright (c) 2008 Isaku Yamahata <yamahata at valinux co jp>
5 * VA Linux Systems Japan K.K.
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 *
21 */
22
23#include <linux/delay.h>
24#include <linux/kernel_stat.h>
25#include <linux/posix-timers.h>
26#include <linux/irq.h>
27#include <linux/clocksource.h>
28
29#include <asm/xen/hypervisor.h>
30
31#include <xen/interface/vcpu.h>
32
33#include "../kernel/fsyscall_gtod_data.h"
34
35DEFINE_PER_CPU(struct vcpu_runstate_info, runstate);
36DEFINE_PER_CPU(unsigned long, processed_stolen_time);
37DEFINE_PER_CPU(unsigned long, processed_blocked_time);
38
39/* taken from i386/kernel/time-xen.c */
40static void xen_init_missing_ticks_accounting(int cpu)
41{
42 struct vcpu_register_runstate_memory_area area;
43 struct vcpu_runstate_info *runstate = &per_cpu(runstate, cpu);
44 int rc;
45
46 memset(runstate, 0, sizeof(*runstate));
47
48 area.addr.v = runstate;
49 rc = HYPERVISOR_vcpu_op(VCPUOP_register_runstate_memory_area, cpu,
50 &area);
51 WARN_ON(rc && rc != -ENOSYS);
52
53 per_cpu(processed_blocked_time, cpu) = runstate->time[RUNSTATE_blocked];
54 per_cpu(processed_stolen_time, cpu) = runstate->time[RUNSTATE_runnable]
55 + runstate->time[RUNSTATE_offline];
56}
57
58/*
59 * Runstate accounting
60 */
61/* stolen from arch/x86/xen/time.c */
62static void get_runstate_snapshot(struct vcpu_runstate_info *res)
63{
64 u64 state_time;
65 struct vcpu_runstate_info *state;
66
67 BUG_ON(preemptible());
68
69 state = &__get_cpu_var(runstate);
70
71 /*
72 * The runstate info is always updated by the hypervisor on
73 * the current CPU, so there's no need to use anything
74 * stronger than a compiler barrier when fetching it.
75 */
76 do {
77 state_time = state->state_entry_time;
78 rmb();
79 *res = *state;
80 rmb();
81 } while (state->state_entry_time != state_time);
82}
83
84#define NS_PER_TICK (1000000000LL/HZ)
85
86static unsigned long
87consider_steal_time(unsigned long new_itm)
88{
89 unsigned long stolen, blocked;
90 unsigned long delta_itm = 0, stolentick = 0;
91 int cpu = smp_processor_id();
92 struct vcpu_runstate_info runstate;
93 struct task_struct *p = current;
94
95 get_runstate_snapshot(&runstate);
96
97 /*
98 * Check for vcpu migration effect
99 * In this case, itc value is reversed.
100 * This causes huge stolen value.
101 * This function just checks and reject this effect.
102 */
103 if (!time_after_eq(runstate.time[RUNSTATE_blocked],
104 per_cpu(processed_blocked_time, cpu)))
105 blocked = 0;
106
107 if (!time_after_eq(runstate.time[RUNSTATE_runnable] +
108 runstate.time[RUNSTATE_offline],
109 per_cpu(processed_stolen_time, cpu)))
110 stolen = 0;
111
112 if (!time_after(delta_itm + new_itm, ia64_get_itc()))
113 stolentick = ia64_get_itc() - new_itm;
114
115 do_div(stolentick, NS_PER_TICK);
116 stolentick++;
117
118 do_div(stolen, NS_PER_TICK);
119
120 if (stolen > stolentick)
121 stolen = stolentick;
122
123 stolentick -= stolen;
124 do_div(blocked, NS_PER_TICK);
125
126 if (blocked > stolentick)
127 blocked = stolentick;
128
129 if (stolen > 0 || blocked > 0) {
130 account_steal_time(NULL, jiffies_to_cputime(stolen));
131 account_steal_time(idle_task(cpu), jiffies_to_cputime(blocked));
132 run_local_timers();
133
134 if (rcu_pending(cpu))
135 rcu_check_callbacks(cpu, user_mode(get_irq_regs()));
136
137 scheduler_tick();
138 run_posix_cpu_timers(p);
139 delta_itm += local_cpu_data->itm_delta * (stolen + blocked);
140
141 if (cpu == time_keeper_id) {
142 write_seqlock(&xtime_lock);
143 do_timer(stolen + blocked);
144 local_cpu_data->itm_next = delta_itm + new_itm;
145 write_sequnlock(&xtime_lock);
146 } else {
147 local_cpu_data->itm_next = delta_itm + new_itm;
148 }
149 per_cpu(processed_stolen_time, cpu) += NS_PER_TICK * stolen;
150 per_cpu(processed_blocked_time, cpu) += NS_PER_TICK * blocked;
151 }
152 return delta_itm;
153}
154
155static int xen_do_steal_accounting(unsigned long *new_itm)
156{
157 unsigned long delta_itm;
158 delta_itm = consider_steal_time(*new_itm);
159 *new_itm += delta_itm;
160 if (time_after(*new_itm, ia64_get_itc()) && delta_itm)
161 return 1;
162
163 return 0;
164}
165
166static void xen_itc_jitter_data_reset(void)
167{
168 u64 lcycle, ret;
169
170 do {
171 lcycle = itc_jitter_data.itc_lastcycle;
172 ret = cmpxchg(&itc_jitter_data.itc_lastcycle, lcycle, 0);
173 } while (unlikely(ret != lcycle));
174}
175
176struct pv_time_ops xen_time_ops __initdata = {
177 .init_missing_ticks_accounting = xen_init_missing_ticks_accounting,
178 .do_steal_accounting = xen_do_steal_accounting,
179 .clocksource_resume = xen_itc_jitter_data_reset,
180};