[PATCH 24/29] ia64/pv_ops/xen: implement xen pv_time_ops.

Isaku Yamahata
2008-07-17T02:10:56Z

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>
---
arch/ia64/xen/Makefile | 2 +-
arch/ia64/xen/time.c | 165 ++++++++++++++++++++++++++++++++++++++++++++
arch/ia64/xen/time.h | 23 ++++++
arch/ia64/xen/xen_pv_ops.c | 2 +
4 files changed, 191 insertions(+), 1 deletions(-)
create mode 100644 arch/ia64/xen/time.c
create mode 100644 arch/ia64/xen/time.h

diff --git a/arch/ia64/xen/Makefile b/arch/ia64/xen/Makefile
index 01c4289..ed31c76 100644
--- a/arch/ia64/xen/Makefile
+++ b/arch/ia64/xen/Makefile
@@ -3,7 +3,7 @@
#

obj-y := hypercall.o xenivt.o xensetup.o xen_pv_ops.o irq_xen.o \
- hypervisor.o xencomm.o xcom_hcall.o grant-table.o
+ hypervisor.o xencomm.o xcom_hcall.o grant-table.o time.o

AFLAGS_xenivt.o += -D__IA64_ASM_PARAVIRTUALIZED_XEN

diff --git a/arch/ia64/xen/time.c b/arch/ia64/xen/time.c
new file mode 100644
index 0000000..3414f1e
--- /dev/null
+++ b/arch/ia64/xen/time.c
@@ -0,0 +1,165 @@
+/******************************************************************************
+ * arch/ia64/xen/time.c
+ *
+ * Copyright (c) 2008 Isaku Yamahata <yamahata at valinux co jp>
+ * VA Linux Systems Japan K.K.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+#include <linux/delay.h>
+#include <linux/kernel_stat.h>
+#include <linux/posix-timers.h>
+#include <linux/irq.h>
+#include <linux/clocksource.h>
+
+#include <asm/xen/hypervisor.h>
+
+#include <xen/interface/vcpu.h>
+
+#include "../kernel/fsyscall_gtod_data.h"
+
+DEFINE_PER_CPU(struct vcpu_runstate_info, runstate);
+DEFINE_PER_CPU(unsigned long, processed_stolen_time);
+DEFINE_PER_CPU(unsigned long, processed_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(runstate, cpu);
+ int rc;
+
+ 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(processed_blocked_time, cpu) = runstate->time[RUNSTATE_blocked];
+ per_cpu(processed_stolen_time, cpu) = runstate->time[RUNSTATE_runnable]
+ + runstate->time[RUNSTATE_offline];
+}
+
+#define NS_PER_TICK (1000000000LL/HZ)
+
+static unsigned long
+consider_steal_time(unsigned long new_itm)
+{
+ unsigned long stolen, blocked, sched_time;
+ unsigned long delta_itm = 0, stolentick = 0;
+ int cpu = smp_processor_id();
+ struct vcpu_runstate_info *runstate;
+ struct task_struct *p = current;
+
+ runstate = &per_cpu(runstate, smp_processor_id());
+
+ do {
+ sched_time = runstate->state_entry_time;
+ mb();
+ stolen = runstate->time[RUNSTATE_runnable] +
+ runstate->time[RUNSTATE_offline] -
+ per_cpu(processed_stolen_time, cpu);
+ blocked = runstate->time[RUNSTATE_blocked] -
+ per_cpu(processed_blocked_time, cpu);
+ mb();
+ } while (sched_time != runstate->state_entry_time);
+
+ /*
+ * Check for vcpu migration effect
+ * In this case, itc value is reversed.
+ * This causes huge stolen value.
+ * This function just checks and reject this effect.
+ */
+ if (!time_after_eq(runstate->time[RUNSTATE_blocked],
+ per_cpu(processed_blocked_time, cpu)))
+ blocked = 0;
+
+ if (!time_after_eq(runstate->time[RUNSTATE_runnable] +
+ runstate->time[RUNSTATE_offline],
+ per_cpu(processed_stolen_time, cpu)))
+ stolen = 0;
+
+ if (!time_after(delta_itm + new_itm, ia64_get_itc()))
+ stolentick = ia64_get_itc() - new_itm;
+
+ do_div(stolentick, NS_PER_TICK);
+ stolentick++;
+
+ do_div(stolen, NS_PER_TICK);
+
+ if (stolen > stolentick)
+ stolen = stolentick;
+
+ stolentick -= stolen;
+ do_div(blocked, NS_PER_TICK);
+
+ if (blocked > stolentick)
+ blocked = stolentick;
+
+ if (stolen > 0 || blocked > 0) {
+ account_steal_time(NULL, jiffies_to_cputime(stolen));
+ account_steal_time(idle_task(cpu), jiffies_to_cputime(blocked));
+ run_local_timers();
+
+ if (rcu_pending(cpu))
+ rcu_check_callbacks(cpu, user_mode(get_irq_regs()));
+
+ scheduler_tick();
+ run_posix_cpu_timers(p);
+ delta_itm += local_cpu_data->itm_delta * (stolen + blocked);
+
+ if (cpu = time_keeper_id) {
+ write_seqlock(&xtime_lock);
+ do_timer(stolen + blocked);
+ local_cpu_data->itm_next = delta_itm + new_itm;
+ write_sequnlock(&xtime_lock);
+ } else {
+ local_cpu_data->itm_next = delta_itm + new_itm;
+ }
+ per_cpu(processed_stolen_time, cpu) += NS_PER_TICK * stolen;
+ per_cpu(processed_blocked_time, cpu) += NS_PER_TICK * blocked;
+ }
+ return delta_itm;
+}
+
+static int xen_do_steal_accounting(unsigned long *new_itm)
+{
+ unsigned long delta_itm;
+ delta_itm = consider_steal_time(*new_itm);
+ *new_itm += delta_itm;
+ if (time_after(*new_itm, ia64_get_itc()) && delta_itm)
+ return 1;
+
+ return 0;
+}
+
+static void xen_itc_jitter_data_reset(void)
+{
+ u64 lcycle, ret;
+
+ do {
+ lcycle = itc_jitter_data.itc_lastcycle;
+ ret = cmpxchg(&itc_jitter_data.itc_lastcycle, lcycle, 0);
+ } while (unlikely(ret != lcycle));
+}
+
+struct pv_time_ops xen_time_ops __initdata = {
+ .init_missing_ticks_accounting = xen_init_missing_ticks_accounting,
+ .do_steal_accounting = xen_do_steal_accounting,
+ .clocksource_resume = xen_itc_jitter_data_reset,
+};
diff --git a/arch/ia64/xen/time.h b/arch/ia64/xen/time.h
new file mode 100644
index 0000000..b9c7ec5
--- /dev/null
+++ b/arch/ia64/xen/time.h
@@ -0,0 +1,23 @@
+/******************************************************************************
+ * arch/ia64/xen/time.h
+ *
+ * Copyright (c) 2008 Isaku Yamahata <yamahata at valinux co jp>
+ * VA Linux Systems Japan K.K.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ */
+
+extern struct pv_time_ops xen_time_ops __initdata;
diff --git a/arch/ia64/xen/xen_pv_ops.c b/arch/ia64/xen/xen_pv_ops.c
index 0ac166c..5f83036 100644
--- a/arch/ia64/xen/xen_pv_ops.c
+++ b/arch/ia64/xen/xen_pv_ops.c
@@ -30,6 +30,7 @@
#include <asm/xen/privop.h>

#include "irq_xen.h"
+#include "time.h"

/***************************************************************************
* general info
@@ -357,6 +358,7 @@ xen_setup_pv_ops(void)
pv_cpu_ops = xen_cpu_ops;
pv_iosapic_ops = xen_iosapic_ops;
pv_irq_ops = xen_irq_ops;
+ pv_time_ops = xen_time_ops;

paravirt_cpu_asm_init(&xen_cpu_asm_switch);
}
--
1.5.3