+++ /dev/null
-/******************************************************************************
- * 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/timex.h>
-
-#include <asm/xen/hypervisor.h>
-
-#include <xen/interface/vcpu.h>
-
-#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;
-
- 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);
-}
-
-#define NS_PER_TICK (1000000000LL/HZ)
-
-static unsigned long
-consider_steal_time(unsigned long new_itm)
-{
- unsigned long stolen, blocked;
- unsigned long delta_itm = 0, stolentick = 0;
- int cpu = smp_processor_id();
- struct vcpu_runstate_info runstate;
- struct task_struct *p = current;
-
- get_runstate_snapshot(&runstate);
-
- /*
- * 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(xen_blocked_time, cpu)))
- blocked = 0;
-
- if (!time_after_eq(runstate.time[RUNSTATE_runnable] +
- runstate.time[RUNSTATE_offline],
- per_cpu(xen_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_ticks(stolen);
- account_idle_ticks(blocked);
- run_local_timers();
-
- 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)
- xtime_update(stolen + blocked);
-
- local_cpu_data->itm_next = delta_itm + new_itm;
-
- per_cpu(xen_stolen_time, cpu) += NS_PER_TICK * stolen;
- per_cpu(xen_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));
-}
-
-/* based on xen_sched_clock() in arch/x86/xen/time.c. */
-/*
- * This relies on HAVE_UNSTABLE_SCHED_CLOCK. If it can't be defined,
- * something similar logic should be implemented here.
- */
-/*
- * Xen sched_clock implementation. Returns the number of unstolen
- * nanoseconds, which is nanoseconds the VCPU spent in RUNNING+BLOCKED
- * states.
- */
-static unsigned long long xen_sched_clock(void)
-{
- struct vcpu_runstate_info runstate;
-
- unsigned long long now;
- unsigned long long offset;
- unsigned long long ret;
-
- /*
- * Ideally sched_clock should be called on a per-cpu basis
- * anyway, so preempt should already be disabled, but that's
- * not current practice at the moment.
- */
- preempt_disable();
-
- /*
- * both ia64_native_sched_clock() and xen's runstate are
- * based on mAR.ITC. So difference of them makes sense.
- */
- now = ia64_native_sched_clock();
-
- get_runstate_snapshot(&runstate);
-
- WARN_ON(runstate.state != RUNSTATE_running);
-
- offset = 0;
- if (now > runstate.state_entry_time)
- offset = now - runstate.state_entry_time;
- ret = runstate.time[RUNSTATE_blocked] +
- runstate.time[RUNSTATE_running] +
- offset;
-
- preempt_enable();
-
- return ret;
-}
-
-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,
- .sched_clock = xen_sched_clock,
-};
-
-/* Called after suspend, to resume time. */
-static void xen_local_tick_resume(void)
-{
- /* Just trigger a tick. */
- ia64_cpu_local_tick();
- touch_softlockup_watchdog();
-}
-
-void
-xen_timer_resume(void)
-{
- unsigned int cpu;
-
- xen_local_tick_resume();
-
- for_each_online_cpu(cpu)
- xen_init_missing_ticks_accounting(cpu);
-}
-
-static void ia64_cpu_local_tick_fn(void *unused)
-{
- xen_local_tick_resume();
- xen_init_missing_ticks_accounting(smp_processor_id());
-}
-
-void
-xen_timer_resume_on_aps(void)
-{
- smp_call_function(&ia64_cpu_local_tick_fn, NULL, 1);
-}
git.samba.org / sfrench / cifs-2.6.git / blobdiff