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Diffstat (limited to 'arch/ia64/xen/time.c')
| -rw-r--r-- | arch/ia64/xen/time.c | 180 |
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 index 00000000000..ec168ec754b --- /dev/null +++ b/arch/ia64/xen/time.c @@ -0,0 +1,180 @@ +/****************************************************************************** + * 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]; +} + +/* + * 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(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(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, +}; |