Optimize loop in smp_call_function a bit.

[linux-2.6/linux-mips.git] / arch / mips64 / kernel / smp.c

/*
 * 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.
 *
 * Copyright (C) 2000, 2001 Kanoj Sarcar
 * Copyright (C) 2000, 2001 Ralf Baechle
 * Copyright (C) 2000, 2001 Silicon Graphics, Inc.
 * Copyright (C) 2000, 2001 Broadcom Corporation
 */
#include <linux/config.h>
#include <linux/cache.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/threads.h>
#include <linux/module.h>
#include <linux/time.h>
#include <linux/timex.h>
#include <linux/sched.h>

#include <asm/atomic.h>
#include <asm/cpu.h>
#include <asm/processor.h>
#include <asm/system.h>
#include <asm/hardirq.h>
#include <asm/mmu_context.h>
#include <asm/smp.h>

int smp_threads_ready;  /* Not used */

// static atomic_t cpus_booted = ATOMIC_INIT(0);
atomic_t cpus_booted = ATOMIC_INIT(0);

cpumask_t phys_cpu_present_map;         /* Bitmask of physically CPUs */
cpumask_t cpu_online_map;               /* Bitmask of currently online CPUs */
int __cpu_number_map[NR_CPUS];
int __cpu_logical_map[NR_CPUS];

/* These are defined by the board-specific code. */

/*
 * Cause the function described by call_data to be executed on the passed
 * cpu.  When the function has finished, increment the finished field of
 * call_data.
 */
void core_send_ipi(int cpu, unsigned int action);

/*
 * Clear all undefined state in the cpu, set up sp and gp to the passed
 * values, and kick the cpu into smp_bootstrap();
 */
void prom_boot_secondary(int cpu, unsigned long sp, unsigned long gp);

/*
 *  After we've done initial boot, this function is called to allow the
 *  board code to clean up state, if needed
 */
void prom_init_secondary(void);

void prom_smp_finish(void);

cycles_t cacheflush_time;
unsigned long cache_decay_ticks;

void smp_tune_scheduling (void)
{
        struct cache_desc *cd = &current_cpu_data.scache;
        unsigned long cachesize;       /* kB   */
        unsigned long bandwidth = 350; /* MB/s */
        unsigned long cpu_khz;

        /*
         * Crude estimate until we actually meassure ...
         */
        cpu_khz = loops_per_jiffy * 2 * HZ / 1000;

        /*
         * Rough estimation for SMP scheduling, this is the number of
         * cycles it takes for a fully memory-limited process to flush
         * the SMP-local cache.
         *
         * (For a P5 this pretty much means we will choose another idle
         *  CPU almost always at wakeup time (this is due to the small
         *  L1 cache), on PIIs it's around 50-100 usecs, depending on
         *  the cache size)
         */
        if (!cpu_khz) {
                /*
                 * This basically disables processor-affinity scheduling on SMP
                 * without a cycle counter.  Currently all SMP capable MIPS
                 * processors have a cycle counter.
                 */
                cacheflush_time = 0;
                return;
        }

        cachesize = cd->linesz * cd->sets * cd->ways;
        cacheflush_time = (cpu_khz>>10) * (cachesize<<10) / bandwidth;
        cache_decay_ticks = (long)cacheflush_time/cpu_khz * HZ / 1000;

        printk("per-CPU timeslice cutoff: %ld.%02ld usecs.\n",
                (long)cacheflush_time/(cpu_khz/1000),
                ((long)cacheflush_time*100/(cpu_khz/1000)) % 100);
        printk("task migration cache decay timeout: %ld msecs.\n",
                (cache_decay_ticks + 1) * 1000 / HZ);
}

void __init smp_callin(void)
{
#if 0
        calibrate_delay();
        smp_store_cpu_info(cpuid);
#endif
}

#ifndef CONFIG_SGI_IP27
/*
 * Hook for doing final board-specific setup after the generic smp setup
 * is done
 */
asmlinkage void start_secondary(void)
{
        unsigned int cpu = smp_processor_id();

        cpu_probe();
        prom_init_secondary();
        per_cpu_trap_init();

        /*
         * XXX parity protection should be folded in here when it's converted
         * to an option instead of something based on .cputype
         */
        pgd_current[cpu] = init_mm.pgd;
        cpu_data[cpu].udelay_val = loops_per_jiffy;
        prom_smp_finish();
        printk("Slave cpu booted successfully\n");
        CPUMASK_SETB(cpu_online_map, cpu);
        atomic_inc(&cpus_booted);
        cpu_idle();
}
#endif /* CONFIG_SGI_IP27 */

/*
 * this function sends a 'reschedule' IPI to another CPU.
 * it goes straight through and wastes no time serializing
 * anything. Worst case is that we lose a reschedule ...
 */
void smp_send_reschedule(int cpu)
{
        core_send_ipi(cpu, SMP_RESCHEDULE_YOURSELF);
}

static spinlock_t call_lock = SPIN_LOCK_UNLOCKED;

struct call_data_struct *call_data;

/*
 * Run a function on all other CPUs.
 *  <func>      The function to run. This must be fast and non-blocking.
 *  <info>      An arbitrary pointer to pass to the function.
 *  <retry>     If true, keep retrying until ready.
 *  <wait>      If true, wait until function has completed on other CPUs.
 *  [RETURNS]   0 on success, else a negative status code.
 *
 * Does not return until remote CPUs are nearly ready to execute <func>
 * or are or have executed.
 *
 * You must not call this function with disabled interrupts or from a
 * hardware interrupt handler or from a bottom half handler.
 */
int smp_call_function (void (*func) (void *info), void *info, int retry,
                                                                int wait)
{
        struct call_data_struct data;
        int i, cpus = num_online_cpus() - 1;
        int cpu = smp_processor_id();

        if (!cpus)
                return 0;

        data.func = func;
        data.info = info;
        atomic_set(&data.started, 0);
        data.wait = wait;
        if (wait)
                atomic_set(&data.finished, 0);

        spin_lock(&call_lock);
        call_data = &data;

        /* Send a message to all other CPUs and wait for them to respond */
        for (i = 0; i < NR_CPUS; i++)
                if (cpu_online(cpu) && i != cpu)
                        core_send_ipi(i, SMP_CALL_FUNCTION);

        /* Wait for response */
        /* FIXME: lock-up detection, backtrace on lock-up */
        while (atomic_read(&data.started) != cpus)
                barrier();

        if (wait)
                while (atomic_read(&data.finished) != cpus)
                        barrier();
        spin_unlock(&call_lock);

        return 0;
}

void smp_call_function_interrupt(void)
{
        void (*func) (void *info) = call_data->func;
        void *info = call_data->info;
        int wait = call_data->wait;

        /*
         * Notify initiating CPU that I've grabbed the data and am
         * about to execute the function.
         */
        mb();
        atomic_inc(&call_data->started);

        /*
         * At this point the info structure may be out of scope unless wait==1.
         */
        irq_enter();
        (*func)(info);
        irq_exit();

        if (wait) {
                mb();
                atomic_inc(&call_data->finished);
        }
}

static void stop_this_cpu(void *dummy)
{
        /*
         * Remove this CPU:
         */
        clear_bit(smp_processor_id(), &cpu_online_map);
        local_irq_enable();     /* May need to service _machine_restart IPI */
        for (;;);               /* Wait if available. */
}

void smp_send_stop(void)
{
        smp_call_function(stop_this_cpu, NULL, 1, 0);
}

/* Not really SMP stuff ... */
int setup_profiling_timer(unsigned int multiplier)
{
        return 0;
}

static void flush_tlb_all_ipi(void *info)
{
        local_flush_tlb_all();
}

void flush_tlb_all(void)
{
        on_each_cpu(flush_tlb_all_ipi, 0, 1, 1);
}

static void flush_tlb_mm_ipi(void *mm)
{
        local_flush_tlb_mm((struct mm_struct *)mm);
}

/*
 * The following tlb flush calls are invoked when old translations are
 * being torn down, or pte attributes are changing. For single threaded
 * address spaces, a new context is obtained on the current cpu, and tlb
 * context on other cpus are invalidated to force a new context allocation
 * at switch_mm time, should the mm ever be used on other cpus. For
 * multithreaded address spaces, intercpu interrupts have to be sent.
 * Another case where intercpu interrupts are required is when the target
 * mm might be active on another cpu (eg debuggers doing the flushes on
 * behalf of debugees, kswapd stealing pages from another process etc).
 * Kanoj 07/00.
 */

void flush_tlb_mm(struct mm_struct *mm)
{
        preempt_disable();

        if ((atomic_read(&mm->mm_users) != 1) || (current->mm != mm)) {
                smp_call_function(flush_tlb_mm_ipi, (void *)mm, 1, 1);
        } else {
                int i;
                for (i = 0; i < num_online_cpus(); i++)
                        if (smp_processor_id() != i)
                                cpu_context(i, mm) = 0;
        }
        local_flush_tlb_mm(mm);

        preempt_enable();
}

struct flush_tlb_data {
        struct vm_area_struct *vma;
        unsigned long addr1;
        unsigned long addr2;
};

static void flush_tlb_range_ipi(void *info)
{
        struct flush_tlb_data *fd = (struct flush_tlb_data *)info;

        local_flush_tlb_range(fd->vma, fd->addr1, fd->addr2);
}

void flush_tlb_range(struct vm_area_struct *vma, unsigned long start, unsigned long end)
{
        struct mm_struct *mm = vma->vm_mm;

        preempt_disable();
        if ((atomic_read(&mm->mm_users) != 1) || (current->mm != mm)) {
                struct flush_tlb_data fd;

                fd.vma = vma;
                fd.addr1 = start;
                fd.addr2 = end;
                smp_call_function(flush_tlb_range_ipi, (void *)&fd, 1, 1);
        } else {
                int i;
                for (i = 0; i < num_online_cpus(); i++)
                        if (smp_processor_id() != i)
                                cpu_context(i, mm) = 0;
        }
        local_flush_tlb_range(vma, start, end);
        preempt_enable();
}

static void flush_tlb_kernel_range_ipi(void *info)
{
        struct flush_tlb_data *fd = (struct flush_tlb_data *)info;

        local_flush_tlb_kernel_range(fd->addr1, fd->addr2);
}

void flush_tlb_kernel_range(unsigned long start, unsigned long end)
{
        struct flush_tlb_data fd;

        fd.addr1 = start;
        fd.addr2 = end;
        smp_call_function(flush_tlb_kernel_range_ipi, (void *)&fd, 1, 1);
        local_flush_tlb_kernel_range(start, end);
}

static void flush_tlb_page_ipi(void *info)
{
        struct flush_tlb_data *fd = (struct flush_tlb_data *)info;

        local_flush_tlb_page(fd->vma, fd->addr1);
}

void flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
{
        preempt_disable();
        if ((atomic_read(&vma->vm_mm->mm_users) != 1) || (current->mm != vma->vm_mm)) {
                struct flush_tlb_data fd;

                fd.vma = vma;
                fd.addr1 = page;
                smp_call_function(flush_tlb_page_ipi, (void *)&fd, 1, 1);
        } else {
                int i;
                for (i = 0; i < num_online_cpus(); i++)
                        if (smp_processor_id() != i)
                                cpu_context(i, vma->vm_mm) = 0;
        }
        local_flush_tlb_page(vma, page);
        preempt_enable();
}

static void flush_tlb_one_ipi(void *info)
{
        unsigned long vaddr = (unsigned long) info;

        local_flush_tlb_one(vaddr);
}

void flush_tlb_one(unsigned long vaddr)
{
        smp_call_function(flush_tlb_one_ipi, (void *) vaddr, 1, 1);
        local_flush_tlb_one(vaddr);
}

EXPORT_SYMBOL(flush_tlb_page);
EXPORT_SYMBOL(flush_tlb_one);
EXPORT_SYMBOL(cpu_data);
EXPORT_SYMBOL(synchronize_irq);