linux内存管理

asmlinkage __visible void __init start_kernel(void)

{

    char *command_line;

    char *after_dashes;

    set_task_stack_end_magic(&init_task);

    smp_setup_processor_id();

    debug_objects_early_init();

    cgroup_init_early();

    local_irq_disable();

    early_boot_irqs_disabled = true;

    /*

     * Interrupts are still disabled. Do necessary setups, then

     * enable them.

     */

    boot_cpu_init();

    page_address_init();

    pr_notice("%s", linux_banner);

    setup_arch(&command_line);

    /*

     * Set up the the initial canary and entropy after arch

     * and after adding latent and command line entropy.

     */

    add_latent_entropy();

    add_device_randomness(command_line, strlen(command_line));

    boot_init_stack_canary();

    mm_init_cpumask(&init_mm);

    setup_command_line(command_line);

    setup_nr_cpu_ids();

    setup_per_cpu_areas();

    smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */

    boot_cpu_hotplug_init();

    build_all_zonelists(NULL);

    page_alloc_init();

    pr_notice("Kernel command line: %s\n", boot_command_line);

    /* parameters may set static keys */

    jump_label_init();

    parse_early_param();

    after_dashes = parse_args("Booting kernel",

                  static_command_line, __start___param,

                  __stop___param - __start___param,

                  -1, -1, NULL, &unknown_bootoption);

    if (!IS_ERR_OR_NULL(after_dashes))

        parse_args("Setting init args", after_dashes, NULL, 0, -1, -1,

               NULL, set_init_arg);

    /*

     * These use large bootmem allocations and must precede

     * kmem_cache_init()

     */

    setup_log_buf(0);

    vfs_caches_init_early();

    sort_main_extable();

    trap_init();

    mm_init();

    ftrace_init();

    /* trace_printk can be enabled here */

    early_trace_init();

    /*

     * Set up the scheduler prior starting any interrupts (such as the

     * timer interrupt). Full topology setup happens at smp_init()

     * time - but meanwhile we still have a functioning scheduler.

     */

    sched_init();

    /*

     * Disable preemption - early bootup scheduling is extremely

     * fragile until we cpu_idle() for the first time.

     */

    preempt_disable();

    if (WARN(!irqs_disabled(),

         "Interrupts were enabled *very* early, fixing it\n"))

        local_irq_disable();

    radix_tree_init();

    /*

     * Set up housekeeping before setting up workqueues to allow the unbound

     * workqueue to take non-housekeeping into account.

     */

    housekeeping_init();

    /*

     * Allow workqueue creation and work item queueing/cancelling

     * early.  Work item execution depends on kthreads and starts after

     * workqueue_init().

     */

    workqueue_init_early();

    rcu_init();

    /* Trace events are available after this */

    trace_init();

    if (initcall_debug)

        initcall_debug_enable();

    context_tracking_init();

    /* init some links before init_ISA_irqs() */

    early_irq_init();

    init_IRQ();

    tick_init();

    rcu_init_nohz();

    init_timers();

    hrtimers_init();

    softirq_init();

    timekeeping_init();

    time_init();

    perf_event_init();

    profile_init();

    call_function_init();

    WARN(!irqs_disabled(), "Interrupts were enabled early\n");

    early_boot_irqs_disabled = false;

    local_irq_enable();

    kmem_cache_init_late();

    /*

     * HACK ALERT! This is early. We're enabling the console before

     * we've done PCI setups etc, and console_init() must be aware of

     * this. But we do want output early, in case something goes wrong.

     */

    console_init();

    if (panic_later)

        panic("Too many boot %s vars at `%s'", panic_later,

              panic_param);

    lockdep_init();

    /*

     * Need to run this when irqs are enabled, because it wants

     * to self-test [hard/soft]-irqs on/off lock inversion bugs

     * too:

     */

    locking_selftest();

    /*

     * This needs to be called before any devices perform DMA

     * operations that might use the SWIOTLB bounce buffers. It will

     * mark the bounce buffers as decrypted so that their usage will

     * not cause "plain-text" data to be decrypted when accessed.

     */

    mem_encrypt_init();

#ifdef CONFIG_BLK_DEV_INITRD

    if (initrd_start && !initrd_below_start_ok &&

        page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {

        pr_crit("initrd overwritten (0x%08lx < 0x%08lx) - disabling it.\n",

            page_to_pfn(virt_to_page((void *)initrd_start)),

            min_low_pfn);

        initrd_start = 0;

    }

#endif

    kmemleak_init();

    debug_objects_mem_init();

    setup_per_cpu_pageset();

    numa_policy_init();

    acpi_early_init();

    if (late_time_init)

        late_time_init();

    sched_clock_init();

    calibrate_delay();

    pid_idr_init();

    anon_vma_init();

#ifdef CONFIG_X86

    if (efi_enabled(EFI_RUNTIME_SERVICES))

        efi_enter_virtual_mode();

#endif

    thread_stack_cache_init();

    cred_init();

    fork_init();

    proc_caches_init();

    uts_ns_init();

    buffer_init();

    key_init();

    security_init();

    dbg_late_init();

    vfs_caches_init();

    pagecache_init();

    signals_init();

    seq_file_init();

    proc_root_init();

    nsfs_init();

    cpuset_init();

    cgroup_init();

    taskstats_init_early();

    delayacct_init();

    check_bugs();

    acpi_subsystem_init();

    arch_post_acpi_subsys_init();

    sfi_init_late();

    if (efi_enabled(EFI_RUNTIME_SERVICES)) {

        efi_free_boot_services();

    }

    /* Do the rest non-__init'ed, we're now alive */

    rest_init();

    prevent_tail_call_optimization();

}