Feedback welcome,
Rusty.
-- Anyone who quotes me in their sig is an idiot. -- Rusty Russell.Name: Hot-plug CPU Boot Changes Author: Rusty Russell Status: Tested on 2.5.25, x86 SMP
D: This patch alters the boot sequence to "plug in" each CPU, one at a D: time. You need the patch for each architecture, as well. The D: interface used to be "smp_boot_cpus()", "smp_commence()", and each D: arch implemented the "maxcpus" boot arg itself. With this patch, D: it is: D: smp_prepare_cpus(maxcpus): probe for cpus and set up cpu_possible(cpu). D: __cpu_up(cpu): called *after* initcalls, for each cpu where D: cpu_possible(cpu) is true. D: smp_cpus_done(maxcpus): called after every cpu has been brought up
diff -urN -I $.*$ --exclude TAGS -X /home/rusty/current-dontdiff --minimal linux-2.5.25/include/linux/notifier.h working-2.5.25-hotcpu/include/linux/notifier.h --- linux-2.5.25/include/linux/notifier.h Mon Jun 24 00:55:28 2002 +++ working-2.5.25-hotcpu/include/linux/notifier.h Mon Jul 15 12:44:55 2002 @@ -58,5 +58,7 @@ #define SYS_HALT 0x0002 /* Notify of system halt */ #define SYS_POWER_OFF 0x0003 /* Notify of system power off */ +#define CPU_ONLINE 0x0002 /* CPU (unsigned)v coming up */ + #endif /* __KERNEL__ */ #endif /* _LINUX_NOTIFIER_H */ diff -urN -I $.*$ --exclude TAGS -X /home/rusty/current-dontdiff --minimal linux-2.5.25/include/linux/sched.h working-2.5.25-hotcpu/include/linux/sched.h --- linux-2.5.25/include/linux/sched.h Sun Jul 7 02:12:24 2002 +++ working-2.5.25-hotcpu/include/linux/sched.h Mon Jul 15 12:44:55 2002 @@ -150,7 +150,6 @@ extern void update_one_process(struct task_struct *p, unsigned long user, unsigned long system, int cpu); extern void scheduler_tick(int user_tick, int system); -extern void migration_init(void); extern unsigned long cache_decay_ticks; diff -urN -I $.*$ --exclude TAGS -X /home/rusty/current-dontdiff --minimal linux-2.5.25/include/linux/smp.h working-2.5.25-hotcpu/include/linux/smp.h --- linux-2.5.25/include/linux/smp.h Fri Jun 21 09:41:55 2002 +++ working-2.5.25-hotcpu/include/linux/smp.h Mon Jul 15 14:45:56 2002 @@ -32,19 +32,19 @@ /* - * Boot processor call to load the other CPU's + * Prepare machine for booting other CPUs. */ -extern void smp_boot_cpus(void); +extern void smp_prepare_cpus(unsigned int max_cpus); /* - * Processor call in. Must hold processors until .. + * Bring a CPU up */ -extern void smp_callin(void); +extern int __cpu_up(unsigned int cpunum); /* - * Multiprocessors may now schedule + * Final polishing of CPUs */ -extern void smp_commence(void); +extern void smp_cpus_done(unsigned int max_cpus); /* * Call a function on all other processors @@ -71,6 +71,13 @@ #define MSG_RESCHEDULE 0x0003 /* Reschedule request from master CPU*/ #define MSG_CALL_FUNCTION 0x0004 /* Call function on all other CPUs */ +struct notifier_block; + +/* Need to know about CPUs going up/down? */ +extern int register_cpu_notifier(struct notifier_block *nb); +extern void unregister_cpu_notifier(struct notifier_block *nb); + +int cpu_up(unsigned int cpu); #else /* !SMP */ /* @@ -92,6 +99,10 @@ #define __per_cpu_data #define per_cpu(var, cpu) var #define this_cpu(var) var + +/* Need to know about CPUs going up/down? */ +#define register_cpu_notifier(nb) 0 +#define unregister_cpu_notifier(nb) do { } while(0) #endif /* !SMP */ diff -urN -I $.*$ --exclude TAGS -X /home/rusty/current-dontdiff --minimal linux-2.5.25/init/main.c working-2.5.25-hotcpu/init/main.c --- linux-2.5.25/init/main.c Thu Jun 20 01:28:52 2002 +++ working-2.5.25-hotcpu/init/main.c Mon Jul 15 12:44:55 2002 @@ -93,6 +93,35 @@ char *execute_command; +/* Setup configured maximum number of CPUs to activate */ +static unsigned int max_cpus = UINT_MAX; + +/* + * Setup routine for controlling SMP activation + * + * Command-line option of "nosmp" or "maxcpus=0" will disable SMP + * activation entirely (the MPS table probe still happens, though). + * + * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer + * greater than 0, limits the maximum number of CPUs activated in + * SMP mode to <NUM>. + */ +static int __init nosmp(char *str) +{ + max_cpus = 0; + return 1; +} + +__setup("nosmp", nosmp); + +static int __init maxcpus(char *str) +{ + get_option(&str, &max_cpus); + return 1; +} + +__setup("maxcpus=", maxcpus); + static char * argv_init[MAX_INIT_ARGS+2] = { "init", NULL, }; char * envp_init[MAX_INIT_ENVS+2] = { "HOME=/", "TERM=linux", NULL, }; @@ -273,6 +302,7 @@ #endif static inline void setup_per_cpu_areas(void) { } +static inline void smp_prepare_cpus(unsigned int maxcpus) { } #else @@ -303,11 +333,27 @@ /* Called by boot processor to activate the rest. */ static void __init smp_init(void) { + unsigned int i; + + /* FIXME: This should be done in userspace --RR */ + for (i = 0; i < NR_CPUS; i++) { + if (num_online_cpus() >= max_cpus) + break; + if (cpu_possible(i) && !cpu_online(i)) { + printk("Bringing up %in", i); + cpu_up(i); + } + } + + /* Any cleanup work */ + printk("CPUS done %un", max_cpus); + smp_cpus_done(max_cpus); +#if 0 /* Get other processors into their bootup holding patterns. */ - smp_boot_cpus(); smp_threads_ready=1; smp_commence(); +#endif } #endif @@ -402,14 +448,12 @@ check_bugs(); printk("POSIX conformance testing by UNIFIXn"); - init_idle(current, smp_processor_id()); - /* * We count on the initial thread going ok * Like idlers init is an unlocked kernel thread, which will * make syscalls (and thus be locked). */ - smp_init(); + init_idle(current, smp_processor_id()); /* Do the rest non-__init'ed, we're now alive */ rest_init(); @@ -441,12 +485,6 @@ static void __init do_basic_setup(void) { /* - * Let the per-CPU migration threads start up: - */ -#if CONFIG_SMP - migration_init(); -#endif - /* * Tell the world that we're going to be the grim * reaper of innocent orphaned children. * @@ -490,7 +528,10 @@ static char * argv_sh[] = { "sh", NULL, }; lock_kernel(); + /* Sets up cpus_possible() */ + smp_prepare_cpus(max_cpus); do_basic_setup(); + smp_init(); prepare_namespace(); diff -urN -I $.*$ --exclude TAGS -X /home/rusty/current-dontdiff --minimal linux-2.5.25/kernel/Makefile working-2.5.25-hotcpu/kernel/Makefile --- linux-2.5.25/kernel/Makefile Mon Jun 10 16:03:56 2002 +++ working-2.5.25-hotcpu/kernel/Makefile Mon Jul 15 12:44:55 2002 @@ -17,6 +17,7 @@ sysctl.o capability.o ptrace.o timer.o user.o signal.o sys.o kmod.o context.o futex.o platform.o +obj-$(CONFIG_SMP) += cpu.o obj-$(CONFIG_UID16) += uid16.o obj-$(CONFIG_MODULES) += ksyms.o obj-$(CONFIG_PM) += pm.o diff -urN -I $.*$ --exclude TAGS -X /home/rusty/current-dontdiff --minimal linux-2.5.25/kernel/cpu.c working-2.5.25-hotcpu/kernel/cpu.c --- linux-2.5.25/kernel/cpu.c Thu Jan 1 10:00:00 1970 +++ working-2.5.25-hotcpu/kernel/cpu.c Mon Jul 15 14:34:49 2002 @@ -0,0 +1,54 @@ +/* CPU control. + * (C) 2001 Rusty Russell + * This code is licenced under the GPL. + */ +#include <linux/proc_fs.h> +#include <linux/smp.h> +#include <linux/init.h> +#include <linux/notifier.h> +#include <linux/sched.h> +#include <linux/unistd.h> +#include <asm/semaphore.h> + +/* This protects CPUs going up and down... */ +DECLARE_MUTEX(cpucontrol); + +static struct notifier_block *cpu_chain = NULL; + +/* Need to know about CPUs going up/down? */ +int register_cpu_notifier(struct notifier_block *nb) +{ + return notifier_chain_register(&cpu_chain, nb); +} + +void unregister_cpu_notifier(struct notifier_block *nb) +{ + notifier_chain_unregister(&cpu_chain,nb); +} + +int __devinit cpu_up(unsigned int cpu) +{ + int ret; + + if ((ret = down_interruptible(&cpucontrol)) != 0) + return ret; + + if (cpu_online(cpu)) { + ret = -EINVAL; + goto out; + } + + /* Arch-specific enabling code. */ + ret = __cpu_up(cpu); + if (ret != 0) goto out; + if (!cpu_online(cpu)) + BUG(); + + /* Now call notifier in preparation. */ + printk("CPU %u IS NOW UP!n", cpu); + notifier_call_chain(&cpu_chain, CPU_ONLINE, (void *)cpu); + + out: + up(&cpucontrol); + return ret; +} diff -urN -I $.*$ --exclude TAGS -X /home/rusty/current-dontdiff --minimal linux-2.5.25/kernel/sched.c working-2.5.25-hotcpu/kernel/sched.c --- linux-2.5.25/kernel/sched.c Sun Jul 7 02:12:24 2002 +++ working-2.5.25-hotcpu/kernel/sched.c Mon Jul 15 12:44:55 2002 @@ -26,6 +26,8 @@ #include <linux/interrupt.h> #include <linux/completion.h> #include <linux/kernel_stat.h> +#include <linux/notifier.h> +#include <linux/delay.h> /* * Convert user-nice values [ -20 ... 0 ... 19 ] @@ -1752,9 +1756,11 @@ migration_req_t req; runqueue_t *rq; +#if 0 /* FIXME: Grab cpu_lock, return error on this case. --RR */ new_mask &= cpu_online_map; if (!new_mask) BUG(); +#endif preempt_disable(); rq = task_rq_lock(p, &flags); @@ -1787,8 +1793,6 @@ preempt_enable(); } -static __initdata int master_migration_thread; - static int migration_thread(void * bind_cpu) { int cpu = (int) (long) bind_cpu; @@ -1800,15 +1804,7 @@ sigfillset(¤t->blocked); set_fs(KERNEL_DS); - /* - * The first migration thread is started on the boot CPU, it - * migrates the other migration threads to their destination CPUs. - */ - if (cpu != master_migration_thread) { - while (!cpu_rq(master_migration_thread)->migration_thread) - yield(); - set_cpus_allowed(current, 1UL << cpu); - } + set_cpus_allowed(current, 1UL << cpu); printk("migration_task %d on cpu=%dn", cpu, smp_processor_id()); ret = setscheduler(0, SCHED_FIFO, ¶m); @@ -1865,27 +1861,31 @@ } } -void __init migration_init(void) +static int migration_call(struct notifier_block *nfb, + unsigned long action, + void *hcpu) { - int cpu; - - master_migration_thread = smp_processor_id(); - current->cpus_allowed = 1UL << master_migration_thread; - - for (cpu = 0; cpu < NR_CPUS; cpu++) { - if (!cpu_online(cpu)) - continue; - if (kernel_thread(migration_thread, (void *) (long) cpu, - CLONE_FS | CLONE_FILES | CLONE_SIGNAL) < 0) - BUG(); + switch (action) { + case CPU_ONLINE: + printk("Starting migration thread for cpu %lin", + (long)hcpu); + kernel_thread(migration_thread, hcpu, + CLONE_FS | CLONE_FILES | CLONE_SIGNAL); + break; } - current->cpus_allowed = -1L; + return NOTIFY_OK; +} - for (cpu = 0; cpu < NR_CPUS; cpu++) { - if (!cpu_online(cpu)) - continue; - while (!cpu_rq(cpu)->migration_thread) - schedule_timeout(2); - } +static struct notifier_block migration_notifier = { &migration_call, NULL, 0 }; + +int __init migration_init(void) +{ + /* Start one for boot CPU. */ + migration_call(&migration_notifier, CPU_ONLINE, + (void *)smp_processor_id()); + register_cpu_notifier(&migration_notifier); + return 0; } + +__initcall(migration_init); #endif diff -urN -I $.*$ --exclude TAGS -X /home/rusty/current-dontdiff --minimal linux-2.5.25/kernel/softirq.c working-2.5.25-hotcpu/kernel/softirq.c --- linux-2.5.25/kernel/softirq.c Sun Jul 7 02:12:24 2002 +++ working-2.5.25-hotcpu/kernel/softirq.c Mon Jul 15 12:44:55 2002 @@ -17,6 +17,7 @@ #include <linux/init.h> #include <linux/tqueue.h> #include <linux/percpu.h> +#include <linux/notifier.h> /* - No shared variables, all the data are CPU local. @@ -397,20 +398,32 @@ } } -static __init int spawn_ksoftirqd(void) +static int __devinit cpu_callback(struct notifier_block *nfb, + unsigned long action, + void *hcpu) { - int cpu; + int hotcpu = (unsigned long)hcpu; - for (cpu = 0; cpu < NR_CPUS; cpu++) { - if (!cpu_online(cpu)) - continue; - if (kernel_thread(ksoftirqd, (void *) (long) cpu, - CLONE_FS | CLONE_FILES | CLONE_SIGNAL) < 0) - printk("spawn_ksoftirqd() failed for cpu %dn", cpu); - else - while (!ksoftirqd_task(cpu)) - yield(); - } + if (action == CPU_ONLINE) { + if (kernel_thread(ksoftirqd, hcpu, + CLONE_FS | CLONE_FILES | CLONE_SIGNAL) < 0) { + printk("ksoftirqd for %i failedn", hotcpu); + return NOTIFY_BAD; + } + + while (!ksoftirqd_task(hotcpu)) + yield(); + return NOTIFY_OK; + } + return NOTIFY_BAD; +} + +static struct notifier_block cpu_nfb = { &cpu_callback, NULL, 0 }; + +static __init int spawn_ksoftirqd(void) +{ + cpu_callback(&cpu_nfb, CPU_ONLINE, (void *)smp_processor_id()); + register_cpu_notifier(&cpu_nfb); return 0; } Name: Hot-plug CPU Boot Rewrite for i386 Author: Rusty Russell Status: Tested 2.5.25, dual SMP Depends: Hotcpu/hotcpu-boot.patch.gz
D: This modifies the i386 boot sequence to "plug in" CPUs one at a D: time. This is the minimal change to make it work (the CPUs are D: brought up as normal during the "smp_prepare_cpus()" probe phase).
diff -urN -I $.*$ --exclude TAGS -X /home/rusty/current-dontdiff --minimal linux-2.5.25/arch/i386/kernel/apic.c working-2.5.25-hotcpu/arch/i386/kernel/apic.c --- linux-2.5.25/arch/i386/kernel/apic.c Thu Jun 20 01:28:47 2002 +++ working-2.5.25-hotcpu/arch/i386/kernel/apic.c Mon Jul 15 18:23:12 2002 @@ -798,9 +798,9 @@ apic_write_around(APIC_TMICT, clocks/APIC_DIVISOR); } -void setup_APIC_timer(void * data) +static void setup_APIC_timer(unsigned int clocks) { - unsigned int clocks = (unsigned int) data, slice, t0, t1; + unsigned int slice, t0, t1; unsigned long flags; int delta; @@ -926,7 +926,7 @@ int dont_use_local_apic_timer __initdata = 0; -void __init setup_APIC_clocks (void) +void __init setup_boot_APIC_clock(void) { /* Disabled by DMI scan or kernel option? */ if (dont_use_local_apic_timer) @@ -941,12 +941,16 @@ /* * Now set up the timer for real. */ - setup_APIC_timer((void *)calibration_result); + setup_APIC_timer(calibration_result); __sti(); +} - /* and update all other cpus */ - smp_call_function(setup_APIC_timer, (void *)calibration_result, 1, 1); +void __init setup_secondary_APIC_clock(void) +{ + __cli(); /* FIXME: Do we need this? --RR */ + setup_APIC_timer(calibration_result); + __sti(); } void __init disable_APIC_timer(void) @@ -1178,7 +1182,7 @@ if (!skip_ioapic_setup && nr_ioapics) setup_IO_APIC(); #endif - setup_APIC_clocks(); + setup_boot_APIC_clock(); return 0; } diff -urN -I $.*$ --exclude TAGS -X /home/rusty/current-dontdiff --minimal linux-2.5.25/arch/i386/kernel/apm.c working-2.5.25-hotcpu/arch/i386/kernel/apm.c --- linux-2.5.25/arch/i386/kernel/apm.c Sun Jul 7 02:12:17 2002 +++ working-2.5.25-hotcpu/arch/i386/kernel/apm.c Mon Jul 15 14:42:18 2002 @@ -1587,7 +1587,7 @@ p = buf; - if ((num_online_cpus() == 1) && + if ((num_possible_cpus() == 1) && !(error = apm_get_power_status(&bx, &cx, &dx))) { ac_line_status = (bx >> 8) & 0xff; battery_status = bx & 0xff; @@ -1718,7 +1718,7 @@ } } - if (debug && (num_online_cpus() == 1)) { + if (debug && (num_possible_cpus() == 1)) { error = apm_get_power_status(&bx, &cx, &dx); if (error) printk(KERN_INFO "apm: power status not availablen"); @@ -1762,7 +1762,7 @@ pm_power_off = apm_power_off; register_sysrq_key('o', &sysrq_poweroff_op); - if (num_online_cpus() == 1) { + if (num_possible_cpus() == 1) { #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT) console_blank_hook = apm_console_blank; #endif @@ -1905,9 +1905,7 @@ printk(KERN_NOTICE "apm: disabled on user request.n"); return -ENODEV; } - /* FIXME: When boot code changes, this will need to be - deactivated when/if a CPU comes up --RR */ - if ((num_online_cpus() > 1) && !power_off) { + if ((num_possible_cpus() > 1) && !power_off) { printk(KERN_NOTICE "apm: disabled - APM is not SMP safe.n"); return -ENODEV; } @@ -1961,9 +1959,7 @@ kernel_thread(apm, NULL, CLONE_FS | CLONE_FILES | CLONE_SIGHAND | SIGCHLD); - /* FIXME: When boot code changes, this will need to be - deactivated when/if a CPU comes up --RR */ - if (num_online_cpus() > 1) { + if (num_possible_cpus() > 1) { printk(KERN_NOTICE "apm: disabled - APM is not SMP safe (power off active).n"); return 0; diff -urN -I $.*$ --exclude TAGS -X /home/rusty/current-dontdiff --minimal linux-2.5.25/arch/i386/kernel/mtrr.c working-2.5.25-hotcpu/arch/i386/kernel/mtrr.c --- linux-2.5.25/arch/i386/kernel/mtrr.c Thu Jun 20 01:28:47 2002 +++ working-2.5.25-hotcpu/arch/i386/kernel/mtrr.c Mon Jul 15 14:42:42 2002 @@ -1055,7 +1055,7 @@ wait_barrier_cache_disable = TRUE; wait_barrier_execute = TRUE; wait_barrier_cache_enable = TRUE; - atomic_set (&undone_count, num_online_cpus() - 1); + atomic_set (&undone_count, num_booting_cpus() - 1); /* Start the ball rolling on other CPUs */ if (smp_call_function (ipi_handler, &data, 1, 0) != 0) panic ("mtrr: timed out waiting for other CPUsn"); @@ -1064,14 +1064,14 @@ /* Wait for all other CPUs to flush and disable their caches */ while (atomic_read (&undone_count) > 0) { rep_nop(); barrier(); } /* Set up for completion wait and then release other CPUs to change MTRRs*/ - atomic_set (&undone_count, num_online_cpus() - 1); + atomic_set (&undone_count, num_booting_cpus() - 1); wait_barrier_cache_disable = FALSE; set_mtrr_cache_disable (&ctxt); /* Wait for all other CPUs to flush and disable their caches */ while (atomic_read (&undone_count) > 0) { rep_nop(); barrier(); } /* Set up for completion wait and then release other CPUs to change MTRRs*/ - atomic_set (&undone_count, num_online_cpus() - 1); + atomic_set (&undone_count, num_booting_cpus() - 1); wait_barrier_execute = FALSE; (*set_mtrr_up) (reg, base, size, type, FALSE); /* Now wait for other CPUs to complete the function */ diff -urN -I $.*$ --exclude TAGS -X /home/rusty/current-dontdiff --minimal linux-2.5.25/arch/i386/kernel/nmi.c working-2.5.25-hotcpu/arch/i386/kernel/nmi.c --- linux-2.5.25/arch/i386/kernel/nmi.c Thu Jun 20 01:28:47 2002 +++ working-2.5.25-hotcpu/arch/i386/kernel/nmi.c Mon Jul 15 15:30:34 2002 @@ -81,6 +81,8 @@ sti(); mdelay((10*1000)/nmi_hz); // wait 10 ticks + /* FIXME: Only boot CPU is online at this stage. Check CPUs + as they come up. */ for (cpu = 0; cpu < NR_CPUS; cpu++) { if (!cpu_online(cpu)) continue; diff -urN -I $.*$ --exclude TAGS -X /home/rusty/current-dontdiff --minimal linux-2.5.25/arch/i386/kernel/smpboot.c working-2.5.25-hotcpu/arch/i386/kernel/smpboot.c --- linux-2.5.25/arch/i386/kernel/smpboot.c Fri Jun 21 09:41:52 2002 +++ working-2.5.25-hotcpu/arch/i386/kernel/smpboot.c Mon Jul 15 17:44:05 2002 @@ -31,7 +31,7 @@ * Maciej W. Rozycki : Bits for genuine 82489DX APICs * Martin J. Bligh : Added support for multi-quad systems * Dave Jones : Report invalid combinations of Athlon CPUs. - */ +* Rusty Russell : Hacked into shape for new "hotplug" boot process. */ #include <linux/config.h> #include <linux/init.h> @@ -53,9 +53,6 @@ /* Set if we find a B stepping CPU */ static int __initdata smp_b_stepping; -/* Setup configured maximum number of CPUs to activate */ -static int __initdata max_cpus = NR_CPUS; - /* Number of siblings per CPU package */ int smp_num_siblings = 1; int __initdata phys_proc_id[NR_CPUS]; /* Package ID of each logical CPU */ @@ -64,7 +61,8 @@ unsigned long cpu_online_map; static volatile unsigned long cpu_callin_map; -static volatile unsigned long cpu_callout_map; +volatile unsigned long cpu_callout_map; +static unsigned long smp_commenced_mask; /* Per CPU bogomips and other parameters */ struct cpuinfo_x86 cpu_data[NR_CPUS] __cacheline_aligned; @@ -73,33 +71,6 @@ int smp_threads_ready; /* - * Setup routine for controlling SMP activation - * - * Command-line option of "nosmp" or "maxcpus=0" will disable SMP - * activation entirely (the MPS table probe still happens, though). - * - * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer - * greater than 0, limits the maximum number of CPUs activated in - * SMP mode to <NUM>. - */ - -static int __init nosmp(char *str) -{ - max_cpus = 0; - return 1; -} - -__setup("nosmp", nosmp); - -static int __init maxcpus(char *str) -{ - get_option(&str, &max_cpus); - return 1; -} - -__setup("maxcpus=", maxcpus); - -/* * Trampoline 80x86 program as an array. */ @@ -139,7 +110,7 @@ * a given CPU */ -void __init smp_store_cpu_info(int id) +static void __init smp_store_cpu_info(int id) { struct cpuinfo_x86 *c = cpu_data + id; @@ -193,29 +164,6 @@ } /* - * Architecture specific routine called by the kernel just before init is - * fired off. This allows the BP to have everything in order [we hope]. - * At the end of this all the APs will hit the system scheduling and off - * we go. Each AP will load the system gdt's and jump through the kernel - * init into idle(). At this point the scheduler will one day take over - * and give them jobs to do. smp_callin is a standard routine - * we use to track CPUs as they power up. - */ - -static atomic_t smp_commenced = ATOMIC_INIT(0); - -void __init smp_commence(void) -{ - /* - * Lets the callins below out of their loop. - */ - Dprintk("Setting commenced=1, go go gon"); - - wmb(); - atomic_set(&smp_commenced,1); -} - -/* * TSC synchronization. * * We first check wether all CPUs have their TSC's synchronized, @@ -268,7 +216,7 @@ unsigned long one_usec; int buggy = 0; - printk("checking TSC synchronization across CPUs: "); + printk("checking TSC synchronization across %u CPUs: ", num_booting_cpus()); one_usec = ((1<<30)/fast_gettimeoffset_quotient)*(1<<2); @@ -289,7 +237,7 @@ /* * all APs synchronize but they loop on '== num_cpus' */ - while (atomic_read(&tsc_count_start) != num_online_cpus()-1) + while (atomic_read(&tsc_count_start) != num_booting_cpus()-1) mb(); atomic_set(&tsc_count_stop, 0); wmb(); @@ -308,7 +256,7 @@ /* * Wait for all APs to leave the synchronization point: */ - while (atomic_read(&tsc_count_stop) != num_online_cpus()-1) + while (atomic_read(&tsc_count_stop) != num_booting_cpus()-1) mb(); atomic_set(&tsc_count_start, 0); wmb(); @@ -317,16 +265,16 @@ sum = 0; for (i = 0; i < NR_CPUS; i++) { - if (cpu_online(i)) { + if (test_bit(i, &cpu_callout_map)) { t0 = tsc_values[i]; sum += t0; } } - avg = div64(sum, num_online_cpus()); + avg = div64(sum, num_booting_cpus()); sum = 0; for (i = 0; i < NR_CPUS; i++) { - if (!cpu_online(i)) + if (!test_bit(i, &cpu_callout_map)) continue; delta = tsc_values[i] - avg; if (delta < 0) @@ -359,7 +307,7 @@ int i; /* - * num_online_cpus is not necessarily known at the time + * Not every cpu is online at the time * this gets called, so we first wait for the BP to * finish SMP initialization: */ @@ -367,7 +315,7 @@ for (i = 0; i < NR_LOOPS; i++) { atomic_inc(&tsc_count_start); - while (atomic_read(&tsc_count_start) != num_online_cpus()) + while (atomic_read(&tsc_count_start) != num_booting_cpus()) mb(); rdtscll(tsc_values[smp_processor_id()]); @@ -375,7 +323,7 @@ write_tsc(0, 0); atomic_inc(&tsc_count_stop); - while (atomic_read(&tsc_count_stop) != num_online_cpus()) mb(); + while (atomic_read(&tsc_count_stop) != num_booting_cpus()) mb(); } } #undef NR_LOOPS @@ -403,7 +351,7 @@ */ phys_id = GET_APIC_ID(apic_read(APIC_ID)); cpuid = smp_processor_id(); - if (test_and_set_bit(cpuid, &cpu_online_map)) { + if (test_bit(cpuid, &cpu_callin_map)) { printk("huh, phys CPU#%d, CPU#%d already present??n", phys_id, cpuid); BUG(); @@ -501,15 +449,17 @@ */ cpu_init(); smp_callin(); - while (!atomic_read(&smp_commenced)) + while (!test_bit(smp_processor_id(), &smp_commenced_mask)) rep_nop(); + setup_secondary_APIC_clock(); enable_APIC_timer(); /* * low-memory mappings have been cleared, flush them from * the local TLBs too. */ local_flush_tlb(); - + set_bit(smp_processor_id(), &cpu_online_map); + wmb(); return cpu_idle(); } @@ -943,7 +893,6 @@ unmap_cpu_to_boot_apicid(cpu, apicid); clear_bit(cpu, &cpu_callout_map); /* was set here (do_boot_cpu()) */ clear_bit(cpu, &cpu_initialized); /* was set by cpu_init() */ - clear_bit(cpu, &cpu_online_map); /* was set in smp_callin() */ cpucount--; } @@ -1015,7 +964,7 @@ int cpu_sibling_map[NR_CPUS] __cacheline_aligned; -void __init smp_boot_cpus(void) +static void __init smp_boot_cpus(unsigned int max_cpus) { int apicid, cpu, bit; @@ -1057,6 +1006,7 @@ * We have the boot CPU online for sure. */ set_bit(0, &cpu_online_map); + set_bit(0, &cpu_callout_map); boot_cpu_logical_apicid = logical_smp_processor_id(); map_cpu_to_boot_apicid(0, boot_cpu_apicid); @@ -1073,11 +1023,11 @@ #ifndef CONFIG_VISWS io_apic_irqs = 0; #endif - cpu_online_map = phys_cpu_present_map = 1; + phys_cpu_present_map = 1; if (APIC_init_uniprocessor()) printk(KERN_NOTICE "Local APIC not detected." " Using dummy APIC emulation.n"); - goto smp_done; + return; } /* @@ -1102,8 +1052,8 @@ #ifndef CONFIG_VISWS io_apic_irqs = 0; #endif - cpu_online_map = phys_cpu_present_map = 1; - goto smp_done; + phys_cpu_present_map = 1; + return; } verify_local_APIC(); @@ -1117,8 +1067,8 @@ #ifndef CONFIG_VISWS io_apic_irqs = 0; #endif - cpu_online_map = phys_cpu_present_map = 1; - goto smp_done; + phys_cpu_present_map = 1; + return; } connect_bsp_APIC(); @@ -1190,7 +1140,7 @@ } else { unsigned long bogosum = 0; for (cpu = 0; cpu < NR_CPUS; cpu++) - if (cpu_online_map & (1<<cpu)) + if (cpu_callout_map & (1<<cpu)) bogosum += cpu_data[cpu].loops_per_jiffy; printk(KERN_INFO "Total of %d processors activated (%lu.%02lu BogoMIPS).n", cpucount+1, @@ -1213,10 +1163,10 @@ for (cpu = 0; cpu < NR_CPUS; cpu++) { int i; - if (!cpu_online(cpu)) continue; + if (!test_bit(cpu, &cpu_callout_map)) continue; for (i = 0; i < NR_CPUS; i++) { - if (i == cpu || !cpu_online(i)) + if (i == cpu || !test_bit(i, &cpu_callout_map)) continue; if (phys_proc_id[cpu] == phys_proc_id[i]) { cpu_sibling_map[cpu] = i; @@ -1240,17 +1190,40 @@ setup_IO_APIC(); #endif - /* - * Set up all local APIC timers in the system: - */ - setup_APIC_clocks(); + setup_boot_APIC_clock(); /* * Synchronize the TSC with the AP */ if (cpu_has_tsc && cpucount) synchronize_tsc_bp(); +} -smp_done: +/* These are wrappers to interface to the new boot process. Someone + who understands all this stuff should rewrite it properly. --RR 15/Jul/02 */ +void __init smp_prepare_cpus(unsigned int max_cpus) +{ + smp_boot_cpus(max_cpus); +} + +int __devinit __cpu_up(unsigned int cpu) +{ + /* This only works at boot for x86. See "rewrite" above. */ + if (test_bit(cpu, &smp_commenced_mask)) + return -ENOSYS; + + /* In case one didn't come up */ + if (!test_bit(cpu, &cpu_callin_map)) + return -EIO; + + /* Unleash the CPU! */ + set_bit(cpu, &smp_commenced_mask); + while (!test_bit(cpu, &cpu_online_map)) + mb(); + return 0; +} + +void __init smp_cpus_done(unsigned int max_cpus) +{ zap_low_mappings(); } diff -urN -I $.*$ --exclude TAGS -X /home/rusty/current-dontdiff --minimal linux-2.5.25/include/asm-i386/apic.h working-2.5.25-hotcpu/include/asm-i386/apic.h --- linux-2.5.25/include/asm-i386/apic.h Mon Apr 15 11:47:44 2002 +++ working-2.5.25-hotcpu/include/asm-i386/apic.h Mon Jul 15 18:22:21 2002 @@ -76,7 +76,8 @@ extern void setup_local_APIC (void); extern void init_apic_mappings (void); extern void smp_local_timer_interrupt (struct pt_regs * regs); -extern void setup_APIC_clocks (void); +extern void setup_boot_APIC_clock (void); +extern void setup_secondary_APIC_clock (void); extern void setup_apic_nmi_watchdog (void); extern inline void nmi_watchdog_tick (struct pt_regs * regs); extern int APIC_init_uniprocessor (void); diff -urN -I $.*$ --exclude TAGS -X /home/rusty/current-dontdiff --minimal linux-2.5.25/include/asm-i386/smp.h working-2.5.25-hotcpu/include/asm-i386/smp.h --- linux-2.5.25/include/asm-i386/smp.h Thu Jun 20 01:28:51 2002 +++ working-2.5.25-hotcpu/include/asm-i386/smp.h Mon Jul 15 14:46:12 2002 @@ -79,19 +79,13 @@ extern volatile int logical_apicid_to_cpu[MAX_APICID]; /* - * General functions that each host system must provide. - */ - -extern void smp_boot_cpus(void); -extern void smp_store_cpu_info(int id); /* Store per CPU info (like the initial udelay numbers */ - -/* * This function is needed by all SMP systems. It must _always_ be valid * from the initial startup. We map APIC_BASE very early in page_setup(), * so this is correct in the x86 case. */ #define smp_processor_id() (current_thread_info()->cpu) +#define cpu_possible(cpu) (phys_cpu_present_map & (1<<(cpu))) #define cpu_online(cpu) (cpu_online_map & (1<<(cpu))) extern inline unsigned int num_online_cpus(void) @@ -117,6 +111,13 @@ { /* we don't want to mark this access volatile - bad code generation */ return GET_APIC_LOGICAL_ID(*(unsigned long *)(APIC_BASE+APIC_LDR)); +} + +extern volatile unsigned long cpu_callout_map; +/* We don't mark CPUs online until __cpu_up(), so we need another measure */ +static inline int num_booting_cpus(void) +{ + return hweight32(cpu_callout_map); } #endif /* !__ASSEMBLY__ */ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/