Len Hello offsched is a platform aimed to assign a service to an off-lined processor. Motivation is explained in: http://sos-linux.svn.sourceforge.net/viewvc/sos-linux/offsched/trunk/Documentation/OFFSCHED.pdf Currently I have implemented two services: HYBRID REAL TIME LINUX Implemented as a A 1us timer. This timer shows how a true real time system may co-exist with a regular linux server. This way there is no enforcement of a real time system requirements on the entire kernel. Full documentation is at: http://sos-linux.svn.sourceforge.net/viewvc/sos-linux/offsched/trunk/Documentation/OFFSCHED-RT.pdf RTOP This piece of software send system statistics to a remove server. The user benefit is that even if the machine is un-accessible (remotely or locally) RTOP still sends system statistics to a remote server. I have showed in a small paper what RTOP is: http://sos-linux.svn.sourceforge.net/viewvc/sos-linux/offsched/trunk/Documentation/OFFSCHED-RTOP.pdf The patch is mostly a facility for offsched. The exporting of tasklist_lock is because RTOP is implemented as a driver and it must lock the tasks list. This is the 4-th post. I will be grateful for your reply. Signed-off-by: Raz Ben Yehuda <raziebe@xxxxxxxxxx> arch/x86/kernel/process.c | 42 ++++++++++++++++++++++++++++++++++++++++++ arch/x86/kernel/smpboot.c | 11 +++++++---- include/linux/cpu.h | 20 ++++++++++++++++++++ include/linux/sched.h | 2 +- kernel/cpu.c | 1 + kernel/fork.c | 6 ++++++ 6 files changed, 77 insertions(+), 5 deletions(-) diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index ca98915..123b32d 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -613,3 +613,45 @@ static int __init idle_setup(char *str) } early_param("idle", idle_setup); +#ifdef CONFIG_HOTPLUG_CPU +struct hotplug_cpu{ + long flags; + void (*hotplug_cpu_dead)(void); +}; + +#define CPU_OFFSCHED 31 + +DEFINE_PER_CPU(struct hotplug_cpu, offschedcpu); + +void unregister_offsched(int cpuid) +{ + struct hotplug_cpu *cpu = &per_cpu(offschedcpu, cpuid); + cpu->hotplug_cpu_dead = NULL; + clear_bit(CPU_OFFSCHED, &cpu->flags); +} +EXPORT_SYMBOL_GPL(unregister_offsched); + +int is_offsched(int cpuid) +{ + struct hotplug_cpu *cpu = &per_cpu(offschedcpu, cpuid); + return test_bit(CPU_OFFSCHED, &cpu->flags); +} + +int register_offsched(void (*offsched_callback)(void), int cpuid) +{ + struct hotplug_cpu *cpu = &per_cpu(offschedcpu, cpuid); + if (is_offsched(cpuid)) + return -1; + cpu->hotplug_cpu_dead = offsched_callback; + set_bit(CPU_OFFSCHED, &cpu->flags); + return 0; +} +EXPORT_SYMBOL_GPL(register_offsched); + +void run_offsched(void) +{ + int cpuid = raw_smp_processor_id(); + struct hotplug_cpu *cpu = &per_cpu(offschedcpu, cpuid); + cpu->hotplug_cpu_dead(); +} +#endif diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 58d24ef..25e70e0 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -686,8 +686,8 @@ static int __cpuinit do_boot_cpu(int apicid, int cpu) }; INIT_WORK(&c_idle.work, do_fork_idle); - - alternatives_smp_switch(1); + if (!is_offsched(cpu)) + alternatives_smp_switch(1); c_idle.idle = get_idle_for_cpu(cpu); @@ -1283,8 +1283,9 @@ void native_cpu_die(unsigned int cpu) for (i = 0; i < 10; i++) { /* They ack this in play_dead by setting CPU_DEAD */ if (per_cpu(cpu_state, cpu) == CPU_DEAD) { - printk(KERN_INFO "CPU %d is now offline\n", cpu); - if (1 == num_online_cpus()) + printk(KERN_INFO "CPU %d is now offline %s\n", cpu, + is_offsched(cpu) ? "and OFFSCHED" : ""); + if (1 == num_online_cpus() && !is_offsched(cpu)) alternatives_smp_switch(0); return; } @@ -1313,6 +1314,8 @@ void play_dead_common(void) void native_play_dead(void) { play_dead_common(); + if (is_offsched(raw_smp_processor_id())) + run_offsched(); wbinvd_halt(); } diff --git a/include/linux/cpu.h b/include/linux/cpu.h index 2643d84..f2048ca 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -43,6 +43,7 @@ extern int sched_create_sysfs_power_savings_entries(struct sysdev_class *cls); #ifdef CONFIG_HOTPLUG_CPU extern void unregister_cpu(struct cpu *cpu); +extern void unregister_offsched(int cpuid); #endif struct notifier_block; @@ -51,6 +52,9 @@ struct notifier_block; #ifdef CONFIG_HOTPLUG_CPU extern int register_cpu_notifier(struct notifier_block *nb); extern void unregister_cpu_notifier(struct notifier_block *nb); +extern int register_offsched(void (*hotplug_cpu_dead)(void), int cpuid); +extern int is_offsched(int cpuid); +extern void run_offsched(void); #else #ifndef MODULE @@ -60,11 +64,27 @@ static inline int register_cpu_notifier(struct notifier_block *nb) { return 0; } + +static inline int register_offsched(void (*hotplug_cpu_dead)(void), int cpuid); +{ + return 0; +} #endif static inline void unregister_cpu_notifier(struct notifier_block *nb) { } + +static inline void unregister_offsched(int cpuid) +{ +} +static inline int is_offsched(int cpuid) +{ + return 0; +} +static inline void run_offsched(void) +{ +} #endif int cpu_up(unsigned int cpu); diff --git a/include/linux/sched.h b/include/linux/sched.h index b4c38bc..8039ee7 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1999,7 +1999,7 @@ struct task_struct *fork_idle(int); extern void set_task_comm(struct task_struct *tsk, char *from); extern char *get_task_comm(char *to, struct task_struct *tsk); - +extern rwlock_t *get_tasklist_lock(void); #ifdef CONFIG_SMP extern unsigned long wait_task_inactive(struct task_struct *, long match_state); #else diff --git a/kernel/cpu.c b/kernel/cpu.c index 395b697..e67190d 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -373,6 +373,7 @@ out: cpu_maps_update_done(); return err; } +EXPORT_SYMBOL(cpu_up); #ifdef CONFIG_PM_SLEEP_SMP static cpumask_var_t frozen_cpus; diff --git a/kernel/fork.c b/kernel/fork.c index b9e2edd..4de4142 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -85,6 +85,12 @@ __cacheline_aligned DEFINE_RWLOCK(tasklist_lock); /* outer */ DEFINE_TRACE(sched_process_fork); +rwlock_t *get_tasklist_lock(void) +{ + return &tasklist_lock; +} +EXPORT_SYMBOL_GPL(get_tasklist_lock); + int nr_processes(void) { int cpu; -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
