diff options
| -rw-r--r-- | Documentation/cpu-hotplug.txt | 6 | ||||
| -rw-r--r-- | arch/powerpc/platforms/pseries/hotplug-cpu.c | 182 | ||||
| -rw-r--r-- | arch/powerpc/platforms/pseries/offline_states.h | 18 | ||||
| -rw-r--r-- | arch/powerpc/platforms/pseries/smp.c | 19 |
4 files changed, 216 insertions, 9 deletions
diff --git a/Documentation/cpu-hotplug.txt b/Documentation/cpu-hotplug.txt index 9d620c153b04..4d4a644b505e 100644 --- a/Documentation/cpu-hotplug.txt +++ b/Documentation/cpu-hotplug.txt @@ -49,6 +49,12 @@ maxcpus=n Restrict boot time cpus to n. Say if you have 4 cpus, using additional_cpus=n (*) Use this to limit hotpluggable cpus. This option sets cpu_possible_map = cpu_present_map + additional_cpus +cede_offline={"off","on"} Use this option to disable/enable putting offlined + processors to an extended H_CEDE state on + supported pseries platforms. + If nothing is specified, + cede_offline is set to "on". + (*) Option valid only for following architectures - ia64 diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c index ebff6d9a4e39..6ea4698d9176 100644 --- a/arch/powerpc/platforms/pseries/hotplug-cpu.c +++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c @@ -30,6 +30,7 @@ #include <asm/pSeries_reconfig.h> #include "xics.h" #include "plpar_wrappers.h" +#include "offline_states.h" /* This version can't take the spinlock, because it never returns */ static struct rtas_args rtas_stop_self_args = { @@ -39,6 +40,55 @@ static struct rtas_args rtas_stop_self_args = { .rets = &rtas_stop_self_args.args[0], }; +static DEFINE_PER_CPU(enum cpu_state_vals, preferred_offline_state) = + CPU_STATE_OFFLINE; +static DEFINE_PER_CPU(enum cpu_state_vals, current_state) = CPU_STATE_OFFLINE; + +static enum cpu_state_vals default_offline_state = CPU_STATE_OFFLINE; + +static int cede_offline_enabled __read_mostly = 1; + +/* + * Enable/disable cede_offline when available. + */ +static int __init setup_cede_offline(char *str) +{ + if (!strcmp(str, "off")) + cede_offline_enabled = 0; + else if (!strcmp(str, "on")) + cede_offline_enabled = 1; + else + return 0; + return 1; +} + +__setup("cede_offline=", setup_cede_offline); + +enum cpu_state_vals get_cpu_current_state(int cpu) +{ + return per_cpu(current_state, cpu); +} + +void set_cpu_current_state(int cpu, enum cpu_state_vals state) +{ + per_cpu(current_state, cpu) = state; +} + +enum cpu_state_vals get_preferred_offline_state(int cpu) +{ + return per_cpu(preferred_offline_state, cpu); +} + +void set_preferred_offline_state(int cpu, enum cpu_state_vals state) +{ + per_cpu(preferred_offline_state, cpu) = state; +} + +void set_default_offline_state(int cpu) +{ + per_cpu(preferred_offline_state, cpu) = default_offline_state; +} + static void rtas_stop_self(void) { struct rtas_args *args = &rtas_stop_self_args; @@ -56,11 +106,61 @@ static void rtas_stop_self(void) static void pseries_mach_cpu_die(void) { + unsigned int cpu = smp_processor_id(); + unsigned int hwcpu = hard_smp_processor_id(); + u8 cede_latency_hint = 0; + local_irq_disable(); idle_task_exit(); xics_teardown_cpu(); - unregister_slb_shadow(hard_smp_processor_id(), __pa(get_slb_shadow())); - rtas_stop_self(); + + if (get_preferred_offline_state(cpu) == CPU_STATE_INACTIVE) { + set_cpu_current_state(cpu, CPU_STATE_INACTIVE); + cede_latency_hint = 2; + + get_lppaca()->idle = 1; + if (!get_lppaca()->shared_proc) + get_lppaca()->donate_dedicated_cpu = 1; + + printk(KERN_INFO + "cpu %u (hwid %u) ceding for offline with hint %d\n", + cpu, hwcpu, cede_latency_hint); + while (get_preferred_offline_state(cpu) == CPU_STATE_INACTIVE) { + extended_cede_processor(cede_latency_hint); + printk(KERN_INFO "cpu %u (hwid %u) returned from cede.\n", + cpu, hwcpu); + printk(KERN_INFO + "Decrementer value = %x Timebase value = %llx\n", + get_dec(), get_tb()); + } + + printk(KERN_INFO "cpu %u (hwid %u) got prodded to go online\n", + cpu, hwcpu); + + if (!get_lppaca()->shared_proc) + get_lppaca()->donate_dedicated_cpu = 0; + get_lppaca()->idle = 0; + } + + if (get_preferred_offline_state(cpu) == CPU_STATE_ONLINE) { + unregister_slb_shadow(hwcpu, __pa(get_slb_shadow())); + + /* + * NOTE: Calling start_secondary() here for now to + * start new context. + * However, need to do it cleanly by resetting the + * stack pointer. + */ + start_secondary(); + + } else if (get_preferred_offline_state(cpu) == CPU_STATE_OFFLINE) { + + set_cpu_current_state(cpu, CPU_STATE_OFFLINE); + unregister_slb_shadow(hard_smp_processor_id(), + __pa(get_slb_shadow())); + rtas_stop_self(); + } + /* Should never get here... */ BUG(); for(;;); @@ -106,18 +206,43 @@ static int pseries_cpu_disable(void) return 0; } +/* + * pseries_cpu_die: Wait for the cpu to die. + * @cpu: logical processor id of the CPU whose death we're awaiting. + * + * This function is called from the context of the thread which is performing + * the cpu-offline. Here we wait for long enough to allow the cpu in question + * to self-destroy so that the cpu-offline thread can send the CPU_DEAD + * notifications. + * + * OTOH, pseries_mach_cpu_die() is called by the @cpu when it wants to + * self-destruct. + */ static void pseries_cpu_die(unsigned int cpu) { int tries; - int cpu_status; + int cpu_status = 1; unsigned int pcpu = get_hard_smp_processor_id(cpu); - for (tries = 0; tries < 25; tries++) { - cpu_status = query_cpu_stopped(pcpu); - if (cpu_status == 0 || cpu_status == -1) - break; - cpu_relax(); + if (get_preferred_offline_state(cpu) == CPU_STATE_INACTIVE) { + cpu_status = 1; + for (tries = 0; tries < 1000; tries++) { + if (get_cpu_current_state(cpu) == CPU_STATE_INACTIVE) { + cpu_status = 0; + break; + } + cpu_relax(); + } + } else if (get_preferred_offline_state(cpu) == CPU_STATE_OFFLINE) { + + for (tries = 0; tries < 25; tries++) { + cpu_status = query_cpu_stopped(pcpu); + if (cpu_status == 0 || cpu_status == -1) + break; + cpu_relax(); + } } + if (cpu_status != 0) { printk("Querying DEAD? cpu %i (%i) shows %i\n", cpu, pcpu, cpu_status); @@ -252,10 +377,41 @@ static struct notifier_block pseries_smp_nb = { .notifier_call = pseries_smp_notifier, }; +#define MAX_CEDE_LATENCY_LEVELS 4 +#define CEDE_LATENCY_PARAM_LENGTH 10 +#define CEDE_LATENCY_PARAM_MAX_LENGTH \ + (MAX_CEDE_LATENCY_LEVELS * CEDE_LATENCY_PARAM_LENGTH * sizeof(char)) +#define CEDE_LATENCY_TOKEN 45 + +static char cede_parameters[CEDE_LATENCY_PARAM_MAX_LENGTH]; + +static int parse_cede_parameters(void) +{ + int call_status; + + memset(cede_parameters, 0, CEDE_LATENCY_PARAM_MAX_LENGTH); + call_status = rtas_call(rtas_token("ibm,get-system-parameter"), 3, 1, + NULL, + CEDE_LATENCY_TOKEN, + __pa(cede_parameters), + CEDE_LATENCY_PARAM_MAX_LENGTH); + + if (call_status != 0) + printk(KERN_INFO "CEDE_LATENCY: \ + %s %s Error calling get-system-parameter(0x%x)\n", + __FILE__, __func__, call_status); + else + printk(KERN_INFO "CEDE_LATENCY: \ + get-system-parameter successful.\n"); + + return call_status; +} + static int __init pseries_cpu_hotplug_init(void) { struct device_node *np; const char *typep; + int cpu; for_each_node_by_name(np, "interrupt-controller") { typep = of_get_property(np, "compatible", NULL); @@ -283,8 +439,16 @@ static int __init pseries_cpu_hotplug_init(void) smp_ops->cpu_die = pseries_cpu_die; /* Processors can be added/removed only on LPAR */ - if (firmware_has_feature(FW_FEATURE_LPAR)) + if (firmware_has_feature(FW_FEATURE_LPAR)) { pSeries_reconfig_notifier_register(&pseries_smp_nb); + cpu_maps_update_begin(); + if (cede_offline_enabled && parse_cede_parameters() == 0) { + default_offline_state = CPU_STATE_INACTIVE; + for_each_online_cpu(cpu) + set_default_offline_state(cpu); + } + cpu_maps_update_done(); + } return 0; } diff --git a/arch/powerpc/platforms/pseries/offline_states.h b/arch/powerpc/platforms/pseries/offline_states.h new file mode 100644 index 000000000000..22574e0d9d91 --- /dev/null +++ b/arch/powerpc/platforms/pseries/offline_states.h @@ -0,0 +1,18 @@ +#ifndef _OFFLINE_STATES_H_ +#define _OFFLINE_STATES_H_ + +/* Cpu offline states go here */ +enum cpu_state_vals { + CPU_STATE_OFFLINE, + CPU_STATE_INACTIVE, + CPU_STATE_ONLINE, + CPU_MAX_OFFLINE_STATES +}; + +extern enum cpu_state_vals get_cpu_current_state(int cpu); +extern void set_cpu_current_state(int cpu, enum cpu_state_vals state); +extern enum cpu_state_vals get_preferred_offline_state(int cpu); +extern void set_preferred_offline_state(int cpu, enum cpu_state_vals state); +extern void set_default_offline_state(int cpu); +extern int start_secondary(void); +#endif diff --git a/arch/powerpc/platforms/pseries/smp.c b/arch/powerpc/platforms/pseries/smp.c index 440000cc7130..8868c012268a 100644 --- a/arch/powerpc/platforms/pseries/smp.c +++ b/arch/powerpc/platforms/pseries/smp.c @@ -48,6 +48,7 @@ #include "plpar_wrappers.h" #include "pseries.h" #include "xics.h" +#include "offline_states.h" /* @@ -84,6 +85,9 @@ static inline int __devinit smp_startup_cpu(unsigned int lcpu) /* Fixup atomic count: it exited inside IRQ handler. */ task_thread_info(paca[lcpu].__current)->preempt_count = 0; + if (get_cpu_current_state(lcpu) == CPU_STATE_INACTIVE) + goto out; + /* * If the RTAS start-cpu token does not exist then presume the * cpu is already spinning. @@ -98,6 +102,7 @@ static inline int __devinit smp_startup_cpu(unsigned int lcpu) return 0; } +out: return 1; } @@ -111,12 +116,16 @@ static void __devinit smp_xics_setup_cpu(int cpu) vpa_init(cpu); cpu_clear(cpu, of_spin_map); + set_cpu_current_state(cpu, CPU_STATE_ONLINE); + set_default_offline_state(cpu); } #endif /* CONFIG_XICS */ static void __devinit smp_pSeries_kick_cpu(int nr) { + long rc; + unsigned long hcpuid; BUG_ON(nr < 0 || nr >= NR_CPUS); if (!smp_startup_cpu(nr)) @@ -128,6 +137,16 @@ static void __devinit smp_pSeries_kick_cpu(int nr) * the processor will continue on to secondary_start */ paca[nr].cpu_start = 1; + + set_preferred_offline_state(nr, CPU_STATE_ONLINE); + + if (get_cpu_current_state(nr) == CPU_STATE_INACTIVE) { + hcpuid = get_hard_smp_processor_id(nr); + rc = plpar_hcall_norets(H_PROD, hcpuid); + if (rc != H_SUCCESS) + panic("Error: Prod to wake up processor %d Ret= %ld\n", + nr, rc); + } } static int smp_pSeries_cpu_bootable(unsigned int nr) |