linux/arch/s390/include/asm/smp.h

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/*
* Copyright IBM Corp. 1999,2009
* Author(s): Denis Joseph Barrow,
* Martin Schwidefsky <schwidefsky@de.ibm.com>,
* Heiko Carstens <heiko.carstens@de.ibm.com>,
*/
#ifndef __ASM_SMP_H
#define __ASM_SMP_H
#ifdef CONFIG_SMP
#include <asm/system.h>
#include <asm/sigp.h>
extern void machine_restart_smp(char *);
extern void machine_halt_smp(void);
extern void machine_power_off_smp(void);
#define raw_smp_processor_id() (S390_lowcore.cpu_nr)
extern int __cpu_disable (void);
extern void __cpu_die (unsigned int cpu);
extern void cpu_die (void) __attribute__ ((noreturn));
extern int __cpu_up (unsigned int cpu);
extern struct mutex smp_cpu_state_mutex;
[S390] Vertical cpu management. If vertical cpu polarization is active then the hypervisor will dispatch certain cpus for a longer time than other cpus for maximum performance. For example if a guest would have three virtual cpus, each of them with a share of 33 percent, then in case of vertical cpu polarization all of the processing time would be combined to a single cpu which would run all the time, while the other two cpus would get nearly no cpu time. There are three different types of vertical cpus: high, medium and low. Low cpus hardly get any real cpu time, while high cpus get a full real cpu. Medium cpus get something in between. In order to switch between the two possible modes (default is horizontal) a 0 for horizontal polarization or a 1 for vertical polarization must be written to the dispatching sysfs attribute: /sys/devices/system/cpu/dispatching The polarization of each single cpu can be figured out by the polarization sysfs attribute of each cpu: /sys/devices/system/cpu/cpuX/polarization horizontal, vertical:high, vertical:medium, vertical:low or unknown. When switching polarization the polarization attribute may contain the value unknown until the configuration change is done and the kernel has figured out the new polarization of each cpu. Note that running a system with different types of vertical cpus may result in significant performance regressions. If possible only one type of vertical cpus should be used. All other cpus should be offlined. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
2008-04-17 05:46:13 +00:00
extern int smp_cpu_polarization[];
extern void arch_send_call_function_single_ipi(int cpu);
extern void arch_send_call_function_ipi_mask(const struct cpumask *mask);
extern struct save_area *zfcpdump_save_areas[NR_CPUS + 1];
extern void smp_switch_to_ipl_cpu(void (*func)(void *), void *);
extern void smp_switch_to_cpu(void (*)(void *), void *, unsigned long sp,
int from, int to);
extern void smp_restart_cpu(void);
/*
* returns 1 if (virtual) cpu is scheduled
* returns 0 otherwise
*/
static inline int smp_vcpu_scheduled(int cpu)
{
u32 status;
switch (sigp_ps(&status, 0, cpu, sigp_sense_running)) {
case sigp_status_stored:
/* Check for running status */
if (status & 0x400)
return 0;
break;
case sigp_not_operational:
return 0;
default:
break;
}
return 1;
}
#else /* CONFIG_SMP */
static inline void smp_switch_to_ipl_cpu(void (*func)(void *), void *data)
{
func(data);
}
#define smp_vcpu_scheduled (1)
#endif /* CONFIG_SMP */
#ifdef CONFIG_HOTPLUG_CPU
extern int smp_rescan_cpus(void);
#else
static inline int smp_rescan_cpus(void) { return 0; }
#endif
#endif /* __ASM_SMP_H */