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![Rusty Russell](/assets/img/avatar_default.png)
Impact: Implementation change to remove cpumask_t from stack. Actually change smp_call_function_mask() to smp_call_function_many(). We avoid cpumasks on the stack in this version. (S390 has its own version, but that's going away apparently). We have to do some dancing to figure out if 0 or 1 other cpus are in the mask supplied and the online mask without allocating a tmp cpumask. It's still fairly cheap. We allocate the cpumask at the end of the call_function_data structure: if allocation fails we fallback to smp_call_function_single rather than using the baroque quiescing code (which needs a cpumask on stack). (Thanks to Hiroshi Shimamoto for spotting several bugs in previous versions!) Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Mike Travis <travis@sgi.com> Cc: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> Cc: npiggin@suse.de Cc: axboe@kernel.dk
188 lines
4.8 KiB
C
188 lines
4.8 KiB
C
#ifndef __LINUX_SMP_H
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#define __LINUX_SMP_H
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/*
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* Generic SMP support
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* Alan Cox. <alan@redhat.com>
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*/
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#include <linux/errno.h>
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#include <linux/types.h>
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#include <linux/list.h>
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#include <linux/cpumask.h>
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extern void cpu_idle(void);
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struct call_single_data {
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struct list_head list;
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void (*func) (void *info);
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void *info;
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u16 flags;
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u16 priv;
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};
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/* total number of cpus in this system (may exceed NR_CPUS) */
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extern unsigned int total_cpus;
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#ifdef CONFIG_SMP
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#include <linux/preempt.h>
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#include <linux/kernel.h>
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#include <linux/compiler.h>
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#include <linux/thread_info.h>
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#include <asm/smp.h>
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/*
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* main cross-CPU interfaces, handles INIT, TLB flush, STOP, etc.
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* (defined in asm header):
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*/
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/*
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* stops all CPUs but the current one:
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*/
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extern void smp_send_stop(void);
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/*
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* sends a 'reschedule' event to another CPU:
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*/
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extern void smp_send_reschedule(int cpu);
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/*
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* Prepare machine for booting other CPUs.
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*/
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extern void smp_prepare_cpus(unsigned int max_cpus);
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/*
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* Bring a CPU up
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*/
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extern int __cpu_up(unsigned int cpunum);
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/*
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* Final polishing of CPUs
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*/
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extern void smp_cpus_done(unsigned int max_cpus);
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/*
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* Call a function on all other processors
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*/
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int smp_call_function(void(*func)(void *info), void *info, int wait);
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void smp_call_function_many(const struct cpumask *mask,
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void (*func)(void *info), void *info, bool wait);
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/* Deprecated: Use smp_call_function_many which takes a pointer to the mask. */
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static inline int
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smp_call_function_mask(cpumask_t mask, void(*func)(void *info), void *info,
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int wait)
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{
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smp_call_function_many(&mask, func, info, wait);
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return 0;
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}
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int smp_call_function_single(int cpuid, void (*func) (void *info), void *info,
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int wait);
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void __smp_call_function_single(int cpuid, struct call_single_data *data);
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/*
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* Generic and arch helpers
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*/
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#ifdef CONFIG_USE_GENERIC_SMP_HELPERS
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void generic_smp_call_function_single_interrupt(void);
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void generic_smp_call_function_interrupt(void);
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void ipi_call_lock(void);
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void ipi_call_unlock(void);
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void ipi_call_lock_irq(void);
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void ipi_call_unlock_irq(void);
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#endif
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/*
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* Call a function on all processors
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*/
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int on_each_cpu(void (*func) (void *info), void *info, int wait);
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#define MSG_ALL_BUT_SELF 0x8000 /* Assume <32768 CPU's */
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#define MSG_ALL 0x8001
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#define MSG_INVALIDATE_TLB 0x0001 /* Remote processor TLB invalidate */
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#define MSG_STOP_CPU 0x0002 /* Sent to shut down slave CPU's
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* when rebooting
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*/
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#define MSG_RESCHEDULE 0x0003 /* Reschedule request from master CPU*/
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#define MSG_CALL_FUNCTION 0x0004 /* Call function on all other CPUs */
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/*
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* Mark the boot cpu "online" so that it can call console drivers in
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* printk() and can access its per-cpu storage.
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*/
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void smp_prepare_boot_cpu(void);
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extern unsigned int setup_max_cpus;
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#else /* !SMP */
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/*
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* These macros fold the SMP functionality into a single CPU system
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*/
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#define raw_smp_processor_id() 0
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static inline int up_smp_call_function(void (*func)(void *), void *info)
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{
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return 0;
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}
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#define smp_call_function(func, info, wait) \
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(up_smp_call_function(func, info))
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#define on_each_cpu(func,info,wait) \
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({ \
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local_irq_disable(); \
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func(info); \
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local_irq_enable(); \
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0; \
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})
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static inline void smp_send_reschedule(int cpu) { }
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#define num_booting_cpus() 1
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#define smp_prepare_boot_cpu() do {} while (0)
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#define smp_call_function_single(cpuid, func, info, wait) \
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({ \
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WARN_ON(cpuid != 0); \
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local_irq_disable(); \
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(func)(info); \
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local_irq_enable(); \
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0; \
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})
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#define smp_call_function_mask(mask, func, info, wait) \
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(up_smp_call_function(func, info))
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#define smp_call_function_many(mask, func, info, wait) \
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(up_smp_call_function(func, info))
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static inline void init_call_single_data(void)
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{
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}
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#endif /* !SMP */
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/*
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* smp_processor_id(): get the current CPU ID.
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*
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* if DEBUG_PREEMPT is enabled the we check whether it is
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* used in a preemption-safe way. (smp_processor_id() is safe
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* if it's used in a preemption-off critical section, or in
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* a thread that is bound to the current CPU.)
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*
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* NOTE: raw_smp_processor_id() is for internal use only
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* (smp_processor_id() is the preferred variant), but in rare
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* instances it might also be used to turn off false positives
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* (i.e. smp_processor_id() use that the debugging code reports but
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* which use for some reason is legal). Don't use this to hack around
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* the warning message, as your code might not work under PREEMPT.
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*/
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#ifdef CONFIG_DEBUG_PREEMPT
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extern unsigned int debug_smp_processor_id(void);
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# define smp_processor_id() debug_smp_processor_id()
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#else
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# define smp_processor_id() raw_smp_processor_id()
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#endif
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#define get_cpu() ({ preempt_disable(); smp_processor_id(); })
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#define put_cpu() preempt_enable()
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#define put_cpu_no_resched() preempt_enable_no_resched()
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void smp_setup_processor_id(void);
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#endif /* __LINUX_SMP_H */
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