ca74a6f84e
On VMs implemented using JITs that cache translated code changing the lock prefixes is a quite costly operation that forces the JIT to throw away and retranslate a lot of code. Previously a SMP kernel would rewrite the locks once for each CPU which is quite unnecessary. This patch changes the code to never switch at boot in the normal case (SMP kernel booting with >1 CPU) or only once for SMP kernel on UP. This makes a significant difference in boot up performance on AMD SimNow! Also I expect it to be a little faster on native systems too because a smp switch does a lot of text_poke()s which each synchronize the pipeline. v1->v2: Rename max_cpus v1->v2: Fix off by one in UP check (Thomas Gleixner) Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
147 lines
3.7 KiB
C
147 lines
3.7 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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extern void cpu_idle(void);
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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 retry, int wait);
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int smp_call_function_single(int cpuid, void (*func) (void *info), void *info,
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int retry, int wait);
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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 retry, 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, retry, wait) \
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(up_smp_call_function(func, info))
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#define on_each_cpu(func,info,retry,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, retry, 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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#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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