sched/preempt, locking: Rework local_bh_{dis,en}able()
Currently local_bh_disable() is out-of-line for no apparent reason. So inline it to save a few cycles on call/return nonsense, the function body is a single add on x86 (a few loads and store extra on load/store archs). Also expose two new local_bh functions: __local_bh_{dis,en}able_ip(unsigned long ip, unsigned int cnt); Which implement the actual local_bh_{dis,en}able() behaviour. The next patch uses the exposed @cnt argument to optimize bh lock functions. With build fixes from Jacob Pan. Cc: rjw@rjwysocki.net Cc: rui.zhang@intel.com Cc: jacob.jun.pan@linux.intel.com Cc: Mike Galbraith <bitbucket@online.de> Cc: hpa@zytor.com Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: lenb@kernel.org Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20131119151338.GF3694@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
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@ -1,9 +1,35 @@
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#ifndef _LINUX_BH_H
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#ifndef _LINUX_BH_H
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#define _LINUX_BH_H
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#define _LINUX_BH_H
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extern void local_bh_disable(void);
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#include <linux/preempt.h>
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#include <linux/preempt_mask.h>
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#ifdef CONFIG_TRACE_IRQFLAGS
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extern void __local_bh_disable_ip(unsigned long ip, unsigned int cnt);
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#else
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static __always_inline void __local_bh_disable_ip(unsigned long ip, unsigned int cnt)
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{
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preempt_count_add(cnt);
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barrier();
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}
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#endif
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static inline void local_bh_disable(void)
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{
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__local_bh_disable_ip(_THIS_IP_, SOFTIRQ_DISABLE_OFFSET);
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}
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extern void _local_bh_enable(void);
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extern void _local_bh_enable(void);
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extern void local_bh_enable(void);
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extern void __local_bh_enable_ip(unsigned long ip, unsigned int cnt);
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extern void local_bh_enable_ip(unsigned long ip);
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static inline void local_bh_enable_ip(unsigned long ip)
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{
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__local_bh_enable_ip(ip, SOFTIRQ_DISABLE_OFFSET);
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}
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static inline void local_bh_enable(void)
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{
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__local_bh_enable_ip(_THIS_IP_, SOFTIRQ_DISABLE_OFFSET);
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}
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#endif /* _LINUX_BH_H */
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#endif /* _LINUX_BH_H */
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@ -5,6 +5,7 @@
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#include <linux/lockdep.h>
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#include <linux/lockdep.h>
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#include <linux/ftrace_irq.h>
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#include <linux/ftrace_irq.h>
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#include <linux/vtime.h>
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#include <linux/vtime.h>
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#include <asm/hardirq.h>
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extern void synchronize_irq(unsigned int irq);
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extern void synchronize_irq(unsigned int irq);
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@ -2,7 +2,6 @@
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#define LINUX_PREEMPT_MASK_H
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#define LINUX_PREEMPT_MASK_H
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#include <linux/preempt.h>
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#include <linux/preempt.h>
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#include <asm/hardirq.h>
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/*
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/*
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* We put the hardirq and softirq counter into the preemption
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* We put the hardirq and softirq counter into the preemption
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@ -89,7 +89,7 @@ static void wakeup_softirqd(void)
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* where hardirqs are disabled legitimately:
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* where hardirqs are disabled legitimately:
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*/
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*/
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#ifdef CONFIG_TRACE_IRQFLAGS
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#ifdef CONFIG_TRACE_IRQFLAGS
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static void __local_bh_disable(unsigned long ip, unsigned int cnt)
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void __local_bh_disable_ip(unsigned long ip, unsigned int cnt)
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{
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{
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unsigned long flags;
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unsigned long flags;
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@ -114,21 +114,9 @@ static void __local_bh_disable(unsigned long ip, unsigned int cnt)
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if (preempt_count() == cnt)
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if (preempt_count() == cnt)
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trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
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trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
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}
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}
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#else /* !CONFIG_TRACE_IRQFLAGS */
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EXPORT_SYMBOL(__local_bh_disable_ip);
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static inline void __local_bh_disable(unsigned long ip, unsigned int cnt)
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{
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preempt_count_add(cnt);
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barrier();
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}
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#endif /* CONFIG_TRACE_IRQFLAGS */
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#endif /* CONFIG_TRACE_IRQFLAGS */
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void local_bh_disable(void)
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{
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__local_bh_disable(_RET_IP_, SOFTIRQ_DISABLE_OFFSET);
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}
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EXPORT_SYMBOL(local_bh_disable);
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static void __local_bh_enable(unsigned int cnt)
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static void __local_bh_enable(unsigned int cnt)
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{
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{
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WARN_ON_ONCE(!irqs_disabled());
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WARN_ON_ONCE(!irqs_disabled());
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@ -151,7 +139,7 @@ void _local_bh_enable(void)
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EXPORT_SYMBOL(_local_bh_enable);
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EXPORT_SYMBOL(_local_bh_enable);
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static inline void _local_bh_enable_ip(unsigned long ip)
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void __local_bh_enable_ip(unsigned long ip, unsigned int cnt)
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{
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{
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WARN_ON_ONCE(in_irq() || irqs_disabled());
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WARN_ON_ONCE(in_irq() || irqs_disabled());
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#ifdef CONFIG_TRACE_IRQFLAGS
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#ifdef CONFIG_TRACE_IRQFLAGS
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@ -166,7 +154,7 @@ static inline void _local_bh_enable_ip(unsigned long ip)
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* Keep preemption disabled until we are done with
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* Keep preemption disabled until we are done with
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* softirq processing:
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* softirq processing:
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*/
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*/
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preempt_count_sub(SOFTIRQ_DISABLE_OFFSET - 1);
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preempt_count_sub(cnt - 1);
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if (unlikely(!in_interrupt() && local_softirq_pending())) {
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if (unlikely(!in_interrupt() && local_softirq_pending())) {
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/*
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/*
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@ -182,18 +170,7 @@ static inline void _local_bh_enable_ip(unsigned long ip)
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#endif
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#endif
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preempt_check_resched();
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preempt_check_resched();
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}
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}
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EXPORT_SYMBOL(__local_bh_enable_ip);
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void local_bh_enable(void)
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{
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_local_bh_enable_ip(_RET_IP_);
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}
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EXPORT_SYMBOL(local_bh_enable);
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void local_bh_enable_ip(unsigned long ip)
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{
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_local_bh_enable_ip(ip);
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}
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EXPORT_SYMBOL(local_bh_enable_ip);
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/*
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/*
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* We restart softirq processing for at most MAX_SOFTIRQ_RESTART times,
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* We restart softirq processing for at most MAX_SOFTIRQ_RESTART times,
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@ -230,7 +207,7 @@ asmlinkage void __do_softirq(void)
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pending = local_softirq_pending();
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pending = local_softirq_pending();
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account_irq_enter_time(current);
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account_irq_enter_time(current);
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__local_bh_disable(_RET_IP_, SOFTIRQ_OFFSET);
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__local_bh_disable_ip(_RET_IP_, SOFTIRQ_OFFSET);
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lockdep_softirq_enter();
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lockdep_softirq_enter();
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cpu = smp_processor_id();
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cpu = smp_processor_id();
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