diff options
| -rw-r--r-- | arch/powerpc/include/asm/hw_irq.h | 4 | ||||
| -rw-r--r-- | arch/powerpc/kernel/irq.c | 2 | ||||
| -rw-r--r-- | arch/powerpc/kernel/perf_counter.c | 22 | ||||
| -rw-r--r-- | arch/x86/include/asm/perf_counter.h | 5 | ||||
| -rw-r--r-- | arch/x86/include/asm/thread_info.h | 4 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/perf_counter.c | 29 | ||||
| -rw-r--r-- | arch/x86/kernel/signal.c | 6 | ||||
| -rw-r--r-- | include/linux/perf_counter.h | 15 | ||||
| -rw-r--r-- | kernel/perf_counter.c | 128 | ||||
| -rw-r--r-- | kernel/timer.c | 3 |
10 files changed, 142 insertions, 76 deletions
diff --git a/arch/powerpc/include/asm/hw_irq.h b/arch/powerpc/include/asm/hw_irq.h index cb32d57..20a44d0 100644 --- a/arch/powerpc/include/asm/hw_irq.h +++ b/arch/powerpc/include/asm/hw_irq.h @@ -132,7 +132,7 @@ static inline int irqs_disabled_flags(unsigned long flags) struct irq_chip; #ifdef CONFIG_PERF_COUNTERS -static inline unsigned long get_perf_counter_pending(void) +static inline unsigned long test_perf_counter_pending(void) { unsigned long x; @@ -160,7 +160,7 @@ extern void perf_counter_do_pending(void); #else -static inline unsigned long get_perf_counter_pending(void) +static inline unsigned long test_perf_counter_pending(void) { return 0; } diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c index 469e963..2cd471f 100644 --- a/arch/powerpc/kernel/irq.c +++ b/arch/powerpc/kernel/irq.c @@ -135,7 +135,7 @@ notrace void raw_local_irq_restore(unsigned long en) iseries_handle_interrupts(); } - if (get_perf_counter_pending()) { + if (test_perf_counter_pending()) { clear_perf_counter_pending(); perf_counter_do_pending(); } diff --git a/arch/powerpc/kernel/perf_counter.c b/arch/powerpc/kernel/perf_counter.c index df007fe..cde720f 100644 --- a/arch/powerpc/kernel/perf_counter.c +++ b/arch/powerpc/kernel/perf_counter.c @@ -650,24 +650,6 @@ hw_perf_counter_init(struct perf_counter *counter) } /* - * Handle wakeups. - */ -void perf_counter_do_pending(void) -{ - int i; - struct cpu_hw_counters *cpuhw = &__get_cpu_var(cpu_hw_counters); - struct perf_counter *counter; - - for (i = 0; i < cpuhw->n_counters; ++i) { - counter = cpuhw->counter[i]; - if (counter && counter->wakeup_pending) { - counter->wakeup_pending = 0; - wake_up(&counter->waitq); - } - } -} - -/* * A counter has overflowed; update its count and record * things if requested. Note that interrupts are hard-disabled * here so there is no possibility of being interrupted. @@ -720,7 +702,7 @@ static void perf_counter_interrupt(struct pt_regs *regs) struct cpu_hw_counters *cpuhw = &__get_cpu_var(cpu_hw_counters); struct perf_counter *counter; long val; - int need_wakeup = 0, found = 0; + int found = 0; for (i = 0; i < cpuhw->n_counters; ++i) { counter = cpuhw->counter[i]; @@ -761,7 +743,7 @@ static void perf_counter_interrupt(struct pt_regs *regs) * immediately; otherwise we'll have do the wakeup when interrupts * get soft-enabled. */ - if (get_perf_counter_pending() && regs->softe) { + if (test_perf_counter_pending() && regs->softe) { irq_enter(); clear_perf_counter_pending(); perf_counter_do_pending(); diff --git a/arch/x86/include/asm/perf_counter.h b/arch/x86/include/asm/perf_counter.h index 1662043..e2b0e66 100644 --- a/arch/x86/include/asm/perf_counter.h +++ b/arch/x86/include/asm/perf_counter.h @@ -84,8 +84,9 @@ union cpuid10_edx { #define MSR_ARCH_PERFMON_FIXED_CTR2 0x30b #define X86_PMC_IDX_FIXED_BUS_CYCLES (X86_PMC_IDX_FIXED + 2) -#define set_perf_counter_pending() \ - set_tsk_thread_flag(current, TIF_PERF_COUNTERS); +#define set_perf_counter_pending() do { } while (0) +#define clear_perf_counter_pending() do { } while (0) +#define test_perf_counter_pending() (0) #ifdef CONFIG_PERF_COUNTERS extern void init_hw_perf_counters(void); diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h index 3ffd5d2..8820a73 100644 --- a/arch/x86/include/asm/thread_info.h +++ b/arch/x86/include/asm/thread_info.h @@ -83,7 +83,6 @@ struct thread_info { #define TIF_SYSCALL_AUDIT 7 /* syscall auditing active */ #define TIF_SECCOMP 8 /* secure computing */ #define TIF_MCE_NOTIFY 10 /* notify userspace of an MCE */ -#define TIF_PERF_COUNTERS 11 /* notify perf counter work */ #define TIF_NOTSC 16 /* TSC is not accessible in userland */ #define TIF_IA32 17 /* 32bit process */ #define TIF_FORK 18 /* ret_from_fork */ @@ -107,7 +106,6 @@ struct thread_info { #define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT) #define _TIF_SECCOMP (1 << TIF_SECCOMP) #define _TIF_MCE_NOTIFY (1 << TIF_MCE_NOTIFY) -#define _TIF_PERF_COUNTERS (1 << TIF_PERF_COUNTERS) #define _TIF_NOTSC (1 << TIF_NOTSC) #define _TIF_IA32 (1 << TIF_IA32) #define _TIF_FORK (1 << TIF_FORK) @@ -141,7 +139,7 @@ struct thread_info { /* Only used for 64 bit */ #define _TIF_DO_NOTIFY_MASK \ - (_TIF_SIGPENDING|_TIF_MCE_NOTIFY|_TIF_PERF_COUNTERS|_TIF_NOTIFY_RESUME) + (_TIF_SIGPENDING|_TIF_MCE_NOTIFY|_TIF_NOTIFY_RESUME) /* flags to check in __switch_to() */ #define _TIF_WORK_CTXSW \ diff --git a/arch/x86/kernel/cpu/perf_counter.c b/arch/x86/kernel/cpu/perf_counter.c index 3f95b0c..7aab177 100644 --- a/arch/x86/kernel/cpu/perf_counter.c +++ b/arch/x86/kernel/cpu/perf_counter.c @@ -227,7 +227,6 @@ static int __hw_perf_counter_init(struct perf_counter *counter) */ hwc->config |= pmc_ops->event_map(perf_event_id(hw_event)); } - counter->wakeup_pending = 0; return 0; } @@ -773,34 +772,6 @@ void smp_perf_counter_interrupt(struct pt_regs *regs) irq_exit(); } -/* - * This handler is triggered by NMI contexts: - */ -void perf_counter_notify(struct pt_regs *regs) -{ - struct cpu_hw_counters *cpuc; - unsigned long flags; - int bit, cpu; - - local_irq_save(flags); - cpu = smp_processor_id(); - cpuc = &per_cpu(cpu_hw_counters, cpu); - - for_each_bit(bit, cpuc->used, X86_PMC_IDX_MAX) { - struct perf_counter *counter = cpuc->counters[bit]; - - if (!counter) - continue; - - if (counter->wakeup_pending) { - counter->wakeup_pending = 0; - wake_up(&counter->waitq); - } - } - - local_irq_restore(flags); -} - void perf_counters_lapic_init(int nmi) { u32 apic_val; diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c index 611615a..0a813b1 100644 --- a/arch/x86/kernel/signal.c +++ b/arch/x86/kernel/signal.c @@ -6,7 +6,6 @@ * 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes * 2000-2002 x86-64 support by Andi Kleen */ -#include <linux/perf_counter.h> #include <linux/sched.h> #include <linux/mm.h> #include <linux/smp.h> @@ -872,11 +871,6 @@ do_notify_resume(struct pt_regs *regs, void *unused, __u32 thread_info_flags) tracehook_notify_resume(regs); } - if (thread_info_flags & _TIF_PERF_COUNTERS) { - clear_thread_flag(TIF_PERF_COUNTERS); - perf_counter_notify(regs); - } - #ifdef CONFIG_X86_32 clear_thread_flag(TIF_IRET); #endif /* CONFIG_X86_32 */ diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h index 6bf67ce..0d83322 100644 --- a/include/linux/perf_counter.h +++ b/include/linux/perf_counter.h @@ -275,6 +275,10 @@ struct perf_mmap_data { void *data_pages[0]; }; +struct perf_wakeup_entry { + struct perf_wakeup_entry *next; +}; + /** * struct perf_counter - performance counter kernel representation: */ @@ -350,7 +354,7 @@ struct perf_counter { /* poll related */ wait_queue_head_t waitq; /* optional: for NMIs */ - int wakeup_pending; + struct perf_wakeup_entry wakeup; void (*destroy)(struct perf_counter *); struct rcu_head rcu_head; @@ -427,7 +431,7 @@ extern void perf_counter_task_sched_out(struct task_struct *task, int cpu); extern void perf_counter_task_tick(struct task_struct *task, int cpu); extern void perf_counter_init_task(struct task_struct *child); extern void perf_counter_exit_task(struct task_struct *child); -extern void perf_counter_notify(struct pt_regs *regs); +extern void perf_counter_do_pending(void); extern void perf_counter_print_debug(void); extern void perf_counter_unthrottle(void); extern u64 hw_perf_save_disable(void); @@ -461,7 +465,7 @@ static inline void perf_counter_task_tick(struct task_struct *task, int cpu) { } static inline void perf_counter_init_task(struct task_struct *child) { } static inline void perf_counter_exit_task(struct task_struct *child) { } -static inline void perf_counter_notify(struct pt_regs *regs) { } +static inline void perf_counter_do_pending(void) { } static inline void perf_counter_print_debug(void) { } static inline void perf_counter_unthrottle(void) { } static inline void hw_perf_restore(u64 ctrl) { } @@ -469,8 +473,9 @@ static inline u64 hw_perf_save_disable(void) { return 0; } static inline int perf_counter_task_disable(void) { return -EINVAL; } static inline int perf_counter_task_enable(void) { return -EINVAL; } -static inline void perf_swcounter_event(u32 event, u64 nr, - int nmi, struct pt_regs *regs) { } +static inline void +perf_swcounter_event(u32 event, u64 nr, int nmi, struct pt_regs *regs) { } + #endif #endif /* __KERNEL__ */ diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index 3b862a7..f70ff80 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -1197,8 +1197,12 @@ static void free_counter_rcu(struct rcu_head *head) kfree(counter); } +static void perf_pending_sync(struct perf_counter *counter); + static void free_counter(struct perf_counter *counter) { + perf_pending_sync(counter); + if (counter->destroy) counter->destroy(counter); @@ -1529,6 +1533,118 @@ static const struct file_operations perf_fops = { }; /* + * Perf counter wakeup + * + * If there's data, ensure we set the poll() state and publish everything + * to user-space before waking everybody up. + */ + +void perf_counter_wakeup(struct perf_counter *counter) +{ + struct perf_mmap_data *data; + + rcu_read_lock(); + data = rcu_dereference(counter->data); + if (data) { + (void)atomic_xchg(&data->wakeup, POLL_IN); + __perf_counter_update_userpage(counter, data); + } + rcu_read_unlock(); + + wake_up_all(&counter->waitq); +} + +/* + * Pending wakeups + * + * Handle the case where we need to wakeup up from NMI (or rq->lock) context. + * + * The NMI bit means we cannot possibly take locks. Therefore, maintain a + * single linked list and use cmpxchg() to add entries lockless. + */ + +#define PENDING_TAIL ((struct perf_wakeup_entry *)-1UL) + +static DEFINE_PER_CPU(struct perf_wakeup_entry *, perf_wakeup_head) = { + PENDING_TAIL, +}; + +static void perf_pending_queue(struct perf_counter *counter) +{ + struct perf_wakeup_entry **head; + struct perf_wakeup_entry *prev, *next; + + if (cmpxchg(&counter->wakeup.next, NULL, PENDING_TAIL) != NULL) + return; + + head = &get_cpu_var(perf_wakeup_head); + + do { + prev = counter->wakeup.next = *head; + next = &counter->wakeup; + } while (cmpxchg(head, prev, next) != prev); + + set_perf_counter_pending(); + + put_cpu_var(perf_wakeup_head); +} + +static int __perf_pending_run(void) +{ + struct perf_wakeup_entry *list; + int nr = 0; + + list = xchg(&__get_cpu_var(perf_wakeup_head), PENDING_TAIL); + while (list != PENDING_TAIL) { + struct perf_counter *counter = container_of(list, + struct perf_counter, wakeup); + + list = list->next; + + counter->wakeup.next = NULL; + /* + * Ensure we observe the unqueue before we issue the wakeup, + * so that we won't be waiting forever. + * -- see perf_not_pending(). + */ + smp_wmb(); + + perf_counter_wakeup(counter); + nr++; + } + + return nr; +} + +static inline int perf_not_pending(struct perf_counter *counter) +{ + /* + * If we flush on whatever cpu we run, there is a chance we don't + * need to wait. + */ + get_cpu(); + __perf_pending_run(); + put_cpu(); + + /* + * Ensure we see the proper queue state before going to sleep + * so that we do not miss the wakeup. -- see perf_pending_handle() + */ + smp_rmb(); + return counter->wakeup.next == NULL; +} + +static void perf_pending_sync(struct perf_counter *counter) +{ + wait_event(counter->waitq, perf_not_pending(counter)); +} + +void perf_counter_do_pending(void) +{ + __perf_pending_run(); +} + +/* * Output */ @@ -1611,13 +1727,10 @@ static void perf_output_copy(struct perf_output_handle *handle, static void perf_output_end(struct perf_output_handle *handle, int nmi) { if (handle->wakeup) { - (void)atomic_xchg(&handle->data->wakeup, POLL_IN); - __perf_counter_update_userpage(handle->counter, handle->data); - if (nmi) { - handle->counter->wakeup_pending = 1; - set_perf_counter_pending(); - } else - wake_up(&handle->counter->waitq); + if (nmi) + perf_pending_queue(handle->counter); + else + perf_counter_wakeup(handle->counter); } rcu_read_unlock(); } @@ -2211,7 +2324,6 @@ perf_counter_alloc(struct perf_counter_hw_event *hw_event, counter->cpu = cpu; counter->hw_event = *hw_event; - counter->wakeup_pending = 0; counter->group_leader = group_leader; counter->hw_ops = NULL; counter->ctx = ctx; diff --git a/kernel/timer.c b/kernel/timer.c index b455556..672ca25 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -37,6 +37,7 @@ #include <linux/delay.h> #include <linux/tick.h> #include <linux/kallsyms.h> +#include <linux/perf_counter.h> #include <asm/uaccess.h> #include <asm/unistd.h> @@ -1167,6 +1168,8 @@ static void run_timer_softirq(struct softirq_action *h) { struct tvec_base *base = __get_cpu_var(tvec_bases); + perf_counter_do_pending(); + hrtimer_run_pending(); if (time_after_eq(jiffies, base->timer_jiffies)) |