From 4ed7c92d68a5387ba5f7030dc76eab03558e27f5 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 23 Nov 2009 11:37:29 +0100 Subject: [PATCH] perf_events: Undo some recursion damage Make perf_swevent_get_recursion_context return a context number and disable preemption. This could be used to remove the IRQ disable from the trace bit and index the per-cpu buffer with. Signed-off-by: Peter Zijlstra Cc: Frederic Weisbecker Cc: Paul Mackerras LKML-Reference: <20091123103819.993226816@chello.nl> Signed-off-by: Ingo Molnar --- include/linux/perf_event.h | 8 ++--- include/trace/ftrace.h | 17 ++++++----- kernel/perf_event.c | 71 +++++++++++++++++++------------------------ kernel/trace/trace_kprobe.c | 14 +++++---- kernel/trace/trace_syscalls.c | 14 +++++---- 5 files changed, 61 insertions(+), 63 deletions(-) diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 74e98b1..43adbd7 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -874,8 +874,8 @@ extern int perf_output_begin(struct perf_output_handle *handle, extern void perf_output_end(struct perf_output_handle *handle); extern void perf_output_copy(struct perf_output_handle *handle, const void *buf, unsigned int len); -extern int perf_swevent_get_recursion_context(int **recursion); -extern void perf_swevent_put_recursion_context(int *recursion); +extern int perf_swevent_get_recursion_context(void); +extern void perf_swevent_put_recursion_context(int rctx); #else static inline void perf_event_task_sched_in(struct task_struct *task, int cpu) { } @@ -904,8 +904,8 @@ static inline void perf_event_mmap(struct vm_area_struct *vma) { } static inline void perf_event_comm(struct task_struct *tsk) { } static inline void perf_event_fork(struct task_struct *tsk) { } static inline void perf_event_init(void) { } -static int perf_swevent_get_recursion_context(int **recursion) { return -1; } -static void perf_swevent_put_recursion_context(int *recursion) { } +static inline int perf_swevent_get_recursion_context(void) { return -1; } +static inline void perf_swevent_put_recursion_context(int rctx) { } #endif diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h index c222ef5..c3417c1 100644 --- a/include/trace/ftrace.h +++ b/include/trace/ftrace.h @@ -724,8 +724,8 @@ __attribute__((section("_ftrace_events"))) event_##call = { \ static void ftrace_profile_##call(proto) \ { \ struct ftrace_data_offsets_##call __maybe_unused __data_offsets;\ - extern int perf_swevent_get_recursion_context(int **recursion); \ - extern void perf_swevent_put_recursion_context(int *recursion); \ + extern int perf_swevent_get_recursion_context(void); \ + extern void perf_swevent_put_recursion_context(int rctx); \ struct ftrace_event_call *event_call = &event_##call; \ extern void perf_tp_event(int, u64, u64, void *, int); \ struct ftrace_raw_##call *entry; \ @@ -736,8 +736,8 @@ static void ftrace_profile_##call(proto) \ int __data_size; \ char *trace_buf; \ char *raw_data; \ - int *recursion; \ int __cpu; \ + int rctx; \ int pc; \ \ pc = preempt_count(); \ @@ -753,8 +753,9 @@ static void ftrace_profile_##call(proto) \ \ local_irq_save(irq_flags); \ \ - if (perf_swevent_get_recursion_context(&recursion)) \ - goto end_recursion; \ + rctx = perf_swevent_get_recursion_context(); \ + if (rctx < 0) \ + goto end_recursion; \ \ __cpu = smp_processor_id(); \ \ @@ -781,9 +782,9 @@ static void ftrace_profile_##call(proto) \ perf_tp_event(event_call->id, __addr, __count, entry, \ __entry_size); \ \ -end: \ - perf_swevent_put_recursion_context(recursion); \ -end_recursion: \ +end: \ + perf_swevent_put_recursion_context(rctx); \ +end_recursion: \ local_irq_restore(irq_flags); \ \ } diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 50f11b5..0b0d5f7 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -3869,45 +3869,50 @@ static void perf_swevent_ctx_event(struct perf_event_context *ctx, } } -/* - * Must be called with preemption disabled - */ -int perf_swevent_get_recursion_context(int **recursion) +int perf_swevent_get_recursion_context(void) { - struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); + struct perf_cpu_context *cpuctx = &get_cpu_var(perf_cpu_context); + int rctx; if (in_nmi()) - *recursion = &cpuctx->recursion[3]; + rctx = 3; else if (in_irq()) - *recursion = &cpuctx->recursion[2]; + rctx = 2; else if (in_softirq()) - *recursion = &cpuctx->recursion[1]; + rctx = 1; else - *recursion = &cpuctx->recursion[0]; + rctx = 0; - if (**recursion) + if (cpuctx->recursion[rctx]) { + put_cpu_var(perf_cpu_context); return -1; + } - (**recursion)++; + cpuctx->recursion[rctx]++; + barrier(); - return 0; + return rctx; } EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context); -void perf_swevent_put_recursion_context(int *recursion) +void perf_swevent_put_recursion_context(int rctx) { - (*recursion)--; + struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); + barrier(); + cpuctx->recursion[rctx]++; + put_cpu_var(perf_cpu_context); } EXPORT_SYMBOL_GPL(perf_swevent_put_recursion_context); -static void __do_perf_sw_event(enum perf_type_id type, u32 event_id, - u64 nr, int nmi, - struct perf_sample_data *data, - struct pt_regs *regs) +static void do_perf_sw_event(enum perf_type_id type, u32 event_id, + u64 nr, int nmi, + struct perf_sample_data *data, + struct pt_regs *regs) { + struct perf_cpu_context *cpuctx; struct perf_event_context *ctx; - struct perf_cpu_context *cpuctx = &__get_cpu_var(perf_cpu_context); + cpuctx = &__get_cpu_var(perf_cpu_context); rcu_read_lock(); perf_swevent_ctx_event(&cpuctx->ctx, type, event_id, nr, nmi, data, regs); @@ -3921,34 +3926,22 @@ static void __do_perf_sw_event(enum perf_type_id type, u32 event_id, rcu_read_unlock(); } -static void do_perf_sw_event(enum perf_type_id type, u32 event_id, - u64 nr, int nmi, - struct perf_sample_data *data, - struct pt_regs *regs) -{ - int *recursion; - - preempt_disable(); - - if (perf_swevent_get_recursion_context(&recursion)) - goto out; - - __do_perf_sw_event(type, event_id, nr, nmi, data, regs); - - perf_swevent_put_recursion_context(recursion); -out: - preempt_enable(); -} - void __perf_sw_event(u32 event_id, u64 nr, int nmi, struct pt_regs *regs, u64 addr) { struct perf_sample_data data; + int rctx; + + rctx = perf_swevent_get_recursion_context(); + if (rctx < 0) + return; data.addr = addr; data.raw = NULL; do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, nmi, &data, regs); + + perf_swevent_put_recursion_context(rctx); } static void perf_swevent_read(struct perf_event *event) @@ -4172,7 +4165,7 @@ void perf_tp_event(int event_id, u64 addr, u64 count, void *record, regs = task_pt_regs(current); /* Trace events already protected against recursion */ - __do_perf_sw_event(PERF_TYPE_TRACEPOINT, event_id, count, 1, + do_perf_sw_event(PERF_TYPE_TRACEPOINT, event_id, count, 1, &data, regs); } EXPORT_SYMBOL_GPL(perf_tp_event); diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 22e6f68..79ce6a2 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -1213,7 +1213,7 @@ static __kprobes int kprobe_profile_func(struct kprobe *kp, unsigned long irq_flags; char *trace_buf; char *raw_data; - int *recursion; + int rctx; pc = preempt_count(); __size = SIZEOF_KPROBE_TRACE_ENTRY(tp->nr_args); @@ -1229,7 +1229,8 @@ static __kprobes int kprobe_profile_func(struct kprobe *kp, */ local_irq_save(irq_flags); - if (perf_swevent_get_recursion_context(&recursion)) + rctx = perf_swevent_get_recursion_context(); + if (rctx < 0) goto end_recursion; __cpu = smp_processor_id(); @@ -1258,7 +1259,7 @@ static __kprobes int kprobe_profile_func(struct kprobe *kp, perf_tp_event(call->id, entry->ip, 1, entry, size); end: - perf_swevent_put_recursion_context(recursion); + perf_swevent_put_recursion_context(rctx); end_recursion: local_irq_restore(irq_flags); @@ -1276,8 +1277,8 @@ static __kprobes int kretprobe_profile_func(struct kretprobe_instance *ri, int size, __size, i, pc, __cpu; unsigned long irq_flags; char *trace_buf; - int *recursion; char *raw_data; + int rctx; pc = preempt_count(); __size = SIZEOF_KRETPROBE_TRACE_ENTRY(tp->nr_args); @@ -1293,7 +1294,8 @@ static __kprobes int kretprobe_profile_func(struct kretprobe_instance *ri, */ local_irq_save(irq_flags); - if (perf_swevent_get_recursion_context(&recursion)) + rctx = perf_swevent_get_recursion_context(); + if (rctx < 0) goto end_recursion; __cpu = smp_processor_id(); @@ -1323,7 +1325,7 @@ static __kprobes int kretprobe_profile_func(struct kretprobe_instance *ri, perf_tp_event(call->id, entry->ret_ip, 1, entry, size); end: - perf_swevent_put_recursion_context(recursion); + perf_swevent_put_recursion_context(rctx); end_recursion: local_irq_restore(irq_flags); diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index 41b6dd9..9189cbe 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -481,8 +481,8 @@ static void prof_syscall_enter(struct pt_regs *regs, long id) unsigned long flags; char *trace_buf; char *raw_data; - int *recursion; int syscall_nr; + int rctx; int size; int cpu; @@ -506,7 +506,8 @@ static void prof_syscall_enter(struct pt_regs *regs, long id) /* Protect the per cpu buffer, begin the rcu read side */ local_irq_save(flags); - if (perf_swevent_get_recursion_context(&recursion)) + rctx = perf_swevent_get_recursion_context(); + if (rctx < 0) goto end_recursion; cpu = smp_processor_id(); @@ -530,7 +531,7 @@ static void prof_syscall_enter(struct pt_regs *regs, long id) perf_tp_event(sys_data->enter_id, 0, 1, rec, size); end: - perf_swevent_put_recursion_context(recursion); + perf_swevent_put_recursion_context(rctx); end_recursion: local_irq_restore(flags); } @@ -582,7 +583,7 @@ static void prof_syscall_exit(struct pt_regs *regs, long ret) int syscall_nr; char *trace_buf; char *raw_data; - int *recursion; + int rctx; int size; int cpu; @@ -609,7 +610,8 @@ static void prof_syscall_exit(struct pt_regs *regs, long ret) /* Protect the per cpu buffer, begin the rcu read side */ local_irq_save(flags); - if (perf_swevent_get_recursion_context(&recursion)) + rctx = perf_swevent_get_recursion_context(); + if (rctx < 0) goto end_recursion; cpu = smp_processor_id(); @@ -634,7 +636,7 @@ static void prof_syscall_exit(struct pt_regs *regs, long ret) perf_tp_event(sys_data->exit_id, 0, 1, rec, size); end: - perf_swevent_put_recursion_context(recursion); + perf_swevent_put_recursion_context(rctx); end_recursion: local_irq_restore(flags); } -- 2.7.4