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perf_events: Undo some recursion damage

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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 <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <20091123103819.993226816@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2009-11-23 11:37:29 +01:00 committed by Ingo Molnar
parent f67218c3e9
commit 4ed7c92d68
5 changed files with 61 additions and 63 deletions
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8
include/linux/perf_event.h
View file

@ -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

17
include/trace/ftrace.h
View file

@ -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); \
\
}

71
kernel/perf_event.c
View file

@ -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);

14
kernel/trace/trace_kprobe.c
View file

@ -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);

14
kernel/trace/trace_syscalls.c
View file

@ -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);
}