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 <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>
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 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_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 @@
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 @@
int __data_size; \
char *trace_buf; \
char *raw_data; \
- int *recursion; \
int __cpu; \
+ int rctx; \
int pc; \
\
pc = preempt_count(); \
@@ -753,8 +753,9 @@
\
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 @@
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); \
\
}