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/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 @@
unsigned long flags;
char *trace_buf;
char *raw_data;
- int *recursion;
int syscall_nr;
+ int rctx;
int size;
int cpu;
@@ -506,7 +506,8 @@
/* 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 @@
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 @@
int syscall_nr;
char *trace_buf;
char *raw_data;
- int *recursion;
+ int rctx;
int size;
int cpu;
@@ -609,7 +610,8 @@
/* 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 @@
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);
}