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tracing/function-graph-tracer: append the tracing_graph_flag

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Impact: Provide a way to pause the function graph tracer

As suggested by Steven Rostedt, the previous patch that prevented from
spinlock function tracing shouldn't use the raw_spinlock to fix it.
It's much better to follow lockdep with normal spinlock, so this patch
adds a new flag for each task to make the function graph tracer able
to be paused. We also can send an ftrace_printk whithout worrying of
the irrelevant traced spinlock during insertion.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Frederic Weisbecker
2008-12-06 03:43:41 +01:00
committed by Ingo Molnar
parent 8e1b82e086
commit 380c4b1411
5 changed files with 26 additions and 14 deletions
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2
kernel/trace/ftrace.c
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@@ -1998,6 +1998,7 @@ static int alloc_retstack_tasklist(struct ftrace_ret_stack **ret_stack_list)
/* Make sure IRQs see the -1 first: */
barrier();
t->ret_stack = ret_stack_list[start++];
atomic_set(&t->tracing_graph_pause, 0);
atomic_set(&t->trace_overrun, 0);
}
} while_each_thread(g, t);
@@ -2077,6 +2078,7 @@ void ftrace_graph_init_task(struct task_struct *t)
if (!t->ret_stack)
return;
t->curr_ret_stack = -1;
atomic_set(&t->tracing_graph_pause, 0);
atomic_set(&t->trace_overrun, 0);
} else
t->ret_stack = NULL;