diff options
author | Paul Mundt <lethal@linux-sh.org> | 2011-03-17 16:44:08 +0900 |
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committer | Paul Mundt <lethal@linux-sh.org> | 2011-03-17 16:44:08 +0900 |
commit | 1d2a1959fe534279cf37aba20b08c24c20840e52 (patch) | |
tree | 67c0b9aa7fe22a44bf0b4af88947799203eb8f67 /kernel/trace/ftrace.c | |
parent | 5a79ce76e9bb8f4b2cd8106ee36d15ee05013bcf (diff) | |
parent | 054cfaacf88865bff1dd58d305443d5d6c068a08 (diff) |
Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 into sh-latest
Diffstat (limited to 'kernel/trace/ftrace.c')
-rw-r--r-- | kernel/trace/ftrace.c | 52 |
1 files changed, 45 insertions, 7 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index f3dadae8388..888b611897d 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -3328,7 +3328,7 @@ static int start_graph_tracing(void) /* The cpu_boot init_task->ret_stack will never be freed */ for_each_online_cpu(cpu) { if (!idle_task(cpu)->ret_stack) - ftrace_graph_init_task(idle_task(cpu)); + ftrace_graph_init_idle_task(idle_task(cpu), cpu); } do { @@ -3418,6 +3418,49 @@ void unregister_ftrace_graph(void) mutex_unlock(&ftrace_lock); } +static DEFINE_PER_CPU(struct ftrace_ret_stack *, idle_ret_stack); + +static void +graph_init_task(struct task_struct *t, struct ftrace_ret_stack *ret_stack) +{ + atomic_set(&t->tracing_graph_pause, 0); + atomic_set(&t->trace_overrun, 0); + t->ftrace_timestamp = 0; + /* make curr_ret_stack visable before we add the ret_stack */ + smp_wmb(); + t->ret_stack = ret_stack; +} + +/* + * Allocate a return stack for the idle task. May be the first + * time through, or it may be done by CPU hotplug online. + */ +void ftrace_graph_init_idle_task(struct task_struct *t, int cpu) +{ + t->curr_ret_stack = -1; + /* + * The idle task has no parent, it either has its own + * stack or no stack at all. + */ + if (t->ret_stack) + WARN_ON(t->ret_stack != per_cpu(idle_ret_stack, cpu)); + + if (ftrace_graph_active) { + struct ftrace_ret_stack *ret_stack; + + ret_stack = per_cpu(idle_ret_stack, cpu); + if (!ret_stack) { + ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH + * sizeof(struct ftrace_ret_stack), + GFP_KERNEL); + if (!ret_stack) + return; + per_cpu(idle_ret_stack, cpu) = ret_stack; + } + graph_init_task(t, ret_stack); + } +} + /* Allocate a return stack for newly created task */ void ftrace_graph_init_task(struct task_struct *t) { @@ -3433,12 +3476,7 @@ void ftrace_graph_init_task(struct task_struct *t) GFP_KERNEL); if (!ret_stack) return; - atomic_set(&t->tracing_graph_pause, 0); - atomic_set(&t->trace_overrun, 0); - t->ftrace_timestamp = 0; - /* make curr_ret_stack visable before we add the ret_stack */ - smp_wmb(); - t->ret_stack = ret_stack; + graph_init_task(t, ret_stack); } } |