* Meenakshi Aggarwal | 2014-05-15 16:08:54 [+0530]:
>--- a/kernel/sched/core.c
>+++ b/kernel/sched/core.c
>@@ -2296,13 +2296,16 @@ void __kprobes add_preempt_count(int val)
> DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
> PREEMPT_MASK - 10);
> #endif
>- if (preempt_count() == val) {
>- unsigned long ip = get_parent_ip(CALLER_ADDR1);
>+
>+ if (preempt_count() == val)
> #ifdef CONFIG_DEBUG_PREEMPT
>- current->preempt_disable_ip = ip;
>+ trace_preempt_off(CALLER_ADDR0,
>+ current->preempt_disable_ip =
>+ get_parent_ip(CALLER_ADDR1));
So if I apply this, I can imagine tglx will run to his armoury looking
for a fine axe and then throwing it at me. So sorry, but I can't apply
this.
I suggest you look into gcc and figure out why this hackery of yours
saves 18 instructions. It does not make sense to me because all you do
is to inline replace ip with "get_parent_ip(CALLER_ADDR1)". It might be
that the compiler unrolls the stack each time ip is accessed but this is
clearly a compiler short comming.
Sebastian
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