Re: [PATCH -v5 08/11] tracing: not trace mips_timecounter_init() in MIPS

Wu Zhangjin
2009-10-26T09:42:45Z

On Mon, 2009-10-26 at 01:27 +0100, Frederic Weisbecker wrote:
> 2009/10/25 Wu Zhangjin <wuzhangjin@gmail.com>:
> > -static inline u64 mips_timecounter_read(void)
> > +static inline u64 notrace mips_timecounter_read(void)
>
>
> You don't need to set notrace functions, unless their addresses
> are referenced somewhere, which unfortunately might happen
> for some functions but this is rare.
>

Okay, Will remove it.

>
> > {
> > #ifdef CONFIG_CSRC_R4K
> > return r4k_timecounter_read();
> > diff --git a/arch/mips/kernel/csrc-r4k.c b/arch/mips/kernel/csrc-r4k.c
> > index 4e7705f..0690bea 100644
> > --- a/arch/mips/kernel/csrc-r4k.c
> > +++ b/arch/mips/kernel/csrc-r4k.c
> > @@ -42,7 +42,7 @@ static struct timecounter r4k_tc = {
> > .cc = NULL,
> > };
> >
> > -static cycle_t r4k_cc_read(const struct cyclecounter *cc)
> > +static cycle_t notrace r4k_cc_read(const struct cyclecounter *cc)
> > {
> > return read_c0_count();
> > }
> > @@ -66,7 +66,7 @@ int __init init_r4k_timecounter(void)
> > return 0;
> > }
> >
> > -u64 r4k_timecounter_read(void)
> > +u64 notrace r4k_timecounter_read(void)
> > {
> > u64 clock;
> >
> > diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
> > index 83d2fbd..2a02992 100644
> > --- a/include/linux/clocksource.h
> > +++ b/include/linux/clocksource.h
> > @@ -73,7 +73,7 @@ struct timecounter {
> > * XXX - This could use some mult_lxl_ll() asm optimization. Same code
> > * as in cyc2ns, but with unsigned result.
> > */
> > -static inline u64 cyclecounter_cyc2ns(const struct cyclecounter *cc,
> > +static inline u64 notrace cyclecounter_cyc2ns(const struct cyclecounter
>
> ditto here.
>

Will remove it too.

>
> *cc,
> > cycle_t cycles)
> > {
> > u64 ret = (u64)cycles;
> > diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
> > index 5e18c6a..9ce9d02 100644
> > --- a/kernel/time/clocksource.c
> > +++ b/kernel/time/clocksource.c
> > @@ -52,7 +52,7 @@ EXPORT_SYMBOL(timecounter_init);
> > * The first call to this function for a new time counter initializes
> > * the time tracking and returns an undefined result.
> > */
> > -static u64 timecounter_read_delta(struct timecounter *tc)
> > +static u64 notrace timecounter_read_delta(struct timecounter *tc)
> > {
> > cycle_t cycle_now, cycle_delta;
> > u64 ns_offset;
> > @@ -72,7 +72,7 @@ static u64 timecounter_read_delta(struct timecounter
>
>
> Hmm yeah this is not very nice to do that in core functions because
> of a specific arch problem.
> At least you have __notrace_funcgraph, this is a notrace
> that only applies if CONFIG_FUNCTION_GRAPH_TRACER
> so that it's still traceable by the function tracer in this case.
>
> But I would rather see a __mips_notrace on these two core functions.

What about this: __arch_notrace? If the arch need this, define it,
otherwise, ignore it! if only graph tracer need it, define it in "#ifdef
CONFIG_FUNCTION_GRAPH_TRACER ... #endif".

diff --git a/arch/mips/include/asm/ftrace.h
b/arch/mips/include/asm/ftrace.h
index d5771e8..eeacd51 100644
--- a/arch/mips/include/asm/ftrace.h
+++ b/arch/mips/include/asm/ftrace.h
@@ -31,6 +31,11 @@ static inline unsigned long
ftrace_call_adjust(unsigned long addr)
struct dyn_arch_ftrace {
};
#endif /* CONFIG_DYNAMIC_FTRACE */
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+#define __arch_notrace
+#endif
+
#endif /* __ASSEMBLY__ */
#endif /* CONFIG_FUNCTION_TRACER */
#endif /* _ASM_MIPS_FTRACE_H */

[...]

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 0b4f97d..959c8b3 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -511,4 +511,12 @@ static inline void trace_hw_branch_oops(void) {}

#endif /* CONFIG_HW_BRANCH_TRACER */

+/* arch specific notrace */
+#ifndef __arch_notrace
+#define __arch_notrace
+#else
+#undef __arch_notrace
+#define __arch_notrace notrace
+#endif
+
#endif /* _LINUX_FTRACE_H */

[...]

diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index 9ce9d02..91acdf7 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -30,6 +30,7 @@
#include <linux/sched.h> /* for spin_unlock_irq() using preempt_count()
m68k */
#include <linux/tick.h>
#include <linux/kthread.h>
+#include <linux/ftrace.h>

void timecounter_init(struct timecounter *tc,
const struct cyclecounter *cc,
@@ -52,7 +53,7 @@ EXPORT_SYMBOL(timecounter_init);
* The first call to this function for a new time counter initializes
* the time tracking and returns an undefined result.
*/
-static u64 notrace timecounter_read_delta(struct timecounter *tc)
+static u64 __arch_notrace timecounter_read_delta(struct timecounter
*tc)
{
cycle_t cycle_now, cycle_delta;
u64 ns_offset;
@@ -72,7 +73,7 @@ static u64 notrace timecounter_read_delta(struct
timecounter *tc)
return ns_offset;
}

-u64 notrace timecounter_read(struct timecounter *tc)
+u64 __arch_notrace timecounter_read(struct timecounter *tc)
{
u64 nsec;

Regards,
Wu Zhangjin