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Date: Mon, 26 Oct 2009 01:27:18 +0100
Message-ID: <c62985530910251727o23beafcco539870e4b2f84637@mail.gmail.com>
Subject: Re: [PATCH -v5 08/11] tracing: not trace mips_timecounter_init() in 
	MIPS
From: Frederic Weisbecker <fweisbec@gmail.com>
To: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: linux-mips@linux-mips.org, linux-kernel@vger.kernel.org,
       rostedt@goodmis.org, Thomas Gleixner <tglx@linutronix.de>,
       Ralf Baechle <ralf@linux-mips.org>,
       Nicholas Mc Guire <der.herr@hofr.at>,
       Richard Sandiford <rdsandiford@googlemail.com>,
       David Daney <ddaney@caviumnetworks.com>,
       Adam Nemet <anemet@caviumnetworks.com>,
       Patrik Kluba <kpajko79@gmail.com>
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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.


> ?{
> ?#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.


*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.
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