From: Ionela Voinescu <ionela.voinescu@arm.com>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Rafael Wysocki <rjw@rjwysocki.net>,
linux-pm@vger.kernel.org,
Vincent Guittot <vincent.guittot@linaro.org>,
Qian Cai <quic_qiancai@quicinc.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH V3 2/4] cpufreq: cppc: Pass structure instance by reference
Date: Wed, 23 Jun 2021 14:45:33 +0100 [thread overview]
Message-ID: <20210623134533.GB12411@arm.com> (raw)
In-Reply-To: <b910f89cf11f6916319f9a2fb48d9146005318b1.1624266901.git.viresh.kumar@linaro.org>
On Monday 21 Jun 2021 at 14:49:35 (+0530), Viresh Kumar wrote:
> Don't pass structure instance by value, pass it by reference instead.
>
Might be best to justify the change a bit :)
For me this is a judgement call, and I don't really see the reasons for
changing it: we don't care if the structure is modified or not, as we're
not reusing the data after the call to cppc_get_rate_from_fbctrs().
More so, in this scenario we might not even want for the called function
to modify the counter values. Also there is no further call to a function
in cppc_get_rate_from_fbctrs(), that might require references to the
fb_ctrs.
So what is the reason behind this change?
Thanks,
Ionela.
> Tested-by: Vincent Guittot <vincent.guittot@linaro.org>
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
> ---
> drivers/cpufreq/cppc_cpufreq.c | 16 ++++++++--------
> 1 file changed, 8 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/cpufreq/cppc_cpufreq.c b/drivers/cpufreq/cppc_cpufreq.c
> index 35b8ae66d1fb..490175d65082 100644
> --- a/drivers/cpufreq/cppc_cpufreq.c
> +++ b/drivers/cpufreq/cppc_cpufreq.c
> @@ -373,18 +373,18 @@ static inline u64 get_delta(u64 t1, u64 t0)
> }
>
> static int cppc_get_rate_from_fbctrs(struct cppc_cpudata *cpu_data,
> - struct cppc_perf_fb_ctrs fb_ctrs_t0,
> - struct cppc_perf_fb_ctrs fb_ctrs_t1)
> + struct cppc_perf_fb_ctrs *fb_ctrs_t0,
> + struct cppc_perf_fb_ctrs *fb_ctrs_t1)
> {
> u64 delta_reference, delta_delivered;
> u64 reference_perf, delivered_perf;
>
> - reference_perf = fb_ctrs_t0.reference_perf;
> + reference_perf = fb_ctrs_t0->reference_perf;
>
> - delta_reference = get_delta(fb_ctrs_t1.reference,
> - fb_ctrs_t0.reference);
> - delta_delivered = get_delta(fb_ctrs_t1.delivered,
> - fb_ctrs_t0.delivered);
> + delta_reference = get_delta(fb_ctrs_t1->reference,
> + fb_ctrs_t0->reference);
> + delta_delivered = get_delta(fb_ctrs_t1->delivered,
> + fb_ctrs_t0->delivered);
>
> /* Check to avoid divide-by zero */
> if (delta_reference || delta_delivered)
> @@ -415,7 +415,7 @@ static unsigned int cppc_cpufreq_get_rate(unsigned int cpu)
> if (ret)
> return ret;
>
> - return cppc_get_rate_from_fbctrs(cpu_data, fb_ctrs_t0, fb_ctrs_t1);
> + return cppc_get_rate_from_fbctrs(cpu_data, &fb_ctrs_t0, &fb_ctrs_t1);
> }
>
> static int cppc_cpufreq_set_boost(struct cpufreq_policy *policy, int state)
> --
> 2.31.1.272.g89b43f80a514
>
next prev parent reply other threads:[~2021-06-23 13:45 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-21 9:19 [PATCH V3 0/4] cpufreq: cppc: Add support for frequency invariance Viresh Kumar
2021-06-21 9:19 ` [PATCH V3 1/4] cpufreq: cppc: Fix potential memleak in cppc_cpufreq_cpu_init Viresh Kumar
2021-06-23 13:44 ` Ionela Voinescu
2021-06-24 2:08 ` Viresh Kumar
2021-06-24 2:10 ` [PATCH V3.1 " Viresh Kumar
2021-06-25 10:33 ` Ionela Voinescu
2021-06-21 9:19 ` [PATCH V3 2/4] cpufreq: cppc: Pass structure instance by reference Viresh Kumar
2021-06-23 13:45 ` Ionela Voinescu [this message]
2021-06-24 2:22 ` Viresh Kumar
2021-06-25 10:30 ` Ionela Voinescu
2021-06-21 9:19 ` [PATCH V3 3/4] arch_topology: Avoid use-after-free for scale_freq_data Viresh Kumar
2021-06-23 13:50 ` Ionela Voinescu
2021-06-21 9:19 ` [PATCH V3 4/4] cpufreq: CPPC: Add support for frequency invariance Viresh Kumar
2021-06-24 9:48 ` Ionela Voinescu
2021-06-24 13:04 ` Viresh Kumar
2021-06-25 8:54 ` Ionela Voinescu
2021-06-25 16:54 ` Viresh Kumar
2021-06-28 10:49 ` Ionela Voinescu
2021-06-29 4:32 ` Viresh Kumar
2021-06-29 8:47 ` Ionela Voinescu
2021-06-29 8:53 ` Viresh Kumar
2021-06-21 20:48 ` [PATCH V3 0/4] cpufreq: cppc: " Qian Cai
2021-06-22 6:52 ` Viresh Kumar
2021-06-23 4:16 ` Viresh Kumar
2021-06-23 12:57 ` Qian Cai
2021-06-24 2:54 ` Viresh Kumar
2021-06-24 9:49 ` Vincent Guittot
2021-06-24 10:48 ` Ionela Voinescu
2021-06-24 11:15 ` Vincent Guittot
2021-06-24 11:23 ` Ionela Voinescu
2021-06-24 11:59 ` Vincent Guittot
2021-06-24 15:17 ` Qian Cai
2021-06-25 10:21 ` Ionela Voinescu
2021-06-25 13:31 ` Qian Cai
2021-06-25 14:37 ` Ionela Voinescu
2021-06-25 16:56 ` Qian Cai
2021-06-26 2:29 ` Qian Cai
2021-06-26 13:41 ` Qian Cai
2021-06-29 4:55 ` Viresh Kumar
2021-06-29 4:52 ` Viresh Kumar
2021-06-29 9:06 ` Ionela Voinescu
2021-06-29 13:38 ` Qian Cai
2021-06-29 4:45 ` Viresh Kumar
2021-06-24 20:44 ` Qian Cai
2021-06-28 11:54 ` Ionela Voinescu
2021-06-28 12:14 ` Vincent Guittot
2021-06-28 12:17 ` Vincent Guittot
2021-06-28 13:08 ` Ionela Voinescu
2021-06-28 21:37 ` Ionela Voinescu
2021-06-29 8:45 ` Vincent Guittot
2021-06-29 5:20 ` Viresh Kumar
2021-06-29 8:46 ` Ionela Voinescu
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