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Date:   Tue, 10 Oct 2023 12:36:29 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Meng Li <li.meng@amd.com>
Cc:     "Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
        Huang Rui <ray.huang@amd.com>, linux-pm@vger.kernel.org,
        linux-kernel@vger.kernel.org, x86@kernel.org,
        linux-acpi@vger.kernel.org, Shuah Khan <skhan@linuxfoundation.org>,
        linux-kselftest@vger.kernel.org,
        Nathan Fontenot <nathan.fontenot@amd.com>,
        Deepak Sharma <deepak.sharma@amd.com>,
        Alex Deucher <alexander.deucher@amd.com>,
        Mario Limonciello <mario.limonciello@amd.com>,
        Shimmer Huang <shimmer.huang@amd.com>,
        Perry Yuan <Perry.Yuan@amd.com>,
        Xiaojian Du <Xiaojian.Du@amd.com>,
        Viresh Kumar <viresh.kumar@linaro.org>,
        Borislav Petkov <bp@alien8.de>
Subject: Re: [PATCH V8 3/7] cpufreq: amd-pstate: Enable amd-pstate preferred
 core supporting.
Message-ID: <20231010103629.GI377@noisy.programming.kicks-ass.net>
References: <20231009024932.2563622-1-li.meng@amd.com>
 <20231009024932.2563622-4-li.meng@amd.com>
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On Mon, Oct 09, 2023 at 10:49:28AM +0800, Meng Li wrote:

> +static void amd_pstate_init_prefcore(struct amd_cpudata *cpudata)
> +{
> +	int ret;
> +	u32 highest_perf;
> +	static u32 max_highest_perf = 0, min_highest_perf = U32_MAX;
> +
> +	ret = amd_pstate_get_highest_perf(cpudata->cpu, &highest_perf);
> +	if (ret)
> +		return;
> +
> +	cpudata->hw_prefcore = true;
> +	/* check if CPPC preferred core feature is enabled*/
> +	if (highest_perf == AMD_PSTATE_MAX_CPPC_PERF) {
> +		pr_debug("AMD CPPC preferred core is unsupported!\n");
> +		cpudata->hw_prefcore = false;
> +		return;
> +	}
> +
> +	if (!amd_pstate_prefcore)
> +		return;
> +
> +	/*
> +	 * The priorities can be set regardless of whether or not
> +	 * sched_set_itmt_support(true) has been called and it is valid to
> +	 * update them at any time after it has been called.
> +	 */
> +	sched_set_itmt_core_prio(highest_perf, cpudata->cpu);

You still got the whole u32 vs int thing confused, I've only pointed
that out *TWICE* before.

Boris, can you pull out the clue hammer please?

> +
> +	if (max_highest_perf <= min_highest_perf) {
> +		if (highest_perf > max_highest_perf)
> +			max_highest_perf = highest_perf;
> +
> +		if (highest_perf < min_highest_perf)
> +			min_highest_perf = highest_perf;
> +
> +		if (max_highest_perf > min_highest_perf) {
> +			/*
> +			 * This code can be run during CPU online under the
> +			 * CPU hotplug locks, so sched_set_itmt_support()
> +			 * cannot be called from here.  Queue up a work item
> +			 * to invoke it.
> +			 */
> +			schedule_work(&sched_prefcore_work);
> +		}
> +	}
> +}