linux-kernel - Re: [PATCH 7/8] cpufreq: amd-pstate: Optimize amd_pstate_update

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <8acd43d7-3eb6-4cba-b962-e6b32c620b51@amd.com>
Date: Tue, 27 Aug 2024 14:02:25 -0500
From: Mario Limonciello <mario.limonciello@....com>
To: "Gautham R. Shenoy" <gautham.shenoy@....com>,
 Mario Limonciello <superm1@...nel.org>
Cc: Borislav Petkov <bp@...en8.de>, Perry Yuan <perry.yuan@....com>,
 "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@...nel.org>,
 "Rafael J . Wysocki" <rafael@...nel.org>,
 "open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
 <linux-kernel@...r.kernel.org>, "open list:ACPI"
 <linux-acpi@...r.kernel.org>,
 "open list:CPU FREQUENCY SCALING FRAMEWORK" <linux-pm@...r.kernel.org>
Subject: Re: [PATCH 7/8] cpufreq: amd-pstate: Optimize
 amd_pstate_update_limits()

On 8/27/2024 11:57, Gautham R. Shenoy wrote:
> On Mon, Aug 26, 2024 at 04:13:57PM -0500, Mario Limonciello wrote:
>> From: Mario Limonciello <mario.limonciello@....com>
>>
>> Don't take and release the mutex when prefcore isn't present and
>> avoid initialization of variables that will be initially set
>> in the function.
>>
>> Signed-off-by: Mario Limonciello <mario.limonciello@....com>
> 
>> ---
>>   drivers/cpufreq/amd-pstate.c | 10 +++++-----
>>   1 file changed, 5 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
>> index 75568d0f84623..ed05d7a0add10 100644
>> --- a/drivers/cpufreq/amd-pstate.c
>> +++ b/drivers/cpufreq/amd-pstate.c
>> @@ -798,17 +798,17 @@ static void amd_pstate_update_limits(unsigned int cpu)
>>   	int ret;
>>   	bool highest_perf_changed = false;
>>   
>> -	mutex_lock(&amd_pstate_driver_lock);
>> -	if ((!amd_pstate_prefcore) || (!cpudata->hw_prefcore))
>> -		goto free_cpufreq_put;
>> +	if (!amd_pstate_prefcore)
>> +		return;
> 
> Looks good to me.
> 
> Wondering if it is worth maintaining a static key for
> amd_pstate_prefcore. Anyway it doesn't change after boot.

As there is a kernel command line option how would you pass the early 
param parsing result over without a static variable?

> 
> Reviewed-by: Gautham R. Shenoy <gautham.shenoy@....com>
> 
Thanks!

> 
> --
> Thanks and Regards
> gautham.