linux-kernel - Re: [PATCH v2 16/23] sched/cache: Introduce sched_cache_present to enable cache aware scheduling for multi LLCs NUMA node

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: <3c9b5f65-1a6b-4df7-8382-5ed51a19626f@intel.com>
Date: Tue, 16 Dec 2025 15:31:44 +0800
From: "Chen, Yu C" <yu.c.chen@...el.com>
To: Peter Zijlstra <peterz@...radead.org>, Tim Chen
	<tim.c.chen@...ux.intel.com>
CC: Ingo Molnar <mingo@...hat.com>, K Prateek Nayak <kprateek.nayak@....com>,
	"Gautham R . Shenoy" <gautham.shenoy@....com>, Vincent Guittot
	<vincent.guittot@...aro.org>, Juri Lelli <juri.lelli@...hat.com>, "Dietmar
 Eggemann" <dietmar.eggemann@....com>, Steven Rostedt <rostedt@...dmis.org>,
	Ben Segall <bsegall@...gle.com>, Mel Gorman <mgorman@...e.de>, "Valentin
 Schneider" <vschneid@...hat.com>, Madadi Vineeth Reddy
	<vineethr@...ux.ibm.com>, Hillf Danton <hdanton@...a.com>, Shrikanth Hegde
	<sshegde@...ux.ibm.com>, Jianyong Wu <jianyong.wu@...look.com>, Yangyu Chen
	<cyy@...self.name>, Tingyin Duan <tingyin.duan@...il.com>, Vern Hao
	<vernhao@...cent.com>, Vern Hao <haoxing990@...il.com>, Len Brown
	<len.brown@...el.com>, Aubrey Li <aubrey.li@...el.com>, Zhao Liu
	<zhao1.liu@...el.com>, Chen Yu <yu.chen.surf@...il.com>, Adam Li
	<adamli@...amperecomputing.com>, Aaron Lu <ziqianlu@...edance.com>, Tim Chen
	<tim.c.chen@...el.com>, <linux-kernel@...r.kernel.org>, Libo Chen
	<libo.chen@...cle.com>
Subject: Re: [PATCH v2 16/23] sched/cache: Introduce sched_cache_present to
 enable cache aware scheduling for multi LLCs NUMA node

On 12/11/2025 12:32 AM, Peter Zijlstra wrote:
> On Wed, Dec 03, 2025 at 03:07:35PM -0800, Tim Chen wrote:
>> From: Chen Yu <yu.c.chen@...el.com>
>>
>> Cache-aware load balancing should only be enabled if there are more
>> than 1 LLCs within 1 NUMA node. sched_cache_present is introduced to
>> indicate whether this platform supports this topology.
>>
>> Suggested-by: Libo Chen <libo.chen@...cle.com>
>> Suggested-by: Adam Li <adamli@...amperecomputing.com>
>> Signed-off-by: Chen Yu <yu.c.chen@...el.com>
>> Signed-off-by: Tim Chen <tim.c.chen@...ux.intel.com>
>> ---
>>
>> Notes:
>>      v1->v2:
>>      	Use flag sched_cache_present to indicate whether a platform
>>      	supports cache aware scheduling. Change this flag from staic key.
>>      	There should be only 1 static key to control the cache aware
>>      	scheduling. (Peter Zijlstra)
>>
>>   kernel/sched/topology.c | 20 +++++++++++++++-----
>>   1 file changed, 15 insertions(+), 5 deletions(-)
>>
>> diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
>> index d583399fc6a1..9799e3a9a609 100644
>> --- a/kernel/sched/topology.c
>> +++ b/kernel/sched/topology.c
>> @@ -24,6 +24,8 @@ int max_llcs;
>>   
>>   #ifdef CONFIG_SCHED_CACHE
>>   
>> +static bool sched_cache_present;
> 
> sched_energy_present
> sched_asym_cpucapacity
> sched_cluster_active
> sched_smt_present
> 
> are all static keys tied to the current topology, why break the streak
> and make this a boolean?

OK, will convert it into a key.

thanks,
Chenyu