linux-kernel - Re: [PATCH -next 4/6] cpuset: move update_domain_attr_tree to cpuset

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: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <3d9464bd-77ee-4ff7-a9e8-90930b994d00@huaweicloud.com>
Date: Thu, 18 Dec 2025 08:44:15 +0800
From: Chen Ridong <chenridong@...weicloud.com>
To: Waiman Long <llong@...hat.com>, tj@...nel.org, hannes@...xchg.org,
 mkoutny@...e.com
Cc: cgroups@...r.kernel.org, linux-kernel@...r.kernel.org,
 lujialin4@...wei.com
Subject: Re: [PATCH -next 4/6] cpuset: move update_domain_attr_tree to
 cpuset_v1.c



On 2025/12/18 1:09, Waiman Long wrote:
> 
> On 12/17/25 3:49 AM, Chen Ridong wrote:
>> From: Chen Ridong <chenridong@...wei.com>
>>
>> Since relax_domain_level is only applicable to v1, move
>> update_domain_attr_tree() to cpuset-v1.c, which solely updates
>> relax_domain_level,
>>
>> Additionally, relax_domain_level is now initialized in cpuset1_inited.
>> Accordingly, the initialization of relax_domain_level in top_cpuset is
>> removed. The unnecessary remote_partition initialization in top_cpuset
>> is also cleaned up.
>>
>> As a result, relax_domain_level can be defined in cpuset only when
>> CONFIG_CPUSETS_V1=y.
>>
>> Signed-off-by: Chen Ridong <chenridong@...wei.com>
>> ---
>>   kernel/cgroup/cpuset-internal.h | 11 ++++++++---
>>   kernel/cgroup/cpuset-v1.c       | 28 ++++++++++++++++++++++++++++
>>   kernel/cgroup/cpuset.c          | 31 -------------------------------
>>   3 files changed, 36 insertions(+), 34 deletions(-)
>>
>> diff --git a/kernel/cgroup/cpuset-internal.h b/kernel/cgroup/cpuset-internal.h
>> index a32517da8231..677053ffb913 100644
>> --- a/kernel/cgroup/cpuset-internal.h
>> +++ b/kernel/cgroup/cpuset-internal.h
>> @@ -150,9 +150,6 @@ struct cpuset {
>>        */
>>       int attach_in_progress;
>>   -    /* for custom sched domain */
>> -    int relax_domain_level;
>> -
>>       /* partition root state */
>>       int partition_root_state;
>>   @@ -182,6 +179,9 @@ struct cpuset {
>>     #ifdef CONFIG_CPUSETS_V1
>>       struct fmeter fmeter;        /* memory_pressure filter */
>> +
>> +    /* for custom sched domain */
>> +    int relax_domain_level;
>>   #endif
>>   };
>>   @@ -296,6 +296,8 @@ void cpuset1_hotplug_update_tasks(struct cpuset *cs,
>>   int cpuset1_validate_change(struct cpuset *cur, struct cpuset *trial);
>>   void cpuset1_init(struct cpuset *cs);
>>   void cpuset1_online_css(struct cgroup_subsys_state *css);
>> +void update_domain_attr_tree(struct sched_domain_attr *dattr,
>> +                    struct cpuset *root_cs);
>>   #else
>>   static inline void cpuset1_update_task_spread_flags(struct cpuset *cs,
>>                       struct task_struct *tsk) {}
>> @@ -307,6 +309,9 @@ static inline int cpuset1_validate_change(struct cpuset *cur,
>>                   struct cpuset *trial) { return 0; }
>>   static inline void cpuset1_init(struct cpuset *cs) {}
>>   static inline void cpuset1_online_css(struct cgroup_subsys_state *css) {}
>> +static inline void update_domain_attr_tree(struct sched_domain_attr *dattr,
>> +                    struct cpuset *root_cs) {}
>> +
>>   #endif /* CONFIG_CPUSETS_V1 */
>>     #endif /* __CPUSET_INTERNAL_H */
>> diff --git a/kernel/cgroup/cpuset-v1.c b/kernel/cgroup/cpuset-v1.c
>> index 574df740f21a..95de6f2a4cc5 100644
>> --- a/kernel/cgroup/cpuset-v1.c
>> +++ b/kernel/cgroup/cpuset-v1.c
>> @@ -502,6 +502,7 @@ static int cpuset_write_u64(struct cgroup_subsys_state *css, struct cftype *cft,
>>   void cpuset1_init(struct cpuset *cs)
>>   {
>>       fmeter_init(&cs->fmeter);
>> +    cs->relax_domain_level = -1;
>>   }
>>     void cpuset1_online_css(struct cgroup_subsys_state *css)
>> @@ -552,6 +553,33 @@ void cpuset1_online_css(struct cgroup_subsys_state *css)
>>       cpuset_callback_unlock_irq();
>>   }
>>   +static void
>> +update_domain_attr(struct sched_domain_attr *dattr, struct cpuset *c)
>> +{
>> +    if (dattr->relax_domain_level < c->relax_domain_level)
>> +        dattr->relax_domain_level = c->relax_domain_level;
>> +}
>> +
>> +void update_domain_attr_tree(struct sched_domain_attr *dattr,
>> +                    struct cpuset *root_cs)
>> +{
>> +    struct cpuset *cp;
>> +    struct cgroup_subsys_state *pos_css;
>> +
>> +    rcu_read_lock();
>> +    cpuset_for_each_descendant_pre(cp, pos_css, root_cs) {
>> +        /* skip the whole subtree if @cp doesn't have any CPU */
>> +        if (cpumask_empty(cp->cpus_allowed)) {
>> +            pos_css = css_rightmost_descendant(pos_css);
>> +            continue;
>> +        }
>> +
>> +        if (is_sched_load_balance(cp))
>> +            update_domain_attr(dattr, cp);
>> +    }
>> +    rcu_read_unlock();
>> +}
>> +
>>   /*
>>    * for the common functions, 'private' gives the type of file
>>    */
>> diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
>> index e836a1f2b951..88ca8b40e01a 100644
>> --- a/kernel/cgroup/cpuset.c
>> +++ b/kernel/cgroup/cpuset.c
>> @@ -215,8 +215,6 @@ static struct cpuset top_cpuset = {
>>       .flags = BIT(CS_CPU_EXCLUSIVE) |
>>            BIT(CS_MEM_EXCLUSIVE) | BIT(CS_SCHED_LOAD_BALANCE),
>>       .partition_root_state = PRS_ROOT,
>> -    .relax_domain_level = -1,
> 
> As the cpuset1_init() function will not be called for top_cpuset, you should not remove the
> initialization of relax_domain_level. Instead, put it inside a "ifdef CONFIG_CPUSETS_V1 block.
> 

In patch 3/6, I've made cpuset_init call cpuset1_init to initialize top_cpuset.fmeter. Thus, I think
we could remove the relax_domain_level initialization here.

>> -    .remote_partition = false,
> 
> Yes, this is not really needed and can be removed.
> 
> Cheers,
> Longman
> 

-- 
Best regards,
Ridong