Re: [PATCH v6 6/8] x86/resctrl: Move default control group creation during mount

Moger, Babu
2023-08-08T18:02:20Z

Hi Reinette,

On 8/4/23 15:42, Reinette Chatre wrote:
> Hi Babu,
>
> On 7/19/2023 4:22 PM, Babu Moger wrote:
>> The resctrl default control group is created during kernel init time. If
>> the new files are to be added to the default group during the mount based
>> on the mount option, then each file needs to be created separately and
>> call kernfs_activate.
>>
>> This can avoided if all the files are created during the mount and
>> destroyed during the umount. Move the root and default group creation
>> in rdt_get_tree and removal in rdt_kill_sb.
>
> Please use () to indicate function names.

Sure.

>
>>
>> Suggested-by: Reinette Chatre <reinette.chatre@intel.com>
>> Signed-off-by: Babu Moger <babu.moger@amd.com>
>> ---
>
> ...
>
>> @@ -3704,10 +3720,8 @@ static struct kernfs_syscall_ops rdtgroup_kf_syscall_ops = {
>> .show_options = rdtgroup_show_options,
>> };
>>
>> -static int __init rdtgroup_setup_root(void)
>> +int rdtgroup_setup_root(void)
>> {
>> - int ret;
>> -
>> rdt_root = kernfs_create_root(&rdtgroup_kf_syscall_ops,
>> KERNFS_ROOT_CREATE_DEACTIVATED |
>> KERNFS_ROOT_EXTRA_OPEN_PERM_CHECK,
>> @@ -3715,28 +3729,17 @@ static int __init rdtgroup_setup_root(void)
>> if (IS_ERR(rdt_root))
>> return PTR_ERR(rdt_root);
>>
>> - mutex_lock(&rdtgroup_mutex);
>> -
>> rdtgroup_default.closid = 0;
>> rdtgroup_default.mon.rmid = 0;
>> rdtgroup_default.type = RDTCTRL_GROUP;
>> + rdtgroup_default.mode = RDT_MODE_SHAREABLE;
>> INIT_LIST_HEAD(&rdtgroup_default.mon.crdtgrp_list);
>>
>> list_add(&rdtgroup_default.rdtgroup_list, &rdt_all_groups);
>>
>> - ret = rdtgroup_add_files(kernfs_root_to_node(rdt_root), RFTYPE_CTRL_BASE);
>> - if (ret) {
>> - kernfs_destroy_root(rdt_root);
>> - goto out;
>> - }
>> -
>> rdtgroup_default.kn = kernfs_root_to_node(rdt_root);
>> - kernfs_activate(rdtgroup_default.kn);
>>
>> -out:
>> - mutex_unlock(&rdtgroup_mutex);
>> -
>> - return ret;
>> + return 0;
>> }
>
> I am missing something here. Why is it now needed to re-initialize
> and add default resource group on every mount of resctrl? I expected
> only the kernfs related changes to move.

Yes. We can do that. I think I started with the previous version and went
that route. We dont have to change the default group initialization.
Will send new version soon.
Thanks
Babu Moger