Re: [PATCH v10 12/14] x86/sgx: Turn on per-cgroup EPC reclamation

[Haitao Huang]

On Mon, 08 Apr 2024 17:37:10 -0500, Huang, Kai <kai.huang@xxxxxxxxx> wrote:

> On 9/04/2024 6:03 am, Haitao Huang wrote:
> > > >
> >  The misc root cgroup is a static similar to sgx_cg_root. So  
> > misc_cg_root()  won't be NULL
> > However, based on how css_misc() was check NULL, I suppose  
> > sgx_get_current_cg() may be NULL when cgroup is disabled (again not  
> > 100% sure but we handle it anyway)
>
> Could you help to check?  Sorry I am busy on something else thus won't  
> be able to do any actual check.
It's always non-NULL based on testing.

It's hard for me to say definitely by reading the code. But IIUC  
cgroup_disable command-line only blocks operations in /sys/fs/cgroup so  
user space can't set up controllers and config limits, etc., for the  
diasabled ones. Each task->cgroups would still have a non-NULL pointer to  
the static root object for each cgroup that is enabled by KConfig, so  
get_current_misc_cg() thus  sgx_get_current_cg() should not return NULL  
regardless 'cgroup_disable=misc'.

Maybe @Michal or @tj can confirm?

Thanks
Haitao