Re: [PATCH v5 27/29] fs/resctrl: Add file system mechanism for architecture info file

[Luck, Tony]

On Mon, Jun 09, 2025 at 05:30:34PM -0700, Reinette Chatre wrote:
> This should be a directory, a directory owned by the arch where it can create
> debug infrastructure required by arch. The directory name chosen and
> assigned by resctrl fs, while arch has freedom to create more directories
> and add files underneath it. Goal is to isolate all arch specific debug to
> a known location.
> 
> Again, we need to prepare for resctrl fs to potentially use debugfs for its own
> debug and when it does this the expectation is that the layout will mirror
> /sys/fs/resctrl. Creating a directory /sys/kernel/debug/resctrl/info/<rdt_resource::name>_MON
> and then handing it off to the arch goes *against* this. It gives arch
> control over a directory that should be owned by resctrl fs.
> 
> What I have been trying to propose is that resctrl fs create a directory
> /sys/kernel/debug/resctrl/info/<rdt_resource::name>_MON/arch_debug_name_TBD and hand
> a dentry pointer to it to the arch where it can do what is needed to support its debugging needs.
> Isn't this exactly what I wrote in the snippet above? Above you respond with
> statement that you were under impression that it was a directory ... and then
> send a patch that does something else. I am so confused. Gaslighting is
> beneath you.

For the precise name of the "arch_debug_name_TBD" directory, is simply "arch"
sufficient? That leaves every other name available for resctrl
filesystem code free choice if it does add some debug files here.

Or would $ARCH ("x86" in my case) be better to keep distinct debug name
spaces between architectures?

-Tony