On Tue, Jul 14, 2026 at 09:06:53PM +0800, Zhanpeng Zhang wrote: > Do not overload the resctrl tasks file with architecture-specific > non-PID tokens. The tasks ABI remains a list of task IDs, while the new > devices file carries external requesters assigned to a resctrl group. > > Add architecture hooks for assigning and showing those external > objects, and reject group removal, reparenting, or pseudo-lock setup > while devices are still assigned. The teardown path performs a > best-effort reset to the default group. > > The devices file is an assignment interface only. It does not describe > a new resource schema or domain; resource allocation and monitoring > policy remain described by the existing schemata and info files. > > Signed-off-by: Zhanpeng Zhang <[email protected]> > --- > Documentation/filesystems/resctrl.rst | 26 ++++ > arch/Kconfig | 6 + > fs/resctrl/rdtgroup.c | 206 +++++++++++++++++++++++++- > include/linux/resctrl.h | 45 ++++++ > 4 files changed, 280 insertions(+), 3 deletions(-) [..] > diff --git a/fs/resctrl/rdtgroup.c b/fs/resctrl/rdtgroup.c > index af2cbab14497..2e424c911049 100644 > --- a/fs/resctrl/rdtgroup.c > +++ b/fs/resctrl/rdtgroup.c [..] > @@ -2067,6 +2236,16 @@ static struct rftype res_common_files[] = { > .seq_show = rdtgroup_tasks_show, > .fflags = RFTYPE_BASE, > }, > +#ifdef CONFIG_ARCH_HAS_RESCTRL_DEVICES > + { > + .name = "devices", > + .mode = 0644, > + .kf_ops = &rdtgroup_kf_single_ops, > + .write = rdtgroup_devices_write, > + .seq_show = rdtgroup_devices_show, > + .fflags = RFTYPE_BASE,
Once CONFIG_ARCH_HAS_RESCTRL_DEVICES is built in, the file shows up in every resctrl group directory, even on hardware whose IOMMU does not implement QOSID. I think it would be better to make fflags zero so rdtgroup_add_files() skips it, and enable it at runtime from resctrl_init(). Thanks, Drew
