Hi Drew, On 8/12/26 10:19 AM, Drew Fustini wrote: > 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
Good point. The build-time architecture capability is not sufficient to expose the file. I will look for an appropriate runtime mechanism to control whether the file is exposed. Thank you for the careful review. I really appreciate it. Thanks, Zhanpeng
