[PATCH 0/2] x86/intel_rdt: Display CPUs associated with pseudo-locked region
From: Reinette Chatre
Date: Sun Jul 01 2018 - 01:18:04 EST
Dear Maintainers,
The cpus and cpus_list resctrl files are locked down when the resource
group enters pseudo-locksetup mode and remains locked down when the
resource group transitions to pseudo-locked mode. This was done to ensure a
resource group in pseudo-locksetup mode is and remain unused until it
transitions to pseudo-locked mode.
With this series read (but not write) access is restored to the cpus and
cpus_list files after a resource group enters pseudo-locked mode. The
information displayed is also adjusted appropriately. It is now possible
for users to view which cpus are associated with a pseudo-locked region
through the existing cpus and cpus_list resctrl files. Only the tasks file
remains locked down.
For example:
# mount -t resctrl resctrl /sys/fs/resctrl
# cd /sys/fs/resctrl
# echo 'L2:1=0xfc' > schemata
# mkdir p1
# ls -l p1/cpus* p1/tasks
-rw-r--r-- 1 root root 0 Jun 30 06:30 p1/cpus
-rw-r--r-- 1 root root 0 Jun 30 06:30 p1/cpus_list
-rw-r--r-- 1 root root 0 Jun 30 06:30 p1/tasks
# echo pseudo-locksetup > p1/mode
# ls -l p1/cpus* p1/tasks
---------- 1 root root 0 Jun 30 06:30 p1/cpus
---------- 1 root root 0 Jun 30 06:30 p1/cpus_list
---------- 1 root root 0 Jun 30 06:30 p1/tasks
# echo 'L2:1=0x3' > p1/schemata
# ls -l p1/cpus* p1/tasks
-r--r--r-- 1 root root 0 Jun 30 06:30 p1/cpus
-r--r--r-- 1 root root 0 Jun 30 06:30 p1/cpus_list
---------- 1 root root 0 Jun 30 06:30 p1/tasks
# grep . p1/*
p1/cpus:c
p1/cpus_list:2-3
p1/mode:pseudo-locked
p1/schemata:L2:1=3
p1/size:L2:1=262144
grep: p1/tasks: Permission denied
Reinette Chatre (2):
x86/intel_rdt: Support restoration of subset of permissions
x86/intel_rdt: cpu information accessible for pseudo-locked regions
Documentation/x86/intel_rdt_ui.txt | 3 +++
arch/x86/kernel/cpu/intel_rdt.h | 3 ++-
arch/x86/kernel/cpu/intel_rdt_pseudo_lock.c | 17 ++++++++++-------
arch/x86/kernel/cpu/intel_rdt_rdtgroup.c | 14 ++++++++++----
4 files changed, 25 insertions(+), 12 deletions(-)
--
2.17.0