Currently we have pqr_state and rdt_default_state which store the cached
CLOSID/RMIDs and the user configured cpu default values respectively. We
touch both of these during context switch. Put all of them in one
structure so that we can spare a cache line.
Reported-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NVikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: peterz@infradead.org
Cc: eranian@google.com
Cc: sai.praneeth.prakhya@intel.com
Cc: ak@linux.intel.com
Cc: davidcc@google.com
Link: http://lkml.kernel.org/r/1502304395-7166-3-git-send-email-vikas.shivappa@linux.intel.com

CPUID.(EAX=0x10, ECX=res#):EBX[31:0] reports a bit mask for a resource.
Each set bit within the length of the CBM indicates the corresponding
unit of the resource allocation may be used by other entities in the
platform (e.g. an integrated graphics engine or hardware units outside
the processor core and have direct access to the resource). Each
cleared bit within the length of the CBM indicates the corresponding
allocation unit can be configured to implement a priority-based
allocation scheme without interference with other hardware agents in
the system. Bits outside the length of the CBM are reserved.

More details on the bit mask are described in x86 Software Developer's
Manual.

The bitmask is shown in "info" directory for each resource. It's
up to user to decide how to use the bitmask within a CBM in a partition
to share or isolate a resource with other executing units.
Suggested-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NFenghua Yu <fenghua.yu@intel.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: ravi.v.shankar@intel.com
Cc: peterz@infradead.org
Cc: eranian@google.com
Cc: ak@linux.intel.com
Cc: davidcc@google.com
Cc: vikas.shivappa@linux.intel.com
Link: http://lkml.kernel.org/r/20170725223904.12996-1-tony.luck@intel.com

Set up a delayed work queue for each domain that will read all
the MBM counters of active RMIDs once per second to make sure
that they don't wrap around between reads from users.

[Tony: Added the initializations for the work structure and completed
the patch]
Signed-off-by: NTony Luck <tony.luck@intel.com>
Signed-off-by: NVikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: ravi.v.shankar@intel.com
Cc: fenghua.yu@intel.com
Cc: peterz@infradead.org
Cc: eranian@google.com
Cc: vikas.shivappa@intel.com
Cc: ak@linux.intel.com
Cc: davidcc@google.com
Cc: reinette.chatre@intel.com
Link: http://lkml.kernel.org/r/1501017287-28083-29-git-send-email-vikas.shivappa@linux.intel.com

MBM counters are monotonically increasing counts representing the total
memory bytes at a particular time. In order to calculate total_bytes for
an rdtgroup, we store the value of the counter when we create an
rdtgroup or when a new domain comes online.

When the total_bytes(all memory controller bytes) or local_bytes(local
memory controller bytes) file in "mon_data" is read it shows the
total bytes for that rdtgroup since its creation. User can snapshot this
at different time intervals to obtain bytes/second.
Signed-off-by: NVikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: peterz@infradead.org
Cc: eranian@google.com
Cc: vikas.shivappa@intel.com
Cc: ak@linux.intel.com
Cc: davidcc@google.com
Cc: reinette.chatre@intel.com
Link: http://lkml.kernel.org/r/1501017287-28083-28-git-send-email-vikas.shivappa@linux.intel.com

Resource groups have a per domain directory under "mon_data". Add or
remove these directories as and when domains come online and go offline.
Also update the per cpu rmids and cache upon onlining and offlining
cpus.
Signed-off-by: NVikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: peterz@infradead.org
Cc: eranian@google.com
Cc: vikas.shivappa@intel.com
Cc: ak@linux.intel.com
Cc: davidcc@google.com
Cc: reinette.chatre@intel.com
Link: http://lkml.kernel.org/r/1501017287-28083-26-git-send-email-vikas.shivappa@linux.intel.com

Add monitoring support during mount and unmount. Since root directory is
a "ctrl_mon" directory which can control and monitor resources create
the "mon_groups" directory which can hold monitor groups and a
"mon_data" directory which would hold all monitoring data like the rest
of resource groups.

The mount succeeds if either of monitoring or control/allocation is
enabled. If only monitoring is enabled user can still create monitor
groups under the "/sys/fs/resctrl/mon_groups/" and any mkdir under root
would fail. If only control/allocation is enabled all of the monitoring
related directories/files would not exist and resctrl would work in
legacy mode.
Signed-off-by: NVikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: peterz@infradead.org
Cc: eranian@google.com
Cc: vikas.shivappa@intel.com
Cc: ak@linux.intel.com
Cc: davidcc@google.com
Cc: reinette.chatre@intel.com
Link: http://lkml.kernel.org/r/1501017287-28083-23-git-send-email-vikas.shivappa@linux.intel.com

Resource groups (ctrl_mon and monitor groups) are represented by
directories in resctrl fs. Add support to remove the directories.

When a ctrl_mon directory is removed all the cpus and tasks are assigned
back to the root rdtgroup. When a monitor group is removed the cpus and
tasks are returned to the parent control group.
Signed-off-by: NVikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: peterz@infradead.org
Cc: eranian@google.com
Cc: vikas.shivappa@intel.com
Cc: ak@linux.intel.com
Cc: davidcc@google.com
Cc: reinette.chatre@intel.com
Link: http://lkml.kernel.org/r/1501017287-28083-22-git-send-email-vikas.shivappa@linux.intel.com

Re-factor the code to separate the ctrl group removal from the rmdir to
prepare to add RDT monitoring group removal.
Signed-off-by: NVikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: peterz@infradead.org
Cc: eranian@google.com
Cc: vikas.shivappa@intel.com
Cc: ak@linux.intel.com
Cc: davidcc@google.com
Cc: reinette.chatre@intel.com
Link: http://lkml.kernel.org/r/1501017287-28083-21-git-send-email-vikas.shivappa@linux.intel.com

Add a mon_data directory for the root rdtgroup and all other rdtgroups.
The directory holds all of the monitored data for all domains and events
of all resources being monitored.

The mon_data itself has a list of directories in the format
mon_<domain_name>_<domain_id>. Each of these subdirectories contain one
file per event in the mode "0444". Reading the file displays a snapshot
of the monitored data for the event the file represents.

For ex, on a 2 socket Broadwell with llc_occupancy being
monitored the mon_data contents look as below:

$ ls /sys/fs/resctrl/p1/mon_data/
mon_L3_00
mon_L3_01

Each domain directory has one file per event:
$ ls /sys/fs/resctrl/p1/mon_data/mon_L3_00/
llc_occupancy

To read current llc_occupancy of ctrl_mon group p1
$ cat /sys/fs/resctrl/p1/mon_data/mon_L3_00/llc_occupancy
33789096

[This patch idea is based on Tony's sample patches to organise data in a
per domain directory and have one file per event (and use the fp->priv to
store mon data bits)]
Signed-off-by: NVikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: peterz@infradead.org
Cc: eranian@google.com
Cc: vikas.shivappa@intel.com
Cc: ak@linux.intel.com
Cc: davidcc@google.com
Cc: reinette.chatre@intel.com
Link: http://lkml.kernel.org/r/1501017287-28083-20-git-send-email-vikas.shivappa@linux.intel.com

The cpus file is extended to support resource monitoring. This is used
to over-ride the RMID of the default group when running on specific
CPUs. It works similar to the resource control. The "cpus" and
"cpus_list" file is present in default group, ctrl_mon groups and
monitor groups.

Each "cpus" file or cpu_list file reads a cpumask or list showing which
CPUs belong to the resource group. By default all online cpus belong to
the default root group. A CPU can be present in one "ctrl_mon" and one
"monitor" group simultaneously. They can be added to a resource group by
writing the CPU to the file. When a CPU is added to a ctrl_mon group it
is automatically removed from the previous ctrl_mon group. A CPU can be
added to a monitor group only if it is present in the parent ctrl_mon
group and when a CPU is added to a monitor group, it is automatically
removed from the previous monitor group. When CPUs go offline, they are
automatically removed from the ctrl_mon and monitor groups.
Signed-off-by: NVikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: peterz@infradead.org
Cc: eranian@google.com
Cc: vikas.shivappa@intel.com
Cc: ak@linux.intel.com
Cc: davidcc@google.com
Cc: reinette.chatre@intel.com
Link: http://lkml.kernel.org/r/1501017287-28083-18-git-send-email-vikas.shivappa@linux.intel.com

Separate the ctrl cpus file handling from the generic cpus file handling
and convert the per cpu closid from u32 to a struct which will be used
later to add rmid to the same struct. Also cleanup some name space.
Signed-off-by: NVikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: peterz@infradead.org
Cc: eranian@google.com
Cc: vikas.shivappa@intel.com
Cc: ak@linux.intel.com
Cc: davidcc@google.com
Cc: reinette.chatre@intel.com
Link: http://lkml.kernel.org/r/1501017287-28083-17-git-send-email-vikas.shivappa@linux.intel.com

The root directory, ctrl_mon and monitor groups are populated
with a read/write file named "tasks". When read, it shows all the task
IDs assigned to the resource group.

Tasks can be added to groups by writing the PID to the file. A task can
be present in one "ctrl_mon" group "and" one "monitor" group. IOW a
PID_x can be seen in a ctrl_mon group and a monitor group at the same
time. When a task is added to a ctrl_mon group, it is automatically
removed from the previous ctrl_mon group where it belonged. Similarly if
a task is moved to a monitor group it is removed from the previous
monitor group . Also since the monitor groups can only have subset of
tasks of parent ctrl_mon group, a task can be moved to a monitor group
only if its already present in the parent ctrl_mon group.

Task membership is indicated by a new field in the task_struct "u32
rmid" which holds the RMID for the task. RMID=0 is reserved for the
default root group where the tasks belong to at mount.

[tony: zero the rmid if rdtgroup was deleted when task was being moved]
Signed-off-by: NTony Luck <tony.luck@linux.intel.com>
Signed-off-by: NVikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: peterz@infradead.org
Cc: eranian@google.com
Cc: vikas.shivappa@intel.com
Cc: ak@linux.intel.com
Cc: davidcc@google.com
Cc: reinette.chatre@intel.com
Link: http://lkml.kernel.org/r/1501017287-28083-16-git-send-email-vikas.shivappa@linux.intel.com

OS associates a CLOSid(Class of service id) to a task by writing the
high 32 bits of per CPU IA32_PQR_ASSOC MSR when a task is scheduled in.
CPUID.(EAX=10H, ECX=1):EDX[15:0] enumerates the max CLOSID supported and
it is zero indexed. Hence change the type to u32 from int.
Signed-off-by: NVikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: peterz@infradead.org
Cc: eranian@google.com
Cc: vikas.shivappa@intel.com
Cc: ak@linux.intel.com
Cc: davidcc@google.com
Cc: reinette.chatre@intel.com
Link: http://lkml.kernel.org/r/1501017287-28083-15-git-send-email-vikas.shivappa@linux.intel.com

Resource control groups can be created using mkdir in resctrl
fs(rdtgroup). In order to extend the resctrl interface to support
monitoring the control groups, extend the current mkdir to support
resource monitoring also.

This allows the rdtgroup created under the root directory to be able to
both control and monitor resources (ctrl_mon group). The ctrl_mon groups
are associated with one CLOSID like the legacy rdtgroups and one
RMID(Resource monitoring ID) as well. Hardware uses RMID to track the
resource usage. Once either of the CLOSID or RMID are exhausted, the
mkdir fails with -ENOSPC. If there are RMIDs in limbo list but not free
an -EBUSY is returned. User can also monitor a subset of the ctrl_mon
rdtgroup's tasks/cpus using the monitor groups. The monitor groups are
created using mkdir under the "mon_groups" directory in every ctrl_mon
group.

[Merged Tony's code: Removed a lot of common mkdir code, a fix to handling
of the list of the child rdtgroups and some cleanups in list
traversal. Also the changes to have similar alloc and free for CLOS/RMID
and return -EBUSY when RMIDs are in limbo and not free]
Signed-off-by: NTony Luck <tony.luck@intel.com>
Signed-off-by: NVikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: ravi.v.shankar@intel.com
Cc: fenghua.yu@intel.com
Cc: peterz@infradead.org
Cc: eranian@google.com
Cc: vikas.shivappa@intel.com
Cc: ak@linux.intel.com
Cc: davidcc@google.com
Cc: reinette.chatre@intel.com
Link: http://lkml.kernel.org/r/1501017287-28083-14-git-send-email-vikas.shivappa@linux.intel.com

Separate the ctrl mkdir code from the rest in order to prepare for
adding support for RDT monitoring mkdir support as well.
Signed-off-by: NVikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: peterz@infradead.org
Cc: eranian@google.com
Cc: vikas.shivappa@intel.com
Cc: ak@linux.intel.com
Cc: davidcc@google.com
Cc: reinette.chatre@intel.com
Link: http://lkml.kernel.org/r/1501017287-28083-13-git-send-email-vikas.shivappa@linux.intel.com

Add info directory files specific to RDT monitoring.

 num_rmids:
    The number of RMIDs which are valid for the resource.

 mon_features:
    Lists the monitoring events if monitoring is enabled for the
    resource.

 max_threshold_occupancy:
    This is specific to llc_occupancy monitoring and is used to
    determine if an RMID can be reused. Provides an upper bound on the
    threshold and is shown to the user in bytes though the internal
    value will be rounded to the scaling factor supported by the h/w.
Signed-off-by: NVikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: peterz@infradead.org
Cc: eranian@google.com
Cc: vikas.shivappa@intel.com
Cc: ak@linux.intel.com
Cc: davidcc@google.com
Cc: reinette.chatre@intel.com
Link: http://lkml.kernel.org/r/1501017287-28083-12-git-send-email-vikas.shivappa@linux.intel.com

The info directory files and base files need to be different for each
resource like cache and Memory bandwidth. With in each resource, the
files would be further different for monitoring and ctrl. This leads to
a lot of different static array declarations given that we are adding
resctrl monitoring.

Simplify this to one common list of files and then declare a set of
flags to choose the files based on the resource, whether it is info or
base and if it is control type file. This is as a preparation to include
monitoring based info and base files.

No functional change.

[Vikas: Extended the flags to have few bits per category like resource,
	info/base etc]
Signed-off-by: NTony luck <tony.luck@intel.com>
Signed-off-by: NVikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: ravi.v.shankar@intel.com
Cc: fenghua.yu@intel.com
Cc: peterz@infradead.org
Cc: eranian@google.com
Cc: vikas.shivappa@intel.com
Cc: ak@linux.intel.com
Cc: davidcc@google.com
Cc: reinette.chatre@intel.com
Link: http://lkml.kernel.org/r/1501017287-28083-11-git-send-email-vikas.shivappa@linux.intel.com

Few of the data-structures have generic names although they are RDT
allocation specific. Rename them to be allocation specific to
accommodate RDT monitoring. E.g. s/enabled/alloc_enabled/

No functional change.
Signed-off-by: NVikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: peterz@infradead.org
Cc: eranian@google.com
Cc: vikas.shivappa@intel.com
Cc: ak@linux.intel.com
Cc: davidcc@google.com
Cc: reinette.chatre@intel.com
Link: http://lkml.kernel.org/r/1501017287-28083-7-git-send-email-vikas.shivappa@linux.intel.com

Sparse reports that both of these can be static.

Make it so.
Signed-off-by: NReinette Chatre <reinette.chatre@intel.com>
Signed-off-by: NVikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: peterz@infradead.org
Cc: eranian@google.com
Cc: vikas.shivappa@intel.com
Cc: ak@linux.intel.com
Cc: davidcc@google.com
Link: http://lkml.kernel.org/r/1501017287-28083-6-git-send-email-vikas.shivappa@linux.intel.com

Because the "perf cqm" and resctrl code were separately added and
indivdually configurable, there seem to be separate context switch code
and also things on global .h which are not really needed.

Move only the scheduling specific code and definitions to
<asm/intel_rdt_sched.h> and the put all the other declarations to a
local intel_rdt.h.

h/t to Reinette Chatre for pointing out that we should separate the
public interfaces used by other parts of the kernel from private
objects shared between the various files comprising RDT.

No functional change.
Signed-off-by: NVikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: peterz@infradead.org
Cc: eranian@google.com
Cc: vikas.shivappa@intel.com
Cc: ak@linux.intel.com
Cc: davidcc@google.com
Cc: reinette.chatre@intel.com
Link: http://lkml.kernel.org/r/1501017287-28083-5-git-send-email-vikas.shivappa@linux.intel.com

If mount fails, the kn_info directory is not freed causing memory leak.

Add the missing error handling path.

Fixes: 4e978d06 ("x86/intel_rdt: Add "info" files to resctrl file system")
Signed-off-by: NVikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: peterz@infradead.org
Cc: vikas.shivappa@intel.com
Cc: andi.kleen@intel.com
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1498503368-20173-3-git-send-email-vikas.shivappa@linux.intel.com

The files in the info directory for MBA are as follows:

 num_closids
 	The maximum number of CLOSids available for MBA

 min_bandwidth
 	The minimum memory bandwidth percentage value

 bandwidth_gran
 	The granularity of the bandwidth control in percent for the
	particular CPU SKU. Intermediate values entered are rounded off
	to the previous control step available. Available bandwidth
	control steps are minimum_bandwidth + N * bandwidth_gran.

 delay_linear
 	When set, the OS writes a linear percentage based value to the
	control MSRs ranging from minimum_bandwidth to 100 percent.

	This value is informational and has no influence on the values
	written to the schemata files. The values written to the
	schemata are always bandwidth percentage that is requested.
Signed-off-by: NVikas Shivappa <vikas.shivappa@linux.intel.com>
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: vikas.shivappa@intel.com
Link: http://lkml.kernel.org/r/1491611637-20417-7-git-send-email-vikas.shivappa@linux.intel.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Cache allocation and memory bandwidth allocation require different
information files in the resctrl/info directory, but the current
implementation does not allow to have files per resource.

Add the necessary fields to the resource struct and assign the files
dynamically depending on the resource type.
Signed-off-by: NVikas Shivappa <vikas.shivappa@linux.intel.com>
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: vikas.shivappa@intel.com
Link: http://lkml.kernel.org/r/1491611637-20417-6-git-send-email-vikas.shivappa@linux.intel.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Memory bandwidth allocation requires different information than cache
allocation.

To avoid a lump of data in struct rdt_resource, move all cache related
information into a seperate structure and add that to struct rdt_resource.

Sanitize the data types while at it.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: vikas.shivappa@intel.com

Lot of data structures and functions are named after cache specific
resources(named after cbm, cache etc). In many cases other non cache
resources may need to share the same data structures/functions.

Generalize such naming to prepare to add more resources like memory
bandwidth.
Signed-off-by: NVikas Shivappa <vikas.shivappa@linux.intel.com>
Cc: ravi.v.shankar@intel.com
Cc: tony.luck@intel.com
Cc: fenghua.yu@intel.com
Cc: vikas.shivappa@intel.com
Link: http://lkml.kernel.org/r/1491611637-20417-3-git-send-email-vikas.shivappa@linux.intel.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

The resource control filesystem provides only a bitmask based cpus file for
assigning CPUs to a resource group. That's cumbersome with large cpumasks
and non-intuitive when modifying the file from the command line.

Range based cpu lists are commonly used along with bitmask based cpu files
in various subsystems throughout the kernel.

Add 'cpus_list' file which is CPU range based.

  # cd /sys/fs/resctrl/
  # echo 1-10 > krava/cpus_list
  # cat krava/cpus_list
  1-10
  # cat krava/cpus
  0007fe
  # cat cpus
  fffff9
  # cat cpus_list
  0,3-23

[ tglx: Massaged changelog and replaced "bitmask lists" by "CPU ranges" ]
Signed-off-by: NJiri Olsa <jolsa@kernel.org>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Shaohua Li <shli@fb.com>
Link: http://lkml.kernel.org/r/20170410145232.GF25354@kravaSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

The rdtgroup_kn_unlock waits for the last user to release and put its
node. But it's calling kernfs_put on the node which calls the
rdtgroup_kn_unlock, which might not be the group's directory node, but
another group's file node.

This race could be easily reproduced by running 2 instances
of following script:

  mount -t resctrl resctrl /sys/fs/resctrl/
  pushd /sys/fs/resctrl/
  mkdir krava
  echo "krava" > krava/schemata
  rmdir krava
  popd
  umount  /sys/fs/resctrl

It triggers the slub debug error message with following command
line config: slub_debug=,kernfs_node_cache.

Call kernfs_put on the group's node to fix it.

Fixes: 60cf5e10 ("x86/intel_rdt: Add mkdir to resctrl file system")
Signed-off-by: NJiri Olsa <jolsa@kernel.org>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Shaohua Li <shli@fb.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/1489501253-20248-1-git-send-email-jolsa@kernel.orgSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

We are going to split <linux/sched/task.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/task.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

We are going to split <linux/sched/signal.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.

Create a trivial placeholder <linux/sched/signal.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.

Include the new header in the files that are going to need it.
Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NIngo Molnar <mingo@kernel.org>

Signed-off-by: NMasanari Iida <standby24x7@gmail.com>
Cc: fenghua.yu@intel.com
Link: http://lkml.kernel.org/r/20170227130703.26968-1-standby24x7@gmail.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Implement show_options() callback for intel resource control filesystem
to expose the active mount options in /proc/
Signed-off-by: NShaohua Li <shli@fb.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Link: http://lkml.kernel.org/r/7dce7c1886ac9289442d254ea18322c92bd968da.1480717072.git.shli@fb.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

intel_rdt_sched_in() must be called with preemption disabled because the
function accesses percpu variables (pqr_state and closid).

If a task moves itself via move_myself() preemption is enabled, which
violates the calling convention and can result in incorrect closid
selection when the task gets preempted or migrated.

Add the required protection and a comment about the calling convention.
Signed-off-by: NFenghua Yu <fenghua.yu@intel.com>
Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com>
Cc: "Tony Luck" <tony.luck@intel.com>
Cc: "Marcelo Tosatti" <mtosatti@redhat.com>
Cc: "Sai Prakhya" <sai.praneeth.prakhya@intel.com>
Cc: "Vikas Shivappa" <vikas.shivappa@linux.intel.com>
Cc: "H. Peter Anvin" <h.peter.anvin@intel.com>
Link: http://lkml.kernel.org/r/1480625714-54246-1-git-send-email-fenghua.yu@intel.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

When removing a sub directory/rdtgroup by rmdir or umount, closid in a
task in the sub directory is set to default rdtgroup's closid which is 0.
If the task is running on a CPU, the PQR_ASSOC MSR is only updated
when the task runs through a context switch. Up to the context switch,
the task runs with the wrong closid.

Make the change immediately effective by invoking a smp function call on
all CPUs which are running moved task. If one of the affected tasks was
moved or scheduled out before the function call is executed on the CPU the
only damage is the extra interruption of the CPU.

[ tglx: Reworked it to avoid blindly interrupting all CPUs and extra loops ]
Signed-off-by: NFenghua Yu <fenghua.yu@intel.com>
Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com>
Cc: "Tony Luck" <tony.luck@intel.com>
Cc: "Sai Prakhya" <sai.praneeth.prakhya@intel.com>
Cc: "Vikas Shivappa" <vikas.shivappa@linux.intel.com>
Cc: "H. Peter Anvin" <h.peter.anvin@intel.com>
Link: http://lkml.kernel.org/r/1479511084-59727-2-git-send-email-fenghua.yu@intel.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

There was a cut & paste error when adding code to update the per-cpu
closid when changing the bitmask of CPUs to an rdt group.

The update erronously assigns the closid of the default group to the CPUs
which are moved to a group instead of assigning the closid of their new
group. Use the proper closid.

Fixes: f4107702 ("x86/intel_rdt: Update percpu closid immeditately on CPUs affected by change")
Signed-off-by: NFenghua Yu <fenghua.yu@intel.com>
Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com>
Cc: "Tony Luck" <tony.luck@intel.com>
Cc: "Sai Prakhya" <sai.praneeth.prakhya@intel.com>
Cc: "Vikas Shivappa" <vikas.shivappa@linux.intel.com>
Cc: "H. Peter Anvin" <h.peter.anvin@intel.com>
Link: http://lkml.kernel.org/r/1479511084-59727-1-git-send-email-fenghua.yu@intel.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

If CPUs are moved to or removed from a rdtgroup, the percpu closid storage
is updated. If tasks running on an affected CPU use the percpu closid then
the PQR_ASSOC MSR is only updated when the task runs through a context
switch. Up to the context switch the CPUs operate on the wrong closid. This
state is potentially unbound.
    
Make the change immediately effective by invoking a smp function call on
the affected CPUs which stores the new closid in the perpu storage and
calls the rdt_sched_in() function which updates the MSR, if the current
task uses the percpu closid.

[ tglx: Made it work and massaged changelog once more ]
Signed-off-by: NFenghua Yu <fenghua.yu@intel.com>
Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com>
Cc: "Tony Luck" <tony.luck@intel.com>
Cc: "Sai Prakhya" <sai.praneeth.prakhya@intel.com>
Cc: "Vikas Shivappa" <vikas.shivappa@linux.intel.com>
Cc: "Ingo Molnar" <mingo@elte.hu>
Cc: "H. Peter Anvin" <h.peter.anvin@intel.com>
Link: http://lkml.kernel.org/r/1478912558-55514-3-git-send-email-fenghua.yu@intel.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

All CPUs in a rdtgroup are given back to the default rdtgroup before the
rdtgroup is removed during umount. After umount, the default rdtgroup
contains all online CPUs, but the per cpu closids are not cleared. As a
result the stale closid value will be used immediately after the next
mount.

Move all cpus to the default group and update the percpu closid storage.

[ tglx: Massaged changelong ]
Signed-off-by: NFenghua Yu <fenghua.yu@intel.com>
Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com>
Cc: "Tony Luck" <tony.luck@intel.com>
Cc: "Sai Prakhya" <sai.praneeth.prakhya@intel.com>
Cc: "Vikas Shivappa" <vikas.shivappa@linux.intel.com>
Cc: "Ingo Molnar" <mingo@elte.hu>
Cc: "H. Peter Anvin" <h.peter.anvin@intel.com>
Link: http://lkml.kernel.org/r/1478912558-55514-2-git-send-email-fenghua.yu@intel.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

The cpu online/offline callbacks of intel_rdt lock rdtgroup_mutex nested
inside of cpu hotplug lock. rdtgroup_cpus_write() does it in reverse order.

Remove the get/put_online_cpus() calls from rdtgroup_cpus_write(). This is
safe against cpu hotplug as the resource group cpumasks are protected by
rdtgroup_mutex.

Found by review, but should have been found if authors would have bothered
to test cpu hotplug with lockdep enabled.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Shaohua Li <shli@fb.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Tony Luck <tony.luck@intel.com>

The info directory and the per-resource subdirectories of the info
directory have no reference to a struct rdtgroup in kn->priv. An attempt to
remove one of those directories results in a NULL pointer dereference.

Protect the directories from removal and return -EPERM instead of -ENOENT.

[ tglx: Massaged changelog ]
Signed-off-by: NFenghua Yu <fenghua.yu@intel.com>
Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com>
Cc: "Tony Luck" <tony.luck@intel.com>
Cc: "Sai Prakhya" <sai.praneeth.prakhya@intel.com>
Cc: "Vikas Shivappa" <vikas.shivappa@linux.intel.com>
Cc: "Ingo Molnar" <mingo@elte.hu>
Cc: "H. Peter Anvin" <h.peter.anvin@intel.com>
Link: http://lkml.kernel.org/r/1478912558-55514-1-git-send-email-fenghua.yu@intel.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

The minimum number of bits set for a cache mask is checked by the kernel
when writing a mask, but there is no way for the user to retrieve this
information.

Add a new file 'min_cbm_bits' to the info directory and export the
information to user space.

[ tglx: Massaged changelog ]
Signed-off-by: NShaohua Li <shli@fb.com>
Cc: fenghua.yu@intel.com
Cc: tony.luck@intel.com
Link: http://lkml.kernel.org/r/e69b1ffa206d0353eea58101e1bf9b677d9732f7.1478207143.git.shli@fb.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

gcc complains:
"warning: ‘dentry’ may be used uninitialized in this function"

The error exit path in rdt_mount(), which deals with a failure in
rdtgroup_create_info_dir(), does not set the error code in dentry and
returns the uninitialized dentry value.

Add the missing error propagation.

[tglx: Massaged changelog ]
Fixes: 4e978d06 ("x86/intel_rdt: Add "info" files to resctrl file system")
Signed-off-by: NShaohua Li <shli@fb.com>
Cc: fenghua.yu@intel.com
Cc: tony.luck@intel.com
Link: http://lkml.kernel.org/r/a56a556f6768dc12cadbf97f49e000189056f90e.1478207143.git.shli@fb.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>