When a resource group is used for Cache Pseudo-Locking then the region of
cache ends up being orphaned with no class of service referring to it. The
resctrl files intended to manage how the classes of services are utilized
thus become irrelevant.
The fact that a resctrl file is not relevant can be communicated to the
user by setting all of its permissions to zero. That is, its read, write,
and execute permissions are unset for all users.
Introduce two utilities, rdtgroup_kn_mode_restrict() and
rdtgroup_kn_mode_restore(), that can be used to restrict and restore the
permissions of a file or directory belonging to a resource group.
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: fenghua.yu@intel.com
Cc: tony.luck@intel.com
Cc: vikas.shivappa@linux.intel.com
Cc: gavin.hindman@intel.com
Cc: jithu.joseph@intel.com
Cc: dave.hansen@intel.com
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/7afdbf5551b2f93cd45d61fbf5e01d87331f529a.1529706536.git.reinette.chatre@intel.com
By default, if the opener has CAP_DAC_OVERRIDE, a kernfs file can be opened
regardless of RW permissions. Writing to a kernfs file will thus succeed
even if permissions are 0000.
It's required to restrict the actions that can be performed on a resource
group from userspace based on the mode of the resource group. This
restriction will be done through a modification of the file
permissions. That is, for example, if a resource group is locked then the
user cannot add tasks to the resource group.
For this restriction through file permissions to work it has to be ensured
that the permissions are always respected. To do so the resctrl filesystem
is created with the KERNFS_ROOT_EXTRA_OPEN_PERM_CHECK flag that will result
in open(2) failing with -EACCESS regardless of CAP_DAC_OVERRIDE if the
permission does not have the respective read or write access.
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: fenghua.yu@intel.com
Cc: tony.luck@intel.com
Cc: vikas.shivappa@linux.intel.com
Cc: gavin.hindman@intel.com
Cc: jithu.joseph@intel.com
Cc: dave.hansen@intel.com
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/26f4fc25f110bfc07c2d2c8b2c4ee904922fedf7.1529706536.git.reinette.chatre@intel.com
With cache regions now explicitly marked as "shareable" or "exclusive"
we would like to communicate to the user how portions of the cache
are used.
Introduce "bit_usage" that indicates for each resource
how portions of the cache are configured to be used.
To assist the user to distinguish whether the sharing is from software or
hardware we add the following annotation:
0 - currently unused
X - currently available for sharing and used by software and hardware
H - currently used by hardware only but available for software use
S - currently used and shareable by software only
E - currently used exclusively by one resource group
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: fenghua.yu@intel.com
Cc: tony.luck@intel.com
Cc: vikas.shivappa@linux.intel.com
Cc: gavin.hindman@intel.com
Cc: jithu.joseph@intel.com
Cc: dave.hansen@intel.com
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/105d44c40e582c2b7e2dccf0ae247e5e61137d4b.1529706536.git.reinette.chatre@intel.com
Currently when a new resource group is created its allocations would be
those that belonged to the resource group to which its closid belonged
previously.
That is, we can encounter a case like:
mkdir newgroup
cat newgroup/schemata
L2:0=ff;1=ff
echo 'L2:0=0xf0;1=0xf0' > newgroup/schemata
cat newgroup/schemata
L2:0=0xf0;1=0xf0
rmdir newgroup
mkdir newnewgroup
cat newnewgroup/schemata
L2:0=0xf0;1=0xf0
When the new group is created it would be reasonable to expect its
allocations to be initialized with all regions that it can possibly use.
At this time these regions would be all that are shareable by other
resource groups as well as regions that are not currently used.
If the available cache region is found to be non-contiguous the
available region is adjusted to enforce validity.
When a new resource group is created the hardware is initialized with
these new default allocations.
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: fenghua.yu@intel.com
Cc: tony.luck@intel.com
Cc: vikas.shivappa@linux.intel.com
Cc: gavin.hindman@intel.com
Cc: jithu.joseph@intel.com
Cc: dave.hansen@intel.com
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/c468ed79340b63024111978e01430bb9589d85c0.1529706536.git.reinette.chatre@intel.com
When MBA software controller is enabled, a per domain storage is required
for user specified bandwidth in "MBps" and the "percentage" values which
are programmed into the IA32_MBA_THRTL_MSR. Add support for these data
structures and initialization.
The MBA percentage values have a default max value of 100 but however the
max value in MBps is not available from the hardware so it's set to
U32_MAX.
This simply says that the control group can use all bandwidth by default
but does not say what is the actual max bandwidth available. The actual
bandwidth that is available may depend on lot of factors like QPI link,
number of memory channels, memory channel frequency, its width and memory
speed, how many channels are configured and also if memory interleaving is
enabled. So there is no way to determine the maximum at runtime reliably.
Signed-off-by: Vikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: Thomas 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
Cc: ak@linux.intel.com
Cc: hpa@zytor.com
Link: https://lkml.kernel.org/r/1524263781-14267-4-git-send-email-vikas.shivappa@linux.intel.com
If no monitoring feature is detected because all monitoring features are
disabled during boot time or there is no monitoring feature in hardware,
creating rdtgroup sub-directory by "mkdir" command reports error:
mkdir: cannot create directory ‘/sys/fs/resctrl/p1’: No such file or directory
But the sub-directory actually is generated and content is correct:
cpus cpus_list schemata tasks
The error is because rdtgroup_mkdir_ctrl_mon() returns non zero value after
the sub-directory is created and the returned value is reported as an error
to user.
Clear the returned value to report to user that the sub-directory is
actually created successfully.
Signed-off-by: Wang Hui <john.wanghui@huawei.com>
Signed-off-by: Zhang Yanfei <yanfei.zhang@huawei.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi V Shankar <ravi.v.shankar@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vikas <vikas.shivappa@intel.com>
Cc: Xiaochen Shen <xiaochen.shen@intel.com>
Link: http://lkml.kernel.org/r/1519356363-133085-1-git-send-email-fenghua.yu@intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Bit 0 in MSR IA32_L2_QOS_CFG (0xc82) is L2 CDP enable bit. By default,
the bit is zero, i.e. L2 CAT is enabled, and L2 CDP is disabled. When
the resctrl mount parameter "cdpl2" is given, the bit is set to 1 and L2
CDP is enabled.
In L2 CDP mode, the L2 CAT mask MSRs are re-mapped into interleaved pairs
of mask MSRs for code (referenced by an odd CLOSID) and data (referenced by
an even CLOSID).
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com>
Cc: "Tony Luck" <tony.luck@intel.com>
Cc: Vikas" <vikas.shivappa@intel.com>
Cc: Sai Praneeth" <sai.praneeth.prakhya@intel.com>
Cc: Reinette" <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/1513810644-78015-6-git-send-email-fenghua.yu@intel.com
The assignment to the 'files' variable is immediately overwritten
in the following line. Remove the older assignment, which was meant
specifially for creating control groups files.
Fixes: c7d9aac613 ("x86/intel_rdt/cqm: Add mkdir support for RDT monitoring")
Reported-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Jithu Joseph <jithu.joseph@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Fenghua Yu <fenghua.yu@intel.com>
Cc: tony.luck@intel.com
Cc: vikas.shivappa@intel.com
Link: https://lkml.kernel.org/r/1507157337-18118-1-git-send-email-jithu.joseph@intel.com
Mostly this is about running out of RMIDs or CLOSIDs. Other
errors are various internal errors.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Vikas Shivappa <vikas.shivappa@intel.com>
Cc: Boris Petkov <bp@suse.de>
Cc: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/027cf1ffb3a3695f2d54525813a1d644887353cf.1506382469.git.tony.luck@intel.com
Can't add a cpu to a monitor group unless it belongs to parent
group. Can't delete cpus from the default group.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Vikas Shivappa <vikas.shivappa@intel.com>
Cc: Boris Petkov <bp@suse.de>
Cc: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/757a869a25e9fc1b7a2e9bc43e1159455c1964a0.1506382469.git.tony.luck@intel.com
About the only tricky case is trying to move a task into a monitor
group that is a subdirectory of a different control group. But cover
the simple cases too.
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Vikas Shivappa <vikas.shivappa@intel.com>
Cc: Boris Petkov <bp@suse.de>
Cc: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/f1841cce6a242aed37cb926dee8942727331bf78.1506382469.git.tony.luck@intel.com
Commands are given to the resctrl file system by making/removing
directories, or by writing to files. When something goes wrong
the user is generally left wondering why they got:
bash: echo: write error: Invalid argument
Add a new file "last_cmd_status" to the "info" directory that
will give the user some better clues on what went wrong.
Provide functions to clear and update last_cmd_status which
check that we hold the rdtgroup_mutex.
[ tglx: Made last_cmd_status static and folded back the hunk from patch 3
which replaces the open coded access to last_cmd_status with the
accessor function ]
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Vikas Shivappa <vikas.shivappa@intel.com>
Cc: Boris Petkov <bp@suse.de>
Cc: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/edc4e0e9741eee89bba569f0021b1b2662fd9508.1506382469.git.tony.luck@intel.com
The use of the ternary operator is redundant as ret can never be
non-zero at that point. Instead, just return nbytes.
Detected by CoverityScan, CID#1452658 ("Logically dead code")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Vikas Shivappa <vikas.shivappa@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: kernel-janitors@vger.kernel.org
Link: http://lkml.kernel.org/r/20170808092859.13021-1-colin.king@canonical.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: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Thomas 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
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: Vikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: Thomas 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: Vikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: Thomas 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
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: Tony Luck <tony.luck@linux.intel.com>
Signed-off-by: Vikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: Thomas 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
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: Tony Luck <tony.luck@intel.com>
Signed-off-by: Vikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: Thomas 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
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: Tony luck <tony.luck@intel.com>
Signed-off-by: Vikas Shivappa <vikas.shivappa@linux.intel.com>
Signed-off-by: Thomas 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
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: Vikas 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.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
