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-rw-r--r--Documentation/admin-guide/acpi/fan_performance_states.rst62
-rw-r--r--Documentation/admin-guide/acpi/index.rst1
-rw-r--r--Documentation/admin-guide/cgroup-v2.rst29
-rw-r--r--Documentation/admin-guide/kernel-parameters.txt58
-rw-r--r--Documentation/admin-guide/pm/cpuidle.rst3
-rw-r--r--Documentation/admin-guide/pm/intel_idle.rst246
-rw-r--r--Documentation/admin-guide/pm/working-state.rst1
7 files changed, 390 insertions, 10 deletions
diff --git a/Documentation/admin-guide/acpi/fan_performance_states.rst b/Documentation/admin-guide/acpi/fan_performance_states.rst
new file mode 100644
index 000000000000..21d233ca50d8
--- /dev/null
+++ b/Documentation/admin-guide/acpi/fan_performance_states.rst
@@ -0,0 +1,62 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+===========================
+ACPI Fan Performance States
+===========================
+
+When the optional _FPS object is present under an ACPI device representing a
+fan (for example, PNP0C0B or INT3404), the ACPI fan driver creates additional
+"state*" attributes in the sysfs directory of the ACPI device in question.
+These attributes list properties of fan performance states.
+
+For more information on _FPS refer to the ACPI specification at:
+
+http://uefi.org/specifications
+
+For instance, the contents of the INT3404 ACPI device sysfs directory
+may look as follows::
+
+ $ ls -l /sys/bus/acpi/devices/INT3404:00/
+ total 0
+...
+ -r--r--r-- 1 root root 4096 Dec 13 20:38 state0
+ -r--r--r-- 1 root root 4096 Dec 13 20:38 state1
+ -r--r--r-- 1 root root 4096 Dec 13 20:38 state10
+ -r--r--r-- 1 root root 4096 Dec 13 20:38 state11
+ -r--r--r-- 1 root root 4096 Dec 13 20:38 state2
+ -r--r--r-- 1 root root 4096 Dec 13 20:38 state3
+ -r--r--r-- 1 root root 4096 Dec 13 20:38 state4
+ -r--r--r-- 1 root root 4096 Dec 13 20:38 state5
+ -r--r--r-- 1 root root 4096 Dec 13 20:38 state6
+ -r--r--r-- 1 root root 4096 Dec 13 20:38 state7
+ -r--r--r-- 1 root root 4096 Dec 13 20:38 state8
+ -r--r--r-- 1 root root 4096 Dec 13 20:38 state9
+ -r--r--r-- 1 root root 4096 Dec 13 01:00 status
+ ...
+
+where each of the "state*" files represents one performance state of the fan
+and contains a colon-separated list of 5 integer numbers (fields) with the
+following interpretation::
+
+control_percent:trip_point_index:speed_rpm:noise_level_mdb:power_mw
+
+* ``control_percent``: The percent value to be used to set the fan speed to a
+ specific level using the _FSL object (0-100).
+
+* ``trip_point_index``: The active cooling trip point number that corresponds
+ to this performance state (0-9).
+
+* ``speed_rpm``: Speed of the fan in rotations per minute.
+
+* ``noise_level_mdb``: Audible noise emitted by the fan in this state in
+ millidecibels.
+
+* ``power_mw``: Power draw of the fan in this state in milliwatts.
+
+For example::
+
+ $cat /sys/bus/acpi/devices/INT3404:00/state1
+ 25:0:3200:12500:1250
+
+When a given field is not populated or its value provided by the platform
+firmware is invalid, the "not-defined" string is shown instead of the value.
diff --git a/Documentation/admin-guide/acpi/index.rst b/Documentation/admin-guide/acpi/index.rst
index 4d13eeea1eca..71277689ad97 100644
--- a/Documentation/admin-guide/acpi/index.rst
+++ b/Documentation/admin-guide/acpi/index.rst
@@ -12,3 +12,4 @@ the Linux ACPI support.
dsdt-override
ssdt-overlays
cppc_sysfs
+ fan_performance_states
diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index 0636bcb60b5a..3f801461f0f3 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -61,6 +61,8 @@ v1 is available under Documentation/admin-guide/cgroup-v1/.
5-6. Device
5-7. RDMA
5-7-1. RDMA Interface Files
+ 5-8. HugeTLB
+ 5.8-1. HugeTLB Interface Files
5-8. Misc
5-8-1. perf_event
5-N. Non-normative information
@@ -2056,6 +2058,33 @@ RDMA Interface Files
mlx4_0 hca_handle=1 hca_object=20
ocrdma1 hca_handle=1 hca_object=23
+HugeTLB
+-------
+
+The HugeTLB controller allows to limit the HugeTLB usage per control group and
+enforces the controller limit during page fault.
+
+HugeTLB Interface Files
+~~~~~~~~~~~~~~~~~~~~~~~
+
+ hugetlb.<hugepagesize>.current
+ Show current usage for "hugepagesize" hugetlb. It exists for all
+ the cgroup except root.
+
+ hugetlb.<hugepagesize>.max
+ Set/show the hard limit of "hugepagesize" hugetlb usage.
+ The default value is "max". It exists for all the cgroup except root.
+
+ hugetlb.<hugepagesize>.events
+ A read-only flat-keyed file which exists on non-root cgroups.
+
+ max
+ The number of allocation failure due to HugeTLB limit
+
+ hugetlb.<hugepagesize>.events.local
+ Similar to hugetlb.<hugepagesize>.events but the fields in the file
+ are local to the cgroup i.e. not hierarchical. The file modified event
+ generated on this file reflects only the local events.
Misc
----
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index ade4e6ec23e0..ec92120a7952 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -511,7 +511,7 @@
1 -- check protection requested by application.
Default value is set via a kernel config option.
Value can be changed at runtime via
- /selinux/checkreqprot.
+ /sys/fs/selinux/checkreqprot.
cio_ignore= [S390]
See Documentation/s390/common_io.rst for details.
@@ -1165,10 +1165,10 @@
efi= [EFI]
Format: { "old_map", "nochunk", "noruntime", "debug",
- "nosoftreserve" }
+ "nosoftreserve", "disable_early_pci_dma",
+ "no_disable_early_pci_dma" }
old_map [X86-64]: switch to the old ioremap-based EFI
- runtime services mapping. 32-bit still uses this one by
- default.
+ runtime services mapping. [Needs CONFIG_X86_UV=y]
nochunk: disable reading files in "chunks" in the EFI
boot stub, as chunking can cause problems with some
firmware implementations.
@@ -1180,6 +1180,10 @@
claim. Specify efi=nosoftreserve to disable this
reservation and treat the memory by its base type
(i.e. EFI_CONVENTIONAL_MEMORY / "System RAM").
+ disable_early_pci_dma: Disable the busmaster bit on all
+ PCI bridges while in the EFI boot stub
+ no_disable_early_pci_dma: Leave the busmaster bit set
+ on all PCI bridges while in the EFI boot stub
efi_no_storage_paranoia [EFI; X86]
Using this parameter you can use more than 50% of
@@ -1245,7 +1249,8 @@
0 -- permissive (log only, no denials).
1 -- enforcing (deny and log).
Default value is 0.
- Value can be changed at runtime via /selinux/enforce.
+ Value can be changed at runtime via
+ /sys/fs/selinux/enforce.
erst_disable [ACPI]
Disable Error Record Serialization Table (ERST)
@@ -1933,9 +1938,31 @@
<cpu number> begins at 0 and the maximum value is
"number of CPUs in system - 1".
- The format of <cpu-list> is described above.
-
+ managed_irq
+
+ Isolate from being targeted by managed interrupts
+ which have an interrupt mask containing isolated
+ CPUs. The affinity of managed interrupts is
+ handled by the kernel and cannot be changed via
+ the /proc/irq/* interfaces.
+
+ This isolation is best effort and only effective
+ if the automatically assigned interrupt mask of a
+ device queue contains isolated and housekeeping
+ CPUs. If housekeeping CPUs are online then such
+ interrupts are directed to the housekeeping CPU
+ so that IO submitted on the housekeeping CPU
+ cannot disturb the isolated CPU.
+
+ If a queue's affinity mask contains only isolated
+ CPUs then this parameter has no effect on the
+ interrupt routing decision, though interrupts are
+ only delivered when tasks running on those
+ isolated CPUs submit IO. IO submitted on
+ housekeeping CPUs has no influence on those
+ queues.
+ The format of <cpu-list> is described above.
iucv= [HW,NET]
@@ -3978,6 +4005,19 @@
test until boot completes in order to avoid
interference.
+ rcuperf.kfree_rcu_test= [KNL]
+ Set to measure performance of kfree_rcu() flooding.
+
+ rcuperf.kfree_nthreads= [KNL]
+ The number of threads running loops of kfree_rcu().
+
+ rcuperf.kfree_alloc_num= [KNL]
+ Number of allocations and frees done in an iteration.
+
+ rcuperf.kfree_loops= [KNL]
+ Number of loops doing rcuperf.kfree_alloc_num number
+ of allocations and frees.
+
rcuperf.nreaders= [KNL]
Set number of RCU readers. The value -1 selects
N, where N is the number of CPUs. A value
@@ -4348,9 +4388,7 @@
See security/selinux/Kconfig help text.
0 -- disable.
1 -- enable.
- Default value is set via kernel config option.
- If enabled at boot time, /selinux/disable can be used
- later to disable prior to initial policy load.
+ Default value is 1.
apparmor= [APPARMOR] Disable or enable AppArmor at boot time
Format: { "0" | "1" }
diff --git a/Documentation/admin-guide/pm/cpuidle.rst b/Documentation/admin-guide/pm/cpuidle.rst
index e70b365dbc60..311cd7cc2b75 100644
--- a/Documentation/admin-guide/pm/cpuidle.rst
+++ b/Documentation/admin-guide/pm/cpuidle.rst
@@ -506,6 +506,9 @@ object corresponding to it, as follows:
``disable``
Whether or not this idle state is disabled.
+``default_status``
+ The default status of this state, "enabled" or "disabled".
+
``latency``
Exit latency of the idle state in microseconds.
diff --git a/Documentation/admin-guide/pm/intel_idle.rst b/Documentation/admin-guide/pm/intel_idle.rst
new file mode 100644
index 000000000000..afbf778035f8
--- /dev/null
+++ b/Documentation/admin-guide/pm/intel_idle.rst
@@ -0,0 +1,246 @@
+.. SPDX-License-Identifier: GPL-2.0
+.. include:: <isonum.txt>
+
+==============================================
+``intel_idle`` CPU Idle Time Management Driver
+==============================================
+
+:Copyright: |copy| 2020 Intel Corporation
+
+:Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
+
+
+General Information
+===================
+
+``intel_idle`` is a part of the
+:doc:`CPU idle time management subsystem <cpuidle>` in the Linux kernel
+(``CPUIdle``). It is the default CPU idle time management driver for the
+Nehalem and later generations of Intel processors, but the level of support for
+a particular processor model in it depends on whether or not it recognizes that
+processor model and may also depend on information coming from the platform
+firmware. [To understand ``intel_idle`` it is necessary to know how ``CPUIdle``
+works in general, so this is the time to get familiar with :doc:`cpuidle` if you
+have not done that yet.]
+
+``intel_idle`` uses the ``MWAIT`` instruction to inform the processor that the
+logical CPU executing it is idle and so it may be possible to put some of the
+processor's functional blocks into low-power states. That instruction takes two
+arguments (passed in the ``EAX`` and ``ECX`` registers of the target CPU), the
+first of which, referred to as a *hint*, can be used by the processor to
+determine what can be done (for details refer to Intel Software Developer’s
+Manual [1]_). Accordingly, ``intel_idle`` refuses to work with processors in
+which the support for the ``MWAIT`` instruction has been disabled (for example,
+via the platform firmware configuration menu) or which do not support that
+instruction at all.
+
+``intel_idle`` is not modular, so it cannot be unloaded, which means that the
+only way to pass early-configuration-time parameters to it is via the kernel
+command line.
+
+
+.. _intel-idle-enumeration-of-states:
+
+Enumeration of Idle States
+==========================
+
+Each ``MWAIT`` hint value is interpreted by the processor as a license to
+reconfigure itself in a certain way in order to save energy. The processor
+configurations (with reduced power draw) resulting from that are referred to
+as C-states (in the ACPI terminology) or idle states. The list of meaningful
+``MWAIT`` hint values and idle states (i.e. low-power configurations of the
+processor) corresponding to them depends on the processor model and it may also
+depend on the configuration of the platform.
+
+In order to create a list of available idle states required by the ``CPUIdle``
+subsystem (see :ref:`idle-states-representation` in :doc:`cpuidle`),
+``intel_idle`` can use two sources of information: static tables of idle states
+for different processor models included in the driver itself and the ACPI tables
+of the system. The former are always used if the processor model at hand is
+recognized by ``intel_idle`` and the latter are used if that is required for
+the given processor model (which is the case for all server processor models
+recognized by ``intel_idle``) or if the processor model is not recognized.
+
+If the ACPI tables are going to be used for building the list of available idle
+states, ``intel_idle`` first looks for a ``_CST`` object under one of the ACPI
+objects corresponding to the CPUs in the system (refer to the ACPI specification
+[2]_ for the description of ``_CST`` and its output package). Because the
+``CPUIdle`` subsystem expects that the list of idle states supplied by the
+driver will be suitable for all of the CPUs handled by it and ``intel_idle`` is
+registered as the ``CPUIdle`` driver for all of the CPUs in the system, the
+driver looks for the first ``_CST`` object returning at least one valid idle
+state description and such that all of the idle states included in its return
+package are of the FFH (Functional Fixed Hardware) type, which means that the
+``MWAIT`` instruction is expected to be used to tell the processor that it can
+enter one of them. The return package of that ``_CST`` is then assumed to be
+applicable to all of the other CPUs in the system and the idle state
+descriptions extracted from it are stored in a preliminary list of idle states
+coming from the ACPI tables. [This step is skipped if ``intel_idle`` is
+configured to ignore the ACPI tables; see `below <intel-idle-parameters_>`_.]
+
+Next, the first (index 0) entry in the list of available idle states is
+initialized to represent a "polling idle state" (a pseudo-idle state in which
+the target CPU continuously fetches and executes instructions), and the
+subsequent (real) idle state entries are populated as follows.
+
+If the processor model at hand is recognized by ``intel_idle``, there is a
+(static) table of idle state descriptions for it in the driver. In that case,
+the "internal" table is the primary source of information on idle states and the
+information from it is copied to the final list of available idle states. If
+using the ACPI tables for the enumeration of idle states is not required
+(depending on the processor model), all of the listed idle state are enabled by
+default (so all of them will be taken into consideration by ``CPUIdle``
+governors during CPU idle state selection). Otherwise, some of the listed idle
+states may not be enabled by default if there are no matching entries in the
+preliminary list of idle states coming from the ACPI tables. In that case user
+space still can enable them later (on a per-CPU basis) with the help of
+the ``disable`` idle state attribute in ``sysfs`` (see
+:ref:`idle-states-representation` in :doc:`cpuidle`). This basically means that
+the idle states "known" to the driver may not be enabled by default if they have
+not been exposed by the platform firmware (through the ACPI tables).
+
+If the given processor model is not recognized by ``intel_idle``, but it
+supports ``MWAIT``, the preliminary list of idle states coming from the ACPI
+tables is used for building the final list that will be supplied to the
+``CPUIdle`` core during driver registration. For each idle state in that list,
+the description, ``MWAIT`` hint and exit latency are copied to the corresponding
+entry in the final list of idle states. The name of the idle state represented
+by it (to be returned by the ``name`` idle state attribute in ``sysfs``) is
+"CX_ACPI", where X is the index of that idle state in the final list (note that
+the minimum value of X is 1, because 0 is reserved for the "polling" state), and
+its target residency is based on the exit latency value. Specifically, for
+C1-type idle states the exit latency value is also used as the target residency
+(for compatibility with the majority of the "internal" tables of idle states for
+various processor models recognized by ``intel_idle``) and for the other idle
+state types (C2 and C3) the target residency value is 3 times the exit latency
+(again, that is because it reflects the target residency to exit latency ratio
+in the majority of cases for the processor models recognized by ``intel_idle``).
+All of the idle states in the final list are enabled by default in this case.
+
+
+.. _intel-idle-initialization:
+
+Initialization
+==============
+
+The initialization of ``intel_idle`` starts with checking if the kernel command
+line options forbid the use of the ``MWAIT`` instruction. If that is the case,
+an error code is returned right away.
+
+The next step is to check whether or not the processor model is known to the
+driver, which determines the idle states enumeration method (see
+`above <intel-idle-enumeration-of-states_>`_), and whether or not the processor
+supports ``MWAIT`` (the initialization fails if that is not the case). Then,
+the ``MWAIT`` support in the processor is enumerated through ``CPUID`` and the
+driver initialization fails if the level of support is not as expected (for
+example, if the total number of ``MWAIT`` substates returned is 0).
+
+Next, if the driver is not configured to ignore the ACPI tables (see
+`below <intel-idle-parameters_>`_), the idle states information provided by the
+platform firmware is extracted from them.
+
+Then, ``CPUIdle`` device objects are allocated for all CPUs and the list of
+available idle states is created as explained
+`above <intel-idle-enumeration-of-states_>`_.
+
+Finally, ``intel_idle`` is registered with the help of cpuidle_register_driver()
+as the ``CPUIdle`` driver for all CPUs in the system and a CPU online callback
+for configuring individual CPUs is registered via cpuhp_setup_state(), which
+(among other things) causes the callback routine to be invoked for all of the
+CPUs present in the system at that time (each CPU executes its own instance of
+the callback routine). That routine registers a ``CPUIdle`` device for the CPU
+running it (which enables the ``CPUIdle`` subsystem to operate that CPU) and
+optionally performs some CPU-specific initialization actions that may be
+required for the given processor model.
+
+
+.. _intel-idle-parameters:
+
+Kernel Command Line Options and Module Parameters
+=================================================
+
+The *x86* architecture support code recognizes three kernel command line
+options related to CPU idle time management: ``idle=poll``, ``idle=halt``,
+and ``idle=nomwait``. If any of them is present in the kernel command line, the
+``MWAIT`` instruction is not allowed to be used, so the initialization of
+``intel_idle`` will fail.
+
+Apart from that there are two module parameters recognized by ``intel_idle``
+itself that can be set via the kernel command line (they cannot be updated via
+sysfs, so that is the only way to change their values).
+
+The ``max_cstate`` parameter value is the maximum idle state index in the list
+of idle states supplied to the ``CPUIdle`` core during the registration of the
+driver. It is also the maximum number of regular (non-polling) idle states that
+can be used by ``intel_idle``, so the enumeration of idle states is terminated
+after finding that number of usable idle states (the other idle states that
+potentially might have been used if ``max_cstate`` had been greater are not
+taken into consideration at all). Setting ``max_cstate`` can prevent
+``intel_idle`` from exposing idle states that are regarded as "too deep" for
+some reason to the ``CPUIdle`` core, but it does so by making them effectively
+invisible until the system is shut down and started again which may not always
+be desirable. In practice, it is only really necessary to do that if the idle
+states in question cannot be enabled during system startup, because in the
+working state of the system the CPU power management quality of service (PM
+QoS) feature can be used to prevent ``CPUIdle`` from touching those idle states
+even if they have been enumerated (see :ref:`cpu-pm-qos` in :doc:`cpuidle`).
+Setting ``max_cstate`` to 0 causes the ``intel_idle`` initialization to fail.
+
+The ``noacpi`` module parameter (which is recognized by ``intel_idle`` if the
+kernel has been configured with ACPI support), can be set to make the driver
+ignore the system's ACPI tables entirely (it is unset by default).
+
+
+.. _intel-idle-core-and-package-idle-states:
+
+Core and Package Levels of Idle States
+======================================
+
+Typically, in a processor supporting the ``MWAIT`` instruction there are (at
+least) two levels of idle states (or C-states). One level, referred to as
+"core C-states", covers individual cores in the processor, whereas the other
+level, referred to as "package C-states", covers the entire processor package
+and it may also involve other components of the system (GPUs, memory
+controllers, I/O hubs etc.).
+
+Some of the ``MWAIT`` hint values allow the processor to use core C-states only
+(most importantly, that is the case for the ``MWAIT`` hint value corresponding
+to the ``C1`` idle state), but the majority of them give it a license to put
+the target core (i.e. the core containing the logical CPU executing ``MWAIT``
+with the given hint value) into a specific core C-state and then (if possible)
+to enter a specific package C-state at the deeper level. For example, the
+``MWAIT`` hint value representing the ``C3`` idle state allows the processor to
+put the target core into the low-power state referred to as "core ``C3``" (or
+``CC3``), which happens if all of the logical CPUs (SMT siblings) in that core
+have executed ``MWAIT`` with the ``C3`` hint value (or with a hint value
+representing a deeper idle state), and in addition to that (in the majority of
+cases) it gives the processor a license to put the entire package (possibly
+including some non-CPU components such as a GPU or a memory controller) into the
+low-power state referred to as "package ``C3``" (or ``PC3``), which happens if
+all of the cores have gone into the ``CC3`` state and (possibly) some additional
+conditions are satisfied (for instance, if the GPU is covered by ``PC3``, it may
+be required to be in a certain GPU-specific low-power state for ``PC3`` to be
+reachable).
+
+As a rule, there is no simple way to make the processor use core C-states only
+if the conditions for entering the corresponding package C-states are met, so
+the logical CPU executing ``MWAIT`` with a hint value that is not core-level
+only (like for ``C1``) must always assume that this may cause the processor to
+enter a package C-state. [That is why the exit latency and target residency
+values corresponding to the majority of ``MWAIT`` hint values in the "internal"
+tables of idle states in ``intel_idle`` reflect the properties of package
+C-states.] If using package C-states is not desirable at all, either
+:ref:`PM QoS <cpu-pm-qos>` or the ``max_cstate`` module parameter of
+``intel_idle`` described `above <intel-idle-parameters_>`_ must be used to
+restrict the range of permissible idle states to the ones with core-level only
+``MWAIT`` hint values (like ``C1``).
+
+
+References
+==========
+
+.. [1] *Intel® 64 and IA-32 Architectures Software Developer’s Manual Volume 2B*,
+ https://www.intel.com/content/www/us/en/architecture-and-technology/64-ia-32-architectures-software-developer-vol-2b-manual.html
+
+.. [2] *Advanced Configuration and Power Interface (ACPI) Specification*,
+ https://uefi.org/specifications
diff --git a/Documentation/admin-guide/pm/working-state.rst b/Documentation/admin-guide/pm/working-state.rst
index fc298eb1234b..88f717e59a42 100644
--- a/Documentation/admin-guide/pm/working-state.rst
+++ b/Documentation/admin-guide/pm/working-state.rst
@@ -8,6 +8,7 @@ Working-State Power Management
:maxdepth: 2
cpuidle
+ intel_idle
cpufreq
intel_pstate
intel_epb