diff options
Diffstat (limited to 'Documentation/admin-guide')
| -rw-r--r-- | Documentation/admin-guide/README.rst | 32 | ||||
| -rw-r--r-- | Documentation/admin-guide/cgroup-v2.rst | 16 | ||||
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 49 | ||||
| -rw-r--r-- | Documentation/admin-guide/mm/pagemap.rst | 9 | ||||
| -rw-r--r-- | Documentation/admin-guide/pm/cpuidle.rst | 104 |
5 files changed, 169 insertions, 41 deletions
diff --git a/Documentation/admin-guide/README.rst b/Documentation/admin-guide/README.rst index 0797eec76be1..47e577264198 100644 --- a/Documentation/admin-guide/README.rst +++ b/Documentation/admin-guide/README.rst @@ -1,9 +1,9 @@ .. _readme: -Linux kernel release 4.x <http://kernel.org/> +Linux kernel release 5.x <http://kernel.org/> ============================================= -These are the release notes for Linux version 4. Read them carefully, +These are the release notes for Linux version 5. Read them carefully, as they tell you what this is all about, explain how to install the kernel, and what to do if something goes wrong. @@ -63,7 +63,7 @@ Installing the kernel source directory where you have permissions (e.g. your home directory) and unpack it:: - xz -cd linux-4.X.tar.xz | tar xvf - + xz -cd linux-5.x.tar.xz | tar xvf - Replace "X" with the version number of the latest kernel. @@ -72,26 +72,26 @@ Installing the kernel source files. They should match the library, and not get messed up by whatever the kernel-du-jour happens to be. - - You can also upgrade between 4.x releases by patching. Patches are + - You can also upgrade between 5.x releases by patching. Patches are distributed in the xz format. To install by patching, get all the newer patch files, enter the top level directory of the kernel source - (linux-4.X) and execute:: + (linux-5.x) and execute:: - xz -cd ../patch-4.x.xz | patch -p1 + xz -cd ../patch-5.x.xz | patch -p1 - Replace "x" for all versions bigger than the version "X" of your current + Replace "x" for all versions bigger than the version "x" of your current source tree, **in_order**, and you should be ok. You may want to remove the backup files (some-file-name~ or some-file-name.orig), and make sure that there are no failed patches (some-file-name# or some-file-name.rej). If there are, either you or I have made a mistake. - Unlike patches for the 4.x kernels, patches for the 4.x.y kernels + Unlike patches for the 5.x kernels, patches for the 5.x.y kernels (also known as the -stable kernels) are not incremental but instead apply - directly to the base 4.x kernel. For example, if your base kernel is 4.0 - and you want to apply the 4.0.3 patch, you must not first apply the 4.0.1 - and 4.0.2 patches. Similarly, if you are running kernel version 4.0.2 and - want to jump to 4.0.3, you must first reverse the 4.0.2 patch (that is, - patch -R) **before** applying the 4.0.3 patch. You can read more on this in + directly to the base 5.x kernel. For example, if your base kernel is 5.0 + and you want to apply the 5.0.3 patch, you must not first apply the 5.0.1 + and 5.0.2 patches. Similarly, if you are running kernel version 5.0.2 and + want to jump to 5.0.3, you must first reverse the 5.0.2 patch (that is, + patch -R) **before** applying the 5.0.3 patch. You can read more on this in :ref:`Documentation/process/applying-patches.rst <applying_patches>`. Alternatively, the script patch-kernel can be used to automate this @@ -114,7 +114,7 @@ Installing the kernel source Software requirements --------------------- - Compiling and running the 4.x kernels requires up-to-date + Compiling and running the 5.x kernels requires up-to-date versions of various software packages. Consult :ref:`Documentation/process/changes.rst <changes>` for the minimum version numbers required and how to get updates for these packages. Beware that using @@ -132,12 +132,12 @@ Build directory for the kernel place for the output files (including .config). Example:: - kernel source code: /usr/src/linux-4.X + kernel source code: /usr/src/linux-5.x build directory: /home/name/build/kernel To configure and build the kernel, use:: - cd /usr/src/linux-4.X + cd /usr/src/linux-5.x make O=/home/name/build/kernel menuconfig make O=/home/name/build/kernel sudo make O=/home/name/build/kernel modules_install install diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index 7bf3f129c68b..53d3288c328b 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -1189,6 +1189,10 @@ PAGE_SIZE multiple when read back. Amount of cached filesystem data that was modified and is currently being written back to disk + anon_thp + Amount of memory used in anonymous mappings backed by + transparent hugepages + inactive_anon, active_anon, inactive_file, active_file, unevictable Amount of memory, swap-backed and filesystem-backed, on the internal memory management lists used by the @@ -1248,6 +1252,18 @@ PAGE_SIZE multiple when read back. Amount of reclaimed lazyfree pages + thp_fault_alloc + + Number of transparent hugepages which were allocated to satisfy + a page fault, including COW faults. This counter is not present + when CONFIG_TRANSPARENT_HUGEPAGE is not set. + + thp_collapse_alloc + + Number of transparent hugepages which were allocated to allow + collapsing an existing range of pages. This counter is not + present when CONFIG_TRANSPARENT_HUGEPAGE is not set. + memory.swap.current A read-only single value file which exists on non-root cgroups. diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 2d28ef850781..a422560fbc15 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -461,6 +461,11 @@ possible to determine what the correct size should be. This option provides an override for these situations. + carrier_timeout= + [NET] Specifies amount of time (in seconds) that + the kernel should wait for a network carrier. By default + it waits 120 seconds. + ca_keys= [KEYS] This parameter identifies a specific key(s) on the system trusted keyring to be used for certificate trust validation. @@ -910,6 +915,10 @@ The filter can be disabled or changed to another driver later using sysfs. + driver_async_probe= [KNL] + List of driver names to be probed asynchronously. + Format: <driver_name1>,<driver_name2>... + drm.edid_firmware=[<connector>:]<file>[,[<connector>:]<file>] Broken monitors, graphic adapters, KVMs and EDIDless panels may send no or incorrect EDID data sets. @@ -1073,9 +1082,15 @@ specified address. The serial port must already be setup and configured. Options are not yet supported. + efifb,[options] + Start an early, unaccelerated console on the EFI + memory mapped framebuffer (if available). On cache + coherent non-x86 systems that use system memory for + the framebuffer, pass the 'ram' option so that it is + mapped with the correct attributes. + earlyprintk= [X86,SH,ARM,M68k,S390] earlyprintk=vga - earlyprintk=efi earlyprintk=sclp earlyprintk=xen earlyprintk=serial[,ttySn[,baudrate]] @@ -3653,19 +3668,6 @@ latencies, which will choose a value aligned with the appropriate hardware boundaries. - rcutree.jiffies_till_sched_qs= [KNL] - Set required age in jiffies for a - given grace period before RCU starts - soliciting quiescent-state help from - rcu_note_context_switch(). If not specified, the - kernel will calculate a value based on the most - recent settings of rcutree.jiffies_till_first_fqs - and rcutree.jiffies_till_next_fqs. - This calculated value may be viewed in - rcutree.jiffies_to_sched_qs. Any attempt to - set rcutree.jiffies_to_sched_qs will be - cheerfully overwritten. - rcutree.jiffies_till_first_fqs= [KNL] Set delay from grace-period initialization to first attempt to force quiescent states. @@ -3677,6 +3679,20 @@ quiescent states. Units are jiffies, minimum value is one, and maximum value is HZ. + rcutree.jiffies_till_sched_qs= [KNL] + Set required age in jiffies for a + given grace period before RCU starts + soliciting quiescent-state help from + rcu_note_context_switch() and cond_resched(). + If not specified, the kernel will calculate + a value based on the most recent settings + of rcutree.jiffies_till_first_fqs + and rcutree.jiffies_till_next_fqs. + This calculated value may be viewed in + rcutree.jiffies_to_sched_qs. Any attempt to set + rcutree.jiffies_to_sched_qs will be cheerfully + overwritten. + rcutree.kthread_prio= [KNL,BOOT] Set the SCHED_FIFO priority of the RCU per-CPU kthreads (rcuc/N). This value is also used for @@ -3720,6 +3736,11 @@ This wake_up() will be accompanied by a WARN_ONCE() splat and an ftrace_dump(). + rcutree.sysrq_rcu= [KNL] + Commandeer a sysrq key to dump out Tree RCU's + rcu_node tree with an eye towards determining + why a new grace period has not yet started. + rcuperf.gp_async= [KNL] Measure performance of asynchronous grace-period primitives such as call_rcu(). diff --git a/Documentation/admin-guide/mm/pagemap.rst b/Documentation/admin-guide/mm/pagemap.rst index 3f7bade2c231..340a5aee9b80 100644 --- a/Documentation/admin-guide/mm/pagemap.rst +++ b/Documentation/admin-guide/mm/pagemap.rst @@ -75,9 +75,10 @@ number of times a page is mapped. 20. NOPAGE 21. KSM 22. THP - 23. BALLOON + 23. OFFLINE 24. ZERO_PAGE 25. IDLE + 26. PGTABLE * ``/proc/kpagecgroup``. This file contains a 64-bit inode number of the memory cgroup each page is charged to, indexed by PFN. Only available when @@ -118,8 +119,8 @@ Short descriptions to the page flags identical memory pages dynamically shared between one or more processes 22 - THP contiguous pages which construct transparent hugepages -23 - BALLOON - balloon compaction page +23 - OFFLINE + page is logically offline 24 - ZERO_PAGE zero page for pfn_zero or huge_zero page 25 - IDLE @@ -128,6 +129,8 @@ Short descriptions to the page flags Note that this flag may be stale in case the page was accessed via a PTE. To make sure the flag is up-to-date one has to read ``/sys/kernel/mm/page_idle/bitmap`` first. +26 - PGTABLE + page is in use as a page table IO related page flags --------------------- diff --git a/Documentation/admin-guide/pm/cpuidle.rst b/Documentation/admin-guide/pm/cpuidle.rst index 106379e2619f..9c58b35a81cb 100644 --- a/Documentation/admin-guide/pm/cpuidle.rst +++ b/Documentation/admin-guide/pm/cpuidle.rst @@ -155,14 +155,14 @@ governor uses that information depends on what algorithm is implemented by it and that is the primary reason for having more than one governor in the ``CPUIdle`` subsystem. -There are two ``CPUIdle`` governors available, ``menu`` and ``ladder``. Which -of them is used depends on the configuration of the kernel and in particular on -whether or not the scheduler tick can be `stopped by the idle -loop <idle-cpus-and-tick_>`_. It is possible to change the governor at run time -if the ``cpuidle_sysfs_switch`` command line parameter has been passed to the -kernel, but that is not safe in general, so it should not be done on production -systems (that may change in the future, though). The name of the ``CPUIdle`` -governor currently used by the kernel can be read from the +There are three ``CPUIdle`` governors available, ``menu``, `TEO <teo-gov_>`_ +and ``ladder``. Which of them is used by default depends on the configuration +of the kernel and in particular on whether or not the scheduler tick can be +`stopped by the idle loop <idle-cpus-and-tick_>`_. It is possible to change the +governor at run time if the ``cpuidle_sysfs_switch`` command line parameter has +been passed to the kernel, but that is not safe in general, so it should not be +done on production systems (that may change in the future, though). The name of +the ``CPUIdle`` governor currently used by the kernel can be read from the :file:`current_governor_ro` (or :file:`current_governor` if ``cpuidle_sysfs_switch`` is present in the kernel command line) file under :file:`/sys/devices/system/cpu/cpuidle/` in ``sysfs``. @@ -256,6 +256,8 @@ the ``menu`` governor by default and if it is not tickless, the default ``CPUIdle`` governor on it will be ``ladder``. +.. _menu-gov: + The ``menu`` Governor ===================== @@ -333,6 +335,92 @@ that time, the governor may need to select a shallower state with a suitable target residency. +.. _teo-gov: + +The Timer Events Oriented (TEO) Governor +======================================== + +The timer events oriented (TEO) governor is an alternative ``CPUIdle`` governor +for tickless systems. It follows the same basic strategy as the ``menu`` `one +<menu-gov_>`_: it always tries to find the deepest idle state suitable for the +given conditions. However, it applies a different approach to that problem. + +First, it does not use sleep length correction factors, but instead it attempts +to correlate the observed idle duration values with the available idle states +and use that information to pick up the idle state that is most likely to +"match" the upcoming CPU idle interval. Second, it does not take the tasks +that were running on the given CPU in the past and are waiting on some I/O +operations to complete now at all (there is no guarantee that they will run on +the same CPU when they become runnable again) and the pattern detection code in +it avoids taking timer wakeups into account. It also only uses idle duration +values less than the current time till the closest timer (with the scheduler +tick excluded) for that purpose. + +Like in the ``menu`` governor `case <menu-gov_>`_, the first step is to obtain +the *sleep length*, which is the time until the closest timer event with the +assumption that the scheduler tick will be stopped (that also is the upper bound +on the time until the next CPU wakeup). That value is then used to preselect an +idle state on the basis of three metrics maintained for each idle state provided +by the ``CPUIdle`` driver: ``hits``, ``misses`` and ``early_hits``. + +The ``hits`` and ``misses`` metrics measure the likelihood that a given idle +state will "match" the observed (post-wakeup) idle duration if it "matches" the +sleep length. They both are subject to decay (after a CPU wakeup) every time +the target residency of the idle state corresponding to them is less than or +equal to the sleep length and the target residency of the next idle state is +greater than the sleep length (that is, when the idle state corresponding to +them "matches" the sleep length). The ``hits`` metric is increased if the +former condition is satisfied and the target residency of the given idle state +is less than or equal to the observed idle duration and the target residency of +the next idle state is greater than the observed idle duration at the same time +(that is, it is increased when the given idle state "matches" both the sleep +length and the observed idle duration). In turn, the ``misses`` metric is +increased when the given idle state "matches" the sleep length only and the +observed idle duration is too short for its target residency. + +The ``early_hits`` metric measures the likelihood that a given idle state will +"match" the observed (post-wakeup) idle duration if it does not "match" the +sleep length. It is subject to decay on every CPU wakeup and it is increased +when the idle state corresponding to it "matches" the observed (post-wakeup) +idle duration and the target residency of the next idle state is less than or +equal to the sleep length (i.e. the idle state "matching" the sleep length is +deeper than the given one). + +The governor walks the list of idle states provided by the ``CPUIdle`` driver +and finds the last (deepest) one with the target residency less than or equal +to the sleep length. Then, the ``hits`` and ``misses`` metrics of that idle +state are compared with each other and it is preselected if the ``hits`` one is +greater (which means that that idle state is likely to "match" the observed idle +duration after CPU wakeup). If the ``misses`` one is greater, the governor +preselects the shallower idle state with the maximum ``early_hits`` metric +(or if there are multiple shallower idle states with equal ``early_hits`` +metric which also is the maximum, the shallowest of them will be preselected). +[If there is a wakeup latency constraint coming from the `PM QoS framework +<cpu-pm-qos_>`_ which is hit before reaching the deepest idle state with the +target residency within the sleep length, the deepest idle state with the exit +latency within the constraint is preselected without consulting the ``hits``, +``misses`` and ``early_hits`` metrics.] + +Next, the governor takes several idle duration values observed most recently +into consideration and if at least a half of them are greater than or equal to +the target residency of the preselected idle state, that idle state becomes the +final candidate to ask for. Otherwise, the average of the most recent idle +duration values below the target residency of the preselected idle state is +computed and the governor walks the idle states shallower than the preselected +one and finds the deepest of them with the target residency within that average. +That idle state is then taken as the final candidate to ask for. + +Still, at this point the governor may need to refine the idle state selection if +it has not decided to `stop the scheduler tick <idle-cpus-and-tick_>`_. That +generally happens if the target residency of the idle state selected so far is +less than the tick period and the tick has not been stopped already (in a +previous iteration of the idle loop). Then, like in the ``menu`` governor +`case <menu-gov_>`_, the sleep length used in the previous computations may not +reflect the real time until the closest timer event and if it really is greater +than that time, a shallower state with a suitable target residency may need to +be selected. + + .. _idle-states-representation: Representation of Idle States |