diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/admin-guide/cgroup-v2.rst | 20 | ||||
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 4 | ||||
| -rw-r--r-- | Documentation/arm64/memory.rst | 9 | ||||
| -rw-r--r-- | Documentation/core-api/index.rst | 1 | ||||
| -rw-r--r-- | Documentation/core-api/memory-allocation.rst | 4 | ||||
| -rw-r--r-- | Documentation/core-api/symbol-namespaces.rst (renamed from Documentation/kbuild/namespaces.rst) | 0 | ||||
| -rw-r--r-- | Documentation/dev-tools/kselftest.rst | 16 | ||||
| -rw-r--r-- | Documentation/process/coding-style.rst | 2 | ||||
| -rw-r--r-- | Documentation/process/deprecated.rst | 33 |
9 files changed, 71 insertions, 18 deletions
diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index 0fa8c0e615c2..5361ebec3361 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -615,8 +615,8 @@ on an IO device and is an example of this type. Protections ----------- -A cgroup is protected to be allocated upto the configured amount of -the resource if the usages of all its ancestors are under their +A cgroup is protected upto the configured amount of the resource +as long as the usages of all its ancestors are under their protected levels. Protections can be hard guarantees or best effort soft boundaries. Protections can also be over-committed in which case only upto the amount available to the parent is protected among @@ -1096,7 +1096,10 @@ PAGE_SIZE multiple when read back. is within its effective min boundary, the cgroup's memory won't be reclaimed under any conditions. If there is no unprotected reclaimable memory available, OOM killer - is invoked. + is invoked. Above the effective min boundary (or + effective low boundary if it is higher), pages are reclaimed + proportionally to the overage, reducing reclaim pressure for + smaller overages. Effective min boundary is limited by memory.min values of all ancestor cgroups. If there is memory.min overcommitment @@ -1118,7 +1121,10 @@ PAGE_SIZE multiple when read back. Best-effort memory protection. If the memory usage of a cgroup is within its effective low boundary, the cgroup's memory won't be reclaimed unless memory can be reclaimed - from unprotected cgroups. + from unprotected cgroups. Above the effective low boundary (or + effective min boundary if it is higher), pages are reclaimed + proportionally to the overage, reducing reclaim pressure for + smaller overages. Effective low boundary is limited by memory.low values of all ancestor cgroups. If there is memory.low overcommitment @@ -2482,8 +2488,10 @@ system performance due to overreclaim, to the point where the feature becomes self-defeating. The memory.low boundary on the other hand is a top-down allocated -reserve. A cgroup enjoys reclaim protection when it's within its low, -which makes delegation of subtrees possible. +reserve. A cgroup enjoys reclaim protection when it's within its +effective low, which makes delegation of subtrees possible. It also +enjoys having reclaim pressure proportional to its overage when +above its effective low. The original high boundary, the hard limit, is defined as a strict limit that can not budge, even if the OOM killer has to be called. diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index c7ac2f3ac99f..a84a83f8881e 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -5302,6 +5302,10 @@ the unplug protocol never -- do not unplug even if version check succeeds + xen_legacy_crash [X86,XEN] + Crash from Xen panic notifier, without executing late + panic() code such as dumping handler. + xen_nopvspin [X86,XEN] Disables the ticketlock slowpath using Xen PV optimizations. diff --git a/Documentation/arm64/memory.rst b/Documentation/arm64/memory.rst index b040909e45f8..02e02175e6f5 100644 --- a/Documentation/arm64/memory.rst +++ b/Documentation/arm64/memory.rst @@ -154,11 +154,18 @@ return virtual addresses to userspace from a 48-bit range. Software can "opt-in" to receiving VAs from a 52-bit space by specifying an mmap hint parameter that is larger than 48-bit. + For example: - maybe_high_address = mmap(~0UL, size, prot, flags,...); + +.. code-block:: c + + maybe_high_address = mmap(~0UL, size, prot, flags,...); It is also possible to build a debug kernel that returns addresses from a 52-bit space by enabling the following kernel config options: + +.. code-block:: sh + CONFIG_EXPERT=y && CONFIG_ARM64_FORCE_52BIT=y Note that this option is only intended for debugging applications diff --git a/Documentation/core-api/index.rst b/Documentation/core-api/index.rst index fa16a0538dcb..ab0eae1c153a 100644 --- a/Documentation/core-api/index.rst +++ b/Documentation/core-api/index.rst @@ -38,6 +38,7 @@ Core utilities protection-keys ../RCU/index gcc-plugins + symbol-namespaces Interfaces for kernel debugging diff --git a/Documentation/core-api/memory-allocation.rst b/Documentation/core-api/memory-allocation.rst index 7744aa3bf2e0..939e3dfc86e9 100644 --- a/Documentation/core-api/memory-allocation.rst +++ b/Documentation/core-api/memory-allocation.rst @@ -98,6 +98,10 @@ limited. The actual limit depends on the hardware and the kernel configuration, but it is a good practice to use `kmalloc` for objects smaller than page size. +The address of a chunk allocated with `kmalloc` is aligned to at least +ARCH_KMALLOC_MINALIGN bytes. For sizes which are a power of two, the +alignment is also guaranteed to be at least the respective size. + For large allocations you can use :c:func:`vmalloc` and :c:func:`vzalloc`, or directly request pages from the page allocator. The memory allocated by `vmalloc` and related functions is diff --git a/Documentation/kbuild/namespaces.rst b/Documentation/core-api/symbol-namespaces.rst index 982ed7b568ac..982ed7b568ac 100644 --- a/Documentation/kbuild/namespaces.rst +++ b/Documentation/core-api/symbol-namespaces.rst diff --git a/Documentation/dev-tools/kselftest.rst b/Documentation/dev-tools/kselftest.rst index 25604904fa6e..ecdfdc9d4b03 100644 --- a/Documentation/dev-tools/kselftest.rst +++ b/Documentation/dev-tools/kselftest.rst @@ -89,6 +89,22 @@ To build, save output files in a separate directory with KBUILD_OUTPUT :: $ export KBUILD_OUTPUT=/tmp/kselftest; make TARGETS="size timers" kselftest +Additionally you can use the "SKIP_TARGETS" variable on the make command +line to specify one or more targets to exclude from the TARGETS list. + +To run all tests but a single subsystem:: + + $ make -C tools/testing/selftests SKIP_TARGETS=ptrace run_tests + +You can specify multiple tests to skip:: + + $ make SKIP_TARGETS="size timers" kselftest + +You can also specify a restricted list of tests to run together with a +dedicated skiplist:: + + $ make TARGETS="bpf breakpoints size timers" SKIP_TARGETS=bpf kselftest + See the top-level tools/testing/selftests/Makefile for the list of all possible targets. diff --git a/Documentation/process/coding-style.rst b/Documentation/process/coding-style.rst index f4a2198187f9..ada573b7d703 100644 --- a/Documentation/process/coding-style.rst +++ b/Documentation/process/coding-style.rst @@ -56,7 +56,7 @@ instead of ``double-indenting`` the ``case`` labels. E.g.: case 'K': case 'k': mem <<= 10; - /* fall through */ + fallthrough; default: break; } diff --git a/Documentation/process/deprecated.rst b/Documentation/process/deprecated.rst index 053b24a6dd38..179f2a5625a0 100644 --- a/Documentation/process/deprecated.rst +++ b/Documentation/process/deprecated.rst @@ -122,14 +122,27 @@ memory adjacent to the stack (when built without `CONFIG_VMAP_STACK=y`) Implicit switch case fall-through --------------------------------- -The C language allows switch cases to "fall through" when -a "break" statement is missing at the end of a case. This, -however, introduces ambiguity in the code, as it's not always -clear if the missing break is intentional or a bug. As there -have been a long list of flaws `due to missing "break" statements +The C language allows switch cases to "fall-through" when a "break" statement +is missing at the end of a case. This, however, introduces ambiguity in the +code, as it's not always clear if the missing break is intentional or a bug. + +As there have been a long list of flaws `due to missing "break" statements <https://cwe.mitre.org/data/definitions/484.html>`_, we no longer allow -"implicit fall-through". In order to identify an intentional fall-through -case, we have adopted the marking used by static analyzers: a comment -saying `/* Fall through */`. Once the C++17 `__attribute__((fallthrough))` -is more widely handled by C compilers, static analyzers, and IDEs, we can -switch to using that instead. +"implicit fall-through". + +In order to identify intentional fall-through cases, we have adopted a +pseudo-keyword macro 'fallthrough' which expands to gcc's extension +__attribute__((__fallthrough__)). `Statement Attributes +<https://gcc.gnu.org/onlinedocs/gcc/Statement-Attributes.html>`_ + +When the C17/C18 [[fallthrough]] syntax is more commonly supported by +C compilers, static analyzers, and IDEs, we can switch to using that syntax +for the macro pseudo-keyword. + +All switch/case blocks must end in one of: + + break; + fallthrough; + continue; + goto <label>; + return [expression]; |
