diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2024-11-20 09:16:45 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2024-11-20 09:16:45 -0800 |
| commit | c3cda60e83c803a3b3b832f371c776e57194b2f0 (patch) | |
| tree | 2f5e1b95dfbae06cc447ef91f0b2066469c98313 /Documentation/admin-guide | |
| parent | bf9aa14fc523d2763fc9a10672a709224e8fcaf4 (diff) | |
| parent | c818d5c64c9a8cc14853d716bf7ce6674a6126d0 (diff) | |
Merge tag 'docs-6.13' of git://git.lwn.net/linux
Pull documentation updates from Jonathan Corbet:
"Another moderately busy cycle in docsland:
- Work on Chinese translations has picked up again. Happily, they are
maintaining the existing translations and not just adding new ones.
- Some maintenance of the Japanese and Italian translations as well.
- The removal of the venerable "dontdiff" file. It has long outlived
its usefulness and contained entries ("parse.*") that would
actively mask actual source change.
- The addition of enforcement information to the code-of-conduct
documentation.
Along with some build-system fixes and a lot of typo and language
fixes"
* tag 'docs-6.13' of git://git.lwn.net/linux: (52 commits)
Documentation/CoC: spell out enforcement for unacceptable behaviors
docs: fix typos and whitespace in Documentation/process/backporting.rst
docs/zh_CN: fix one sentence in llvm.rst
docs: bug-bisect: add a note about bisecting -next
docs/zh_CN: add the translation of kbuild/llvm.rst
Documentation: Fix incorrect paths/magic in magic numbers rst
Documentation/maintainer-tip: Fix typos
Documentation: Improve crash_kexec_post_notifiers description
Docs/zh_CN: Translate physical_memory.rst to Simplified Chinese
Documentation: admin: reorganize kernel-parameters intro
docs/zh_CN: update the translation of process/programming-language.rst
docs/zh_CN: update the translation of mm/page_owner.rst
docs/zh_CN: update the translation of mm/page_table_check.rst
docs/zh_CN: update the translation of mm/overcommit-accounting.rst
docs/zh_CN: update the translation of mm/admon/faq.rst
docs/zh_CN: update the translation of mm/active_mm.rst
docs/zh_CN: update the translation of mm/hmm.rst
docs: remove Documentation/dontdiff
docs/zh_CN: Add a entry in Chinese glossary
Docs/zh_CN: Fix the pfn calculation error in page_tables.rst
...
Diffstat (limited to 'Documentation/admin-guide')
| -rw-r--r-- | Documentation/admin-guide/bug-bisect.rst | 21 | ||||
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.rst | 36 | ||||
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 22 |
3 files changed, 60 insertions, 19 deletions
diff --git a/Documentation/admin-guide/bug-bisect.rst b/Documentation/admin-guide/bug-bisect.rst index 585630d14581..f4f867cabb17 100644 --- a/Documentation/admin-guide/bug-bisect.rst +++ b/Documentation/admin-guide/bug-bisect.rst @@ -108,6 +108,27 @@ a fully reliable and straight-forward way to reproduce the regression, too.* With that the process is complete. Now report the regression as described by Documentation/admin-guide/reporting-issues.rst. +Bisecting linux-next +-------------------- + +If you face a problem only happening in linux-next, bisect between the +linux-next branches 'stable' and 'master'. The following commands will start +the process for a linux-next tree you added as a remote called 'next':: + + git bisect start + git bisect good next/stable + git bisect bad next/master + +The 'stable' branch refers to the state of linux-mainline that the current +linux-next release (found in the 'master' branch) is based on -- the former +thus should be free of any problems that show up in -next, but not in Linus' +tree. + +This will bisect across a wide range of changes, some of which you might have +used in earlier linux-next releases without problems. Sadly there is no simple +way to avoid checking them: bisecting from one linux-next release to a later +one (say between 'next-20241020' and 'next-20241021') is impossible, as they +share no common history. Additional reading material --------------------------- diff --git a/Documentation/admin-guide/kernel-parameters.rst b/Documentation/admin-guide/kernel-parameters.rst index fdea7c26ef80..6247bbc9547c 100644 --- a/Documentation/admin-guide/kernel-parameters.rst +++ b/Documentation/admin-guide/kernel-parameters.rst @@ -27,6 +27,16 @@ kernel command line (/proc/cmdline) and collects module parameters when it loads a module, so the kernel command line can be used for loadable modules too. +This document may not be entirely up to date and comprehensive. The command +"modinfo -p ${modulename}" shows a current list of all parameters of a loadable +module. Loadable modules, after being loaded into the running kernel, also +reveal their parameters in /sys/module/${modulename}/parameters/. Some of these +parameters may be changed at runtime by the command +``echo -n ${value} > /sys/module/${modulename}/parameters/${parm}``. + +Special handling +---------------- + Hyphens (dashes) and underscores are equivalent in parameter names, so:: log_buf_len=1M print-fatal-signals=1 @@ -39,8 +49,8 @@ Double-quotes can be used to protect spaces in values, e.g.:: param="spaces in here" -cpu lists: ----------- +cpu lists +~~~~~~~~~ Some kernel parameters take a list of CPUs as a value, e.g. isolcpus, nohz_full, irqaffinity, rcu_nocbs. The format of this list is: @@ -82,12 +92,17 @@ so that "nohz_full=all" is the equivalent of "nohz_full=0-N". The semantics of "N" and "all" is supported on a level of bitmaps and holds for all users of bitmap_parselist(). -This document may not be entirely up to date and comprehensive. The command -"modinfo -p ${modulename}" shows a current list of all parameters of a loadable -module. Loadable modules, after being loaded into the running kernel, also -reveal their parameters in /sys/module/${modulename}/parameters/. Some of these -parameters may be changed at runtime by the command -``echo -n ${value} > /sys/module/${modulename}/parameters/${parm}``. +Metric suffixes +~~~~~~~~~~~~~~~ + +The [KMG] suffix is commonly described after a number of kernel +parameter values. 'K', 'M', 'G', 'T', 'P', and 'E' suffixes are allowed. +These letters represent the _binary_ multipliers 'Kilo', 'Mega', 'Giga', +'Tera', 'Peta', and 'Exa', equaling 2^10, 2^20, 2^30, 2^40, 2^50, and +2^60 bytes respectively. Such letter suffixes can also be entirely omitted. + +Kernel Build Options +-------------------- The parameters listed below are only valid if certain kernel build options were enabled and if respective hardware is present. This list should be kept @@ -211,10 +226,5 @@ a fixed number of characters. This limit depends on the architecture and is between 256 and 4096 characters. It is defined in the file ./include/uapi/asm-generic/setup.h as COMMAND_LINE_SIZE. -Finally, the [KMG] suffix is commonly described after a number of kernel -parameter values. These 'K', 'M', and 'G' letters represent the _binary_ -multipliers 'Kilo', 'Mega', and 'Giga', equaling 2^10, 2^20, and 2^30 -bytes respectively. Such letter suffixes can also be entirely omitted: - .. include:: kernel-parameters.txt :literal: diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 7e1315ee0507..2e66fef83468 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -921,12 +921,16 @@ the parameter has no effect. crash_kexec_post_notifiers - Run kdump after running panic-notifiers and dumping - kmsg. This only for the users who doubt kdump always - succeeds in any situation. - Note that this also increases risks of kdump failure, - because some panic notifiers can make the crashed - kernel more unstable. + Only jump to kdump kernel after running the panic + notifiers and dumping kmsg. This option increases + the risks of a kdump failure, since some panic + notifiers can make the crashed kernel more unstable. + In configurations where kdump may not be reliable, + running the panic notifiers could allow collecting + more data on dmesg, like stack traces from other CPUS + or extra data dumped by panic_print. Note that some + configurations enable this option unconditionally, + like Hyper-V, PowerPC (fadump) and AMD SEV-SNP. crashkernel=size[KMG][@offset[KMG]] [KNL,EARLY] Using kexec, Linux can switch to a 'crash kernel' @@ -6882,6 +6886,12 @@ reserve_mem=12M:4096:trace trace_instance=boot_map^traceoff^traceprintk@trace,sched,irq + Note, saving the trace buffer across reboots does require that the system + is set up to not wipe memory. For instance, CONFIG_RESET_ATTACK_MITIGATION + can force a memory reset on boot which will clear any trace that was stored. + This is just one of many ways that can clear memory. Make sure your system + keeps the content of memory across reboots before relying on this option. + See also Documentation/trace/debugging.rst |
