40 Commits
Author SHA1 Message Date
Borislav Petkov (AMD)andJonathan Corbet f690e07859 Documentation/kernel-parameters: Move the kernel build options
Move the kernel build options abbreviations to the .txt file so that
they are together instead of one having to go hunt them in the .rst
file.

Tweak the formatting so that the inclusion of kernel-parameters.txt
still keeps the whole thing somewhat presentable in the html output too.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20251112114641.8230-1-bp@kernel.org>
2025-11-18 09:18:51 -07:00
Bartlomiej KubikandJonathan Corbet e56878b477 docs: kernel-parameters: typo fix and add missing SPDX-License tag
Fix documentation issues by removing a duplicated word and adding the
missing SPDX-License identifier.

Signed-off-by: Bartlomiej Kubik <kubik.bartlomiej@gmail.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250819113551.34356-1-kubik.bartlomiej@gmail.com
2025-08-21 11:55:54 -06:00
Borislav Petkov (AMD) ab0e7f2076 Documentation: Merge x86-specific boot options doc into kernel-parameters.txt
Documentation/arch/x86/x86_64/boot-options.rst is causing unnecessary
confusion by being a second place where one can put x86 boot options.
Move them into the main one.

Drop removed ones like "acpi=ht", while at it.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Sohil Mehta <sohil.mehta@intel.com>
Link: https://lore.kernel.org/r/20241202190011.11979-1-bp@kernel.org
2024-12-10 18:25:40 +01:00
Linus Torvalds 9ad55a67a7 Merge tag 'soundwire-6.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vkoul/soundwire
Pull soundwire updates from Vinod Koul:

 - structure optimization of few bus structures and header updates

 - support for 2.0 disco spec

 - amd driver updates for acp revision, refactoring code and support for
   acp6.3

 - soft reset support for cadence driver

* tag 'soundwire-6.13-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vkoul/soundwire: (24 commits)
  soundwire: Minor formatting fixups in sdw.h header
  soundwire: Update the includes on the sdw.h header
  soundwire: cadence: clear MCP BLOCK_WAKEUP in init
  soundwire: cadence: add soft-reset on startup
  soundwire: intel_auxdevice: add kernel parameter for mclk divider
  soundwire: mipi-disco: add support for DP0/DPn 'lane-list' property
  soundwire: mipi-disco: add new properties from 2.0 spec
  soundwire: mipi-disco: add comment on DP0-supported property
  soundwire: mipi-disco: add support for peripheral channelprepare timeout
  soundwire: mipi_disco: add support for clock-scales property
  soundwire: mipi-disco: add error handling for property array read
  soundwire: mipi-disco: remove DPn audio-modes
  soundwire: optimize sdw_dpn_prop
  soundwire: optimize sdw_dp0_prop
  soundwire: optimize sdw_slave_prop
  soundwire: optimize sdw_bus structure
  soundwire: optimize sdw_master_prop
  soundwire: optimize sdw_stream_runtime memory layout
  soundwire: mipi_disco: add MIPI-specific property_read_bool() helpers
  soundwire: Correct some typos in comments
  ...
2024-11-27 13:38:09 -08:00
Randy DunlapandJonathan Corbet 32643e10df Documentation: admin: reorganize kernel-parameters intro
Reorganize the introduction to the kernel-parameters file to place
related paragraphs together:

- move module info together and near the beginning
- add a Special Handling section for dashes, underscores, double quotes,
  cpu lists, and metric (KMG) suffixes. Expand the KMG suffixes to
  include TPE as well.
- add a Kernel Build Options section

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20241029180320.412629-1-rdunlap@infradead.org
2024-11-04 11:03:24 -07:00
Pierre-Louis BossartandVinod Koul cbcb7edd09 soundwire: intel_auxdevice: add kernel parameter for mclk divider
Add a kernel parameter to work-around discrepancies between hardware
and platform firmware, it's not unusual to see e.g. 38.4MHz listed in
_DSD properties as the SoundWire clock source, but the hardware may be
based on a 19.2 MHz mclk source.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20241004021850.9758-1-yung-chuan.liao@linux.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
2024-10-10 17:43:55 +05:30
Thomas HuthandJonathan Corbet 661404644d Documentation: Remove IA-64 from kernel-parameters
IA-64 has been removed from the tree, so we should also remove
the corresponding kernel-parameters documentation now.

Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240627162458.387700-1-thuth@redhat.com
2024-06-27 11:31:52 -06:00
Paul E. McKenneyandBoqun Feng 600716592a doc: Add EARLY flag to early-parsed kernel boot parameters
Kernel boot parameters declared with early_param() are parsed before
embedded parameters are extracted from initrd, and early_param()
parameters are not helpful when embedded in initrd.  Therefore,
mark early_param() kernel boot parameters with "EARLY" in
kernel-parameters.txt.

The following early_param() calls declare kernel boot parameters that
are undocumented:

early_param("atmel.pm_modes", at91_pm_modes_select);
early_param("mem_fclk_21285", early_fclk);
early_param("ecc", early_ecc);
early_param("cachepolicy", early_cachepolicy);
early_param("nodebugmon", early_debug_disable);
early_param("kfence.sample_interval", parse_kfence_early_init);
early_param("additional_cpus", setup_additional_cpus);
early_param("stram_pool", atari_stram_setup);
early_param("disable_octeon_edac", disable_octeon_edac);
early_param("rd_start", rd_start_early);
early_param("rd_size", rd_size_early);
early_param("coherentio", setcoherentio);
early_param("nocoherentio", setnocoherentio);
early_param("fadump", early_fadump_param);
early_param("fadump_reserve_mem", early_fadump_reserve_mem);
early_param("no_stf_barrier", handle_no_stf_barrier);
early_param("no_rfi_flush", handle_no_rfi_flush);
early_param("smt-enabled", early_smt_enabled);
early_param("ppc_pci_reset_phbs", pci_reset_phbs_setup);
early_param("ps3fb", early_parse_ps3fb);
early_param("ps3flash", early_parse_ps3flash);
early_param("novx", disable_vector_extension);
early_param("nobp", nobp_setup_early);
early_param("nospec", nospec_setup_early);
early_param("possible_cpus", _setup_possible_cpus);
early_param("stp", early_parse_stp);
early_param("nopfault", nopfault);
early_param("nmi_mode", nmi_mode_setup);
early_param("sh_mv", early_parse_mv);
early_param("pmb", early_pmb);
early_param("hvirq", early_hvirq_major);
early_param("cfi", cfi_parse_cmdline);
early_param("disableapic", setup_disableapic);
early_param("noapictimer", parse_disable_apic_timer);
early_param("disable_cpu_apicid", apic_set_disabled_cpu_apicid);
early_param("uv_memblksize", parse_mem_block_size);
early_param("retbleed", retbleed_parse_cmdline);
early_param("no-kvmclock-vsyscall", parse_no_kvmclock_vsyscall);
early_param("update_mptable", update_mptable_setup);
early_param("alloc_mptable", parse_alloc_mptable_opt);
early_param("possible_cpus", _setup_possible_cpus);
early_param("lsmsi", early_parse_ls_scfg_msi);
early_param("nokgdbroundup", opt_nokgdbroundup);
early_param("kgdbcon", opt_kgdb_con);
early_param("kasan", early_kasan_flag);
early_param("kasan.mode", early_kasan_mode);
early_param("kasan.vmalloc", early_kasan_flag_vmalloc);
early_param("kasan.page_alloc.sample", early_kasan_flag_page_alloc_sample);
early_param("kasan.page_alloc.sample.order", early_kasan_flag_page_alloc_sample_order);
early_param("kasan.fault", early_kasan_fault);
early_param("kasan.stacktrace", early_kasan_flag_stacktrace);
early_param("kasan.stack_ring_size", early_kasan_flag_stack_ring_size);
early_param("accept_memory", accept_memory_parse);
early_param("page_table_check", early_page_table_check_param);
sh_early_platform_init("earlytimer", &sh_cmt_device_driver);
early_param_on_off("gbpages", "nogbpages", direct_gbpages, CONFIG_X86_DIRECT_GBPAGES);

These are not necessarily bugs, given that some kernel boot parameters
are intended for deep debugging rather than general use.

This work does not cover all of the kernel boot parameters declared using
cmdline_find_option() and cmdline_find_option_bool().  If these are in
fact guaranteed to be early (which appears to be the case), they can be
added in a later version of this patch.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Petr Malat <oss@malat.biz>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: <linux-doc@vger.kernel.org>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
2024-02-14 07:53:50 -08:00
Vegard NossumandJonathan Corbet ea7dcd8a48 doc: admin-guide/kernel-parameters: remove useless comment
This comment about DRM drivers has been there since the first git
commit. It simply doesn't belong in kernel-parameters; remove it.

Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240111085220.3693059-1-vegard.nossum@oracle.com
2024-01-23 14:46:52 -07:00
Andy ShevchenkoandJonathan Corbet d0c1f8dc5c docs: kernel-parameters: Refer to the correct bitmap function
The parser of the CPU lists is bitmap_parselist() that supports
special notations with the plain numbers. bitmap_parse() never
supported those and will fail in case one will try it.

Fixes: b18def121f ("bitmap_parse: Support 'all' semantics")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20230817140432.507889-1-andriy.shevchenko@linux.intel.com
2023-08-18 11:03:52 -06:00
Randy DunlapandJonathan Corbet fe1185941b Docs: kernel-parameters: sort the LEGEND list
Sort the list of kernel build options and hardware support options.
Add a comment that the list should be kept sorted instead of having
new options inserted willy nilly.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20230725174247.32393-1-rdunlap@infradead.org
2023-07-31 09:56:11 -06:00
Linus Torvalds c23f28975a Merge tag 'docs-6.4' of git://git.lwn.net/linux
Pull documentation updates from Jonathan Corbet:
 "Commit volume in documentation is relatively low this time, but there
  is still a fair amount going on, including:

   - Reorganize the architecture-specific documentation under
     Documentation/arch

     This makes the structure match the source directory and helps to
     clean up the mess that is the top-level Documentation directory a
     bit. This work creates the new directory and moves x86 and most of
     the less-active architectures there.

     The current plan is to move the rest of the architectures in 6.5,
     with the patches going through the appropriate subsystem trees.

   - Some more Spanish translations and maintenance of the Italian
     translation

   - A new "Kernel contribution maturity model" document from Ted

   - A new tutorial on quickly building a trimmed kernel from Thorsten

  Plus the usual set of updates and fixes"

* tag 'docs-6.4' of git://git.lwn.net/linux: (47 commits)
  media: Adjust column width for pdfdocs
  media: Fix building pdfdocs
  docs: clk: add documentation to log which clocks have been disabled
  docs: trace: Fix typo in ftrace.rst
  Documentation/process: always CC responsible lists
  docs: kmemleak: adjust to config renaming
  ELF: document some de-facto PT_* ABI quirks
  Documentation: arm: remove stih415/stih416 related entries
  docs: turn off "smart quotes" in the HTML build
  Documentation: firmware: Clarify firmware path usage
  docs/mm: Physical Memory: Fix grammar
  Documentation: Add document for false sharing
  dma-api-howto: typo fix
  docs: move m68k architecture documentation under Documentation/arch/
  docs: move parisc documentation under Documentation/arch/
  docs: move ia64 architecture docs under Documentation/arch/
  docs: Move arc architecture docs under Documentation/arch/
  docs: move nios2 documentation under Documentation/arch/
  docs: move openrisc documentation under Documentation/arch/
  docs: move superh documentation under Documentation/arch/
  ...
2023-04-24 12:35:49 -07:00
Huacai Chen 16c52e5030 LoongArch: Make WriteCombine configurable for ioremap()
LoongArch maintains cache coherency in hardware, but when paired with
LS7A chipsets the WUC attribute (Weak-ordered UnCached, which is similar
to WriteCombine) is out of the scope of cache coherency machanism for
PCIe devices (this is a PCIe protocol violation, which may be fixed in
newer chipsets).

This means WUC can only used for write-only memory regions now, so this
option is disabled by default, making WUC silently fallback to SUC for
ioremap(). You can enable this option if the kernel is ensured to run on
hardware without this bug.

Kernel parameter writecombine=on/off can be used to override the Kconfig
option.

Cc: stable@vger.kernel.org
Suggested-by: WANG Xuerui <kernel@xen0n.name>
Reviewed-by: WANG Xuerui <kernel@xen0n.name>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2023-04-18 19:38:58 +08:00
Jonathan Corbet 790a6c21c1 docs: move m68k architecture documentation under Documentation/arch/
Architecture-specific documentation is being moved into Documentation/arch/
as a way of cleaning up the top-level documentation directory and making
the docs hierarchy more closely match the source hierarchy.  Move
Documentation/m68k into arch/ and fix all in-tree references.

Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2023-04-10 16:46:11 -06:00
Jonathan Corbet ff61f0791c docs: move x86 documentation into Documentation/arch/
Move the x86 documentation under Documentation/arch/ as a way of cleaning
up the top-level directory and making the structure of our docs more
closely match the structure of the source directories it describes.

All in-kernel references to the old paths have been updated.

Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: linux-arch@vger.kernel.org
Cc: x86@kernel.org
Cc: Borislav Petkov <bp@alien8.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/lkml/20230315211523.108836-1-corbet@lwn.net/
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2023-03-30 12:58:51 -06:00
Ondrej ZaryandDamien Le Moal 7750d8b510 drivers/block: Remove PARIDE core and high-level protocols
Remove PARIDE core and high level protocols, taking care not to break
low-level drivers (used by pata_parport). Also update documentation.

Signed-off-by: Ondrej Zary <linux@zary.sk>
Acked-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
2023-01-31 10:41:32 +09:00
Randy DunlapandJonathan Corbet d2fc83c149 Docs/admin: alphabetize some kernel-parameters (part 1)
Move some out-of-place kernel parameters into their correct
locations.

Move one out-of-order keyword/legend in kernel-parameters.rst.

Add some missing keyword legends in kernel-parameters.rst:
  HIBERNATION HYPER_V
and drop some obsolete/removed keyword legends:
 EIDE IOSCHED OSS TS XT

Correct the location of the setup.h file.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2022-04-16 02:49:05 -06:00
Yury NorovandPaul E. McKenney b18def121f bitmap_parse: Support 'all' semantics
RCU code supports an 'all' group as a special case when parsing rcu_nocbs
parameter. This patch moves the 'all' support to the core bitmap_parse
code, so that all bitmap users can enjoy this extension.

Moving 'all' parsing to a bitmap_parse level also allows users to pass
patterns together with 'all' in regular group:pattern format, for example,
"rcu_nocbs=all:1/2" would offload all the even-numbered CPUs regardless
of the number of CPUs on the system.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-05-10 15:38:20 -07:00
Linus Torvalds 9a45da9270 Merge tag 'core-rcu-2021-04-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull RCU updates from Ingo Molnar:

 - Support for "N" as alias for last bit in bitmap parsing library (eg
   using syntax like "nohz_full=2-N")

 - kvfree_rcu updates

 - mm_dump_obj() updates. (One of these is to mm, but was suggested by
   Andrew Morton.)

 - RCU callback offloading update

 - Polling RCU grace-period interfaces

 - Realtime-related RCU updates

 - Tasks-RCU updates

 - Torture-test updates

 - Torture-test scripting updates

 - Miscellaneous fixes

* tag 'core-rcu-2021-04-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (77 commits)
  rcutorture: Test start_poll_synchronize_rcu() and poll_state_synchronize_rcu()
  rcu: Provide polling interfaces for Tiny RCU grace periods
  torture: Fix kvm.sh --datestamp regex check
  torture: Consolidate qemu-cmd duration editing into kvm-transform.sh
  torture: Print proper vmlinux path for kvm-again.sh runs
  torture: Make TORTURE_TRUST_MAKE available in kvm-again.sh environment
  torture: Make kvm-transform.sh update jitter commands
  torture: Add --duration argument to kvm-again.sh
  torture: Add kvm-again.sh to rerun a previous torture-test
  torture: Create a "batches" file for build reuse
  torture: De-capitalize TORTURE_SUITE
  torture: Make upper-case-only no-dot no-slash scenario names official
  torture: Rename SRCU-t and SRCU-u to avoid lowercase characters
  torture: Remove no-mpstat error message
  torture: Record kvm-test-1-run.sh and kvm-test-1-run-qemu.sh PIDs
  torture: Record jitter start/stop commands
  torture: Extract kvm-test-1-run-qemu.sh from kvm-test-1-run.sh
  torture: Record TORTURE_KCONFIG_GDB_ARG in qemu-cmd
  torture: Abstract jitter.sh start/stop into scripts
  rcu: Provide polling interfaces for Tree RCU grace periods
  ...
2021-04-28 12:00:13 -07:00
Barry SongandJonathan Corbet 00b072c011 Documentation/admin-guide: kernel-parameters: correct the architectures for numa_balancing
X86 isn't the only architecture supporting NUMA_BALANCING. ARM64, PPC,
S390 and RISCV also support it:

arch$ git grep NUMA_BALANCING
arm64/Kconfig:  select ARCH_SUPPORTS_NUMA_BALANCING
arm64/configs/defconfig:CONFIG_NUMA_BALANCING=y
arm64/include/asm/pgtable.h:#ifdef CONFIG_NUMA_BALANCING
powerpc/configs/powernv_defconfig:CONFIG_NUMA_BALANCING=y
powerpc/configs/ppc64_defconfig:CONFIG_NUMA_BALANCING=y
powerpc/configs/pseries_defconfig:CONFIG_NUMA_BALANCING=y
powerpc/include/asm/book3s/64/pgtable.h:#ifdef CONFIG_NUMA_BALANCING
powerpc/include/asm/book3s/64/pgtable.h:#ifdef CONFIG_NUMA_BALANCING
powerpc/include/asm/book3s/64/pgtable.h:#endif /* CONFIG_NUMA_BALANCING */
powerpc/include/asm/book3s/64/pgtable.h:#ifdef CONFIG_NUMA_BALANCING
powerpc/include/asm/book3s/64/pgtable.h:#endif /* CONFIG_NUMA_BALANCING */
powerpc/include/asm/nohash/pgtable.h:#ifdef CONFIG_NUMA_BALANCING
powerpc/include/asm/nohash/pgtable.h:#endif /* CONFIG_NUMA_BALANCING */
powerpc/platforms/Kconfig.cputype:      select ARCH_SUPPORTS_NUMA_BALANCING
riscv/Kconfig:  select ARCH_SUPPORTS_NUMA_BALANCING
riscv/include/asm/pgtable.h:#ifdef CONFIG_NUMA_BALANCING
s390/Kconfig:   select ARCH_SUPPORTS_NUMA_BALANCING
s390/configs/debug_defconfig:CONFIG_NUMA_BALANCING=y
s390/configs/defconfig:CONFIG_NUMA_BALANCING=y
s390/include/asm/pgtable.h:#ifdef CONFIG_NUMA_BALANCING
x86/Kconfig:    select ARCH_SUPPORTS_NUMA_BALANCING     if X86_64
x86/include/asm/pgtable.h:#ifdef CONFIG_NUMA_BALANCING
x86/include/asm/pgtable.h:#endif /* CONFIG_NUMA_BALANCING */

On the other hand, setup_numabalancing() is implemented in mm/mempolicy.c
which doesn't depend on architectures.

Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
Acked-by: Palmer Dabbelt <palmerdabbelt@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210302084159.33688-1-song.bao.hua@hisilicon.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-03-08 17:19:05 -07:00
Paul GortmakerandPaul E. McKenney 2c4885d24e lib: bitmap: support "N" as an alias for size of bitmap
While this is done for all bitmaps, the original use case in mind was
for CPU masks and cpulist_parse() as described below.

It seems that a common configuration is to use the 1st couple cores for
housekeeping tasks.  This tends to leave the remaining ones to form a
pool of similarly configured cores to take on the real workload of
interest to the user.

So on machine A - with 32 cores, it could be 0-3 for "system" and then
4-31 being used in boot args like nohz_full=, or rcu_nocbs= as part of
setting up the worker pool of CPUs.

But then newer machine B is added, and it has 48 cores, and so while
the 0-3 part remains unchanged, the pool setup cpu list becomes 4-47.

Multiple deployment becomes easier when we can just simply replace 31
and 47 with "N" and let the system substitute in the actual number at
boot; a number that it knows better than we do.

Cc: Yury Norov <yury.norov@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Suggested-by: Yury Norov <yury.norov@gmail.com> # move it from CPU code
Acked-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2021-03-08 14:16:58 -08:00
Wolfram SangandJonathan Corbet 187623b1d8 Documentation: kernel-parameters: add missing '<'
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Link: https://lore.kernel.org/r/20210127104343.5647-1-wsa+renesas@sang-engineering.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2021-01-28 15:24:06 -07:00
Randy DunlapandJonathan Corbet 81e7906300 Documentation: admin: early_param()s are also listed in kernel-parameters
Add info that "early_param()" kernel boot parameters are also listed
in kernel-parameters.txt.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Link: https://lore.kernel.org/r/20201226174433.7885-1-rdunlap@infradead.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-12-31 15:46:18 -07:00
Barry SongandJonathan Corbet 4c8e3de4b3 Documentation/admin-guide: mark memmap parameter is supported by a few architectures
early_param memmap is only implemented on X86, MIPS and XTENSA. To avoid
wasting users’ time on trying this on platform like ARM, mark it clearly.

Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Link: https://lore.kernel.org/r/20201128195121.2556-1-song.bao.hua@hisilicon.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2020-11-30 10:35:32 -07:00
Saravana KannanandGreg Kroah-Hartman a3e1d1a7f5 of: property: Add functional dependency link from DT bindings
Add device links after the devices are created (but before they are
probed) by looking at common DT bindings like clocks and
interconnects.

Automatically adding device links for functional dependencies at the
framework level provides the following benefits:

- Optimizes device probe order and avoids the useless work of
  attempting probes of devices that will not probe successfully
  (because their suppliers aren't present or haven't probed yet).

  For example, in a commonly available mobile SoC, registering just
  one consumer device's driver at an initcall level earlier than the
  supplier device's driver causes 11 failed probe attempts before the
  consumer device probes successfully. This was with a kernel with all
  the drivers statically compiled in. This problem gets a lot worse if
  all the drivers are loaded as modules without direct symbol
  dependencies.

- Supplier devices like clock providers, interconnect providers, etc
  need to keep the resources they provide active and at a particular
  state(s) during boot up even if their current set of consumers don't
  request the resource to be active. This is because the rest of the
  consumers might not have probed yet and turning off the resource
  before all the consumers have probed could lead to a hang or
  undesired user experience.

  Some frameworks (Eg: regulator) handle this today by turning off
  "unused" resources at late_initcall_sync and hoping all the devices
  have probed by then. This is not a valid assumption for systems with
  loadable modules. Other frameworks (Eg: clock) just don't handle
  this due to the lack of a clear signal for when they can turn off
  resources. This leads to downstream hacks to handle cases like this
  that can easily be solved in the upstream kernel.

  By linking devices before they are probed, we give suppliers a clear
  count of the number of dependent consumers. Once all of the
  consumers are active, the suppliers can turn off the unused
  resources without making assumptions about the number of consumers.

By default we just add device-links to track "driver presence" (probe
succeeded) of the supplier device. If any other functionality provided
by device-links are needed, it is left to the consumer/supplier
devices to change the link when they probe.

kbuild test robot reported clang error about missing const
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Saravana Kannan <saravanak@google.com>
Link: https://lore.kernel.org/r/20190904211126.47518-4-saravanak@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-10-04 17:29:50 +02:00