path: root/Documentation/kernel-parameters.txt
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authorLinus Torvalds <torvalds@linux-foundation.org>2016-10-04 13:54:07 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-10-04 13:54:07 -0700
commit02bafd96f3a5d8e610b19033ffec55b92459aaae (patch)
tree6f59becfaaaa724077f3855328e5825b896a68e7 /Documentation/kernel-parameters.txt
parent2105b9ff733c5e5ab3e0481f1c953ac3f7d7c44a (diff)
parent3c76ff4765fbd382c095acc37f87e136a8dfc73d (diff)
Merge tag 'docs-4.9' of git://git.lwn.net/linux
Pull documentation updates from Jonathan Corbet: "This is the documentation update pull for the 4.9 merge window. The Sphinx transition is still creating a fair amount of work. Here we have a number of fixes and, importantly, a proper PDF output solution, thanks to Jani Nikula, Mauro Carvalho Chehab and Markus Heiser. I've started a couple of new books: a driver API book (based on the old device-drivers.tmpl) and a development tools book. Both are meant to show how we can integrate together our existing documentation into a more coherent and accessible whole. It involves moving some stuff around and formatting changes, but, I think, the results are worth it. The good news is that most of our existing Documentation/*.txt files are *almost* in RST format already; the amount of messing around required is minimal. And, of course, there's the usual set of updates, typo fixes, and more" * tag 'docs-4.9' of git://git.lwn.net/linux: (120 commits) URL changed for Linux Foundation TAB dax : Fix documentation with respect to struct pages iio: Documentation: Correct the path used to create triggers. docs: Remove space-before-label guidance from CodingStyle docs-rst: add inter-document cross references Documentation/email-clients.txt: convert it to ReST markup Documentation/kernel-docs.txt: reorder based on timestamp Documentation/kernel-docs.txt: Add dates for online docs Documentation/kernel-docs.txt: get rid of broken docs Documentation/kernel-docs.txt: move in-kernel docs Documentation/kernel-docs.txt: remove more legacy references Documentation/kernel-docs.txt: add two published books Documentation/kernel-docs.txt: sort books per publication date Documentation/kernel-docs.txt: adjust LDD references Documentation/kernel-docs.txt: some improvements on the ReST output Documentation/kernel-docs.txt: Consistent indenting: 4 spaces Documentation/kernel-docs.txt: Add 4 paper/book references Documentation/kernel-docs.txt: Improve layouting of book list Documentation/kernel-docs.txt: Remove offline or outdated entries docs: Clean up bare :: lines ...
Diffstat (limited to 'Documentation/kernel-parameters.txt')
1 files changed, 14 insertions, 10 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 01085cdc47c1..fcf05a07b06a 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1698,7 +1698,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
intel_idle.max_cstate= [KNL,HW,ACPI,X86]
0 disables intel_idle and fall back on acpi_idle.
- 1 to 6 specify maximum depth of C-state.
+ 1 to 9 specify maximum depth of C-state.
intel_pstate= [X86]
@@ -2171,10 +2171,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
than or equal to this physical address is ignored.
maxcpus= [SMP] Maximum number of processors that an SMP kernel
- should make use of. maxcpus=n : n >= 0 limits the
- kernel to using 'n' processors. n=0 is a special case,
- it is equivalent to "nosmp", which also disables
- the IO APIC.
+ will bring up during bootup. maxcpus=n : n >= 0 limits
+ the kernel to bring up 'n' processors. Surely after
+ bootup you can bring up the other plugged cpu by executing
+ "echo 1 > /sys/devices/system/cpu/cpuX/online". So maxcpus
+ only takes effect during system bootup.
+ While n=0 is a special case, it is equivalent to "nosmp",
+ which also disables the IO APIC.
max_loop= [LOOP] The number of loop block devices that get
(loop.max_loop) unconditionally pre-created at init time. The default
@@ -2581,8 +2584,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
nodelayacct [KNL] Disable per-task delay accounting
- nodisconnect [HW,SCSI,M68K] Disables SCSI disconnects.
nodsp [SH] Disable hardware DSP at boot time.
noefi Disable EFI runtime services support.
@@ -2783,9 +2784,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
nr_cpus= [SMP] Maximum number of processors that an SMP kernel
could support. nr_cpus=n : n >= 1 limits the kernel to
- supporting 'n' processors. Later in runtime you can not
- use hotplug cpu feature to put more cpu back to online.
- just like you compile the kernel NR_CPUS=n
+ support 'n' processors. It could be larger than the
+ number of already plugged CPU during bootup, later in
+ runtime you can physically add extra cpu until it reaches
+ n. So during boot up some boot time memory for per-cpu
+ variables need be pre-allocated for later physical cpu
+ hot plugging.
nr_uarts= [SERIAL] maximum number of UARTs to be registered.