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Documentation/kernel-parameters: Remove "Deprecated" from isolcpus=

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The isolcpus= option has been marked as deprecated in 2017. Back then it
was desired for the domain sub option to be configured dynamically at
runtime instead using this boot command line which provides a static
configuration. In the meantime this option was extended by other sub
options which don't have runtime counterpart or it does not make sense
to provide one.

The deprecated part always referred to the default `domain' sub option
but it was not obvious. Also the reasoning behind the deprecation is
sort of dubious: There is nothing wrong with a static configuration if
there is no desired to reconfigure. This is useful on systems which
have one purpose and the CPU partition configuration is not changed for
the entire lifetime.

Remove the "Deprecated" note. Remove the part of the description which
suggest to use cpuset.sched_load_balance and instead point to the
documentation file which explains how to use cpusets to configure this
at runtime.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Waiman Long <longman@redhat.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20260427150739.bwVmmkj2@linutronix.de>
This commit is contained in:
Sebastian Andrzej Siewior 2026-04-27 17:07:39 +02:00 committed by Jonathan Corbet
parent 27e6bf7df2
commit 75ff0feaa2
1 changed files with 4 additions and 6 deletions
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10
Documentation/admin-guide/kernel-parameters.txt
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@ -2751,7 +2751,6 @@ Kernel parameters
Format: <RDP>,<reset>,<pci_scan>,<verbosity>
isolcpus= [KNL,SMP,ISOL] Isolate a given set of CPUs from disturbance.
[Deprecated - use cpusets instead]
Format: [flag-list,]<cpu-list>
Specify one or more CPUs to isolate from disturbances
@ -2776,11 +2775,10 @@ Kernel parameters
Isolate from the general SMP balancing and scheduling
algorithms. Note that performing domain isolation this way
is irreversible: it's not possible to bring back a CPU to
the domains once isolated through isolcpus. It's strongly
advised to use cpusets instead to disable scheduler load
balancing through the "cpuset.sched_load_balance" file.
It offers a much more flexible interface where CPUs can
move in and out of an isolated set anytime.
the domains once isolated through this boot time
configuration. Use cpusets for a dynamic configuration
which can be altered at runtime. For details see
Documentation/admin-guide/cpu-isolation.rst.
You can move a process onto or off an "isolated" CPU via
the CPU affinity syscalls or cpuset.