Messages in this thread Patch in this message | | | From | paulmck@kernel ... | Subject | [PATCH RFC cpumask 3/5] cpumask: Add a "none" alias to complement "all" | Date | Tue, 5 Jan 2021 16:49:54 -0800 |
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From: Paul Gortmaker <paul.gortmaker@windriver.com>
With global support for a CPU list alias of "all", it seems to just make sense to also trivially extend support for an opposite "none" specifier.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> --- Documentation/admin-guide/kernel-parameters.rst | 6 ++++++ lib/cpumask.c | 5 +++++ 2 files changed, 11 insertions(+)
diff --git a/Documentation/admin-guide/kernel-parameters.rst b/Documentation/admin-guide/kernel-parameters.rst index cdf4e81..7dd1224 100644 --- a/Documentation/admin-guide/kernel-parameters.rst +++ b/Documentation/admin-guide/kernel-parameters.rst @@ -76,6 +76,12 @@ is equivalent to "foo_cpus=0-N" -- where "N" is the numerically last CPU on the system, thus avoiding looking up the value in "/sys/devices/system/cpu" in advance on each deployed system. + foo_cpus=none + +will provide an empty/cleared cpu mask for the associated boot argument. + +Note that "all" and "none" are not necessarily valid/sensible input values +for each available parameter expecting a CPU list. 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 diff --git a/lib/cpumask.c b/lib/cpumask.c index 9f8ff72..7fbcab8 100644 --- a/lib/cpumask.c +++ b/lib/cpumask.c @@ -110,6 +110,11 @@ int cpulist_parse(const char *buf, struct cpumask *dstp) return 0; } + if (!strcmp(buf, "none")) { + cpumask_clear(dstp); + return 0; + } + return bitmap_parselist(buf, cpumask_bits(dstp), nr_cpumask_bits); } EXPORT_SYMBOL(cpulist_parse); -- 2.9.5
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