diff options
| author | Heiko Carstens <hca@linux.ibm.com> | 2025-03-27 10:14:43 +0100 |
|---|---|---|
| committer | Vasily Gorbik <gor@linux.ibm.com> | 2025-03-31 12:20:39 +0200 |
| commit | 1018424ace7ed6dee9ddc36256162250017e4401 (patch) | |
| tree | 78f6e08e316a6a26ca8e9a5812bd22a7de44176e /Documentation | |
| parent | 991a20173a1fbafd9fc0df0c7e17bb62d44a4deb (diff) | |
s390/smp: Add support for HOTPLUG_SMT
Add support for HOTPLUG_SMT. With this the s390 specific "nosmt" kernel
command line parameter handling is replaced with common code handling.
This means that just specifying "nosmt" still enables smt from an
architectural point of view, however only the primary (base) cpu can be set
online. Enabling smt during runtime via /sys/devices/system/cpu/smt/control
allows to set secondary cpus online. This way "nosmt" works like on other
architectures where enabling and disabling smt during runtime is possible.
If "nosmt=force" is specified smt is also still enabled from an
architectural point of view, but there is no way to set secondary cpus
online during runtime, also like on other architectures.
In order to disable smt from architectural point of view, which was
previously achieved with the s390 specific "nosmt" command line option,
"smt=1" can be used.
Tested-by: Mete Durlu <meted@linux.ibm.com>
Reviewed-by: Mete Durlu <meted@linux.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 5e351ac52cca..0d97f811d8b1 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -4236,10 +4236,10 @@ nosmp [SMP,EARLY] Tells an SMP kernel to act as a UP kernel, and disable the IO APIC. legacy for "maxcpus=0". - nosmt [KNL,MIPS,PPC,S390,EARLY] Disable symmetric multithreading (SMT). + nosmt [KNL,MIPS,PPC,EARLY] Disable symmetric multithreading (SMT). Equivalent to smt=1. - [KNL,X86,PPC] Disable symmetric multithreading (SMT). + [KNL,X86,PPC,S390] Disable symmetric multithreading (SMT). nosmt=force: Force disable SMT, cannot be undone via the sysfs control file. |