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| author | Michael Ellerman <mpe@ellerman.id.au> | 2023-07-05 16:51:39 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2023-07-28 09:53:37 +0200 |
| commit | 38253464bc821d6de6bba81bb1412ebb36f6cbd1 (patch) | |
| tree | ebd0d0eb49869b596cd4bc19ee99429fa8931168 /arch/Kconfig | |
| parent | cpu/SMT: Remove topology_smt_supported() (diff) | |
| download | linux-38253464bc821d6de6bba81bb1412ebb36f6cbd1.tar.xz linux-38253464bc821d6de6bba81bb1412ebb36f6cbd1.zip | |
cpu/SMT: Create topology_smt_thread_allowed()
Some architectures allows partial SMT states, i.e. when not all SMT threads
are brought online.
To support that, add an architecture helper which checks whether a given
CPU is allowed to be brought online depending on how many SMT threads are
currently enabled. Since this is only applicable to architecture supporting
partial SMT, only these architectures should select the new configuration
variable CONFIG_SMT_NUM_THREADS_DYNAMIC. For the other architectures, not
supporting the partial SMT states, there is no need to define
topology_cpu_smt_allowed(), the generic code assumed that all the threads
are allowed or only the primary ones.
Call the helper from cpu_smt_enable(), and cpu_smt_allowed() when SMT is
enabled, to check if the particular thread should be onlined. Notably,
also call it from cpu_smt_disable() if CPU_SMT_ENABLED, to allow
offlining some threads to move from a higher to lower number of threads
online.
[ ldufour: Slightly reword the commit's description ]
[ ldufour: Introduce CONFIG_SMT_NUM_THREADS_DYNAMIC ]
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Zhang Rui <rui.zhang@intel.com>
Link: https://lore.kernel.org/r/20230705145143.40545-7-ldufour@linux.ibm.com
Diffstat (limited to 'arch/Kconfig')
| -rw-r--r-- | arch/Kconfig | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/Kconfig b/arch/Kconfig index aff2746c8af2..63c5d6a2022b 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -34,6 +34,9 @@ config ARCH_HAS_SUBPAGE_FAULTS config HOTPLUG_SMT bool +config SMT_NUM_THREADS_DYNAMIC + bool + # Selected by HOTPLUG_CORE_SYNC_DEAD or HOTPLUG_CORE_SYNC_FULL config HOTPLUG_CORE_SYNC bool |