From: Ingo Molnar mingo@kernel.org
mainline inclusion from mainline-v5.14-rc1 commit d2343cb8d154fe20c4499711bb3a9af2095b2b4b category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5OOWG CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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This option at minimum adds extra code to the scheduler - even if it's default unused - and most users wouldn't want it.
Reported-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Lin Shengwang linshengwang1@huawei.com Reviewed-by: lihua hucool.lihua@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- kernel/Kconfig.preempt | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/Kconfig.preempt b/kernel/Kconfig.preempt index bd7c4147b9a8..5876e30c5740 100644 --- a/kernel/Kconfig.preempt +++ b/kernel/Kconfig.preempt @@ -102,7 +102,6 @@ config PREEMPT_DYNAMIC
config SCHED_CORE bool "Core Scheduling for SMT" - default y depends on SCHED_SMT help This option permits Core Scheduling, a means of coordinated task @@ -115,7 +114,8 @@ config SCHED_CORE - mitigation of some (not all) SMT side channels; - limiting SMT interference to improve determinism and/or performance.
- SCHED_CORE is default enabled when SCHED_SMT is enabled -- when - unused there should be no impact on performance. + SCHED_CORE is default disabled. When it is enabled and unused, + which is the likely usage by Linux distributions, there should + be no measurable impact on performance.