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... -------------------------------------------------------------------------- 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. -- 2.20.1