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authorThomas Gleixner2018-11-25 19:33:37 +0100
committerThomas Gleixner2018-11-28 11:57:07 +0100
commitdbe733642e01dd108f71436aaea7b328cb28fd87 (patch)
treeba7418e20eebce576f1a3961e081beb5e5a5a6a8 /arch/x86/Kconfig
parentsched/smt: Make sched_smt_present track topology (diff)
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x86/Kconfig: Select SCHED_SMT if SMP enabled
CONFIG_SCHED_SMT is enabled by all distros, so there is not a real point to have it configurable. The runtime overhead in the core scheduler code is minimal because the actual SMT scheduling parts are conditional on a static key. This allows to expose the scheduler's SMT state static key to the speculation control code. Alternatively the scheduler's static key could be made always available when CONFIG_SMP is enabled, but that's just adding an unused static key to every other architecture for nothing. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Woodhouse <dwmw@amazon.co.uk> Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Casey Schaufler <casey.schaufler@intel.com> Cc: Asit Mallick <asit.k.mallick@intel.com> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Jon Masters <jcm@redhat.com> Cc: Waiman Long <longman9394@gmail.com> Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Dave Stewart <david.c.stewart@intel.com> Cc: Kees Cook <keescook@chromium.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20181125185004.337452245@linutronix.de
Diffstat (limited to 'arch/x86/Kconfig')
-rw-r--r--arch/x86/Kconfig8
1 files changed, 1 insertions, 7 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index b5286ad2a982..8689e794a43c 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1000,13 +1000,7 @@ config NR_CPUS
to the kernel image.
config SCHED_SMT
- bool "SMT (Hyperthreading) scheduler support"
- depends on SMP
- ---help---
- SMT scheduler support improves the CPU scheduler's decision making
- when dealing with Intel Pentium 4 chips with HyperThreading at a
- cost of slightly increased overhead in some places. If unsure say
- N here.
+ def_bool y if SMP
config SCHED_MC
def_bool y