4.19-stable review patch. If anyone has any objections, please let me know.
------------------ From: Thomas Gleixner t...@linutronix.de commit dbe733642e01dd108f71436aaea7b328cb28fd87 upstream 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 <t...@linutronix.de> Reviewed-by: Ingo Molnar <mi...@kernel.org> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Andy Lutomirski <l...@kernel.org> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Jiri Kosina <jkos...@suse.cz> Cc: Tom Lendacky <thomas.lenda...@amd.com> Cc: Josh Poimboeuf <jpoim...@redhat.com> Cc: Andrea Arcangeli <aarca...@redhat.com> Cc: David Woodhouse <d...@amazon.co.uk> Cc: Tim Chen <tim.c.c...@linux.intel.com> Cc: Andi Kleen <a...@linux.intel.com> Cc: Dave Hansen <dave.han...@intel.com> Cc: Casey Schaufler <casey.schauf...@intel.com> Cc: Asit Mallick <asit.k.mall...@intel.com> Cc: Arjan van de Ven <ar...@linux.intel.com> Cc: Jon Masters <j...@redhat.com> Cc: Waiman Long <longman9...@gmail.com> Cc: Greg KH <gre...@linuxfoundation.org> Cc: Dave Stewart <david.c.stew...@intel.com> Cc: Kees Cook <keesc...@chromium.org> Cc: sta...@vger.kernel.org Link: https://lkml.kernel.org/r/20181125185004.337452...@linutronix.de Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- arch/x86/Kconfig | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1001,13 +1001,7 @@ 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
