4.19-stable review patch. If anyone has any objections, please let me know.
------------------ From: Thomas Gleixner [email protected] 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 <[email protected]> Reviewed-by: Ingo Molnar <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Jiri Kosina <[email protected]> Cc: Tom Lendacky <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: Andrea Arcangeli <[email protected]> Cc: David Woodhouse <[email protected]> Cc: Tim Chen <[email protected]> Cc: Andi Kleen <[email protected]> Cc: Dave Hansen <[email protected]> Cc: Casey Schaufler <[email protected]> Cc: Asit Mallick <[email protected]> Cc: Arjan van de Ven <[email protected]> Cc: Jon Masters <[email protected]> Cc: Waiman Long <[email protected]> Cc: Greg KH <[email protected]> Cc: Dave Stewart <[email protected]> Cc: Kees Cook <[email protected]> Cc: [email protected] Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]> --- 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
