From: tip-bot for Thomas Gleixner <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: keescook@chromium.org, ak@linux.intel.com, tglx@linutronix.de,
linux-kernel@vger.kernel.org, casey.schaufler@intel.com,
asit.k.mallick@intel.com, jcm@redhat.com, mingo@kernel.org,
dave.hansen@intel.com, gregkh@linuxfoundation.org,
luto@kernel.org, aarcange@redhat.com, jkosina@suse.cz,
torvalds@linux-foundation.org, longman9394@gmail.com,
dwmw@amazon.co.uk, hpa@zytor.com, david.c.stewart@intel.com,
arjan@linux.intel.com, jpoimboe@redhat.com, peterz@infradead.org,
thomas.lendacky@amd.com, tim.c.chen@linux.intel.com
Subject: [tip:x86/pti] x86/Kconfig: Select SCHED_SMT if SMP enabled
Date: Wed, 28 Nov 2018 06:24:59 -0800 [thread overview]
Message-ID: <tip-dbe733642e01dd108f71436aaea7b328cb28fd87@git.kernel.org> (raw)
In-Reply-To: <20181125185004.337452245@linutronix.de>
Commit-ID: dbe733642e01dd108f71436aaea7b328cb28fd87
Gitweb: https://git.kernel.org/tip/dbe733642e01dd108f71436aaea7b328cb28fd87
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Sun, 25 Nov 2018 19:33:37 +0100
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Wed, 28 Nov 2018 11:57:07 +0100
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
---
arch/x86/Kconfig | 8 +-------
1 file changed, 1 insertion(+), 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
next prev parent reply other threads:[~2018-11-28 14:26 UTC|newest]
Thread overview: 112+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-25 18:33 [patch V2 00/28] x86/speculation: Remedy the STIBP/IBPB overhead Thomas Gleixner
2018-11-25 18:33 ` [patch V2 01/28] x86/speculation: Update the TIF_SSBD comment Thomas Gleixner
2018-11-28 14:20 ` [tip:x86/pti] " tip-bot for Tim Chen
2018-11-29 14:27 ` [patch V2 01/28] " Konrad Rzeszutek Wilk
2018-11-25 18:33 ` [patch V2 02/28] x86/speculation: Clean up spectre_v2_parse_cmdline() Thomas Gleixner
2018-11-28 14:20 ` [tip:x86/pti] " tip-bot for Tim Chen
2018-11-29 14:28 ` [patch V2 02/28] " Konrad Rzeszutek Wilk
2018-11-25 18:33 ` [patch V2 03/28] x86/speculation: Remove unnecessary ret variable in cpu_show_common() Thomas Gleixner
2018-11-28 14:21 ` [tip:x86/pti] " tip-bot for Tim Chen
2018-11-29 14:28 ` [patch V2 03/28] " Konrad Rzeszutek Wilk
2018-11-25 18:33 ` [patch V2 04/28] x86/speculation: Reorganize cpu_show_common() Thomas Gleixner
2018-11-26 15:08 ` Borislav Petkov
2018-11-28 14:22 ` [tip:x86/pti] x86/speculation: Move STIPB/IBPB string conditionals out of cpu_show_common() tip-bot for Tim Chen
2018-11-29 14:29 ` [patch V2 04/28] x86/speculation: Reorganize cpu_show_common() Konrad Rzeszutek Wilk
2018-11-25 18:33 ` [patch V2 05/28] x86/speculation: Disable STIBP when enhanced IBRS is in use Thomas Gleixner
2018-11-28 14:22 ` [tip:x86/pti] " tip-bot for Tim Chen
2018-11-29 14:35 ` [patch V2 05/28] " Konrad Rzeszutek Wilk
2018-11-25 18:33 ` [patch V2 06/28] x86/speculation: Rename SSBD update functions Thomas Gleixner
2018-11-26 15:24 ` Borislav Petkov
2018-11-28 14:23 ` [tip:x86/pti] " tip-bot for Thomas Gleixner
2018-11-29 14:37 ` [patch V2 06/28] " Konrad Rzeszutek Wilk
2018-11-25 18:33 ` [patch V2 07/28] x86/speculation: Reorganize speculation control MSRs update Thomas Gleixner
2018-11-26 15:47 ` Borislav Petkov
2018-11-28 14:23 ` [tip:x86/pti] " tip-bot for Tim Chen
2018-11-29 14:41 ` [patch V2 07/28] " Konrad Rzeszutek Wilk
2018-11-25 18:33 ` [patch V2 08/28] sched/smt: Make sched_smt_present track topology Thomas Gleixner
2018-11-28 14:24 ` [tip:x86/pti] " tip-bot for Peter Zijlstra (Intel)
2018-11-29 14:42 ` [patch V2 08/28] " Konrad Rzeszutek Wilk
2018-11-29 14:50 ` Konrad Rzeszutek Wilk
2018-11-29 15:48 ` Peter Zijlstra
2018-11-25 18:33 ` [patch V2 09/28] x86/Kconfig: Select SCHED_SMT if SMP enabled Thomas Gleixner
2018-11-28 14:24 ` tip-bot for Thomas Gleixner [this message]
2018-11-29 14:44 ` Konrad Rzeszutek Wilk
2018-11-25 18:33 ` [patch V2 10/28] sched/smt: Expose sched_smt_present static key Thomas Gleixner
2018-11-28 14:25 ` [tip:x86/pti] " tip-bot for Thomas Gleixner
2018-11-29 14:44 ` [patch V2 10/28] " Konrad Rzeszutek Wilk
2018-11-25 18:33 ` [patch V2 11/28] x86/speculation: Rework SMT state change Thomas Gleixner
2018-11-28 14:26 ` [tip:x86/pti] " tip-bot for Thomas Gleixner
2018-11-25 18:33 ` [patch V2 12/28] x86/l1tf: Show actual SMT state Thomas Gleixner
2018-11-28 14:26 ` [tip:x86/pti] " tip-bot for Thomas Gleixner
2018-11-25 18:33 ` [patch V2 13/28] x86/speculation: Reorder the spec_v2 code Thomas Gleixner
2018-11-26 22:21 ` Borislav Petkov
2018-11-28 14:27 ` [tip:x86/pti] " tip-bot for Thomas Gleixner
2018-11-25 18:33 ` [patch V2 14/28] x86/speculation: Mark string arrays const correctly Thomas Gleixner
2018-11-28 14:27 ` [tip:x86/pti] " tip-bot for Thomas Gleixner
2018-11-25 18:33 ` [patch V2 15/28] x86/speculataion: Mark command line parser data __initdata Thomas Gleixner
2018-11-28 14:28 ` [tip:x86/pti] " tip-bot for Thomas Gleixner
2018-11-25 18:33 ` [patch V2 16/28] x86/speculation: Unify conditional spectre v2 print functions Thomas Gleixner
2018-11-28 14:29 ` [tip:x86/pti] " tip-bot for Thomas Gleixner
2018-11-25 18:33 ` [patch V2 17/28] x86/speculation: Add command line control for indirect branch speculation Thomas Gleixner
2018-11-28 14:29 ` [tip:x86/pti] " tip-bot for Thomas Gleixner
2018-11-25 18:33 ` [patch V2 18/28] x86/speculation: Prepare for per task indirect branch speculation control Thomas Gleixner
2018-11-27 17:25 ` Lendacky, Thomas
2018-11-27 19:51 ` Tim Chen
2018-11-28 9:39 ` Thomas Gleixner
2018-11-27 20:39 ` Thomas Gleixner
2018-11-27 20:42 ` Thomas Gleixner
2018-11-27 21:52 ` Lendacky, Thomas
2018-11-28 14:30 ` [tip:x86/pti] " tip-bot for Tim Chen
2018-11-25 18:33 ` [patch V2 19/28] x86/process: Consolidate and simplify switch_to_xtra() code Thomas Gleixner
2018-11-26 18:30 ` Borislav Petkov
2018-11-28 14:30 ` [tip:x86/pti] " tip-bot for Thomas Gleixner
2018-11-25 18:33 ` [patch V2 20/28] x86/speculation: Avoid __switch_to_xtra() calls Thomas Gleixner
2018-11-28 14:31 ` [tip:x86/pti] " tip-bot for Thomas Gleixner
2018-11-25 18:33 ` [patch V2 21/28] x86/speculation: Prepare for conditional IBPB in switch_mm() Thomas Gleixner
2018-11-25 19:11 ` Thomas Gleixner
2018-11-25 20:53 ` Andi Kleen
2018-11-25 22:20 ` Thomas Gleixner
2018-11-25 23:04 ` Andy Lutomirski
2018-11-26 7:10 ` Thomas Gleixner
2018-11-26 13:36 ` Ingo Molnar
2018-11-26 3:07 ` Andi Kleen
2018-11-26 6:50 ` Thomas Gleixner
2018-11-28 14:31 ` [tip:x86/pti] " tip-bot for Thomas Gleixner
2018-11-25 18:33 ` [patch V2 22/28] ptrace: Remove unused ptrace_may_access_sched() and MODE_IBRS Thomas Gleixner
2018-11-28 14:32 ` [tip:x86/pti] " tip-bot for Thomas Gleixner
2018-11-25 18:33 ` [patch V2 23/28] x86/speculation: Split out TIF update Thomas Gleixner
2018-11-28 14:33 ` [tip:x86/pti] " tip-bot for Thomas Gleixner
2018-11-25 18:33 ` [patch V2 24/28] x86/speculation: Prepare arch_smt_update() for PRCTL mode Thomas Gleixner
2018-11-27 20:18 ` Lendacky, Thomas
2018-11-27 20:30 ` Thomas Gleixner
2018-11-27 21:20 ` Lendacky, Thomas
2018-11-28 14:34 ` [tip:x86/pti] " tip-bot for Thomas Gleixner
2018-11-25 18:33 ` [patch V2 25/28] x86/speculation: Add prctl() control for indirect branch speculation Thomas Gleixner
2018-11-28 14:34 ` [tip:x86/pti] " tip-bot for Thomas Gleixner
2018-11-25 18:33 ` [patch V2 26/28] x86/speculation: Enable prctl mode for spectre_v2_user Thomas Gleixner
2018-11-26 7:56 ` Dominik Brodowski
2018-11-28 14:35 ` [tip:x86/pti] " tip-bot for Thomas Gleixner
2018-11-25 18:33 ` [patch V2 27/28] x86/speculation: Add seccomp Spectre v2 user space protection mode Thomas Gleixner
2018-11-25 19:35 ` Randy Dunlap
2018-11-25 20:40 ` Linus Torvalds
2018-11-25 20:52 ` Jiri Kosina
2018-11-25 22:28 ` Thomas Gleixner
2018-11-26 13:30 ` Ingo Molnar
2018-11-26 20:48 ` Andrea Arcangeli
2018-11-26 20:58 ` Thomas Gleixner
2018-11-26 21:52 ` Lendacky, Thomas
2018-11-27 0:37 ` Tim Chen
2018-12-04 1:38 ` Tim Chen
2018-12-04 8:39 ` Jiri Kosina
2018-12-04 9:43 ` Arjan van de Ven
2018-12-04 9:46 ` Arjan van de Ven
2018-12-04 17:20 ` Linus Torvalds
2018-12-04 18:58 ` Tim Chen
2018-11-28 14:35 ` [tip:x86/pti] " tip-bot for Thomas Gleixner
2018-12-04 18:45 ` [patch V2 27/28] " Dave Hansen
2018-11-25 18:33 ` [patch V2 28/28] x86/speculation: Provide IBPB always command line options Thomas Gleixner
2018-11-28 14:36 ` [tip:x86/pti] " tip-bot for Thomas Gleixner
2018-11-26 13:37 ` [patch V2 00/28] x86/speculation: Remedy the STIBP/IBPB overhead Ingo Molnar
2018-11-28 14:24 ` Thomas Gleixner
2018-11-29 19:02 ` Tim Chen
2018-12-10 23:43 ` Pavel Machek
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