This is a note to let you know that I've just added the patch titled
x86/mm: If INVPCID is available, use it to flush global mappings
to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: x86-mm-if-invpcid-is-available-use-it-to-flush-global-mappings.patch and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From d8bced79af1db6734f66b42064cc773cada2ce99 Mon Sep 17 00:00:00 2001
From: Andy Lutomirski luto@kernel.org Date: Fri, 29 Jan 2016 11:42:59 -0800 Subject: x86/mm: If INVPCID is available, use it to flush global mappings
From: Andy Lutomirski luto@kernel.org
commit d8bced79af1db6734f66b42064cc773cada2ce99 upstream.
On my Skylake laptop, INVPCID function 2 (flush absolutely everything) takes about 376ns, whereas saving flags, twiddling CR4.PGE to flush global mappings, and restoring flags takes about 539ns.
Signed-off-by: Andy Lutomirski luto@kernel.org Reviewed-by: Borislav Petkov bp@suse.de Cc: Andrew Morton akpm@linux-foundation.org Cc: Andrey Ryabinin aryabinin@virtuozzo.com Cc: Andy Lutomirski luto@amacapital.net Cc: Borislav Petkov bp@alien8.de Cc: Brian Gerst brgerst@gmail.com Cc: Dave Hansen dave.hansen@linux.intel.com Cc: Denys Vlasenko dvlasenk@redhat.com Cc: H. Peter Anvin hpa@zytor.com Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Luis R. Rodriguez mcgrof@suse.com Cc: Oleg Nesterov oleg@redhat.com Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Cc: Toshi Kani toshi.kani@hp.com Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/ed0ef62581c0ea9c99b9bf6df726015e96d44743.1454096309... Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/include/asm/tlbflush.h | 9 +++++++++ 1 file changed, 9 insertions(+)
--- a/arch/x86/include/asm/tlbflush.h +++ b/arch/x86/include/asm/tlbflush.h @@ -159,6 +159,15 @@ static inline void __native_flush_tlb_gl { unsigned long flags;
+ if (static_cpu_has(X86_FEATURE_INVPCID)) { + /* + * Using INVPCID is considerably faster than a pair of writes + * to CR4 sandwiched inside an IRQ flag save/restore. + */ + invpcid_flush_all(); + return; + } + /* * Read-modify-write to CR4 - protect it from preemption and * from interrupts. (Use the raw variant because this code can
Patches currently in stable-queue which might be from luto@kernel.org are
queue-4.4/x86-mm-sched-core-uninline-switch_mm.patch queue-4.4/x86-mm-add-a-noinvpcid-boot-option-to-turn-off-invpcid.patch queue-4.4/x86-irq-do-not-substract-irq_tlb_count-from-irq_call_count.patch queue-4.4/x86-mm-if-invpcid-is-available-use-it-to-flush-global-mappings.patch queue-4.4/x86-mm-add-invpcid-helpers.patch queue-4.4/sched-core-add-switch_mm_irqs_off-and-use-it-in-the-scheduler.patch queue-4.4/arm-hide-finish_arch_post_lock_switch-from-modules.patch queue-4.4/x86-mm-sched-core-turn-off-irqs-in-switch_mm.patch queue-4.4/mm-mmu_context-sched-core-fix-mmu_context.h-assumption.patch queue-4.4/x86-mm-build-arch-x86-mm-tlb.c-even-on-smp.patch queue-4.4/sched-core-idle_task_exit-shouldn-t-use-switch_mm_irqs_off.patch