Patch "x86/mm: If INVPCID is available, use it to flush global mappings" has been added to the 4.4-stable tree
Subsystems (2)
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;a=summary
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 <[email protected]> know about it.
Quoted 1 line
From
d8bced79af1db6734f66b42064cc773cada2ce99Mon Sep 17 00:00:00 2001
From: Andy Lutomirski <[email protected]>
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 <[email protected]>
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.
--- arch/x86/include/asm/tlbflush.h | 9 +++++++++ 1 file changed, 9 insertions(+)
arch/x86/include/asm/tlbflush.h +9 -0
@@ -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 [email protected] 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