+ powerpc-64s-enable-mmu_lazy_tlb_shootdown.patch added to -mm tree

+ powerpc-64s-enable-mmu_lazy_tlb_shootdown.patch added to -mm tree

[akpm]

The patch titled
     Subject: powerpc/64s: enable MMU_LAZY_TLB_SHOOTDOWN
has been added to the -mm tree.  Its filename is
     powerpc-64s-enable-mmu_lazy_tlb_shootdown.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/powerpc-64s-enable-mmu_lazy_tlb_shootdown.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/powerpc-64s-enable-mmu_lazy_tlb_shootdown.patch

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------------------------------------------------------
From: Nicholas Piggin <npiggin@gmail.com>
Subject: powerpc/64s: enable MMU_LAZY_TLB_SHOOTDOWN

On a 16-socket 192-core POWER8 system, a context switching benchmark
with as many software threads as CPUs (so each switch will go in and
out of idle), upstream can achieve a rate of about 1 million context
switches per second. After this patch it goes up to 118 million.

Link: https://lkml.kernel.org/r/20210605014216.446867-5-npiggin@gmail.com
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Anton Blanchard <anton@ozlabs.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/powerpc/Kconfig |    1 +
 1 file changed, 1 insertion(+)

--- a/arch/powerpc/Kconfig~powerpc-64s-enable-mmu_lazy_tlb_shootdown
+++ a/arch/powerpc/Kconfig
@@ -252,6 +252,7 @@ config PPC
 	select IRQ_FORCED_THREADING
 	select MMU_GATHER_PAGE_SIZE
 	select MMU_GATHER_RCU_TABLE_FREE
+	select MMU_LAZY_TLB_SHOOTDOWN		if PPC_BOOK3S_64
 	select MODULES_USE_ELF_RELA
 	select NEED_DMA_MAP_STATE		if PPC64 || NOT_COHERENT_CACHE
 	select NEED_SG_DMA_LENGTH
_

Patches currently in -mm which might be from npiggin@gmail.com are

lazy-tlb-introduce-lazy-mm-refcount-helper-functions.patch
lazy-tlb-allow-lazy-tlb-mm-refcounting-to-be-configurable.patch
lazy-tlb-shoot-lazies-a-non-refcounting-lazy-tlb-option.patch
powerpc-64s-enable-mmu_lazy_tlb_shootdown.patch