arm64: mm: remove dsb from update_mmu_cache

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update_mmu_cache() consists of a dsb(ishst) instruction so that new user
mappings are guaranteed to be visible to the page table walker on
exception return.

In reality this can be a very expensive operation which is rarely needed.
Removing this barrier shows a modest improvement in hackbench scores and
, in the worst case, we re-take the user fault and establish that there
was nothing to do.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

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Will Deacon 2015-10-06 18:46:30 +01:00 • committed by Catalin Marinas

parent 28c6fbc3b4

commit 120798d2e7

1 changed files with 3 additions and 3 deletions

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arch/arm64/include/asm/pgtable.h

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