arm64/mm: implement new [get_and_]clear_full_ptes() batch APIs

Optimize the contpte implementation to fix some of the
exit/munmap/dontneed performance regression introduced by the initial
contpte commit.  Subsequent patches will solve it entirely.

During exit(), munmap() or madvise(MADV_DONTNEED), mappings must be
cleared.  Previously this was done 1 PTE at a time.  But the core-mm
supports batched clear via the new [get_and_]clear_full_ptes() APIs.  So
let's implement those APIs and for fully covered contpte mappings, we no
longer need to unfold the contpte.  This significantly reduces unfolding
operations, reducing the number of tlbis that must be issued.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ryan Roberts <[email protected]>
Tested-by: John Hubbard <[email protected]>
Acked-by: Mark Rutland <[email protected]>
Acked-by: Catalin Marinas <[email protected]>
Cc: Alistair Popple <[email protected]>
Cc: Andrey Ryabinin <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Cc: Barry Song <[email protected]>
Cc: Borislav Petkov (AMD) <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: James Morse <[email protected]>
Cc: Kefeng Wang <[email protected]>
Cc: Marc Zyngier <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Yang Shi <[email protected]>
Cc: Zi Yan <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions