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flush_tlb_range is special in that we don't specify the page size used for the translation. Hence when flushing TLB we flush the translation cache for all possible page sizes. The kernel also uses the same interface when moving page tables around. Such a move requires us to flush the page walk cache. Instead of adding another interface to force page walk cache flush, update flush_tlb_range to flush page walk cache if the range flushed is more than the PMD range. A page table move will always involve an invalidate range more than PMD_SIZE. Running microbenchmark with mprotect and parallel memory access didn't show any observable performance impact. Link: https://lkml.kernel.org/r/20210616045735.374532-3-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Hugh Dickins <hughd@google.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>