From a6d60245d6d9b1caf66b0d94419988c4836980af Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Thu, 23 Aug 2018 21:01:46 +0100 Subject: asm-generic/tlb: Track which levels of the page tables have been cleared It is common for architectures with hugepage support to require only a single TLB invalidation operation per hugepage during unmap(), rather than iterating through the mapping at a PAGE_SIZE increment. Currently, however, the level in the page table where the unmap() operation occurs is not stored in the mmu_gather structure, therefore forcing architectures to issue additional TLB invalidation operations or to give up and over-invalidate by e.g. invalidating the entire TLB. Ideally, we could add an interval rbtree to the mmu_gather structure, which would allow us to associate the correct mapping granule with the various sub-mappings within the range being invalidated. However, this is costly in terms of book-keeping and memory management, so instead we approximate by keeping track of the page table levels that are cleared and provide a means to query the smallest granule required for invalidation. Acked-by: Peter Zijlstra (Intel) Acked-by: Nicholas Piggin Signed-off-by: Will Deacon --- mm/memory.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'mm/memory.c') diff --git a/mm/memory.c b/mm/memory.c index c467102a5cbc..9135f48e8d84 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -267,8 +267,10 @@ void arch_tlb_finish_mmu(struct mmu_gather *tlb, { struct mmu_gather_batch *batch, *next; - if (force) + if (force) { + __tlb_reset_range(tlb); __tlb_adjust_range(tlb, start, end - start); + } tlb_flush_mmu(tlb); -- cgit v1.2.3-58-ga151