From fb7332a9fedfd62b1ba6530c86f39f0fa38afd49 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Wed, 29 Oct 2014 10:03:09 +0000 Subject: mmu_gather: move minimal range calculations into generic code On architectures with hardware broadcasting of TLB invalidation messages , it makes sense to reduce the range of the mmu_gather structure when unmapping page ranges based on the dirty address information passed to tlb_remove_tlb_entry. arm64 already does this by directly manipulating the start/end fields of the gather structure, but this confuses the generic code which does not expect these fields to change and can end up calculating invalid, negative ranges when forcing a flush in zap_pte_range. This patch moves the minimal range calculation out of the arm64 code and into the generic implementation, simplifying zap_pte_range in the process (which no longer needs to care about start/end, since they will point to the appropriate ranges already). With the range being tracked by core code, the need_flush flag is dropped in favour of checking that the end of the range has actually been set. Cc: Benjamin Herrenschmidt Cc: Peter Zijlstra Cc: Russell King - ARM Linux Cc: Michal Simek Acked-by: Linus Torvalds Signed-off-by: Will Deacon --- mm/memory.c | 30 ++++++++---------------------- 1 file changed, 8 insertions(+), 22 deletions(-) (limited to 'mm/memory.c') diff --git a/mm/memory.c b/mm/memory.c index 1cc6bfbd872e..c71edae9ba44 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -220,9 +220,6 @@ void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned long /* Is it from 0 to ~0? */ tlb->fullmm = !(start | (end+1)); tlb->need_flush_all = 0; - tlb->start = start; - tlb->end = end; - tlb->need_flush = 0; tlb->local.next = NULL; tlb->local.nr = 0; tlb->local.max = ARRAY_SIZE(tlb->__pages); @@ -232,15 +229,20 @@ void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned long #ifdef CONFIG_HAVE_RCU_TABLE_FREE tlb->batch = NULL; #endif + + __tlb_reset_range(tlb); } static void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb) { - tlb->need_flush = 0; + if (!tlb->end) + return; + tlb_flush(tlb); #ifdef CONFIG_HAVE_RCU_TABLE_FREE tlb_table_flush(tlb); #endif + __tlb_reset_range(tlb); } static void tlb_flush_mmu_free(struct mmu_gather *tlb) @@ -256,8 +258,6 @@ static void tlb_flush_mmu_free(struct mmu_gather *tlb) void tlb_flush_mmu(struct mmu_gather *tlb) { - if (!tlb->need_flush) - return; tlb_flush_mmu_tlbonly(tlb); tlb_flush_mmu_free(tlb); } @@ -292,7 +292,7 @@ int __tlb_remove_page(struct mmu_gather *tlb, struct page *page) { struct mmu_gather_batch *batch; - VM_BUG_ON(!tlb->need_flush); + VM_BUG_ON(!tlb->end); batch = tlb->active; batch->pages[batch->nr++] = page; @@ -359,8 +359,6 @@ void tlb_remove_table(struct mmu_gather *tlb, void *table) { struct mmu_table_batch **batch = &tlb->batch; - tlb->need_flush = 1; - /* * When there's less then two users of this mm there cannot be a * concurrent page-table walk. @@ -1185,20 +1183,8 @@ again: arch_leave_lazy_mmu_mode(); /* Do the actual TLB flush before dropping ptl */ - if (force_flush) { - unsigned long old_end; - - /* - * Flush the TLB just for the previous segment, - * then update the range to be the remaining - * TLB range. - */ - old_end = tlb->end; - tlb->end = addr; + if (force_flush) tlb_flush_mmu_tlbonly(tlb); - tlb->start = addr; - tlb->end = old_end; - } pte_unmap_unlock(start_pte, ptl); /* -- cgit v1.2.3