commit e77b0852b551ffd8b29fa0225e1ef62c195e3160
author Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Tue Jul 26 15:24:12 2016 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> Tue Jul 26 16:19:19 2016 -0700
tree a9f49cde2ef4814f78423addd7af592c549a0403
parent e9d55e157034a9efd99405c99c1565d64619d82b

mm/mmu_gather: track page size with mmu gather and force flush if page size change

This allows an arch which needs to do special handing with respect to
different page size when flushing tlb to implement the same in mmu
gather.

Link: http://lkml.kernel.org/r/1465049193-22197-3-git-send-email-aneesh.kumar@linux.vnet.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/huge_memory.c

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 343a2b7..23d1bf4 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1689,7 +1689,7 @@
 		pte_free(tlb->mm, pgtable_trans_huge_withdraw(tlb->mm, pmd));
 		atomic_long_dec(&tlb->mm->nr_ptes);
 		spin_unlock(ptl);
-		tlb_remove_page(tlb, page);
+		tlb_remove_page_size(tlb, page, HPAGE_PMD_SIZE);
 	}
 	return 1;
 }

mm/hugetlb.c

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 524c078..a9a8c31 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3250,7 +3250,7 @@
 		page_remove_rmap(page, true);
 
 		spin_unlock(ptl);
-		tlb_remove_page(tlb, page);
+		tlb_remove_page_size(tlb, page, huge_page_size(h));
 		/*
 		 * Bail out after unmapping reference page if supplied
 		 */

mm/memory.c

diff --git a/mm/memory.c b/mm/memory.c
index 12f3150..a329149 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -233,6 +233,7 @@
 #ifdef CONFIG_HAVE_RCU_TABLE_FREE
 	tlb->batch = NULL;
 #endif
+	tlb->page_size = 0;
 
 	__tlb_reset_range(tlb);
 }
@@ -294,12 +295,19 @@
  *	When out of page slots we must call tlb_flush_mmu().
  *returns true if the caller should flush.
  */
-bool __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
+bool __tlb_remove_page_size(struct mmu_gather *tlb, struct page *page, int page_size)
 {
 	struct mmu_gather_batch *batch;
 
 	VM_BUG_ON(!tlb->end);
 
+	if (!tlb->page_size)
+		tlb->page_size = page_size;
+	else {
+		if (page_size != tlb->page_size)
+			return true;
+	}
+
 	batch = tlb->active;
 	if (batch->nr == batch->max) {
 		if (!tlb_next_batch(tlb))