From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Date: Thu, 6 Jun 2013 00:14:04 +0000 (-0700)
Subject: mm/THP: withdraw the pgtable after pmdp related operations
X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=a6bf2bb03e5bad7e9289d80ecb5faac11630c7ab;p=deliverable%2Flinux.git

mm/THP: withdraw the pgtable after pmdp related operations

For architectures like ppc64 we look at deposited pgtable when calling
pmdp_get_and_clear.  So do the pgtable_trans_huge_withdraw after finishing
pmdp related operations.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 6b785e17b679..5c4fac2d239e 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1360,9 +1360,15 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
 		struct page *page;
 		pgtable_t pgtable;
 		pmd_t orig_pmd;
-		pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd);
+		/*
+		 * For architectures like ppc64 we look at deposited pgtable
+		 * when calling pmdp_get_and_clear. So do the
+		 * pgtable_trans_huge_withdraw after finishing pmdp related
+		 * operations.
+		 */
 		orig_pmd = pmdp_get_and_clear(tlb->mm, addr, pmd);
 		tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
+		pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd);
 		if (is_huge_zero_pmd(orig_pmd)) {
 			tlb->mm->nr_ptes--;
 			spin_unlock(&tlb->mm->page_table_lock);