Subject: [merged] 
mm-thp-use-pmd_populate-to-update-the-pmd-with-pgtable_t-pointer.patch removed 
from -mm tree
To: 
[email protected],[email protected],[email protected],[email protected],[email protected],[email protected]
From: [email protected]
Date: Tue, 28 May 2013 12:36:57 -0700


The patch titled
     Subject: mm/THP: use pmd_populate() to update the pmd with pgtable_t 
pointer
has been removed from the -mm tree.  Its filename was
     mm-thp-use-pmd_populate-to-update-the-pmd-with-pgtable_t-pointer.patch

This patch was dropped because it was merged into mainline or a subsystem tree

------------------------------------------------------
From: "Aneesh Kumar K.V" <[email protected]>
Subject: mm/THP: use pmd_populate() to update the pmd with pgtable_t pointer

We should not use set_pmd_at to update pmd_t with pgtable_t pointer. 
set_pmd_at is used to set pmd with huge pte entries and architectures like
ppc64, clear few flags from the pte when saving a new entry.  Without this
change we observe bad pte errors like below on ppc64 with THP enabled.

BUG: Bad page map in process ld mm=0xc000001ee39f4780 pte:7fc3f37848000001 
pmd:c000001ec0000000

Signed-off-by: Aneesh Kumar K.V <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Reviewed-by: Andrea Arcangeli <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
---

 mm/huge_memory.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff -puN 
mm/huge_memory.c~mm-thp-use-pmd_populate-to-update-the-pmd-with-pgtable_t-pointer
 mm/huge_memory.c
--- 
a/mm/huge_memory.c~mm-thp-use-pmd_populate-to-update-the-pmd-with-pgtable_t-pointer
+++ a/mm/huge_memory.c
@@ -2325,7 +2325,12 @@ static void collapse_huge_page(struct mm
                pte_unmap(pte);
                spin_lock(&mm->page_table_lock);
                BUG_ON(!pmd_none(*pmd));
-               set_pmd_at(mm, address, pmd, _pmd);
+               /*
+                * We can only use set_pmd_at when establishing
+                * hugepmds and never for establishing regular pmds that
+                * points to regular pagetables. Use pmd_populate for that
+                */
+               pmd_populate(mm, pmd, pmd_pgtable(_pmd));
                spin_unlock(&mm->page_table_lock);
                anon_vma_unlock_write(vma->anon_vma);
                goto out;
_

Patches currently in -mm which might be from [email protected] are

mm-thp-use-the-right-function-when-updating-access-flags.patch
mm-thp-add-pmd-args-to-pgtable-deposit-and-withdraw-apis.patch
mm-thp-withdraw-the-pgtable-after-pmdp-related-operations.patch
mm-thp-withdraw-the-pgtable-after-pmdp-related-operations-fix.patch
mm-thp-dont-use-hpage_shift-in-transparent-hugepage-code.patch
mm-thp-deposit-the-transpare-huge-pgtable-before-set_pmd.patch

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