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Subject: + mm-mremap-calculate-extent-in-one-place.patch added to -mm tree
Date: Tue, 30 Jun 2020 19:31:33 -0700	[thread overview]
Message-ID: <> (raw)

The patch titled
     Subject: mm/mremap: calculate extent in one place
has been added to the -mm tree.  Its filename is

This patch should soon appear at
and later at

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From: Wei Yang <>
Subject: mm/mremap: calculate extent in one place

Page tables are moved on the base of PMD.  This requires both source and
destination range should meet the requirement.

Current code works well since move_huge_pmd() and move_normal_pmd() would
check old_addr and new_addr again.  And then return to move_ptes() if the
either of them is not aligned.

In stead of calculating the extent separately, it is better to calculate
in one place, so we know it is not necessary to try move pmd.  By doing
so, the logic seems a little clear.

Signed-off-by: Wei Yang <>
Tested-by: Dmitry Osipenko <>
Cc: Aneesh Kumar K.V <>
Cc: Anshuman Khandual <>
Cc: Kirill A. Shutemov <>
Cc: Matthew Wilcox (Oracle) <>
Cc: Michel Lespinasse <>
Cc: Peter Xu <>
Cc: Sean Christopherson <>
Cc: Thomas Hellstrom <>
Cc: Thomas Hellstrom (VMware) <>
Cc: Vlastimil Babka <>
Cc: Yang Shi <>
Signed-off-by: Andrew Morton <>

 mm/mremap.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/mm/mremap.c~mm-mremap-calculate-extent-in-one-place
+++ a/mm/mremap.c
@@ -258,6 +258,9 @@ unsigned long move_page_tables(struct vm
 		extent = next - old_addr;
 		if (extent > old_end - old_addr)
 			extent = old_end - old_addr;
+		next = (new_addr + PMD_SIZE) & PMD_MASK;
+		if (extent > next - new_addr)
+			extent = next - new_addr;
 		old_pmd = get_old_pmd(vma->vm_mm, old_addr);
 		if (!old_pmd)
@@ -301,9 +304,6 @@ unsigned long move_page_tables(struct vm
 		if (pte_alloc(new_vma->vm_mm, new_pmd))
-		next = (new_addr + PMD_SIZE) & PMD_MASK;
-		if (extent > next - new_addr)
-			extent = next - new_addr;
 		move_ptes(vma, old_pmd, old_addr, old_addr + extent, new_vma,
 			  new_pmd, new_addr, need_rmap_locks);

Patches currently in -mm which might be from are


             reply	other threads:[~2020-07-01  2:31 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-01  2:31 akpm [this message]
  -- strict thread matches above, loose matches on Subject: below --
2020-07-03 22:14 incoming Andrew Morton
2020-07-08 23:16 ` + mm-mremap-calculate-extent-in-one-place.patch added to -mm tree Andrew Morton
2020-01-19  0:07 akpm

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