The patch titled
Subject: mm/hugetlb: introduce set_huge_swap_pte_at() helper
has been added to the -mm tree. Its filename is
mm-hugetlb-introduce-set_huge_swap_pte_at-helper.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-hugetlb-introduce-set_huge_swap_pte_at-helper.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-hugetlb-introduce-set_huge_swap_pte_at-helper.patch
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------------------------------------------------------
From: Punit Agrawal <punit.agrawal@xxxxxxx>
Subject: mm/hugetlb: introduce set_huge_swap_pte_at() helper
set_huge_pte_at(), an architecture callback to populate hugepage ptes,
does not provide the range of virtual memory that is targeted. This leads
to ambiguity when dealing with swap entries on architectures that support
hugepages consisting of contiguous ptes.
Fix the problem by introducing an overridable helper that is called when
populating the page tables with swap entries. The size of the targeted
region is provided to the helper to help determine the number of entries
to be updated.
Provide a default implementation that maintains the current behaviour.
Link: http://lkml.kernel.org/r/20170522133604.11392-6-punit.agrawal@xxxxxxx
Signed-off-by: Punit Agrawal <punit.agrawal@xxxxxxx>
Acked-by: Steve Capper <steve.capper@xxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Hillf Danton <hillf.zj@xxxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/hugetlb.h | 3 +++
mm/hugetlb.c | 14 +++++++++++---
2 files changed, 14 insertions(+), 3 deletions(-)
diff -puN include/linux/hugetlb.h~mm-hugetlb-introduce-set_huge_swap_pte_at-helper include/linux/hugetlb.h
--- a/include/linux/hugetlb.h~mm-hugetlb-introduce-set_huge_swap_pte_at-helper
+++ a/include/linux/hugetlb.h
@@ -158,6 +158,9 @@ unsigned long hugetlb_change_protection(
unsigned long address, unsigned long end, pgprot_t newprot);
bool is_hugetlb_entry_migration(pte_t pte);
+
+void set_huge_swap_pte_at(struct mm_struct *mm, unsigned long addr,
+ pte_t *ptep, pte_t pte, unsigned long sz);
#else /* !CONFIG_HUGETLB_PAGE */
static inline void reset_vma_resv_huge_pages(struct vm_area_struct *vma)
diff -puN mm/hugetlb.c~mm-hugetlb-introduce-set_huge_swap_pte_at-helper mm/hugetlb.c
--- a/mm/hugetlb.c~mm-hugetlb-introduce-set_huge_swap_pte_at-helper
+++ a/mm/hugetlb.c
@@ -3224,6 +3224,12 @@ static int is_hugetlb_entry_hwpoisoned(p
return 0;
}
+void __weak set_huge_swap_pte_at(struct mm_struct *mm, unsigned long addr,
+ pte_t *ptep, pte_t pte, unsigned long sz)
+{
+ set_huge_pte_at(mm, addr, ptep, pte);
+}
+
int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
struct vm_area_struct *vma)
{
@@ -3276,9 +3282,10 @@ int copy_hugetlb_page_range(struct mm_st
*/
make_migration_entry_read(&swp_entry);
entry = swp_entry_to_pte(swp_entry);
- set_huge_pte_at(src, addr, src_pte, entry);
+ set_huge_swap_pte_at(src, addr, src_pte,
+ entry, sz);
}
- set_huge_pte_at(dst, addr, dst_pte, entry);
+ set_huge_swap_pte_at(dst, addr, dst_pte, entry, sz);
} else {
if (cow) {
huge_ptep_set_wrprotect(src, addr, src_pte);
@@ -4290,7 +4297,8 @@ unsigned long hugetlb_change_protection(
make_migration_entry_read(&entry);
newpte = swp_entry_to_pte(entry);
- set_huge_pte_at(mm, address, ptep, newpte);
+ set_huge_swap_pte_at(mm, address, ptep,
+ newpte, huge_page_size(h));
pages++;
}
spin_unlock(ptl);
_
Patches currently in -mm which might be from punit.agrawal@xxxxxxx are
mm-gup-ensure-real-head-page-is-ref-counted-when-using-hugepages.patch
mm-hugetlb-add-size-parameter-to-huge_pte_offset.patch
mm-hugetlb-allow-architectures-to-override-huge_pte_clear.patch
mm-hugetlb-introduce-set_huge_swap_pte_at-helper.patch
mm-rmap-use-correct-helper-when-poisoning-hugepages.patch
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