The patch titled
Subject: mm/hugetlb: simplify hugetlb unmap
has been added to the -mm tree. Its filename is
mm-hugetlb-simplify-hugetlb-unmap.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-hugetlb-simplify-hugetlb-unmap.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-hugetlb-simplify-hugetlb-unmap.patch
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------------------------------------------------------
From: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Subject: mm/hugetlb: simplify hugetlb unmap
For hugetlb like THP (and unlike regular page), we do tlb flush after
dropping ptl. Because of the above, we don't need to track force_flush
like we do now. Instead we can simply call tlb_remove_page() which will
do the flush if needed.
No functionality change in this patch.
Link: http://lkml.kernel.org/r/1464860389-29019-1-git-send-email-aneesh.kumar@xxxxxxxxxxxxxxxxxx
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Minchan Kim <minchan.kim@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/hugetlb.c | 54 +++++++++++++++++++------------------------------
1 file changed, 21 insertions(+), 33 deletions(-)
diff -puN mm/hugetlb.c~mm-hugetlb-simplify-hugetlb-unmap mm/hugetlb.c
--- a/mm/hugetlb.c~mm-hugetlb-simplify-hugetlb-unmap
+++ a/mm/hugetlb.c
@@ -3176,7 +3176,6 @@ void __unmap_hugepage_range(struct mmu_g
unsigned long start, unsigned long end,
struct page *ref_page)
{
- int force_flush = 0;
struct mm_struct *mm = vma->vm_mm;
unsigned long address;
pte_t *ptep;
@@ -3195,19 +3194,22 @@ void __unmap_hugepage_range(struct mmu_g
tlb_start_vma(tlb, vma);
mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
address = start;
-again:
for (; address < end; address += sz) {
ptep = huge_pte_offset(mm, address);
if (!ptep)
continue;
ptl = huge_pte_lock(h, mm, ptep);
- if (huge_pmd_unshare(mm, &address, ptep))
- goto unlock;
+ if (huge_pmd_unshare(mm, &address, ptep)) {
+ spin_unlock(ptl);
+ continue;
+ }
pte = huge_ptep_get(ptep);
- if (huge_pte_none(pte))
- goto unlock;
+ if (huge_pte_none(pte)) {
+ spin_unlock(ptl);
+ continue;
+ }
/*
* Migrating hugepage or HWPoisoned hugepage is already
@@ -3215,7 +3217,8 @@ again:
*/
if (unlikely(!pte_present(pte))) {
huge_pte_clear(mm, address, ptep);
- goto unlock;
+ spin_unlock(ptl);
+ continue;
}
page = pte_page(pte);
@@ -3225,9 +3228,10 @@ again:
* are about to unmap is the actual page of interest.
*/
if (ref_page) {
- if (page != ref_page)
- goto unlock;
-
+ if (page != ref_page) {
+ spin_unlock(ptl);
+ continue;
+ }
/*
* Mark the VMA as having unmapped its page so that
* future faults in this VMA will fail rather than
@@ -3243,30 +3247,14 @@ again:
hugetlb_count_sub(pages_per_huge_page(h), mm);
page_remove_rmap(page, true);
- force_flush = !__tlb_remove_page(tlb, page);
- if (force_flush) {
- address += sz;
- spin_unlock(ptl);
- break;
- }
- /* Bail out after unmapping reference page if supplied */
- if (ref_page) {
- spin_unlock(ptl);
- break;
- }
-unlock:
+
spin_unlock(ptl);
- }
- /*
- * mmu_gather ran out of room to batch pages, we break out of
- * the PTE lock to avoid doing the potential expensive TLB invalidate
- * and page-free while holding it.
- */
- if (force_flush) {
- force_flush = 0;
- tlb_flush_mmu(tlb);
- if (address < end && !ref_page)
- goto again;
+ tlb_remove_page(tlb, page);
+ /*
+ * Bail out after unmapping reference page if supplied
+ */
+ if (ref_page)
+ break;
}
mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
tlb_end_vma(tlb, vma);
_
Patches currently in -mm which might be from aneesh.kumar@xxxxxxxxxxxxxxxxxx are
mm-debug-add-vm_warn-which-maps-to-warn.patch
powerpc-mm-check-for-irq-disabled-only-if-debug_vm-is-enabled.patch
mm-hugetlb-simplify-hugetlb-unmap.patch
mm-change-the-interface-for-__tlb_remove_page.patch
mm-mmu_gather-track-page-size-with-mmu-gather-and-force-flush-if-page-size-change.patch
powerpc-mm-radix-implement-tlb-mmu-gather-flush-efficiently.patch
a.patch
--
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