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.
Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.vnet.ibm.com>
---
NOTE: This patch is already applied to -mm tree
mm/hugetlb.c | 54 +++++++++++++++++++++---------------------------------
1 file changed, 21 insertions(+), 33 deletions(-)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index c1f3c0be150a..0352296502b1 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3177,7 +3177,6 @@ void __unmap_hugepage_range(struct mmu_gather *tlb,
struct vm_area_struct *vma,
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;
@@ -3196,19 +3195,22 @@ void __unmap_hugepage_range(struct mmu_gather *tlb,
struct vm_area_struct *vma,
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
@@ -3216,7 +3218,8 @@ again:
*/
if (unlikely(!pte_present(pte))) {
huge_pte_clear(mm, address, ptep);
- goto unlock;
+ spin_unlock(ptl);
+ continue;
}
page = pte_page(pte);
@@ -3226,9 +3229,10 @@ 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
@@ -3244,30 +3248,14 @@ 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);
--
2.7.4
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