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-rw-r--r--mm/rmap.c68
1 files changed, 37 insertions, 31 deletions
diff --git a/mm/rmap.c b/mm/rmap.c
index b0f612df7b9d..2c78f8cadc95 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -562,6 +562,27 @@ unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma)
return address;
}
+pmd_t *mm_find_pmd(struct mm_struct *mm, unsigned long address)
+{
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd = NULL;
+
+ pgd = pgd_offset(mm, address);
+ if (!pgd_present(*pgd))
+ goto out;
+
+ pud = pud_offset(pgd, address);
+ if (!pud_present(*pud))
+ goto out;
+
+ pmd = pmd_offset(pud, address);
+ if (!pmd_present(*pmd))
+ pmd = NULL;
+out:
+ return pmd;
+}
+
/*
* Check that @page is mapped at @address into @mm.
*
@@ -574,8 +595,6 @@ unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma)
pte_t *__page_check_address(struct page *page, struct mm_struct *mm,
unsigned long address, spinlock_t **ptlp, int sync)
{
- pgd_t *pgd;
- pud_t *pud;
pmd_t *pmd;
pte_t *pte;
spinlock_t *ptl;
@@ -586,17 +605,10 @@ pte_t *__page_check_address(struct page *page, struct mm_struct *mm,
goto check;
}
- pgd = pgd_offset(mm, address);
- if (!pgd_present(*pgd))
+ pmd = mm_find_pmd(mm, address);
+ if (!pmd)
return NULL;
- pud = pud_offset(pgd, address);
- if (!pud_present(*pud))
- return NULL;
-
- pmd = pmd_offset(pud, address);
- if (!pmd_present(*pmd))
- return NULL;
if (pmd_trans_huge(*pmd))
return NULL;
@@ -1139,9 +1151,11 @@ void page_remove_rmap(struct page *page)
* containing the swap entry, but page not yet written to swap.
*
* And we can skip it on file pages, so long as the filesystem
- * participates in dirty tracking; but need to catch shm and tmpfs
- * and ramfs pages which have been modified since creation by read
- * fault.
+ * participates in dirty tracking (note that this is not only an
+ * optimization but also solves problems caused by dirty flag in
+ * storage key getting set by a write from inside kernel); but need to
+ * catch shm and tmpfs and ramfs pages which have been modified since
+ * creation by read fault.
*
* Note that mapping must be decided above, before decrementing
* mapcount (which luckily provides a barrier): once page is unmapped,
@@ -1235,12 +1249,14 @@ int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
update_hiwater_rss(mm);
if (PageHWPoison(page) && !(flags & TTU_IGNORE_HWPOISON)) {
- if (PageAnon(page))
- dec_mm_counter(mm, MM_ANONPAGES);
- else
- dec_mm_counter(mm, MM_FILEPAGES);
+ if (!PageHuge(page)) {
+ if (PageAnon(page))
+ dec_mm_counter(mm, MM_ANONPAGES);
+ else
+ dec_mm_counter(mm, MM_FILEPAGES);
+ }
set_pte_at(mm, address, pte,
- swp_entry_to_pte(make_hwpoison_entry(page)));
+ swp_entry_to_pte(make_hwpoison_entry(page)));
} else if (PageAnon(page)) {
swp_entry_t entry = { .val = page_private(page) };
@@ -1345,8 +1361,6 @@ static int try_to_unmap_cluster(unsigned long cursor, unsigned int *mapcount,
struct vm_area_struct *vma, struct page *check_page)
{
struct mm_struct *mm = vma->vm_mm;
- pgd_t *pgd;
- pud_t *pud;
pmd_t *pmd;
pte_t *pte;
pte_t pteval;
@@ -1366,16 +1380,8 @@ static int try_to_unmap_cluster(unsigned long cursor, unsigned int *mapcount,
if (end > vma->vm_end)
end = vma->vm_end;
- pgd = pgd_offset(mm, address);
- if (!pgd_present(*pgd))
- return ret;
-
- pud = pud_offset(pgd, address);
- if (!pud_present(*pud))
- return ret;
-
- pmd = pmd_offset(pud, address);
- if (!pmd_present(*pmd))
+ pmd = mm_find_pmd(mm, address);
+ if (!pmd)
return ret;
mmun_start = address;