aboutsummaryrefslogtreecommitdiffstats
path: root/mm/huge_memory.c
diff options
context:
space:
mode:
Diffstat (limited to 'mm/huge_memory.c')
-rw-r--r--mm/huge_memory.c71
1 files changed, 51 insertions, 20 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 283963032eff..51068ef1dff5 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2078,7 +2078,7 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
put_page(page);
add_mm_counter(mm, MM_FILEPAGES, -HPAGE_PMD_NR);
return;
- } else if (is_huge_zero_pmd(*pmd)) {
+ } else if (pmd_trans_huge(*pmd) && is_huge_zero_pmd(*pmd)) {
return __split_huge_zero_page_pmd(vma, haddr, pmd);
}
@@ -2131,27 +2131,33 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
pte = pte_offset_map(&_pmd, addr);
BUG_ON(!pte_none(*pte));
set_pte_at(mm, addr, pte, entry);
- atomic_inc(&page[i]._mapcount);
- pte_unmap(pte);
- }
-
- /*
- * Set PG_double_map before dropping compound_mapcount to avoid
- * false-negative page_mapped().
- */
- if (compound_mapcount(page) > 1 && !TestSetPageDoubleMap(page)) {
- for (i = 0; i < HPAGE_PMD_NR; i++)
+ if (!pmd_migration)
atomic_inc(&page[i]._mapcount);
+ pte_unmap(pte);
}
- if (atomic_add_negative(-1, compound_mapcount_ptr(page))) {
- /* Last compound_mapcount is gone. */
- __dec_node_page_state(page, NR_ANON_THPS);
- if (TestClearPageDoubleMap(page)) {
- /* No need in mapcount reference anymore */
+ if (!pmd_migration) {
+ /*
+ * Set PG_double_map before dropping compound_mapcount to avoid
+ * false-negative page_mapped().
+ */
+ if (compound_mapcount(page) > 1 &&
+ !TestSetPageDoubleMap(page)) {
for (i = 0; i < HPAGE_PMD_NR; i++)
- atomic_dec(&page[i]._mapcount);
+ atomic_inc(&page[i]._mapcount);
+ }
+
+ lock_page_memcg(page);
+ if (atomic_add_negative(-1, compound_mapcount_ptr(page))) {
+ /* Last compound_mapcount is gone. */
+ __dec_lruvec_page_state(page, NR_ANON_THPS);
+ if (TestClearPageDoubleMap(page)) {
+ /* No need in mapcount reference anymore */
+ for (i = 0; i < HPAGE_PMD_NR; i++)
+ atomic_dec(&page[i]._mapcount);
+ }
}
+ unlock_page_memcg(page);
}
smp_wmb(); /* make pte visible before pmd */
@@ -2193,6 +2199,8 @@ void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
spinlock_t *ptl;
struct mm_struct *mm = vma->vm_mm;
unsigned long haddr = address & HPAGE_PMD_MASK;
+ bool was_locked = false;
+ pmd_t _pmd;
mmu_notifier_invalidate_range_start(mm, haddr, haddr + HPAGE_PMD_SIZE);
ptl = pmd_lock(mm, pmd);
@@ -2202,11 +2210,32 @@ void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
* pmd against. Otherwise we can end up replacing wrong page.
*/
VM_BUG_ON(freeze && !page);
- if (page && page != pmd_page(*pmd))
- goto out;
+ if (page) {
+ VM_WARN_ON_ONCE(!PageLocked(page));
+ was_locked = true;
+ if (page != pmd_page(*pmd))
+ goto out;
+ }
+repeat:
if (pmd_trans_huge(*pmd)) {
- page = pmd_page(*pmd);
+ if (!page) {
+ page = pmd_page(*pmd);
+ if (unlikely(!trylock_page(page))) {
+ get_page(page);
+ _pmd = *pmd;
+ spin_unlock(ptl);
+ lock_page(page);
+ spin_lock(ptl);
+ if (unlikely(!pmd_same(*pmd, _pmd))) {
+ unlock_page(page);
+ put_page(page);
+ page = NULL;
+ goto repeat;
+ }
+ put_page(page);
+ }
+ }
if (PageMlocked(page))
clear_page_mlock(page);
} else if (!(pmd_devmap(*pmd) || is_pmd_migration_entry(*pmd)))
@@ -2214,6 +2243,8 @@ void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
__split_huge_pmd_locked(vma, pmd, haddr, freeze);
out:
spin_unlock(ptl);
+ if (!was_locked && page)
+ unlock_page(page);
mmu_notifier_invalidate_range_end(mm, haddr, haddr + HPAGE_PMD_SIZE);
}