With TRANSPARENT_HUGEPAGE_PUD enabled the kernel can find huge PUD entries.
Add a helper to move huge PUD entries on mremap().
This will be used by a later patch to optimize mremap of PUD_SIZE aligned
level 4 PTE mapped address
This also make sure we support mremap on huge PUD entries even with
CONFIG_HAVE_MOVE_PUD disabled.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
---
mm/mremap.c | 80 ++++++++++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 73 insertions(+), 7 deletions(-)
diff --git a/mm/mremap.c b/mm/mremap.c
index 47c255b60150..92ab7d24a587 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -324,10 +324,62 @@ static inline bool move_normal_pud(struct vm_area_struct *vma,
}
#endif
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE_PUD
+static bool move_huge_pud(struct vm_area_struct *vma, unsigned long old_addr,
+ unsigned long new_addr, pud_t *old_pud, pud_t *new_pud)
+{
+ spinlock_t *old_ptl, *new_ptl;
+ struct mm_struct *mm = vma->vm_mm;
+ pud_t pud;
+
+ /*
+ * The destination pud shouldn't be established, free_pgtables()
+ * should have released it.
+ */
+ if (WARN_ON_ONCE(!pud_none(*new_pud)))
+ return false;
+
+ /*
+ * We don't have to worry about the ordering of src and dst
+ * ptlocks because exclusive mmap_lock prevents deadlock.
+ */
+ old_ptl = pud_lock(vma->vm_mm, old_pud);
+ new_ptl = pud_lockptr(mm, new_pud);
+ if (new_ptl != old_ptl)
+ spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING);
+
+ /* Clear the pud */
+ pud = *old_pud;
+ pud_clear(old_pud);
+
+ VM_BUG_ON(!pud_none(*new_pud));
+
+ /* Set the new pud */
+ /* mark soft_ditry when we add pud level soft dirty support */
+ set_pud_at(mm, new_addr, new_pud, pud);
+ flush_pud_tlb_range(vma, old_addr, old_addr + HPAGE_PUD_SIZE);
+ if (new_ptl != old_ptl)
+ spin_unlock(new_ptl);
+ spin_unlock(old_ptl);
+
+ return true;
+}
+#else
+static bool move_huge_pud(struct vm_area_struct *vma, unsigned long old_addr,
+ unsigned long new_addr, pud_t *old_pud, pud_t *new_pud)
+{
+ WARN_ON_ONCE(1);
+ return false;
+
+}
+#endif
+
enum pgt_entry {
NORMAL_PMD,
HPAGE_PMD,
NORMAL_PUD,
+ HPAGE_PUD,
};
/*
@@ -347,6 +399,7 @@ static __always_inline unsigned long get_extent(enum pgt_entry entry,
mask = PMD_MASK;
size = PMD_SIZE;
break;
+ case HPAGE_PUD:
case NORMAL_PUD:
mask = PUD_MASK;
size = PUD_SIZE;
@@ -395,6 +448,11 @@ static bool move_pgt_entry(enum pgt_entry entry, struct vm_area_struct *vma,
move_huge_pmd(vma, old_addr, new_addr, old_entry,
new_entry);
break;
+ case HPAGE_PUD:
+ moved = move_huge_pud(vma, old_addr, new_addr, old_entry,
+ new_entry);
+ break;
+
default:
WARN_ON_ONCE(1);
break;
@@ -414,6 +472,7 @@ unsigned long move_page_tables(struct vm_area_struct *vma,
unsigned long extent, old_end;
struct mmu_notifier_range range;
pmd_t *old_pmd, *new_pmd;
+ pud_t *old_pud, *new_pud;
old_end = old_addr + len;
flush_cache_range(vma, old_addr, old_end);
@@ -429,15 +488,22 @@ unsigned long move_page_tables(struct vm_area_struct *vma,
* PUD level if possible.
*/
extent = get_extent(NORMAL_PUD, old_addr, old_end, new_addr);
- if (IS_ENABLED(CONFIG_HAVE_MOVE_PUD) && extent == PUD_SIZE) {
- pud_t *old_pud, *new_pud;
- old_pud = get_old_pud(vma->vm_mm, old_addr);
- if (!old_pud)
+ old_pud = get_old_pud(vma->vm_mm, old_addr);
+ if (!old_pud)
+ continue;
+ new_pud = alloc_new_pud(vma->vm_mm, vma, new_addr);
+ if (!new_pud)
+ break;
+ if (pud_trans_huge(*old_pud) || pud_devmap(*old_pud)) {
+ if (extent == HPAGE_PUD_SIZE) {
+ move_pgt_entry(HPAGE_PUD, vma, old_addr, new_addr,
+ old_pud, new_pud, need_rmap_locks);
+ /* We ignore and continue on error? */
continue;
- new_pud = alloc_new_pud(vma->vm_mm, vma, new_addr);
- if (!new_pud)
- break;
+ }
+ } else if (IS_ENABLED(CONFIG_HAVE_MOVE_PUD) && extent == PUD_SIZE) {
+
if (move_pgt_entry(NORMAL_PUD, vma, old_addr, new_addr,
old_pud, new_pud, need_rmap_locks))
continue;
--
2.31.1
