The patch titled
Subject: mm/mremap: convert huge PUD move to separate helper
has been added to the -mm tree. Its filename is
mm-mremap-convert-huge-pud-move-to-separate-helper.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-mremap-convert-huge-pud-move-to-separate-helper.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-mremap-convert-huge-pud-move-to-separate-helper.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxx>
Subject: mm/mremap: convert huge PUD move to separate helper
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.
Link: https://lkml.kernel.org/r/20210616045239.370802-4-aneesh.kumar@xxxxxxxxxxxxx
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Joel Fernandes <joel@xxxxxxxxxxxxxxxxx>
Cc: Kalesh Singh <kaleshsingh@xxxxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Nicholas Piggin <npiggin@xxxxxxxxx>
Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mremap.c | 79 +++++++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 72 insertions(+), 7 deletions(-)
--- a/mm/mremap.c~mm-mremap-convert-huge-pud-move-to-separate-helper
+++ a/mm/mremap.c
@@ -324,10 +324,61 @@ static inline bool move_normal_pud(struc
}
#endif
+#ifdef CONFIG_HAVE_ARCH_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 +398,7 @@ static __always_inline unsigned long get
mask = PMD_MASK;
size = PMD_SIZE;
break;
+ case HPAGE_PUD:
case NORMAL_PUD:
mask = PUD_MASK;
size = PUD_SIZE;
@@ -395,6 +447,11 @@ static bool move_pgt_entry(enum pgt_entr
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 +471,7 @@ unsigned long move_page_tables(struct vm
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 +487,22 @@ unsigned long move_page_tables(struct vm
* 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;
_
Patches currently in -mm which might be from aneesh.kumar@xxxxxxxxxxxxx are
mm-rename-pud_page_vaddr-to-pud_pgtable-and-make-it-return-pmd_t.patch
mm-rename-pud_page_vaddr-to-pud_pgtable-and-make-it-return-pmd_t-fix-2.patch
mm-rename-p4d_page_vaddr-to-p4d_pgtable-and-make-it-return-pud_t.patch
mm-rename-p4d_page_vaddr-to-p4d_pgtable-and-make-it-return-pud_t-fix.patch
selftest-mremap_test-update-the-test-to-handle-pagesize-other-than-4k.patch
selftest-mremap_test-avoid-crash-with-static-build.patch
mm-mremap-convert-huge-pud-move-to-separate-helper.patch
mm-mremap-dont-enable-optimized-pud-move-if-page-table-levels-is-2.patch
mm-mremap-use-pmd-pud_poplulate-to-update-page-table-entries.patch
mm-mremap-hold-the-rmap-lock-in-write-mode-when-moving-page-table-entries.patch
mm-mremap-allow-arch-runtime-override.patch
powerpc-book3s64-mm-update-flush_tlb_range-to-flush-page-walk-cache.patch
powerpc-mm-enable-have_move_pmd-support.patch
