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mm-allocate-thp-on-hugezeropage-wp-fault.patch removed from -mm tree

merged mm-stable Andrew Morton 1 participant 1 message Nov 6, 2024

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The quilt patch titled
Subject: mm: allocate THP on hugezeropage wp-fault
has been removed from the -mm tree. Its filename was
mm-allocate-thp-on-hugezeropage-wp-fault.patch

This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Dev Jain <[email protected]>
Subject: mm: allocate THP on hugezeropage wp-fault
Date: Tue, 8 Oct 2024 11:47:46 +0530

Introduce do_huge_zero_wp_pmd() to handle wp-fault on a hugezeropage and replace it with a PMD-mapped THP. Remember to flush TLB entry corresponding to the hugezeropage. In case of failure, fallback to splitting the PMD.

Link https://lkml.kernel.org/r/[email protected] open here
Signed-off-by Dev Jain <[email protected]>
Acked-by David Hildenbrand <[email protected]>
Reviewed-by Kefeng Wang <[email protected]>
Cc Alistair Popple <[email protected]>
Cc Aneesh Kumar K.V <[email protected]>
Cc Anshuman Khandual <[email protected]>
Cc Barry Song <[email protected]>
Cc Catalin Marinas <[email protected]>
Cc Christoph Lameter <[email protected]>
Cc Dave Hansen <[email protected]>
Cc Dev Jain <[email protected]>
Cc Hugh Dickins <[email protected]>
Cc Jan Kara <[email protected]>
Cc Kirill A. Shutemov <[email protected]>
Cc Lance Yang <[email protected]>
Cc Mark Rutland <[email protected]>
Cc Matthew Wilcox <[email protected]>
Cc Michal Hocko <[email protected]>
Cc Peter Xu <[email protected]>
Cc Ryan Roberts <[email protected]>
Cc Vlastimil Babka <[email protected]>
Cc Will Deacon <[email protected]>
Cc Yang Shi <[email protected]>
Cc Zi Yan <[email protected]>
Signed-off-by Andrew Morton <[email protected]>

---

 mm/huge_memory.c |   41 ++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 40 insertions(+), 1 deletion(-)
mm/huge_memory.c renamed from mm/huge_memory.c~mm-allocate-thp-on-hugezeropage-wp-fault +40 -1
@@ -1781,6 +1781,38 @@ unlock:
 	spin_unlock(vmf->ptl);
 }
 
+static vm_fault_t do_huge_zero_wp_pmd(struct vm_fault *vmf)
+{
+	unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
+	struct vm_area_struct *vma = vmf->vma;
+	struct mmu_notifier_range range;
+	struct folio *folio;
+	vm_fault_t ret = 0;
+
+	folio = vma_alloc_anon_folio_pmd(vma, vmf->address);
+	if (unlikely(!folio))
+		return VM_FAULT_FALLBACK;
+
+	mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma->vm_mm, haddr,
+				haddr + HPAGE_PMD_SIZE);
+	mmu_notifier_invalidate_range_start(&range);
+	vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd);
+	if (unlikely(!pmd_same(pmdp_get(vmf->pmd), vmf->orig_pmd)))
+		goto release;
+	ret = check_stable_address_space(vma->vm_mm);
+	if (ret)
+		goto release;
+	(void)pmdp_huge_clear_flush(vma, haddr, vmf->pmd);
+	map_anon_folio_pmd(folio, vmf->pmd, vma, haddr);
+	goto unlock;
+release:
+	folio_put(folio);
+unlock:
+	spin_unlock(vmf->ptl);
+	mmu_notifier_invalidate_range_end(&range);
+	return ret;
+}
+
 vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf)
 {
 	const bool unshare = vmf->flags & FAULT_FLAG_UNSHARE;

@@ -1793,8 +1825,15 @@ vm_fault_t do_huge_pmd_wp_page(struct vm
 	vmf->ptl = pmd_lockptr(vma->vm_mm, vmf->pmd);
 	VM_BUG_ON_VMA(!vma->anon_vma, vma);
 
-	if (is_huge_zero_pmd(orig_pmd))
+	if (is_huge_zero_pmd(orig_pmd)) {
+		vm_fault_t ret = do_huge_zero_wp_pmd(vmf);
+
+		if (!(ret & VM_FAULT_FALLBACK))
+			return ret;
+
+		/* Fallback to splitting PMD if THP cannot be allocated */
 		goto fallback;
+	}
 
 	spin_lock(vmf->ptl);

_

Patches currently in -mm which might be from [email protected] are