Re: [PATCH 1/3] mm: introduce VM_MAYBE_GUARD and make visible for guard regions
From: Randy Dunlap <rdunlap@infradead.org>
Date: 2025-10-29 19:50:24
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On 10/29/25 9:50 AM, Lorenzo Stoakes wrote:
quoted hunk ↗ jump to hunk
diff --git a/mm/memory.c b/mm/memory.c index 4c3a7e09a159..a2c79ee43d68 100644 --- a/mm/memory.c +++ b/mm/memory.c@@ -1478,6 +1478,10 @@ vma_needs_copy(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma) if (src_vma->anon_vma) return true; + /* Guard regions have momdified page tables that require copying. */
modified
+ if (src_vma->vm_flags & VM_MAYBE_GUARD) + return true; + /* * Don't copy ptes where a page fault will fill them correctly. Fork * becomes much lighter when there are big shared or private readonly
-- ~Randy