[PATCH 05/13] mm: Introduce vma_pgtable_walk_{begin|end}()
From: peterx@redhat.com
Date: 2023-12-19 07:57:00
Also in:
linux-arm-kernel, linux-mm, linux-riscv, lkml
Subsystem:
memory management, memory management - core, the rest · Maintainers:
Andrew Morton, David Hildenbrand, Linus Torvalds
From: Peter Xu <peterx@redhat.com> Introduce per-vma begin()/end() helpers for pgtable walks. This is a preparation work to merge hugetlb pgtable walkers with generic mm. The helpers need to be called before and after a pgtable walk, will start to be needed if the pgtable walker code supports hugetlb pages. It's a hook point for any type of VMA, but for now only hugetlb uses it to stablize the pgtable pages from getting away (due to possible pmd unsharing). Reviewed-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Peter Xu <peterx@redhat.com> --- include/linux/mm.h | 3 +++ mm/memory.c | 12 ++++++++++++ 2 files changed, 15 insertions(+)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index b72bf25a45cf..85e43775824b 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h@@ -4181,4 +4181,7 @@ static inline bool pfn_is_unaccepted_memory(unsigned long pfn) return range_contains_unaccepted_memory(paddr, paddr + PAGE_SIZE); } +void vma_pgtable_walk_begin(struct vm_area_struct *vma); +void vma_pgtable_walk_end(struct vm_area_struct *vma); + #endif /* _LINUX_MM_H */
diff --git a/mm/memory.c b/mm/memory.c
index 1795aba53cf5..9ac6a9db971e 100644
--- a/mm/memory.c
+++ b/mm/memory.c@@ -6270,3 +6270,15 @@ void ptlock_free(struct ptdesc *ptdesc) kmem_cache_free(page_ptl_cachep, ptdesc->ptl); } #endif + +void vma_pgtable_walk_begin(struct vm_area_struct *vma) +{ + if (is_vm_hugetlb_page(vma)) + hugetlb_vma_lock_read(vma); +} + +void vma_pgtable_walk_end(struct vm_area_struct *vma) +{ + if (is_vm_hugetlb_page(vma)) + hugetlb_vma_unlock_read(vma); +}
--
2.41.0