diff mbox series

[05/13] mm: Introduce vma_pgtable_walk_{begin|end}()

Message ID 20231219075538.414708-6-peterx@redhat.com (mailing list archive)
State New
Headers show
Series mm/gup: Unify hugetlb, part 2 | expand

Commit Message

Peter Xu Dec. 19, 2023, 7:55 a.m. UTC 
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(+)

Comments

Muchun Song Dec. 25, 2023, 6:34 a.m. UTC | #1 
> On Dec 19, 2023, at 15:55, peterx@redhat.com wrote:
> 
> 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>

Reviewed-by: Muchun Song <songmuchun@bytedance.com>

Thanks.
Muchun Song Jan. 2, 2024, 6:29 a.m. UTC | #2 
> On Jan 2, 2024, at 13:39, Peter Xu <peterx@redhat.com> wrote:
> 
> On Mon, Dec 25, 2023 at 02:34:48PM +0800, Muchun Song wrote:
>> Reviewed-by: Muchun Song <songmuchun@bytedance.com>
> 
> You're using the old email address here.  Do you want me to also use the
> linux.dev one that you suggested me to use?

Either is OK for the RB tag.

> 
> -- 
> Peter Xu
>
diff mbox series

Patch

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);
+}