diff mbox series

[v3,04/12] mm: Introduce vma_pgtable_walk_{begin|end}()

Message ID 20240321220802.679544-5-peterx@redhat.com (mailing list archive)
State Superseded
Headers show
Series mm/gup: Unify hugetlb, part 2 | expand

Checks

Context Check Description
conchuod/vmtest-fixes-PR fail merge-conflict

Commit Message

Peter Xu March 21, 2024, 10:07 p.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>
Reviewed-by: Muchun Song <muchun.song@linux.dev>
Signed-off-by: Peter Xu <peterx@redhat.com>
---
 include/linux/mm.h |  3 +++
 mm/memory.c        | 12 ++++++++++++
 2 files changed, 15 insertions(+)

Comments

Jason Gunthorpe March 22, 2024, 12:27 p.m. UTC | #1 
On Thu, Mar 21, 2024 at 06:07:54PM -0400, 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>
> Reviewed-by: Muchun Song <muchun.song@linux.dev>
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>  include/linux/mm.h |  3 +++
>  mm/memory.c        | 12 ++++++++++++
>  2 files changed, 15 insertions(+)

is_vm_hugetlb_page(vma) seems weirdly named. Regardless

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Jason
diff mbox series

Patch

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 8147b1302413..d10eb89f4096 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -4198,4 +4198,7 @@  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 9bce1fa76dd7..4f2caf1c3c4d 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -6438,3 +6438,15 @@  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);
+}