diff options
| author | David Hildenbrand <david@redhat.com> | 2023-12-20 23:44:28 +0100 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-12-29 11:58:48 -0800 |
| commit | ebe2e35ec0f256372c158a18de459fb60070b313 (patch) | |
| tree | 83ad314d721c02f1d3608413631f89c5b36f693b /include/linux/rmap.h | |
| parent | 44887f39945519fa8405133b1acd098fda9c9746 (diff) | |
mm/rmap: introduce and use hugetlb_try_dup_anon_rmap()
hugetlb rmap handling differs quite a lot from "ordinary" rmap code. For
example, hugetlb currently only supports entire mappings, and treats any
mapping as mapped using a single "logical PTE". Let's move it out of the
way so we can overhaul our "ordinary" rmap. implementation/interface.
So let's introduce and use hugetlb_try_dup_anon_rmap() to make all hugetlb
handling use dedicated hugetlb_* rmap functions.
Add sanity checks that we end up with the right folios in the right
functions.
Note that is_device_private_page() does not apply to hugetlb.
Link: https://lkml.kernel.org/r/20231220224504.646757-5-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Yin Fengwei <fengwei.yin@intel.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'include/linux/rmap.h')
| -rw-r--r-- | include/linux/rmap.h | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/include/linux/rmap.h b/include/linux/rmap.h index 56900a16f41a..5f26752de945 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -211,6 +211,22 @@ void hugetlb_add_anon_rmap(struct folio *, struct vm_area_struct *, void hugetlb_add_new_anon_rmap(struct folio *, struct vm_area_struct *, unsigned long address); +/* See page_try_dup_anon_rmap() */ +static inline int hugetlb_try_dup_anon_rmap(struct folio *folio, + struct vm_area_struct *vma) +{ + VM_WARN_ON_FOLIO(!folio_test_hugetlb(folio), folio); + VM_WARN_ON_FOLIO(!folio_test_anon(folio), folio); + + if (PageAnonExclusive(&folio->page)) { + if (unlikely(folio_needs_cow_for_dma(vma, folio))) + return -EBUSY; + ClearPageAnonExclusive(&folio->page); + } + atomic_inc(&folio->_entire_mapcount); + return 0; +} + static inline void hugetlb_add_file_rmap(struct folio *folio) { VM_WARN_ON_FOLIO(!folio_test_hugetlb(folio), folio); @@ -228,6 +244,8 @@ static inline void hugetlb_remove_rmap(struct folio *folio) static inline void __page_dup_rmap(struct page *page, bool compound) { + VM_WARN_ON(folio_test_hugetlb(page_folio(page))); + if (compound) { struct folio *folio = (struct folio *)page; |