On 6/27/23 15:08, Yu Zhao wrote:
On Mon, Jun 26, 2023 at 11:14 AM Ryan Roberts <ryan.roberts@xxxxxxx> wrote:Like folio_add_new_anon_rmap() but batch-rmaps a range of pages belonging to a folio, for effciency savings. All pages are accounted as small pages. Signed-off-by: Ryan Roberts <ryan.roberts@xxxxxxx> --- include/linux/rmap.h | 2 ++ mm/rmap.c | 43 +++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 45 insertions(+) diff --git a/include/linux/rmap.h b/include/linux/rmap.h index a3825ce81102..15433a3d0cbf 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -196,6 +196,8 @@ void page_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long address); void folio_add_new_anon_rmap(struct folio *, struct vm_area_struct *, unsigned long address); +void folio_add_new_anon_rmap_range(struct folio *folio, struct page *page, + int nr, struct vm_area_struct *vma, unsigned long address);We should update folio_add_new_anon_rmap() to support large() && !folio_test_pmd_mappable() folios instead. I double checked all places currently using folio_add_new_anon_rmap(), and as expected, none actually allocates large() && !folio_test_pmd_mappable() and maps it one by one, which makes the cases simpler, i.e., if (!large()) // the existing basepage case else if (!folio_test_pmd_mappable()) // our new case else // the existing THP case
I suppose we can merge the new case and existing THP case. Regards Yin, Fengwei
void page_add_file_rmap(struct page *, struct vm_area_struct *, bool compound); void folio_add_file_rmap_range(struct folio *, struct page *, unsigned int nr, diff --git a/mm/rmap.c b/mm/rmap.c index 1d8369549424..4050bcea7ae7 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1305,6 +1305,49 @@ void folio_add_new_anon_rmap(struct folio *folio, struct vm_area_struct *vma, __page_set_anon_rmap(folio, &folio->page, vma, address, 1); } +/** + * folio_add_new_anon_rmap_range - Add mapping to a set of pages within a new + * anonymous potentially large folio. + * @folio: The folio containing the pages to be mapped + * @page: First page in the folio to be mapped + * @nr: Number of pages to be mapped + * @vma: the vm area in which the mapping is added + * @address: the user virtual address of the first page to be mapped + * + * Like folio_add_new_anon_rmap() but batch-maps a range of pages within a folio + * using non-THP accounting. Like folio_add_new_anon_rmap(), the inc-and-test is + * bypassed and the folio does not have to be locked. All pages in the folio are + * individually accounted. + * + * As the folio is new, it's assumed to be mapped exclusively by a single + * process. + */ +void folio_add_new_anon_rmap_range(struct folio *folio, struct page *page, + int nr, struct vm_area_struct *vma, unsigned long address) +{ + int i; + + VM_BUG_ON_VMA(address < vma->vm_start || + address + (nr << PAGE_SHIFT) > vma->vm_end, vma);BTW, VM_BUG_ON* shouldn't be used in new code: Documentation/process/coding-style.rst
