Commit 86f35f69 authored by Yin Fengwei's avatar Yin Fengwei Committed by Andrew Morton
Browse files

rmap: add folio_add_file_rmap_range() 

folio_add_file_rmap_range() allows to add pte mapping to a specific range
of file folio.  Comparing to page_add_file_rmap(), it batched updates
__lruvec_stat for large folio.

Link: https://lkml.kernel.org/r/20230802151406.3735276-36-willy@infradead.org


Signed-off-by: default avatarYin Fengwei <fengwei.yin@intel.com>
Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent de74976e

include/linux/rmap.h

+2 −0
Original line number Diff line number Diff line
@@ -198,6 +198,8 @@ void folio_add_new_anon_rmap(struct folio *, struct vm_area_struct *, 
		unsigned long address);

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,

		struct vm_area_struct *, bool compound);

void page_remove_rmap(struct page *, struct vm_area_struct *,

		bool compound);

mm/rmap.c

+46 −14
Original line number Diff line number Diff line
@@ -1294,31 +1294,39 @@ void folio_add_new_anon_rmap(struct folio *folio, struct vm_area_struct *vma, 
}



/**

 * page_add_file_rmap - add pte mapping to a file page

 * @page:	the page to add the mapping to

 * folio_add_file_rmap_range - add pte mapping to page range of a folio

 * @folio:	The folio to add the mapping to

 * @page:	The first page to add

 * @nr_pages:	The number of pages which will be mapped

 * @vma:	the vm area in which the mapping is added

 * @compound:	charge the page as compound or small page

 *

 * The page range of folio is defined by [first_page, first_page + nr_pages)

 *

 * The caller needs to hold the pte lock.

 */

void page_add_file_rmap(struct page *page, struct vm_area_struct *vma,

void folio_add_file_rmap_range(struct folio *folio, struct page *page,

			unsigned int nr_pages, struct vm_area_struct *vma,

			bool compound)

{

	struct folio *folio = page_folio(page);

	atomic_t *mapped = &folio->_nr_pages_mapped;

	int nr = 0, nr_pmdmapped = 0;

	bool first;

	unsigned int nr_pmdmapped = 0, first;

	int nr = 0;



	VM_BUG_ON_PAGE(compound && !PageTransHuge(page), page);

	VM_WARN_ON_FOLIO(compound && !folio_test_pmd_mappable(folio), folio);



	/* Is page being mapped by PTE? Is this its first map to be added? */

	if (likely(!compound)) {

		do {

			first = atomic_inc_and_test(&page->_mapcount);

		nr = first;

			if (first && folio_test_large(folio)) {

			nr = atomic_inc_return_relaxed(mapped);

			nr = (nr < COMPOUND_MAPPED);

				first = atomic_inc_return_relaxed(mapped);

				first = (first < COMPOUND_MAPPED);

			}



			if (first)

				nr++;

		} while (page++, --nr_pages > 0);

	} else if (folio_test_pmd_mappable(folio)) {

		/* That test is redundant: it's for safety or to optimize out */
@@ -1347,6 +1355,30 @@ void page_add_file_rmap(struct page *page, struct vm_area_struct *vma, 
	mlock_vma_folio(folio, vma, compound);

}



/**

 * page_add_file_rmap - add pte mapping to a file page

 * @page:	the page to add the mapping to

 * @vma:	the vm area in which the mapping is added

 * @compound:	charge the page as compound or small page

 *

 * The caller needs to hold the pte lock.

 */

void page_add_file_rmap(struct page *page, struct vm_area_struct *vma,

		bool compound)

{

	struct folio *folio = page_folio(page);

	unsigned int nr_pages;



	VM_WARN_ON_ONCE_PAGE(compound && !PageTransHuge(page), page);



	if (likely(!compound))

		nr_pages = 1;

	else

		nr_pages = folio_nr_pages(folio);



	folio_add_file_rmap_range(folio, page, nr_pages, vma, compound);

}



/**

 * page_remove_rmap - take down pte mapping from a page

 * @page:	page to remove mapping from