Unverified Commit 57733053 authored by openeuler-ci-bot's avatar openeuler-ci-bot Committed by Gitee
Browse files

!10188 Part of "mm: mapcount for large folios + page_mapcount() cleanups" 

Merge Pull Request from: @ci-robot 
 
PR sync from: Liu Shixin <liushixin2@huawei.com>
https://mailweb.openeuler.org/hyperkitty/list/kernel@openeuler.org/message/YXD7LKVKSNTJ5I4B7IZMNDD2RPJPDQGK/ 
Backport three patches from series "mm: mapcount for large folios +
page_mapcount() cleanups".

David Hildenbrand (3):
  mm: allow for detecting underflows with page_mapcount() again
  mm/rmap: always inline anon/file rmap duplication of a single PTE
  mm/rmap: add fast-path for small folios when
    adding/removing/duplicating


-- 
2.25.1
 
https://gitee.com/openeuler/kernel/issues/IAE0PK 
 
Link:https://gitee.com/openeuler/kernel/pulls/10188

 

Reviewed-by: default avatarKefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: default avatarZhang Peng <zhangpeng362@huawei.com>
parents bdc7d729 02916a9c

include/linux/mm.h

+1 −1
Original line number Diff line number Diff line
@@ -1228,7 +1228,7 @@ static inline int page_mapcount(struct page *page) 
	int mapcount = atomic_read(&page->_mapcount) + 1;



	/* Handle page_has_type() pages */

	if (mapcount < 0)

	if (mapcount < PAGE_MAPCOUNT_RESERVE + 1)

		mapcount = 0;

	if (unlikely(PageCompound(page)))

		mapcount += folio_entire_mapcount(page_folio(page));

include/linux/rmap.h

+26 −4
Original line number Diff line number Diff line
@@ -319,6 +319,11 @@ static __always_inline void __folio_dup_file_rmap(struct folio *folio, 


	switch (level) {

	case RMAP_LEVEL_PTE:

		if (!folio_test_large(folio)) {

			atomic_inc(&page->_mapcount);

			break;

		}



		do {

			atomic_inc(&page->_mapcount);

		} while (page++, --nr_pages > 0);
@@ -344,8 +349,12 @@ static inline void folio_dup_file_rmap_ptes(struct folio *folio, 
{

	__folio_dup_file_rmap(folio, page, nr_pages, RMAP_LEVEL_PTE);

}

#define folio_dup_file_rmap_pte(folio, page) \

	folio_dup_file_rmap_ptes(folio, page, 1)



static __always_inline void folio_dup_file_rmap_pte(struct folio *folio,

		struct page *page)

{

	__folio_dup_file_rmap(folio, page, 1, RMAP_LEVEL_PTE);

}



/**

 * folio_dup_file_rmap_pmd - duplicate a PMD mapping of a page range of a folio
@@ -398,6 +407,14 @@ static __always_inline int __folio_try_dup_anon_rmap(struct folio *folio, 
				if (PageAnonExclusive(page + i))

					return -EBUSY;

		}



		if (!folio_test_large(folio)) {

			if (PageAnonExclusive(page))

				ClearPageAnonExclusive(page);

			atomic_inc(&page->_mapcount);

			break;

		}



		do {

			if (PageAnonExclusive(page))

				ClearPageAnonExclusive(page);
@@ -445,8 +462,13 @@ static inline int folio_try_dup_anon_rmap_ptes(struct folio *folio, 
	return __folio_try_dup_anon_rmap(folio, page, nr_pages, src_vma,

					 RMAP_LEVEL_PTE);

}

#define folio_try_dup_anon_rmap_pte(folio, page, vma) \

	folio_try_dup_anon_rmap_ptes(folio, page, 1, vma)



static __always_inline int folio_try_dup_anon_rmap_pte(struct folio *folio,

		struct page *page, struct vm_area_struct *src_vma)

{

	return __folio_try_dup_anon_rmap(folio, page, 1, src_vma,

					 RMAP_LEVEL_PTE);

}



/**

 * folio_try_dup_anon_rmap_pmd - try duplicating a PMD mapping of a page range

mm/rmap.c

+16 −10
Original line number Diff line number Diff line
@@ -1137,15 +1137,18 @@ static __always_inline unsigned int __folio_add_rmap(struct folio *folio, 


	switch (level) {

	case RMAP_LEVEL_PTE:

		if (!folio_test_large(folio)) {

			nr = atomic_inc_and_test(&page->_mapcount);

			break;

		}



		do {

			first = atomic_inc_and_test(&page->_mapcount);

			if (first && folio_test_large(folio)) {

			if (first) {

				first = atomic_inc_return_relaxed(mapped);

				first = (first < ENTIRELY_MAPPED);

			}



			if (first)

				if (first < ENTIRELY_MAPPED)

					nr++;

			}

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

		break;

	case RMAP_LEVEL_PMD:
@@ -1480,15 +1483,18 @@ static __always_inline void __folio_remove_rmap(struct folio *folio, 


	switch (level) {

	case RMAP_LEVEL_PTE:

		if (!folio_test_large(folio)) {

			nr = atomic_add_negative(-1, &page->_mapcount);

			break;

		}



		do {

			last = atomic_add_negative(-1, &page->_mapcount);

			if (last && folio_test_large(folio)) {

			if (last) {

				last = atomic_dec_return_relaxed(mapped);

				last = (last < ENTIRELY_MAPPED);

			}



			if (last)

				if (last < ENTIRELY_MAPPED)

					nr++;

			}

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



		partially_mapped = nr && atomic_read(mapped);