Commit 09c02e56 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Andrew Morton
Browse files

swap: convert add_to_swap() to take a folio 

The only caller already has a folio available, so this saves a conversion.
Also convert the return type to boolean.

Link: https://lkml.kernel.org/r/20220504182857.4013401-9-willy@infradead.org


Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent e2e3fdc7

mm/swap.h

+3 −3
Original line number Diff line number Diff line
@@ -32,7 +32,7 @@ extern struct address_space *swapper_spaces[]; 
		>> SWAP_ADDRESS_SPACE_SHIFT])



void show_swap_cache_info(void);

int add_to_swap(struct page *page);

bool add_to_swap(struct folio *folio);

void *get_shadow_from_swap_cache(swp_entry_t entry);

int add_to_swap_cache(struct page *page, swp_entry_t entry,

		      gfp_t gfp, void **shadowp);
@@ -119,9 +119,9 @@ struct page *find_get_incore_page(struct address_space *mapping, pgoff_t index) 
	return find_get_page(mapping, index);

}



static inline int add_to_swap(struct page *page)

static inline bool add_to_swap(struct folio *folio)

{

	return 0;

	return false;

}



static inline void *get_shadow_from_swap_cache(swp_entry_t entry)

mm/swap_state.c

+25 −22
Original line number Diff line number Diff line
@@ -176,24 +176,26 @@ void __delete_from_swap_cache(struct page *page, 
}



/**

 * add_to_swap - allocate swap space for a page

 * @page: page we want to move to swap

 * add_to_swap - allocate swap space for a folio

 * @folio: folio we want to move to swap

 *

 * Allocate swap space for the page and add the page to the

 * swap cache.  Caller needs to hold the page lock. 

 * Allocate swap space for the folio and add the folio to the

 * swap cache.

 *

 * Context: Caller needs to hold the folio lock.

 * Return: Whether the folio was added to the swap cache.

 */

int add_to_swap(struct page *page)

bool add_to_swap(struct folio *folio)

{

	struct folio *folio = page_folio(page);

	swp_entry_t entry;

	int err;



	VM_BUG_ON_PAGE(!PageLocked(page), page);

	VM_BUG_ON_PAGE(!PageUptodate(page), page);

	VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio);

	VM_BUG_ON_FOLIO(!folio_test_uptodate(folio), folio);



	entry = folio_alloc_swap(folio);

	if (!entry.val)

		return 0;

		return false;



	/*

	 * XArray node allocations from PF_MEMALLOC contexts could
@@ -206,7 +208,7 @@ int add_to_swap(struct page *page) 
	/*

	 * Add it to the swap cache.

	 */

	err = add_to_swap_cache(page, entry,

	err = add_to_swap_cache(&folio->page, entry,

			__GFP_HIGH|__GFP_NOMEMALLOC|__GFP_NOWARN, NULL);

	if (err)

		/*
@@ -215,22 +217,23 @@ int add_to_swap(struct page *page) 
		 */

		goto fail;

	/*

	 * Normally the page will be dirtied in unmap because its pte should be

	 * dirty. A special case is MADV_FREE page. The page's pte could have

	 * dirty bit cleared but the page's SwapBacked bit is still set because

	 * clearing the dirty bit and SwapBacked bit has no lock protected. For

	 * such page, unmap will not set dirty bit for it, so page reclaim will

	 * not write the page out. This can cause data corruption when the page

	 * is swap in later. Always setting the dirty bit for the page solves

	 * the problem.

	 * Normally the folio will be dirtied in unmap because its

	 * pte should be dirty. A special case is MADV_FREE page. The

	 * page's pte could have dirty bit cleared but the folio's

	 * SwapBacked flag is still set because clearing the dirty bit

	 * and SwapBacked flag has no lock protected. For such folio,

	 * unmap will not set dirty bit for it, so folio reclaim will

	 * not write the folio out. This can cause data corruption when

	 * the folio is swapped in later. Always setting the dirty flag

	 * for the folio solves the problem.

	 */

	set_page_dirty(page);

	folio_mark_dirty(folio);



	return 1;

	return true;



fail:

	put_swap_page(page, entry);

	return 0;

	put_swap_page(&folio->page, entry);

	return false;

}



/*

mm/vmscan.c

+3 −3
Original line number Diff line number Diff line
@@ -1731,8 +1731,8 @@ static unsigned int shrink_page_list(struct list_head *page_list, 
								page_list))

						goto activate_locked;

				}

				if (!add_to_swap(page)) {

					if (!PageTransHuge(page))

				if (!add_to_swap(folio)) {

					if (!folio_test_large(folio))

						goto activate_locked_split;

					/* Fallback to swap normal pages */

					if (split_folio_to_list(folio,
@@ -1741,7 +1741,7 @@ static unsigned int shrink_page_list(struct list_head *page_list, 
#ifdef CONFIG_TRANSPARENT_HUGEPAGE

					count_vm_event(THP_SWPOUT_FALLBACK);

#endif

					if (!add_to_swap(page))

					if (!add_to_swap(folio))

						goto activate_locked_split;

				}