[Devel] [PATCH rh7 2/2] mm/swap: activate swapped in pages on fault

[Andrey Ryabinin]

Move swapped in anon pages directly to active list. This should
help us to prevent anon thrashing. Recently swapped in pages
has more chances to stay in memory.

https://pmc.acronis.com/browse/VSTOR-20859
Signed-off-by: Andrey Ryabinin <aryabinin at virtuozzo.com>
---
 include/linux/swap.h |  5 +++--
 mm/madvise.c         |  4 ++--
 mm/swap_state.c      | 16 ++++++++++------
 mm/swapfile.c        |  2 +-
 mm/zswap.c           |  2 +-
 5 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/include/linux/swap.h b/include/linux/swap.h
index 7797cb88870b..51d71b089f26 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -463,10 +463,11 @@ extern void free_page_and_swap_cache(struct page *);
 extern void free_pages_and_swap_cache(struct page **, int);
 extern struct page *lookup_swap_cache(swp_entry_t);
 extern struct page *read_swap_cache_async(swp_entry_t, gfp_t,
-			struct vm_area_struct *vma, unsigned long addr);
+			struct vm_area_struct *vma, unsigned long addr,
+			bool activate);
 extern struct page *__read_swap_cache_async(swp_entry_t, gfp_t,
 			struct vm_area_struct *vma, unsigned long addr,
-			bool *new_page_allocated);
+			bool *new_page_allocated, bool activate);
 extern struct page *swapin_readahead(swp_entry_t, gfp_t,
 			struct vm_area_struct *vma, unsigned long addr);
 
diff --git a/mm/madvise.c b/mm/madvise.c
index 586705116e6f..08afdc72f07a 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -212,7 +212,7 @@ static int swapin_walk_pmd_entry(pmd_t *pmd, unsigned long start,
 			continue;
 
 		page = read_swap_cache_async(entry, GFP_HIGHUSER_MOVABLE,
-								vma, index);
+							vma, index, false);
 		if (page)
 			page_cache_release(page);
 	}
@@ -253,7 +253,7 @@ static void force_shm_swapin_readahead(struct vm_area_struct *vma,
 		}
 		swap = radix_to_swp_entry(page);
 		page = read_swap_cache_async(swap, GFP_HIGHUSER_MOVABLE,
-								NULL, 0);
+								NULL, 0, false);
 		if (page)
 			page_cache_release(page);
 	}
diff --git a/mm/swap_state.c b/mm/swap_state.c
index 83e48a7edb28..d05043084a38 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -319,7 +319,7 @@ struct page * lookup_swap_cache(swp_entry_t entry)
 
 struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
 			struct vm_area_struct *vma, unsigned long addr,
-			bool *new_page_allocated)
+			bool *new_page_allocated, bool activate)
 {
 	struct page *found_page, *new_page = NULL;
 	struct address_space *swapper_space = swap_address_space(entry);
@@ -401,7 +401,9 @@ struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
 			/*
 			 * Initiate read into locked page and return.
 			 */
-			lru_cache_add_anon(new_page);
+			if (activate)
+				SetPageActive(new_page);
+			lru_cache_add(new_page);
 			*new_page_allocated = true;
 			return new_page;
 		}
@@ -427,11 +429,12 @@ struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
  * the swap entry is no longer in use.
  */
 struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
-			struct vm_area_struct *vma, unsigned long addr)
+			struct vm_area_struct *vma, unsigned long addr,
+			bool activate)
 {
 	bool page_was_allocated;
 	struct page *retpage = __read_swap_cache_async(entry, gfp_mask,
-			vma, addr, &page_was_allocated);
+			vma, addr, &page_was_allocated, activate);
 
 	if (page_was_allocated)
 		swap_readpage(retpage);
@@ -463,6 +466,7 @@ struct page *swapin_readahead(swp_entry_t entry, gfp_t gfp_mask,
 {
 	struct page *page;
 	unsigned long offset = swp_offset(entry);
+	unsigned long orig_offset = offset;
 	unsigned long start_offset, end_offset;
 	unsigned long mask = (1UL << page_cluster) - 1;
 	struct swap_info_struct *si = swp_swap_info(entry);
@@ -480,7 +484,7 @@ struct page *swapin_readahead(swp_entry_t entry, gfp_t gfp_mask,
 	for (offset = start_offset; offset <= end_offset ; offset++) {
 		/* Ok, do the async read-ahead now */
 		page = read_swap_cache_async(swp_entry(swp_type(entry), offset),
-						gfp_mask, vma, addr);
+				gfp_mask, vma, addr, orig_offset == offset);
 		if (!page)
 			continue;
 		page_cache_release(page);
@@ -488,7 +492,7 @@ struct page *swapin_readahead(swp_entry_t entry, gfp_t gfp_mask,
 	blk_finish_plug(&plug);
 
 	lru_add_drain();	/* Push any new pages onto the LRU now */
-	return read_swap_cache_async(entry, gfp_mask, vma, addr);
+	return read_swap_cache_async(entry, gfp_mask, vma, addr, true);
 }
 
 int init_swap_address_space(unsigned int type, unsigned long nr_pages)
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 14043e6bf776..e3923544a31f 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1705,7 +1705,7 @@ int try_to_unuse(unsigned int type, bool frontswap,
 		swap_map = &si->swap_map[i];
 		entry = swp_entry(type, i);
 		page = read_swap_cache_async(entry,
-					GFP_HIGHUSER_MOVABLE, NULL, 0);
+					GFP_HIGHUSER_MOVABLE, NULL, 0, false);
 		if (!page) {
 			/*
 			 * Either swap_duplicate() failed because entry
diff --git a/mm/zswap.c b/mm/zswap.c
index 79cdd12ac453..b10275dbedb5 100644
--- a/mm/zswap.c
+++ b/mm/zswap.c
@@ -449,7 +449,7 @@ static int zswap_get_swap_cache_page(swp_entry_t entry,
 	bool page_was_allocated;
 
 	*retpage = __read_swap_cache_async(entry, GFP_KERNEL,
-			NULL, 0, &page_was_allocated);
+			NULL, 0, &page_was_allocated, false);
 	if (page_was_allocated)
 		return ZSWAP_SWAPCACHE_NEW;
 	if (!*retpage)
-- 
2.19.2