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Message-ID: <20250807152720.62032-2-ryncsn@gmail.com>
Date: Thu, 7 Aug 2025 23:27:18 +0800
From: Kairui Song <ryncsn@...il.com>
To: linux-mm@...ck.org
Cc: Andrew Morton <akpm@...ux-foundation.org>,
"Liam R. Howlett" <Liam.Howlett@...cle.com>,
Lorenzo Stoakes <lorenzo.stoakes@...cle.com>,
Vlastimil Babka <vbabka@...e.cz>,
Jann Horn <jannh@...gle.com>,
Pedro Falcato <pfalcato@...e.de>,
Matthew Wilcox <willy@...radead.org>,
Hugh Dickins <hughd@...gle.com>,
David Hildenbrand <david@...hat.com>,
Chris Li <chrisl@...nel.org>,
Barry Song <baohua@...nel.org>,
Baoquan He <bhe@...hat.com>,
Nhat Pham <nphamcs@...il.com>,
Kemeng Shi <shikemeng@...weicloud.com>,
linux-kernel@...r.kernel.org,
Kairui Song <kasong@...cent.com>
Subject: [RFC PATCH 1/3] mm/mincore, swap: consolidate swap cache checking for mincore
From: Kairui Song <kasong@...cent.com>
The filemap_get_incore_folio (previously find_get_incore_page) helper
was introduced by commit 61ef18655704 ("mm: factor find_get_incore_page
out of mincore_page") to be used by later commit f5df8635c5a3 ("mm: use
find_get_incore_page in memcontrol"), so memory cgroup charge move code
can be simplified.
But commit 6b611388b626 ("memcg-v1: remove charge move code") removed
that user completely, it's only used by mincore now.
So this commit basically reverts commit 61ef18655704 ("mm: factor
find_get_incore_page out of mincore_page"). Move it back to mincore side
to simplify the code.
Signed-off-by: Kairui Song <kasong@...cent.com>
---
mm/mincore.c | 29 +++++++++++++++++++++++++++--
mm/swap.h | 10 ----------
mm/swap_state.c | 38 --------------------------------------
3 files changed, 27 insertions(+), 50 deletions(-)
diff --git a/mm/mincore.c b/mm/mincore.c
index 10dabefc3acc..f0d3c9419e58 100644
--- a/mm/mincore.c
+++ b/mm/mincore.c
@@ -64,8 +64,33 @@ static unsigned char mincore_page(struct address_space *mapping, pgoff_t index)
* any other file mapping (ie. marked !present and faulted in with
* tmpfs's .fault). So swapped out tmpfs mappings are tested here.
*/
- folio = filemap_get_incore_folio(mapping, index);
- if (!IS_ERR(folio)) {
+ if (IS_ENABLED(CONFIG_SWAP) && shmem_mapping(mapping)) {
+ folio = filemap_get_entry(mapping, index);
+ /*
+ * shmem/tmpfs may return swap: account for swapcache
+ * page too.
+ */
+ if (xa_is_value(folio)) {
+ struct swap_info_struct *si;
+ swp_entry_t swp = radix_to_swp_entry(folio);
+ /* There might be swapin error entries in shmem mapping. */
+ if (non_swap_entry(swp))
+ return 0;
+ /* Prevent swap device to being swapoff under us */
+ si = get_swap_device(swp);
+ if (si) {
+ folio = filemap_get_folio(swap_address_space(swp),
+ swap_cache_index(swp));
+ put_swap_device(si);
+ } else {
+ return 0;
+ }
+ }
+ } else {
+ folio = filemap_get_folio(mapping, index);
+ }
+
+ if (folio) {
present = folio_test_uptodate(folio);
folio_put(folio);
}
diff --git a/mm/swap.h b/mm/swap.h
index 911ad5ff0f89..1ae44d4193b1 100644
--- a/mm/swap.h
+++ b/mm/swap.h
@@ -64,9 +64,6 @@ void clear_shadow_from_swap_cache(int type, unsigned long begin,
void swapcache_clear(struct swap_info_struct *si, swp_entry_t entry, int nr);
struct folio *swap_cache_get_folio(swp_entry_t entry,
struct vm_area_struct *vma, unsigned long addr);
-struct folio *filemap_get_incore_folio(struct address_space *mapping,
- pgoff_t index);
-
struct folio *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
struct vm_area_struct *vma, unsigned long addr,
struct swap_iocb **plug);
@@ -178,13 +175,6 @@ static inline struct folio *swap_cache_get_folio(swp_entry_t entry,
return NULL;
}
-static inline
-struct folio *filemap_get_incore_folio(struct address_space *mapping,
- pgoff_t index)
-{
- return filemap_get_folio(mapping, index);
-}
-
static inline void *get_shadow_from_swap_cache(swp_entry_t entry)
{
return NULL;
diff --git a/mm/swap_state.c b/mm/swap_state.c
index c354435a0923..99513b74b5d8 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -323,44 +323,6 @@ struct folio *swap_cache_get_folio(swp_entry_t entry,
return folio;
}
-/**
- * filemap_get_incore_folio - Find and get a folio from the page or swap caches.
- * @mapping: The address_space to search.
- * @index: The page cache index.
- *
- * This differs from filemap_get_folio() in that it will also look for the
- * folio in the swap cache.
- *
- * Return: The found folio or %NULL.
- */
-struct folio *filemap_get_incore_folio(struct address_space *mapping,
- pgoff_t index)
-{
- swp_entry_t swp;
- struct swap_info_struct *si;
- struct folio *folio = filemap_get_entry(mapping, index);
-
- if (!folio)
- return ERR_PTR(-ENOENT);
- if (!xa_is_value(folio))
- return folio;
- if (!shmem_mapping(mapping))
- return ERR_PTR(-ENOENT);
-
- swp = radix_to_swp_entry(folio);
- /* There might be swapin error entries in shmem mapping. */
- if (non_swap_entry(swp))
- return ERR_PTR(-ENOENT);
- /* Prevent swapoff from happening to us */
- si = get_swap_device(swp);
- if (!si)
- return ERR_PTR(-ENOENT);
- index = swap_cache_index(swp);
- folio = filemap_get_folio(swap_address_space(swp), index);
- put_swap_device(si);
- return folio;
-}
-
struct folio *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
struct mempolicy *mpol, pgoff_t ilx, bool *new_page_allocated,
bool skip_if_exists)
--
2.50.1
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