The patch titled
Subject: mm/swapfile: remove stale reuse_swap_page()
has been added to the -mm tree. Its filename is
mm-swapfile-remove-stale-reuse_swap_page.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-swapfile-remove-stale-reuse_swap_page.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-swapfile-remove-stale-reuse_swap_page.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: David Hildenbrand <david@xxxxxxxxxx>
Subject: mm/swapfile: remove stale reuse_swap_page()
All users are gone, let's remove it. We'll let SWP_STABLE_WRITES stick
around for now, as it might come in handy in the near future.
Link: https://lkml.kernel.org/r/20220131162940.210846-8-david@xxxxxxxxxx
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Don Dutile <ddutile@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Liang Zhang <zhangliang5@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx>
Cc: Nadav Amit <nadav.amit@xxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Peter Xu <peterx@xxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxxx>
Cc: Roman Gushchin <guro@xxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Yang Shi <shy828301@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/swap.h | 4 -
mm/swapfile.c | 104 -----------------------------------------
2 files changed, 108 deletions(-)
--- a/include/linux/swap.h~mm-swapfile-remove-stale-reuse_swap_page
+++ a/include/linux/swap.h
@@ -514,7 +514,6 @@ extern int __swp_swapcount(swp_entry_t e
extern int swp_swapcount(swp_entry_t entry);
extern struct swap_info_struct *page_swap_info(struct page *);
extern struct swap_info_struct *swp_swap_info(swp_entry_t entry);
-extern bool reuse_swap_page(struct page *);
extern int try_to_free_swap(struct page *);
struct backing_dev_info;
extern int init_swap_address_space(unsigned int type, unsigned long nr_pages);
@@ -680,9 +679,6 @@ static inline int swp_swapcount(swp_entr
return 0;
}
-#define reuse_swap_page(page) \
- (page_trans_huge_mapcount(page) == 1)
-
static inline int try_to_free_swap(struct page *page)
{
return 0;
--- a/mm/swapfile.c~mm-swapfile-remove-stale-reuse_swap_page
+++ a/mm/swapfile.c
@@ -1167,16 +1167,6 @@ out:
return NULL;
}
-static struct swap_info_struct *swap_info_get(swp_entry_t entry)
-{
- struct swap_info_struct *p;
-
- p = _swap_info_get(entry);
- if (p)
- spin_lock(&p->lock);
- return p;
-}
-
static struct swap_info_struct *swap_info_get_cont(swp_entry_t entry,
struct swap_info_struct *q)
{
@@ -1601,100 +1591,6 @@ static bool page_swapped(struct page *pa
return false;
}
-static int page_trans_huge_map_swapcount(struct page *page,
- int *total_swapcount)
-{
- int i, map_swapcount, _total_swapcount;
- unsigned long offset = 0;
- struct swap_info_struct *si;
- struct swap_cluster_info *ci = NULL;
- unsigned char *map = NULL;
- int swapcount = 0;
-
- /* hugetlbfs shouldn't call it */
- VM_BUG_ON_PAGE(PageHuge(page), page);
-
- if (!IS_ENABLED(CONFIG_THP_SWAP) || likely(!PageTransCompound(page))) {
- if (PageSwapCache(page))
- swapcount = page_swapcount(page);
- if (total_swapcount)
- *total_swapcount = swapcount;
- return swapcount + page_trans_huge_mapcount(page);
- }
-
- page = compound_head(page);
-
- _total_swapcount = map_swapcount = 0;
- if (PageSwapCache(page)) {
- swp_entry_t entry;
-
- entry.val = page_private(page);
- si = _swap_info_get(entry);
- if (si) {
- map = si->swap_map;
- offset = swp_offset(entry);
- }
- }
- if (map)
- ci = lock_cluster(si, offset);
- for (i = 0; i < HPAGE_PMD_NR; i++) {
- int mapcount = atomic_read(&page[i]._mapcount) + 1;
- if (map) {
- swapcount = swap_count(map[offset + i]);
- _total_swapcount += swapcount;
- }
- map_swapcount = max(map_swapcount, mapcount + swapcount);
- }
- unlock_cluster(ci);
-
- if (PageDoubleMap(page))
- map_swapcount -= 1;
-
- if (total_swapcount)
- *total_swapcount = _total_swapcount;
-
- return map_swapcount + compound_mapcount(page);
-}
-
-/*
- * We can write to an anon page without COW if there are no other references
- * to it. And as a side-effect, free up its swap: because the old content
- * on disk will never be read, and seeking back there to write new content
- * later would only waste time away from clustering.
- */
-bool reuse_swap_page(struct page *page)
-{
- int count, total_swapcount;
-
- VM_BUG_ON_PAGE(!PageLocked(page), page);
- if (unlikely(PageKsm(page)))
- return false;
- count = page_trans_huge_map_swapcount(page, &total_swapcount);
- if (count == 1 && PageSwapCache(page) &&
- (likely(!PageTransCompound(page)) ||
- /* The remaining swap count will be freed soon */
- total_swapcount == page_swapcount(page))) {
- if (!PageWriteback(page)) {
- page = compound_head(page);
- delete_from_swap_cache(page);
- SetPageDirty(page);
- } else {
- swp_entry_t entry;
- struct swap_info_struct *p;
-
- entry.val = page_private(page);
- p = swap_info_get(entry);
- if (p->flags & SWP_STABLE_WRITES) {
- spin_unlock(&p->lock);
- return false;
- }
- spin_unlock(&p->lock);
- }
- }
-
- return count <= 1;
-}
-
/*
* If swap is getting full, or if there are no more mappings of this page,
* then try_to_free_swap is called to free its swap space.
_
Patches currently in -mm which might be from david@xxxxxxxxxx are
mm-optimize-do_wp_page-for-exclusive-pages-in-the-swapcache.patch
mm-optimize-do_wp_page-for-fresh-pages-in-local-lru-pagevecs.patch
mm-slightly-clarify-ksm-logic-in-do_swap_page.patch
mm-streamline-cow-logic-in-do_swap_page.patch
mm-huge_memory-streamline-cow-logic-in-do_huge_pmd_wp_page.patch
mm-khugepaged-remove-reuse_swap_page-usage.patch
mm-swapfile-remove-stale-reuse_swap_page.patch
mm-huge_memory-remove-stale-page_trans_huge_mapcount.patch
mm-huge_memory-remove-stale-locking-logic-from-__split_huge_pmd.patch
proc-vmcore-fix-possible-deadlock-on-concurrent-mmap-and-read.patch
