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> Acked-by: Vlastimil Babka <vbabka@xxxxxxx> 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: 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 <roman.gushchin@xxxxxxxxx> Cc: Shakeel Butt <shakeelb@xxxxxxxxxx> 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 @@ -515,7 +515,6 @@ 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); @@ -681,9 +680,6 @@ 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. _
