From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx> Subject: mm: remove the total_mapcount argument from page_trans_huge_map_swapcount() Now that we don't report it to the caller of reuse_swap_page(), we don't need to request it from page_trans_huge_map_swapcount(). Link: https://lkml.kernel.org/r/20211220205943.456187-2-willy@xxxxxxxxxxxxx Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Reviewed-by: William Kucharski <william.kucharski@xxxxxxxxxx> Acked-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: David Hildenbrand <david@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/swapfile.c | 32 ++++++++++++-------------------- 1 file changed, 12 insertions(+), 20 deletions(-) --- a/mm/swapfile.c~mm-remove-the-total_mapcount-argument-from-page_trans_huge_map_swapcount +++ a/mm/swapfile.c @@ -1601,31 +1601,30 @@ static bool page_swapped(struct page *pa return false; } -static int page_trans_huge_map_swapcount(struct page *page, int *total_mapcount, +static int page_trans_huge_map_swapcount(struct page *page, int *total_swapcount) { - int i, map_swapcount, _total_mapcount, _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 mapcount, swapcount = 0; + int swapcount = 0; /* hugetlbfs shouldn't call it */ VM_BUG_ON_PAGE(PageHuge(page), page); if (!IS_ENABLED(CONFIG_THP_SWAP) || likely(!PageTransCompound(page))) { - mapcount = page_trans_huge_mapcount(page, total_mapcount); if (PageSwapCache(page)) swapcount = page_swapcount(page); if (total_swapcount) *total_swapcount = swapcount; - return mapcount + swapcount; + return swapcount + page_trans_huge_mapcount(page, NULL); } page = compound_head(page); - _total_mapcount = _total_swapcount = map_swapcount = 0; + _total_swapcount = map_swapcount = 0; if (PageSwapCache(page)) { swp_entry_t entry; @@ -1639,8 +1638,7 @@ static int page_trans_huge_map_swapcount if (map) ci = lock_cluster(si, offset); for (i = 0; i < HPAGE_PMD_NR; i++) { - mapcount = atomic_read(&page[i]._mapcount) + 1; - _total_mapcount += mapcount; + int mapcount = atomic_read(&page[i]._mapcount) + 1; if (map) { swapcount = swap_count(map[offset + i]); _total_swapcount += swapcount; @@ -1648,19 +1646,14 @@ static int page_trans_huge_map_swapcount map_swapcount = max(map_swapcount, mapcount + swapcount); } unlock_cluster(ci); - if (PageDoubleMap(page)) { + + if (PageDoubleMap(page)) map_swapcount -= 1; - _total_mapcount -= HPAGE_PMD_NR; - } - mapcount = compound_mapcount(page); - map_swapcount += mapcount; - _total_mapcount += mapcount; - if (total_mapcount) - *total_mapcount = _total_mapcount; + if (total_swapcount) *total_swapcount = _total_swapcount; - return map_swapcount; + return map_swapcount + compound_mapcount(page); } /* @@ -1671,13 +1664,12 @@ static int page_trans_huge_map_swapcount */ bool reuse_swap_page(struct page *page) { - int count, total_mapcount, total_swapcount; + 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_mapcount, - &total_swapcount); + 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 */ _
