From 650180760be6bb448609d4d155eef3b728ace641 Mon Sep 17 00:00:00 2001 From: Baolin Wang Date: Mon, 12 Aug 2024 15:42:02 +0800 Subject: [PATCH] mm: swap: extend swap_shmem_alloc() to support batch SWAP_MAP_SHMEM flag setting Patch series "support large folio swap-out and swap-in for shmem", v5. Shmem will support large folio allocation [1] [2] to get a better performance, however, the memory reclaim still splits the precious large folios when trying to swap-out shmem, which may lead to the memory fragmentation issue and can not take advantage of the large folio for shmeme. Moreover, the swap code already supports for swapping out large folio without split, and large folio swap-in[3] series is queued into mm-unstable branch. Hence this patch set also supports the large folio swap-out and swap-in for shmem. This patch (of 9): To support shmem large folio swap operations, add a new parameter to swap_shmem_alloc() that allows batch SWAP_MAP_SHMEM flag setting for shmem swap entries. While we are at it, using folio_nr_pages() to get the number of pages of the folio as a preparation. Link: https://lkml.kernel.org/r/cover.1723434324.git.baolin.wang@linux.alibaba.com Link: https://lkml.kernel.org/r/99f64115d04b285e009580eb177352c57119ffd0.1723434324.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang Reviewed-by: Barry Song Cc: Chris Li Cc: Daniel Gomez Cc: David Hildenbrand Cc: "Huang, Ying" Cc: Hugh Dickins Cc: Kefeng Wang Cc: Lance Yang Cc: Matthew Wilcox Cc: Pankaj Raghav Cc: Ryan Roberts Cc: Yang Shi Cc: Zi Yan Signed-off-by: Andrew Morton --- include/linux/swap.h | 4 ++-- mm/shmem.c | 6 ++++-- mm/swapfile.c | 4 ++-- 3 files changed, 8 insertions(+), 6 deletions(-) diff --git a/include/linux/swap.h b/include/linux/swap.h index 1c8f844a9f0f..248db1dd7812 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -481,7 +481,7 @@ void put_swap_folio(struct folio *folio, swp_entry_t entry); extern swp_entry_t get_swap_page_of_type(int); extern int get_swap_pages(int n, swp_entry_t swp_entries[], int order); extern int add_swap_count_continuation(swp_entry_t, gfp_t); -extern void swap_shmem_alloc(swp_entry_t); +extern void swap_shmem_alloc(swp_entry_t, int); extern int swap_duplicate(swp_entry_t); extern int swapcache_prepare(swp_entry_t entry, int nr); extern void swap_free_nr(swp_entry_t entry, int nr_pages); @@ -548,7 +548,7 @@ static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask) return 0; } -static inline void swap_shmem_alloc(swp_entry_t swp) +static inline void swap_shmem_alloc(swp_entry_t swp, int nr) { } diff --git a/mm/shmem.c b/mm/shmem.c index 4a5254bfd610..22cdc10f27ea 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1452,6 +1452,7 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc) struct shmem_sb_info *sbinfo = SHMEM_SB(inode->i_sb); swp_entry_t swap; pgoff_t index; + int nr_pages; /* * Our capabilities prevent regular writeback or sync from ever calling @@ -1484,6 +1485,7 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc) } index = folio->index; + nr_pages = folio_nr_pages(folio); /* * This is somewhat ridiculous, but without plumbing a SWAP_MAP_FALLOC @@ -1536,8 +1538,8 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc) if (add_to_swap_cache(folio, swap, __GFP_HIGH | __GFP_NOMEMALLOC | __GFP_NOWARN, NULL) == 0) { - shmem_recalc_inode(inode, 0, 1); - swap_shmem_alloc(swap); + shmem_recalc_inode(inode, 0, nr_pages); + swap_shmem_alloc(swap, nr_pages); shmem_delete_from_page_cache(folio, swp_to_radix_entry(swap)); mutex_unlock(&shmem_swaplist_mutex); diff --git a/mm/swapfile.c b/mm/swapfile.c index 5e7cbdaf725d..8ff58be40544 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -3657,9 +3657,9 @@ static int __swap_duplicate(swp_entry_t entry, unsigned char usage, int nr) * Help swapoff by noting that swap entry belongs to shmem/tmpfs * (in which case its reference count is never incremented). */ -void swap_shmem_alloc(swp_entry_t entry) +void swap_shmem_alloc(swp_entry_t entry, int nr) { - __swap_duplicate(entry, SWAP_MAP_SHMEM, 1); + __swap_duplicate(entry, SWAP_MAP_SHMEM, nr); } /*