From 36005bae205da3eef0016a5c96a34f10a68afa1e Mon Sep 17 00:00:00 2001 From: Tim Chen Date: Wed, 22 Feb 2017 15:45:33 -0800 Subject: mm/swap: allocate swap slots in batches Currently, the swap slots are allocated one page at a time, causing contention to the swap_info lock protecting the swap partition on every page being swapped. This patch adds new functions get_swap_pages and scan_swap_map_slots to request multiple swap slots at once. This will reduces the lock contention on the swap_info lock. Also scan_swap_map_slots can operate more efficiently as swap slots often occurs in clusters close to each other on a swap device and it is quicker to allocate them together. Link: http://lkml.kernel.org/r/9fec2845544371f62c3763d43510045e33d286a6.1484082593.git.tim.c.chen@linux.intel.com Signed-off-by: Tim Chen Signed-off-by: "Huang, Ying" Cc: Aaron Lu Cc: Andi Kleen Cc: Andrea Arcangeli Cc: Christian Borntraeger Cc: Dave Hansen Cc: Hillf Danton Cc: Huang Ying Cc: Hugh Dickins Cc: Johannes Weiner Cc: Jonathan Corbet escreveu: Cc: Kirill A. Shutemov Cc: Michal Hocko Cc: Minchan Kim Cc: Rik van Riel Cc: Shaohua Li Cc: Vladimir Davydov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/swap.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/swap.h') diff --git a/include/linux/swap.h b/include/linux/swap.h index 3116382067cd..956eae8a8edf 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -27,6 +27,7 @@ struct bio; #define SWAP_FLAGS_VALID (SWAP_FLAG_PRIO_MASK | SWAP_FLAG_PREFER | \ SWAP_FLAG_DISCARD | SWAP_FLAG_DISCARD_ONCE | \ SWAP_FLAG_DISCARD_PAGES) +#define SWAP_BATCH 64 static inline int current_is_kswapd(void) { @@ -386,6 +387,7 @@ static inline long get_nr_swap_pages(void) extern void si_swapinfo(struct sysinfo *); extern swp_entry_t get_swap_page(void); extern swp_entry_t get_swap_page_of_type(int); +extern int get_swap_pages(int n, swp_entry_t swp_entries[]); extern int add_swap_count_continuation(swp_entry_t, gfp_t); extern void swap_shmem_alloc(swp_entry_t); extern int swap_duplicate(swp_entry_t); -- cgit v1.2.1