From 0ff67f990bd45726e0d9e91111d998e7a3595b32 Mon Sep 17 00:00:00 2001 From: Kairui Song Date: Fri, 14 Mar 2025 00:59:34 +0800 Subject: mm, swap: remove swap slot cache Slot cache is no longer needed now, removing it and all related code. - vm-scalability with: `usemem --init-time -O -y -x -R -31 1G`, 12G memory cgroup using simulated pmem as SWAP (32G pmem, 32 CPUs), 16 test runs for each case, measuring the total throughput: Before (KB/s) (stdev) After (KB/s) (stdev) Random (4K): 424907.60 (24410.78) 414745.92 (34554.78) Random (64K): 163308.82 (11635.72) 167314.50 (18434.99) Sequential (4K, !-R): 6150056.79 (103205.90) 6321469.06 (115878.16) The performance changes are below noise level. - Build linux kernel with make -j96, using 4K folio with 1.5G memory cgroup limit and 64K folio with 2G memory cgroup limit, on top of tmpfs, 12 test runs, measuring the system time: Before (s) (stdev) After (s) (stdev) make -j96 (4K): 6445.69 (61.95) 6408.80 (69.46) make -j96 (64K): 6841.71 (409.04) 6437.99 (435.55) Similar to above, 64k mTHP case showed a slight improvement. Link: https://lkml.kernel.org/r/20250313165935.63303-7-ryncsn@gmail.com Signed-off-by: Kairui Song Reviewed-by: Baoquan He Cc: Baolin Wang Cc: Barry Song Cc: Chris Li Cc: "Huang, Ying" Cc: Hugh Dickins Cc: Johannes Weiner Cc: Kalesh Singh Cc: Matthew Wilcow (Oracle) Cc: Nhat Pham Cc: Yosry Ahmed Signed-off-by: Andrew Morton --- include/linux/swap.h | 3 --- include/linux/swap_slots.h | 28 ---------------------------- 2 files changed, 31 deletions(-) delete mode 100644 include/linux/swap_slots.h (limited to 'include/linux') diff --git a/include/linux/swap.h b/include/linux/swap.h index 374bffc87427..c5856dcc263a 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -465,7 +465,6 @@ void free_pages_and_swap_cache(struct encoded_page **, int); extern atomic_long_t nr_swap_pages; extern long total_swap_pages; extern atomic_t nr_rotate_swap; -extern bool has_usable_swap(void); /* Swap 50% full? Release swapcache more aggressively.. */ static inline bool vm_swap_full(void) @@ -483,13 +482,11 @@ swp_entry_t folio_alloc_swap(struct folio *folio); bool folio_free_swap(struct folio *folio); 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, 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); -extern void swapcache_free_entries(swp_entry_t *entries, int n); extern void free_swap_and_cache_nr(swp_entry_t entry, int nr); int swap_type_of(dev_t device, sector_t offset); int find_first_swap(dev_t *device); diff --git a/include/linux/swap_slots.h b/include/linux/swap_slots.h deleted file mode 100644 index 840aec3523b2..000000000000 --- a/include/linux/swap_slots.h +++ /dev/null @@ -1,28 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -#ifndef _LINUX_SWAP_SLOTS_H -#define _LINUX_SWAP_SLOTS_H - -#include -#include -#include - -#define SWAP_SLOTS_CACHE_SIZE SWAP_BATCH -#define THRESHOLD_ACTIVATE_SWAP_SLOTS_CACHE (5*SWAP_SLOTS_CACHE_SIZE) -#define THRESHOLD_DEACTIVATE_SWAP_SLOTS_CACHE (2*SWAP_SLOTS_CACHE_SIZE) - -struct swap_slots_cache { - bool lock_initialized; - struct mutex alloc_lock; /* protects slots, nr, cur */ - swp_entry_t *slots; - int nr; - int cur; - int n_ret; -}; - -void disable_swap_slots_cache_lock(void); -void reenable_swap_slots_cache_unlock(void); -void enable_swap_slots_cache(void); - -extern bool swap_slot_cache_enabled; - -#endif /* _LINUX_SWAP_SLOTS_H */ -- cgit v1.2.3