From e3ae2dec849ba8bc5649c2d0507e02bd4379da71 Mon Sep 17 00:00:00 2001 From: Kairui Song Date: Tue, 14 Jan 2025 01:57:29 +0800 Subject: mm, swap: simplify percpu cluster updating Instead of using a returning argument, we can simply store the next cluster offset to the fixed percpu location, which reduce the stack usage and simplify the function: Object size: ./scripts/bloat-o-meter mm/swapfile.o mm/swapfile.o.new add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-271 (-271) Function old new delta get_swap_pages 2847 2733 -114 alloc_swap_scan_cluster 894 737 -157 Total: Before=30833, After=30562, chg -0.88% Stack usage: Before: swapfile.c:1190:5:get_swap_pages 240 static After: swapfile.c:1185:5:get_swap_pages 216 static Link: https://lkml.kernel.org/r/20250113175732.48099-11-ryncsn@gmail.com Signed-off-by: Kairui Song Cc: Baoquan He Cc: Barry Song Cc: Chis Li Cc: "Huang, Ying" Cc: Hugh Dickens Cc: Johannes Weiner Cc: Kalesh Singh Cc: Nhat Pham Cc: Ryan Roberts Cc: Yosry Ahmed Signed-off-by: Andrew Morton --- include/linux/swap.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/linux/swap.h b/include/linux/swap.h index 5fe650beb77d..75b2b0166cb1 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -274,9 +274,9 @@ enum swap_cluster_flags { * The first page in the swap file is the swap header, which is always marked * bad to prevent it from being allocated as an entry. This also prevents the * cluster to which it belongs being marked free. Therefore 0 is safe to use as - * a sentinel to indicate next is not valid in percpu_cluster. + * a sentinel to indicate an entry is not valid. */ -#define SWAP_NEXT_INVALID 0 +#define SWAP_ENTRY_INVALID 0 #ifdef CONFIG_THP_SWAP #define SWAP_NR_ORDERS (PMD_ORDER + 1) -- cgit v1.2.3