From 539a6fea7fdcade532bd3e77be2862a683f8f0c9 Mon Sep 17 00:00:00 2001 From: Minchan Kim Date: Wed, 15 Nov 2017 17:33:04 -0800 Subject: mm, swap: introduce SWP_SYNCHRONOUS_IO If rw-page based fast storage is used for swap devices, we need to detect it to enhance swap IO operations. This patch is preparation for optimizing of swap-in operation with next patch. Link: http://lkml.kernel.org/r/1505886205-9671-4-git-send-email-minchan@kernel.org Signed-off-by: Minchan Kim Cc: Hugh Dickins Cc: Christoph Hellwig Cc: Dan Williams Cc: Ilya Dryomov Cc: Jens Axboe Cc: Ross Zwisler Cc: Sergey Senozhatsky Cc: Huang Ying Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/swap.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'include/linux/swap.h') diff --git a/include/linux/swap.h b/include/linux/swap.h index f02fb5db8914..933d7c0c3542 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -171,8 +171,9 @@ enum { SWP_AREA_DISCARD = (1 << 8), /* single-time swap area discards */ SWP_PAGE_DISCARD = (1 << 9), /* freed swap page-cluster discards */ SWP_STABLE_WRITES = (1 << 10), /* no overwrite PG_writeback pages */ + SWP_SYNCHRONOUS_IO = (1 << 11), /* synchronous IO is efficient */ /* add others here before... */ - SWP_SCANNING = (1 << 11), /* refcount in scan_swap_map */ + SWP_SCANNING = (1 << 12), /* refcount in scan_swap_map */ }; #define SWAP_CLUSTER_MAX 32UL -- cgit v1.2.3