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Commit 539a6fea authored by Minchan Kim's avatar Minchan Kim Committed by Linus Torvalds
Browse files

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: default avatarMinchan Kim <minchan@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Huang Ying <ying.huang@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 23c47d2a

include/linux/swap.h

+2 −1
Original line number Diff line number Diff line
@@ -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

mm/swapfile.c

+3 −0
Original line number Diff line number Diff line
@@ -3169,6 +3169,9 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags) 
	if (bdi_cap_stable_pages_required(inode_to_bdi(inode)))

		p->flags |= SWP_STABLE_WRITES;



	if (bdi_cap_synchronous_io(inode_to_bdi(inode)))

		p->flags |= SWP_SYNCHRONOUS_IO;



	if (p->bdev && blk_queue_nonrot(bdev_get_queue(p->bdev))) {

		int cpu;

		unsigned long ci, nr_cluster;