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

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.orgSigned-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
......@@ -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
......
......@@ -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;
......
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