From: Minchan Kim <minchan@xxxxxxxxxx> 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@xxxxxxxxxx Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx> Cc: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Christoph Hellwig <hch@xxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Cc: Ilya Dryomov <idryomov@xxxxxxxxx> Cc: Jens Axboe <axboe@xxxxxxxxx> Cc: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx> Cc: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx> Cc: Huang Ying <ying.huang@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/swap.h | 3 ++- mm/swapfile.c | 3 +++ 2 files changed, 5 insertions(+), 1 deletion(-) diff -puN include/linux/swap.h~mm-swap-introduce-swp_synchronous_io include/linux/swap.h --- a/include/linux/swap.h~mm-swap-introduce-swp_synchronous_io +++ a/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 diff -puN mm/swapfile.c~mm-swap-introduce-swp_synchronous_io mm/swapfile.c --- a/mm/swapfile.c~mm-swap-introduce-swp_synchronous_io +++ a/mm/swapfile.c @@ -3169,6 +3169,9 @@ SYSCALL_DEFINE2(swapon, const char __use 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; _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
