On Mon, Jul 31, 2017 at 09:42:06AM +0200, Christoph Hellwig wrote: > On Mon, Jul 31, 2017 at 04:36:47PM +0900, Minchan Kim wrote: > > Do you suggest define something special flag(e.g., SWP_INMEMORY) > > for in-memory swap to swap_info_struct when swapon time manually > > or from bdi_queue_someting automatically? > > And depending the flag of swap_info_struct, use the onstack bio > > instead of dynamic allocation if the swap device is in-memory? > > Currently swap always just does I/O on a single page as far > as I can tell, so it can always just use an on-stack bio and > biovec.
That's for synchronous I/O, aka reads of course. For writes you'll need to do a dynamic allocation if they are asynchronous. But yes, if we want to force certain devices to be synchronous we'll need a flag for that.
