On Tue, Jul 06, 2010 at 10:27:58PM +0200, Johannes Weiner wrote: > It bypasses the fs. On swapon, the blocks are resolved > (mm/swapfile.c::setup_swap_extents) and then the writeout path uses > bios directly (mm/page_io.c::swap_writepage). > > (GFP_NOFS still includes __GFP_IO, so allows swapping) Exactly. Note that while the stack problems for swap writeout aren't as bad as for filesystems as the whole allocator / extent map footprint is missing it might still be an issue. We still splice the whole block I/O stack footprint over a random stack that might be filled up a lot. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>