"Chen, Tim C" <tim.c.chen@xxxxxxxxx> writes: >> >>So this is impossible without THP swapin. While 2M swapout makes a lot of >>sense, I doubt 2M swapin is really useful. What kind of application is 'optimized' >>to do sequential memory access? Anything that touches regions larger than 4K and we want to do the kernel do minimal work to manage the swapping. > > We waste a lot of cpu cycles to re-compact 4K pages back to a large page > under THP. Swapping it back in as a single large page can avoid > fragmentation and this overhead. Also splitting something just to merge it again is wasteful. A lot of big improvements in the block and VM and network layers over the years came from avoiding that kind of wasteful work. -Andi -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>