On 04/30/2016 04:25 AM, Chen, Tim C wrote: > Wonder if choosing the swap device by numa node is the most > effective way to spread the pages among the swap devices. The intent of this patch is not to spread the pages among the swap devices(thus to reduce lock contention on swap device's radix tree), it's about speed up the IOs :-) > The speedup comes from spreading the swap activities among > equal priority swap devices to reduce contention on swap devices. For v4.5, yes. And for this patch, it also has speed ups by doing IOs locally. > If the activities are mostly confined to 1 node, then we still could > have contention on a device. Indeed, but I suppose that would normally happen if people has played with numactl themselves? Otherwise, the scheduler would probably spread the threads evenly. Ying suggests we use a config for people to turn this off in his reply and I can of course add that. > An alternative may be we pick another swap device on each > pass of shrink_page_list to try to swap pages. This can be achieved by setting the two swap devices with equal priority and then the two swap devices will be used round robin. I have already used it as a comparing config: throughput of v4.5(swap device with equal priority) Thanks for the comments! -- 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>