On Tue, 16 Jan 2018, Mel Gorman wrote: > My main source of discomfort is the fact that this is permanent as two > processes perfectly isolated but with a suitably shared COW mapping > will never migrate the data. A potential improvement to get the reported > bandwidth up in the test program would be to skip the rest of the VMA if > page_mapcount != 1 in a COW mapping as it would be reasonable to assume > the remaining pages in the VMA are also affected and the scan is wasteful. > There are counter-examples to this but I suspect that the full VMA being > shared is the common case. Whether you do that or not; Same concern here. Typically CAP_SYS_NICE will bypass the check that the page is only mapped to a single process and the check looks exactly like the ones for manual migration. Using CAP_SYS_NICE would be surprising here since autonuma is not triggered by the currently running process. Can we configure this somehow via sysfs? -- 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>
