On Tuesday 05 March 2013, Marek Szyprowski wrote: > To solving this issue requires preventing locking of the pages, which > are placed in CMA regions, for a long time. Our idea is to migrate > anonymous page content before locking the page in get_user_pages(). This > cannot be done automatically, as get_user_pages() interface is used very > often for various operations, which usually last for a short period of > time (like for example exec syscall). We have added a new flag > indicating that the given get_user_space() call will grab pages for a > long time, thus it is suitable to use the migration workaround in such > cases. Can you explain the tradeoff here? I would have expected that the default should be to migrate pages out, and annotate the instances that we know are performance critical and short-lived. That would at least appear more reliable to me. Arnd -- 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>