On Sat, Apr 14, 2012 at 2:27 AM, Christoph Lameter <cl@xxxxxxxxx> wrote: > On Fri, 13 Apr 2012, Haojian Zhuang wrote: > >> I have one question on memory migration. As we know, malloc() from >> user app will allocate MIGRATE_MOVABLE pages. But if we want to use >> this memory as DMA usage, we can't accept MIGRATE_MOVABLE type. Could >> we change its behavior before DMA working? > > MIGRATE_MOVABLE works fine for DMA. If you keep a reference from a device > driver to user pages then you will have to increase the page refcount > which will in turn pin the page and make it non movable for as long as you > keep the refcount. Hi Christoph, Thanks for your illustration. But it's a little abstract. Could you give me a simple example or show me the code? Best Regards Haojian -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>