14 Apr
2012
14 Apr
'12
2:51 a.m.
On Sat, Apr 14, 2012 at 2:27 AM, Christoph Lameter cl@linux.com 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