Re: [PATCH][RFC][0/4] InfiniBand userspace verbs implementation
From: Timur Tabi
Date: Mon Apr 25 2005 - 17:44:46 EST
Andrew Morton wrote:
This is because there is no file descriptor or anything else associated
with the pages which permits the kernel to clean stuff up on unclean
application exit. Also there are the obvious issues with permitting
pinning of unbounded amounts of memory.
Then that might explain the "bug" that we're seeing with get_user_pages(). We've been
assuming that get_user_pages() mappings are permanent.
Well, I was just about to re-implement get_user_pages() support in our driver to
demonstrate the bug. I guess I'll hold off on that.
If you look at the Infiniband code that was recently submitted, I think you'll see it does
exactly that: after calling mlock(), the driver calls get_user_pages(), and it stores the
page mappings for future use.
Staff Software Engineer
One thing a Southern boy will never say is,
"I don't think duct tape will fix it."
-- Ed Smylie, NASA engineer for Apollo 13
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