Re: [PATCH 10 of 20] ipath - support for userspace apps using coredriver

From: Hugh Dickins
Date: Thu Mar 16 2006 - 15:10:00 EST

On Thu, 16 Mar 2006, Bryan O'Sullivan wrote:
> OK. Would it be correct to say that this is what we should do, then?
> * On 2.6.15 and later kernels, use __GFP_COMP at allocation time,
> and get_page in ->nopage. This is what we're doing as of this
> morning, and it works.
> * For backports to 2.6.14 and earlier, avoid __GFP_COMP, mark each
> page with SetPageReserved at allocation time, and do nothing
> special in ->nopage. Do we need to ClearPageReserved before
> freeing?

Yes, I believe that's exactly right - so long as you do ClearPageReserved
from each of its constituent 0-order-pages before freeing the >0-order
page, in the <= 2.6.14 case.

You wisely remarked earlier that you'd not yet checked for memory leaks:
that is of course the complementary, less obvious, error to the troubles
you've been having so far: and I wish you luck when you come to check,
hoping that I haven't merely misled you from one side to the other!

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at