Re: [PATCH] core remove PageReserved

From: Dave Jones
Date: Thu Nov 03 2005 - 23:42:19 EST


On Sat, Oct 29, 2005 at 10:02:22PM -0700, Linux Kernel wrote:
> tree 835836cb527ec9bd525f93eb7e016f3dfb8c8ae2
> parent f9c98d0287de42221c624482fd4f8d485c98ab22
> author Nick Piggin <nickpiggin@xxxxxxxxxxxx> Sun, 30 Oct 2005 08:16:12 -0700
> committer Linus Torvalds <torvalds@xxxxxxxxxxx> Sun, 30 Oct 2005 11:40:39 -0700
>
> [PATCH] core remove PageReserved
>
> Remove PageReserved() calls from core code by tightening VM_RESERVED
> handling in mm/ to cover PageReserved functionality.
>
> PageReserved special casing is removed from get_page and put_page.
>
> All setting and clearing of PageReserved is retained, and it is now flagged
> in the page_alloc checks to help ensure we don't introduce any refcount
> based freeing of Reserved pages.
>
> MAP_PRIVATE, PROT_WRITE of VM_RESERVED regions is tentatively being
> deprecated. We never completely handled it correctly anyway, and is be
> reintroduced in future if required (Hugh has a proof of concept).

We've got one user reporting that he's getting the following
message..

"program ddcprobe is using MAP_PRIVATE, PROT_WRITE mmap of VM_RESERVED memory"
since this cset.

So what should happen here, does that app need changing? Or do we just
need to get Hugh's changes merged?

It's likely that anything else that uses lrmi is going to be affected
in the same way, though off the top of my head, I don't know what (if any)
other apps there may be.

Dave

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