Re: [PATCH] NOMMU: Separate out VMAs

From: Bernd Schmidt
Date: Tue Aug 07 2007 - 09:40:24 EST

David Howells wrote:
> Here's a preview of my patch to give each process a separate list of VMAs
> under NOMMU mode, just as under MMU mode. Could you have a look over it
> please?

I've managed to apply it to our Blackfin tree and started looking at it.

> Could you also see if you get a memory leak on the blackfin CPU? I see a leak
> when I use this patch, but I'm not sure whether it's this patch, or whether
> it's something else in the arch that is suppressed without this patch.
>
> As far as I can tell by page counting there shouldn't be a leak.

There is a leak:

root:~> while true; do
> cat /proc/buddyinfo
> sleep 1
> done
Node 0, zone DMA 20 1 1 1 0 1 1
1 0 0 0 1 2 0
Node 0, zone DMA 32 1 1 0 0 0 1
0 0 0 0 1 2 0
Node 0, zone DMA 47 1 1 1 1 0 0
1 1 1 1 0 2 0
Node 0, zone DMA 62 1 1 0 1 1 1
1 0 1 1 0 2 0
Node 0, zone DMA 77 1 1 1 0 0 1
0 0 1 1 0 2 0
Node 0, zone DMA 92 1 1 0 0 1 0
1 1 0 1 0 2 0
Node 0, zone DMA 107 1 1 1 1 1 1
1 0 0 1 0 2 0
Node 0, zone DMA 122 1 1 0 1 0 1
0 0 0 1 0 2 0
Node 0, zone DMA 137 1 1 1 0 1 0
1 1 1 0 0 2 0
... and so on. It's a strange pattern of fragmentation, as if it keeps
allocating 8k pages and freeing one half of them.

Will play with this some more. Thanks!


Bernd
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