Re: [PATCH] NOMMU: Separate out VMAs

[Bernd Schmidt <bernds_cb1@t-online.de>]

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