[Fwd: + maps-pssproportional-set-size-accounting-in-smaps.patch added to -mm tree]

[Dan Winship]

Andres Salomon wrote:
> On Mon, 24 Sep 2007 16:51:07 -0400
> Bernardo Innocenti <bernie at codewiz.org> wrote:
> 
>> Cool!  Andrew picked up the patch I liked.
>>
>> Andres, how about adding it to olpc-2.6 too?  Along with the
>> latest Memphis patch, it would give use us invaluable stats
>> for those trying to reduce memory usage.
>>
> 
> Is it useful for the sugar folks' memory donut?  I'm certainly not opposed
> to including the patch (though I'd want to look over the lkml thread before
> committing), if people find it useful.

"PSS" is basically the same measure we're currently calculating (a 
little more accurate in some ways, a little less in others). Having the 
kernel calculate PSS would let us draw the ring faster (which would be 
good), but wouldn't affect the accuracy.

The biggest problem the ring has right now is that it doesn't take into 
account the fact that code pages can be swapped back out to disk to 
create more RAM, and so it needs to count inactive pages differently 
from active pages if we want the free-space wedge in the donut to be an 
accurate estimation of the user's ability to launch another activity. 
AFAIK the PSS kernel patch doesn't help with this.

-- Dan