Re: [PATCH]: Adding a counter in vma to indicate the number ofphysical pages backing it

From: Christoph Lameter
Date: Mon Jun 12 2006 - 12:42:14 EST


On Fri, 9 Jun 2006, Rohit Seth wrote:

> There is currently /proc/<pid>/smaps that prints the detailed
> information about the usage of physical pages but that is a very
> expensive operation as it traverses all the PTs (for some one who is
> just interested in getting that data for each vma).

Adding a new counter to a vma may cause a bouncing cacheline etc. I
would think that such a counter is far more expensive than occasional
scans through the page table because someone is curious about the
number of page in use. /proc/<pid>/numa_maps also uses these scans to
determine dirty pages etc.


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