Re: [RFC][PATCH] show page size in /proc/$pid/numa_maps
From: David Rientjes
Date: Thu Sep 22 2011 - 16:44:05 EST
On Wed, 21 Sep 2011, Dave Hansen wrote:
>
> The output of /proc/$pid/numa_maps is in terms of number of pages
> like anon=22 or dirty=54. Here's some output:
>
> 7f4680000000 default file=/hugetlb/bigfile anon=50 dirty=50 N0=50
> 7f7659600000 default file=/anon_hugepage\040(deleted) anon=50 dirty=50 N0=50
> 7fff8d425000 default stack anon=50 dirty=50 N0=50
>
> Looks like we have a stack and a couple of anonymous hugetlbfs
> areas page which both use the same amount of memory. They don't.
>
> The 'bigfile' uses 1GB pages and takes up ~50GB of space. The
> anon_hugepage uses 2MB pages and takes up ~100MB of space while
> the stack uses normal 4k pages. You can go over to smaps to
> figure out what the page size _really_ is with KernelPageSize
> or MMUPageSize. But, I think this is a pretty nasty and
> counterintuitive interface as it stands.
>
> The following patch adds a pagemult= field. It is placed only
> in cases where the VMA's page size differs from the base kernel
> page size. I'm calling it pagemult to emphasize that it is
> indended to modify the statistics output rather than _really_
> show the page size that the kernel or MMU is using.
>
Why not just add a pagesize={4K,2M,1G,...} field for every output?
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