Re: [RFC][PATCH] show page size in /proc/$pid/numa_maps
From: David Rientjes <rientjes@google.com>
Date: 2011-09-22 20:43:47
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On Wed, 21 Sep 2011, Dave Hansen wrote:
The output of /proc/$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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