[RFC][PATCH 0/3] track pte pages and use in OOM score

From: Dave Hansen
Date: Fri Apr 15 2011 - 13:38:26 EST

PTE pages are a relatively invisible memory user. Neither users
nor the kernel have any way of telling how many of them any given
application is using. Nefarious applications can also
potentially tie up lagre amounts of memory in them:

foo = malloc(big);
madvise(foo, big, MADV_DONTNEED);

That'll leave you with no RSS for "foo", but the pagetable pages
will still be there. Do that enough times, and you can
potentially harm the system. Even worse, the OOM killer will not
necessarily go after such an application since the kernel has no
record of the pages.

For the containers and OpenVZ folks, pte pages are one of the
main consumers of kernel memory. They should be able to use this
code as well.
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