RFC track pte pages and use in OOM score

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);
	touch(foo);
	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.

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to [email protected]. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"[email protected]"> [email protected] </a>