Messages in this thread | | | Date | Mon, 25 Sep 2017 16:07:15 +0300 | From | "Kirill A. Shutemov" <> | Subject | Re: [PATCHv2] mm: Account pud page tables |
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On Mon, Sep 25, 2017 at 01:54:30PM +0200, Michal Hocko wrote: > On Mon 25-09-17 10:39:13, Kirill A. Shutemov wrote: > > On machine with 5-level paging support a process can allocate > > significant amount of memory and stay unnoticed by oom-killer and > > memory cgroup. The trick is to allocate a lot of PUD page tables. > > We don't account PUD page tables, only PMD and PTE. > > > > We already addressed the same issue for PMD page tables, see > > dc6c9a35b66b ("mm: account pmd page tables to the process"). > > Introduction 5-level paging bring the same issue for PUD page tables. > > > > The patch expands accounting to PUD level. > > OK, we definitely need this or something like that but I really do not > like how much code we actually need for each pte level for accounting. > Do we really need to distinguish each level? Do we have any arch that > would use a different number of pages to back pte/pmd/pud?
Looks like we actually do. At least on mips. See PMD_ORDER/PUD_ORDER.
-- Kirill A. Shutemov
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