Re: [PATCHv3] mm: Account pud page tables

[Vlastimil Babka]

On 10/02/2017 10:04 AM, 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.
> 
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> Cc: Michal Hocko <mhocko@xxxxxxxx>
> Cc: Vlastimil Babka <vbabka@xxxxxxx>

Acked-by: Vlastimil Babka <vbabka@xxxxxxx>

Small fix below:

> --- a/fs/proc/task_mmu.c
> +++ b/fs/proc/task_mmu.c
> @@ -25,7 +25,7 @@
>  
>  void task_mem(struct seq_file *m, struct mm_struct *mm)
>  {
> -	unsigned long text, lib, swap, ptes, pmds, anon, file, shmem;
> +	unsigned long text, lib, swap, ptes, pmds, puds, anon, file, shmem;
>  	unsigned long hiwater_vm, total_vm, hiwater_rss, total_rss;
>  
>  	anon = get_mm_counter(mm, MM_ANONPAGES);
> @@ -51,6 +51,7 @@ void task_mem(struct seq_file *m, struct mm_struct *mm)
>  	swap = get_mm_counter(mm, MM_SWAPENTS);
>  	ptes = PTRS_PER_PTE * sizeof(pte_t) * atomic_long_read(&mm->nr_ptes);
>  	pmds = PTRS_PER_PMD * sizeof(pmd_t) * mm_nr_pmds(mm);
> +	puds = PTRS_PER_PUD * sizeof(pmd_t) * mm_nr_puds(mm);

				     ^ pud_t ?