mm: account pud page tables

On a 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 commit
dc6c9a35b66b ("mm: account pmd page tables to the process").
Introduction of 5-level paging brings the same issue for PUD page
tables.

The patch expands accounting to PUD level.

[kirill.shutemov@linux.intel.com: s/pmd_t/pud_t/]
  Link: http://lkml.kernel.org/r/20171004074305.x35eh5u7ybbt5kar@black.fi.intel.com
[heiko.carstens@de.ibm.com: s390/mm: fix pud table accounting]
  Link: http://lkml.kernel.org/r/20171103090551.18231-1-heiko.carstens@de.ibm.com
Link: http://lkml.kernel.org/r/20171002080427.3320-1-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 1 deletions

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 6744bd706ecf..a05ce6186f99 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -26,7 +26,7 @@
 
 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);
@@ -52,6 +52,7 @@ 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(pud_t) * mm_nr_puds(mm);
         seq_printf(m,
                 "VmPeak:\t%8lu kB\n"
                 "VmSize:\t%8lu kB\n"
@@ -68,6 +69,7 @@ void task_mem(struct seq_file *m, struct mm_struct *mm)
                 "VmLib:\t%8lu kB\n"
                 "VmPTE:\t%8lu kB\n"
                 "VmPMD:\t%8lu kB\n"
+                "VmPUD:\t%8lu kB\n"
                 "VmSwap:\t%8lu kB\n",
                 hiwater_vm << (PAGE_SHIFT-10),
                 total_vm << (PAGE_SHIFT-10),
@@ -82,6 +84,7 @@ void task_mem(struct seq_file *m, struct mm_struct *mm)
                 mm->stack_vm << (PAGE_SHIFT-10), text, lib,
                 ptes >> 10,
                 pmds >> 10,
+                puds >> 10,
                 swap << (PAGE_SHIFT-10));
         hugetlb_report_usage(m, mm);
 }