From b4e98d9ac775907cc53fb08fcb6776deb7694e30 Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Wed, 15 Nov 2017 17:35:33 -0800 Subject: 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 Signed-off-by: Heiko Carstens Acked-by: Rik van Riel Acked-by: Michal Hocko Cc: Vlastimil Babka Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/fork.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'kernel/fork.c') diff --git a/kernel/fork.c b/kernel/fork.c index 07cc743698d3..a4eb6f289365 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -819,6 +819,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p, mm->core_state = NULL; atomic_long_set(&mm->nr_ptes, 0); mm_nr_pmds_init(mm); + mm_nr_puds_init(mm); mm->map_count = 0; mm->locked_vm = 0; mm->pinned_vm = 0; @@ -878,6 +879,9 @@ static void check_mm(struct mm_struct *mm) if (mm_nr_pmds(mm)) pr_alert("BUG: non-zero nr_pmds on freeing mm: %ld\n", mm_nr_pmds(mm)); + if (mm_nr_puds(mm)) + pr_alert("BUG: non-zero nr_puds on freeing mm: %ld\n", + mm_nr_puds(mm)); #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS VM_BUG_ON_MM(mm->pmd_huge_pte, mm); -- cgit v1.2.3