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 --- mm/memory.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) (limited to 'mm/memory.c') diff --git a/mm/memory.c b/mm/memory.c index 42fb303..6bbd407 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -506,6 +506,7 @@ static inline void free_pud_range(struct mmu_gather *tlb, p4d_t *p4d, pud = pud_offset(p4d, start); p4d_clear(p4d); pud_free_tlb(tlb, pud, start); + mm_dec_nr_puds(tlb->mm); } static inline void free_p4d_range(struct mmu_gather *tlb, pgd_t *pgd, @@ -4149,15 +4150,17 @@ int __pud_alloc(struct mm_struct *mm, p4d_t *p4d, unsigned long address) spin_lock(&mm->page_table_lock); #ifndef __ARCH_HAS_5LEVEL_HACK - if (p4d_present(*p4d)) /* Another has populated it */ - pud_free(mm, new); - else + if (!p4d_present(*p4d)) { + mm_inc_nr_puds(mm); p4d_populate(mm, p4d, new); -#else - if (pgd_present(*p4d)) /* Another has populated it */ + } else /* Another has populated it */ pud_free(mm, new); - else +#else + if (!pgd_present(*p4d)) { + mm_inc_nr_puds(mm); pgd_populate(mm, p4d, new); + } else /* Another has populated it */ + pud_free(mm, new); #endif /* __ARCH_HAS_5LEVEL_HACK */ spin_unlock(&mm->page_table_lock); return 0; -- cgit v1.1