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authorKirill A. Shutemov <kirill.shutemov@linux.intel.com>2017-11-16 04:35:33 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2017-11-16 05:21:04 +0300
commitb4e98d9ac775907cc53fb08fcb6776deb7694e30 (patch)
tree4a82caff5eab86a66f078622acfd68df5ac92235 /mm/memory.c
parent7d6c4dfa4de96d11b9d6adaf5aa5ca8c54670258 (diff)
downloadlinux-b4e98d9ac775907cc53fb08fcb6776deb7694e30.tar.xz
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>
Diffstat (limited to 'mm/memory.c')
-rw-r--r--mm/memory.c15
1 files changed, 9 insertions, 6 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 42fb30300bb5..6bbd4078ec98 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;