| Message ID | 1539621759-5967-3-git-send-email-schwidefsky@de.ibm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | pgtable bytes mis-accounting v2 | expand |
On Mon, Oct 15, 2018 at 06:42:38PM +0200, Martin Schwidefsky wrote: > The common mm code calls mm_dec_nr_pmds() and mm_dec_nr_puds() > in free_pgtables() if the address range spans a full pud or pmd. > If mm_dec_nr_puds/mm_dec_nr_pmds are non-empty due to configuration > settings they blindly subtract the size of the pmd or pud table from > pgtable_bytes even if the pud or pmd page table layer is folded. > > Add explicit mm_[pmd|pud]_folded checks to the four pgtable_bytes > accounting functions mm_inc_nr_puds, mm_inc_nr_pmds, mm_dec_nr_puds > and mm_dec_nr_pmds. As the check for folded page tables can be > overwritten by the architecture, this allows to keep a correct > pgtable_bytes value for platforms that use a dynamic number of > page table levels. > > Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Looks fine to me. Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
diff --git a/include/linux/mm.h b/include/linux/mm.h index d1029972541c..67f55c71e59a 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1764,11 +1764,15 @@ int __pud_alloc(struct mm_struct *mm, p4d_t *p4d, unsigned long address); static inline void mm_inc_nr_puds(struct mm_struct *mm) { + if (mm_pud_folded(mm)) + return; atomic_long_add(PTRS_PER_PUD * sizeof(pud_t), &mm->pgtables_bytes); } static inline void mm_dec_nr_puds(struct mm_struct *mm) { + if (mm_pud_folded(mm)) + return; atomic_long_sub(PTRS_PER_PUD * sizeof(pud_t), &mm->pgtables_bytes); } #endif @@ -1788,11 +1792,15 @@ int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address); static inline void mm_inc_nr_pmds(struct mm_struct *mm) { + if (mm_pmd_folded(mm)) + return; atomic_long_add(PTRS_PER_PMD * sizeof(pmd_t), &mm->pgtables_bytes); } static inline void mm_dec_nr_pmds(struct mm_struct *mm) { + if (mm_pmd_folded(mm)) + return; atomic_long_sub(PTRS_PER_PMD * sizeof(pmd_t), &mm->pgtables_bytes); } #endif
The common mm code calls mm_dec_nr_pmds() and mm_dec_nr_puds() in free_pgtables() if the address range spans a full pud or pmd. If mm_dec_nr_puds/mm_dec_nr_pmds are non-empty due to configuration settings they blindly subtract the size of the pmd or pud table from pgtable_bytes even if the pud or pmd page table layer is folded. Add explicit mm_[pmd|pud]_folded checks to the four pgtable_bytes accounting functions mm_inc_nr_puds, mm_inc_nr_pmds, mm_dec_nr_puds and mm_dec_nr_pmds. As the check for folded page tables can be overwritten by the architecture, this allows to keep a correct pgtable_bytes value for platforms that use a dynamic number of page table levels. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> --- include/linux/mm.h | 8 ++++++++ 1 file changed, 8 insertions(+)