Commit 6d212db1 authored by Martin Schwidefsky's avatar Martin Schwidefsky
Browse files

mm: add mm_pxd_folded checks to pgtable_bytes accounting functions 



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.

Acked-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 1071fc57

include/linux/mm.h

+8 −0
Original line number Original line Diff line number Diff line
@@ -1742,11 +1742,15 @@ int __pud_alloc(struct mm_struct *mm, p4d_t *p4d, unsigned long address); 




static inline void mm_inc_nr_puds(struct mm_struct *mm)

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);

	atomic_long_add(PTRS_PER_PUD * sizeof(pud_t), &mm->pgtables_bytes);

}

}





static inline void mm_dec_nr_puds(struct mm_struct *mm)

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);

	atomic_long_sub(PTRS_PER_PUD * sizeof(pud_t), &mm->pgtables_bytes);

}

}

#endif

#endif
@@ -1766,11 +1770,15 @@ int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address); 




static inline void mm_inc_nr_pmds(struct mm_struct *mm)

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);

	atomic_long_add(PTRS_PER_PMD * sizeof(pmd_t), &mm->pgtables_bytes);

}

}





static inline void mm_dec_nr_pmds(struct mm_struct *mm)

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);

	atomic_long_sub(PTRS_PER_PMD * sizeof(pmd_t), &mm->pgtables_bytes);

}

}

#endif

#endif

CRA Git | Maintained and supported by SUSTech CRA and CCSE