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Message-Id: <1539621759-5967-3-git-send-email-schwidefsky@de.ibm.com>
Date: Mon, 15 Oct 2018 18:42:38 +0200
From: Martin Schwidefsky <schwidefsky@...ibm.com>
To: Li Wang <liwang@...hat.com>, Guenter Roeck <linux@...ck-us.net>,
Janosch Frank <frankja@...ux.vnet.ibm.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
Heiko Carstens <heiko.carstens@...ibm.com>,
linux-kernel <linux-kernel@...r.kernel.org>,
Linux-MM <linux-mm@...ck.org>,
Martin Schwidefsky <schwidefsky@...ibm.com>
Subject: [PATCH 2/3] 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.
Signed-off-by: Martin Schwidefsky <schwidefsky@...ibm.com>
---
include/linux/mm.h | 8 ++++++++
1 file changed, 8 insertions(+)
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
--
2.16.4
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