tree 33c52199cd919a9f115b41a95b4c98d135e8e815
parent 384221cbb918136863016a582dd7475febc7d4b9
author Martin Schwidefsky <schwidefsky@de.ibm.com> 1539592223 +0200
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1546087077 +0100

mm: add mm_pxd_folded checks to pgtable_bytes accounting functions

[ Upstream commit 6d212db11947ae5464e4717536ed9faf61c01e86 ]

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: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>