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powerpc/mm/thp: update pmd_trans_huge to check for pmd_present 

We need to make sure pmd_trans_huge returns false for a pmd migration entry.
We mark the migration entry by clearing the _PAGE_PRESENT bit. We keep the
_PAGE_PTE bit set to indicate a leaf page table entry. Hence we need to make
sure we check for pmd_present() so that pmd_trans_huge won't return true on
pmd migration entry.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Aneesh Kumar K.V 2018-09-20 23:39:46 +05:30 committed by Michael Ellerman
parent 75646c480f
commit 8890e03380
2 changed files with 21 additions and 0 deletions
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3
arch/powerpc/include/asm/book3s/64/pgtable-64k.h
View File

@ -10,6 +10,9 @@
*
* Defined in such a way that we can optimize away code block at build time
* if CONFIG_HUGETLB_PAGE=n.
*
* returns true for pmd migration entries, THP, devmap, hugetlb
* But compile time dependent on CONFIG_HUGETLB_PAGE
*/
static inline int pmd_huge(pmd_t pmd)
{

18
arch/powerpc/include/asm/book3s/64/pgtable.h
View File

@ -1136,6 +1136,10 @@ pmd_hugepage_update(struct mm_struct *mm, unsigned long addr, pmd_t *pmdp,
return hash__pmd_hugepage_update(mm, addr, pmdp, clr, set);
}
/*
* returns true for pmd migration entries, THP, devmap, hugetlb
* But compile time dependent on THP config
*/
static inline int pmd_large(pmd_t pmd)
{
return !!(pmd_raw(pmd) & cpu_to_be64(_PAGE_PTE));
@ -1170,8 +1174,22 @@ static inline void pmdp_set_wrprotect(struct mm_struct *mm, unsigned long addr,
pmd_hugepage_update(mm, addr, pmdp, 0, _PAGE_PRIVILEGED);
}
/*
* Only returns true for a THP. False for pmd migration entry.
* We also need to return true when we come across a pte that
* in between a thp split. While splitting THP, we mark the pmd
* invalid (pmdp_invalidate()) before we set it with pte page
* address. A pmd_trans_huge() check against a pmd entry during that time
* should return true.
* We should not call this on a hugetlb entry. We should check for HugeTLB
* entry using vma->vm_flags
* The page table walk rule is explained in Documentation/vm/transhuge.rst
*/
static inline int pmd_trans_huge(pmd_t pmd)
{
if (!pmd_present(pmd))
return false;
if (radix_enabled())
return radix__pmd_trans_huge(pmd);
return hash__pmd_trans_huge(pmd);