"Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx> writes:
> "Kirill A. Shutemov" <kirill@xxxxxxxxxxxxx> writes:
>
>>> @@ -184,3 +185,13 @@ void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
>>> }
>>> #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
>>> #endif
>>> +
>>> +#ifndef __HAVE_ARCH_PMDP_SPLITTING_FLUSH_NOTIFY
>>> +#ifdef CONFIG_TRANSPARENT_HUGEPAGE
>>> +void pmdp_splitting_flush_notify(struct vm_area_struct *vma,
>>> + unsigned long address, pmd_t *pmdp)
>>> +{
>>> + pmdp_clear_flush_notify(vma, address, pmdp);
>>> +}
>>> +#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
>>> +#endif
>>
>> I think it worth inlining. Let's put it to <asm-generic/pgtable.h>
>>
>> It probably worth combining with collapse counterpart in the same patch.
>>
>
> I tried that first, But that pulls in mmu_notifier.h and huge_mm.h
> headers and other build failures
>
Putting them in TRANSPATENT_HUGEPAGE helped.
commit 9c60ab5d1d684db2ba454ee1c7f3e9a6bf57f026
Author: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Date: Wed Apr 29 14:57:30 2015 +0530
mm/thp: Use pmdp_splitting_flush_notify to clear pmd on splitting
Some arch may require an explicit IPI before a THP PMD split. This
ensures that a local_irq_disable can prevent a parallel THP PMD split.
So use new function which arch can override
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index fe617b7e4be6..6a0b2ab899d1 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -184,6 +184,24 @@ static inline void pmdp_set_wrprotect(struct mm_struct *mm,
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#endif
+#ifndef __HAVE_ARCH_PMDP_SPLITTING_FLUSH_NOTIFY
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+static inline void pmdp_splitting_flush_notify(struct vm_area_struct *vma,
+ unsigned long address,
+ pmd_t *pmdp)
+{
+ pmdp_clear_flush_notify(vma, address, pmdp);
+}
+#else
+static inline void pmdp_splitting_flush_notify(struct vm_area_struct *vma,
+ unsigned long address,
+ pmd_t *pmdp)
+{
+ BUG();
+}
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+#endif
+
#ifndef __HAVE_ARCH_PGTABLE_DEPOSIT
extern void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
pgtable_t pgtable);
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index cce4604c192f..81e9578bf43a 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2606,9 +2606,10 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
write = pmd_write(*pmd);
young = pmd_young(*pmd);
-
- /* leave pmd empty until pte is filled */
- pmdp_clear_flush_notify(vma, haddr, pmd);
+ /*
+ * leave pmd empty until pte is filled.
+ */
+ pmdp_splitting_flush_notify(vma, haddr, pmd);
pgtable = pgtable_trans_huge_withdraw(mm, pmd);
pmd_populate(mm, &_pmd, pgtable);
--
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