On Thu, Apr 30, 2015 at 01:55:39PM +0530, Aneesh Kumar K.V wrote:
> 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>
> ---
> include/asm-generic/pgtable.h | 5 +++++
> mm/huge_memory.c | 7 ++++---
> mm/pgtable-generic.c | 11 +++++++++++
> 3 files changed, 20 insertions(+), 3 deletions(-)
>
> diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
> index fe617b7e4be6..d091a666f5b1 100644
> --- a/include/asm-generic/pgtable.h
> +++ b/include/asm-generic/pgtable.h
> @@ -184,6 +184,11 @@ static inline void pmdp_set_wrprotect(struct mm_struct *mm,
> #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
> #endif
>
> +#ifndef __HAVE_ARCH_PMDP_SPLITTING_FLUSH_NOTIFY
> +extern void pmdp_splitting_flush_notify(struct vm_area_struct *vma,
> + unsigned long address, pmd_t *pmdp);
> +#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);
> diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
> index 2fe699cedd4d..0fc1f5a06979 100644
> --- a/mm/pgtable-generic.c
> +++ b/mm/pgtable-generic.c
> @@ -7,6 +7,7 @@
> */
>
> #include <linux/pagemap.h>
> +#include <linux/mmu_notifier.h>
> #include <asm/tlb.h>
> #include <asm-generic/pgtable.h>
>
> @@ -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.
--
Kirill A. Shutemov
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