On 2020-01-16 at 08:09 Mike Kravetz wrote:
>On 1/15/20 5:39 AM, Li Xinhai wrote:
>> Checking hstate at early phase when isolating page, instead of during
>> unmap and move phase, to avoid useless isolation.
>>
>> Signed-off-by: Li Xinhai <lixinhai.lxh@xxxxxxxxx>
>> Cc: Michal Hocko <mhocko@xxxxxxxx>
>> Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
>> ---
>> include/linux/hugetlb_inline.h | 7 +++++++
>> include/linux/mempolicy.h | 5 ++---
>> mm/hugetlb.c | 9 +++++++++
>> 3 files changed, 18 insertions(+), 3 deletions(-)
>>
>> diff --git a/include/linux/hugetlb_inline.h b/include/linux/hugetlb_inline.h
>> index 0660a03..fc07139 100644
>> --- a/include/linux/hugetlb_inline.h
>> +++ b/include/linux/hugetlb_inline.h
>> @@ -11,6 +11,8 @@ static inline bool is_vm_hugetlb_page(struct vm_area_struct *vma)
>> return !!(vma->vm_flags & VM_HUGETLB);
>> }
>>
>> +extern bool vm_hugepage_migration_supported(struct vm_area_struct *vma);
>> +
>> #else
>>
>> static inline bool is_vm_hugetlb_page(struct vm_area_struct *vma)
>> @@ -18,6 +20,11 @@ static inline bool is_vm_hugetlb_page(struct vm_area_struct *vma)
>> return false;
>> }
>>
>> +static inline bool vm_hugepage_migration_supported(struct vm_area_struct *vma)
>> +{
>> + return false;
>> +}
>> +
>> #endif
>>
>> #endif
>> diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h
>> index 5228c62..e9ed49e 100644
>> --- a/include/linux/mempolicy.h
>> +++ b/include/linux/mempolicy.h
>> @@ -185,10 +185,9 @@ static inline bool vma_migratable(struct vm_area_struct *vma)
>> if (vma_is_dax(vma))
>> return false;
>>
>> -#ifndef CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION
>> - if (vma->vm_flags & VM_HUGETLB)
>> + if (is_vm_hugetlb_page(vma) &&
>> + !vm_hugepage_migration_supported(vma))
>> return false;
>> -#endif
>>
>> /*
>> * Migration allocates pages in the highest zone. If we cannot
>
>There are not many ways to work around the hugepage_migration_supported
>dependency issue. I suppose you could have moved vma_migratable() into
>mm/mempolicy.c instead of being an inline in the header file. However,
>it is probably best to do what you have done and hide the ugly stuff in
>the hugetlbfs files.
Yes, that looks better, thanks. I will prepare new one.
>
>> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
>> index dd8737a..8ce4a98 100644
>> --- a/mm/hugetlb.c
>> +++ b/mm/hugetlb.c
>> @@ -1316,6 +1316,15 @@ int PageHeadHuge(struct page *page_head)
>> return get_compound_page_dtor(page_head) == free_huge_page;
>> }
>>
>> +bool vm_hugepage_migration_supported(struct vm_area_struct *vma)
>> +{
>> + VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma);
>
>This VM_BUG_ON_VMA() seems unnecessary. The only caller is the one
>added with this patch which is only called if is_vm_hugetlb_page(vma).
>Even though VM_BUG_ON() is only enabled if CONFIG_DEBUG_VM, many distros
>(including the one running my desktop) enable CONFIG_DEBUG_VM in their
>default kernel.
>
>--
>Mike Kravetz
>
>> + if (hugepage_migration_supported(hstate_vma(vma)))
>> + return true;
>> +
>> + return false;
>> +}
>> +
>> pgoff_t __basepage_index(struct page *page)
>> {
>> struct page *page_head = compound_head(page);
>>
