2020년 5월 22일 (금) 오전 5:54, Mike Kravetz <mike.kravetz@xxxxxxxxxx>님이 작성:
>
> On 5/17/20 6:20 PM, js1304@xxxxxxxxx wrote:
> > From: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
> >
> > There is no difference between two migration callback functions,
> > alloc_huge_page_node() and alloc_huge_page_nodemask(), except
> > __GFP_THISNODE handling. This patch adds one more field on to
> > the alloc_control and handles this exception.
> >
> > Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
> > ---
> > include/linux/hugetlb.h | 8 --------
> > mm/hugetlb.c | 23 ++---------------------
> > mm/internal.h | 1 +
> > mm/mempolicy.c | 3 ++-
> > 4 files changed, 5 insertions(+), 30 deletions(-)
> >
> > diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
> > index 6da217e..4892ed3 100644
> > --- a/include/linux/hugetlb.h
> > +++ b/include/linux/hugetlb.h
> > @@ -505,8 +505,6 @@ struct huge_bootmem_page {
> >
> > struct page *alloc_migrate_huge_page(struct hstate *h,
> > struct alloc_control *ac);
> > -struct page *alloc_huge_page_node(struct hstate *h,
> > - struct alloc_control *ac);
> > struct page *alloc_huge_page_nodemask(struct hstate *h,
> > struct alloc_control *ac);
> > struct page *alloc_huge_page_vma(struct hstate *h, struct vm_area_struct *vma,
> > @@ -755,12 +753,6 @@ static inline void huge_ptep_modify_prot_commit(struct vm_area_struct *vma,
> > struct hstate {};
> >
> > static inline struct page *
> > -alloc_huge_page_node(struct hstate *h, struct alloc_control *ac)
> > -{
> > - return NULL;
> > -}
> > -
> > -static inline struct page *
> > alloc_huge_page_nodemask(struct hstate *h, struct alloc_control *ac)
> > {
> > return NULL;
> > diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> > index 859dba4..60b0983 100644
> > --- a/mm/hugetlb.c
> > +++ b/mm/hugetlb.c
> > @@ -1981,31 +1981,12 @@ struct page *alloc_buddy_huge_page_with_mpol(struct hstate *h,
> > }
> >
> > /* page migration callback function */
> > -struct page *alloc_huge_page_node(struct hstate *h,
> > - struct alloc_control *ac)
> > -{
> > - struct page *page = NULL;
> > -
> > - ac->gfp_mask |= htlb_alloc_mask(h);
> > - if (ac->nid != NUMA_NO_NODE)
> > - ac->gfp_mask |= __GFP_THISNODE;
> > -
> > - spin_lock(&hugetlb_lock);
> > - if (h->free_huge_pages - h->resv_huge_pages > 0)
> > - page = dequeue_huge_page_nodemask(h, ac);
> > - spin_unlock(&hugetlb_lock);
> > -
> > - if (!page)
> > - page = alloc_migrate_huge_page(h, ac);
> > -
> > - return page;
> > -}
> > -
> > -/* page migration callback function */
> > struct page *alloc_huge_page_nodemask(struct hstate *h,
> > struct alloc_control *ac)
> > {
> > ac->gfp_mask |= htlb_alloc_mask(h);
> > + if (ac->thisnode && ac->nid != NUMA_NO_NODE)
> > + ac->gfp_mask |= __GFP_THISNODE;
> >
> > spin_lock(&hugetlb_lock);
> > if (h->free_huge_pages - h->resv_huge_pages > 0) {
> > diff --git a/mm/internal.h b/mm/internal.h
> > index 75b3f8e..574722d0 100644
> > --- a/mm/internal.h
> > +++ b/mm/internal.h
> > @@ -618,6 +618,7 @@ struct alloc_control {
> > int nid;
> > nodemask_t *nmask;
> > gfp_t gfp_mask;
> > + bool thisnode;
>
> I wonder if the new field is necessary?
>
> IIUC, it simply prevents the check for NUMA_NO_NODE and possible setting
> of __GFP_THISNODE in previous alloc_huge_page_nodemask() calling sequences.
> However, it appears that node (preferred_nid) is always set to something
> other than NUMA_NO_NODE in those callers.
Okay. I will check it.
> It obviously makes sense to add the field to guarantee no changes to
> functionality while making the conversions. However, it it is not really
> necessary then it may cause confusion later.
Agreed.
Thanks.
