On Fri 20-11-20 14:43:19, Muchun Song wrote: > Because we reuse the first tail page, if we set PageHWPosion on a > tail page. It indicates that we may set PageHWPoison on a series > of pages. So we can use the head[4].mapping to record the real > error page index and set the raw error page PageHWPoison later.
This really begs more explanation. Maybe I misremember but If there is a HWPoison hole in a hugepage then the whole page is demolished, no? If that is the case then why do we care about tail pages? > Signed-off-by: Muchun Song <songmuc...@bytedance.com> > --- > mm/hugetlb.c | 11 +++-------- > mm/hugetlb_vmemmap.h | 39 +++++++++++++++++++++++++++++++++++++++ > 2 files changed, 42 insertions(+), 8 deletions(-) > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index 055604d07046..b853aacd5c16 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -1383,6 +1383,7 @@ static void __free_hugepage(struct hstate *h, struct > page *page) > int i; > > alloc_huge_page_vmemmap(h, page); > + subpage_hwpoison_deliver(page); > > for (i = 0; i < pages_per_huge_page(h); i++) { > page[i].flags &= ~(1 << PG_locked | 1 << PG_error | > @@ -1944,14 +1945,8 @@ int dissolve_free_huge_page(struct page *page) > int nid = page_to_nid(head); > if (h->free_huge_pages - h->resv_huge_pages == 0) > goto out; > - /* > - * Move PageHWPoison flag from head page to the raw error page, > - * which makes any subpages rather than the error page reusable. > - */ > - if (PageHWPoison(head) && page != head) { > - SetPageHWPoison(page); > - ClearPageHWPoison(head); > - } > + > + set_subpage_hwpoison(head, page); > list_del(&head->lru); > h->free_huge_pages--; > h->free_huge_pages_node[nid]--; > diff --git a/mm/hugetlb_vmemmap.h b/mm/hugetlb_vmemmap.h > index 779d3cb9333f..65e94436ffff 100644 > --- a/mm/hugetlb_vmemmap.h > +++ b/mm/hugetlb_vmemmap.h > @@ -20,6 +20,29 @@ void __init gather_vmemmap_pgtable_init(struct > huge_bootmem_page *m, > void alloc_huge_page_vmemmap(struct hstate *h, struct page *head); > void free_huge_page_vmemmap(struct hstate *h, struct page *head); > > +static inline void subpage_hwpoison_deliver(struct page *head) > +{ > + struct page *page = head; > + > + if (PageHWPoison(head)) > + page = head + page_private(head + 4); > + > + /* > + * Move PageHWPoison flag from head page to the raw error page, > + * which makes any subpages rather than the error page reusable. > + */ > + if (page != head) { > + SetPageHWPoison(page); > + ClearPageHWPoison(head); > + } > +} > + > +static inline void set_subpage_hwpoison(struct page *head, struct page *page) > +{ > + if (PageHWPoison(head)) > + set_page_private(head + 4, page - head); > +} > + > static inline unsigned int free_vmemmap_pages_per_hpage(struct hstate *h) > { > return h->nr_free_vmemmap_pages; > @@ -56,6 +79,22 @@ static inline void free_huge_page_vmemmap(struct hstate > *h, struct page *head) > { > } > > +static inline void subpage_hwpoison_deliver(struct page *head) > +{ > +} > + > +static inline void set_subpage_hwpoison(struct page *head, struct page *page) > +{ > + /* > + * Move PageHWPoison flag from head page to the raw error page, > + * which makes any subpages rather than the error page reusable. > + */ > + if (PageHWPoison(head) && page != head) { > + SetPageHWPoison(page); > + ClearPageHWPoison(head); > + } > +} > + > static inline unsigned int free_vmemmap_pages_per_hpage(struct hstate *h) > { > return 0; > -- > 2.11.0 > -- Michal Hocko SUSE Labs