On Mon 08-03-21 18:28:03, Muchun Song wrote: > Because we reuse the first tail vmemmap page frame and remap it > with read-only, we cannot set the PageHWPosion on some tail pages. > So we can use the head[4].private (There are at least 128 struct > page structures associated with the optimized HugeTLB page, so > using head[4].private is safe) to record the real error page index > and set the raw error page PageHWPoison later.
Can we have more poisoned tail pages? Also who does consume that index and set the HWPoison on the proper tail page? > Signed-off-by: Muchun Song <[email protected]> > Reviewed-by: Oscar Salvador <[email protected]> > Acked-by: David Rientjes <[email protected]> > Tested-by: Chen Huang <[email protected]> > Tested-by: Bodeddula Balasubramaniam <[email protected]> > --- > mm/hugetlb.c | 80 > ++++++++++++++++++++++++++++++++++++++++++++++++++++++------ > 1 file changed, 72 insertions(+), 8 deletions(-) > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index 377e0c1b283f..c0c1b7635ca9 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -1304,6 +1304,74 @@ static inline void > destroy_compound_gigantic_page(struct page *page, > unsigned int order) { } > #endif > > +#ifdef CONFIG_HUGETLB_PAGE_FREE_VMEMMAP > +static inline void hwpoison_subpage_deliver(struct hstate *h, struct page > *head) > +{ > + struct page *page; > + > + if (!PageHWPoison(head) || !free_vmemmap_pages_per_hpage(h)) > + return; > + > + 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 hwpoison_subpage_set(struct hstate *h, struct page *head, > + struct page *page) > +{ > + if (!PageHWPoison(head)) > + return; > + > + if (free_vmemmap_pages_per_hpage(h)) { > + set_page_private(head + 4, page - head); > + } else if (page != head) { > + /* > + * Move PageHWPoison flag from head page to the raw error page, > + * which makes any subpages rather than the error page reusable. > + */ > + SetPageHWPoison(page); > + ClearPageHWPoison(head); > + } > +} > + > +static inline void hwpoison_subpage_clear(struct hstate *h, struct page > *head) > +{ > + if (!PageHWPoison(head) || !free_vmemmap_pages_per_hpage(h)) > + return; > + > + set_page_private(head + 4, 0); > +} > +#else > +static inline void hwpoison_subpage_deliver(struct hstate *h, struct page > *head) > +{ > +} > + > +static inline void hwpoison_subpage_set(struct hstate *h, struct page *head, > + struct page *page) > +{ > + if (PageHWPoison(head) && page != head) { > + /* > + * Move PageHWPoison flag from head page to the raw error page, > + * which makes any subpages rather than the error page reusable. > + */ > + SetPageHWPoison(page); > + ClearPageHWPoison(head); > + } > +} > + > +static inline void hwpoison_subpage_clear(struct hstate *h, struct page > *head) > +{ > +} > +#endif > + > static int update_and_free_page(struct hstate *h, struct page *page) > __releases(&hugetlb_lock) __acquires(&hugetlb_lock) > { > @@ -1357,6 +1425,8 @@ static int update_and_free_page(struct hstate *h, > struct page *page) > return -ENOMEM; > } > > + hwpoison_subpage_deliver(h, page); > + > for (i = 0; i < pages_per_huge_page(h); > i++, subpage = mem_map_next(subpage, page, i)) { > subpage->flags &= ~(1 << PG_locked | 1 << PG_error | > @@ -1801,14 +1871,7 @@ int dissolve_free_huge_page(struct page *page) > goto retry; > } > > - /* > - * 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); > - } > + hwpoison_subpage_set(h, head, page); > list_del(&head->lru); > h->free_huge_pages--; > h->free_huge_pages_node[nid]--; > @@ -1818,6 +1881,7 @@ int dissolve_free_huge_page(struct page *page) > h->surplus_huge_pages--; > h->surplus_huge_pages_node[nid]--; > h->max_huge_pages++; > + hwpoison_subpage_clear(h, head); > } > } > out: > -- > 2.11.0 > -- Michal Hocko SUSE Labs
