On Mon, Jul 11, 2022 at 03:09:01PM +0800, Miaohe Lin wrote:
> On 2022/7/8 13:36, Naoya Horiguchi wrote:
> > From: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
> >
> > Raw error info list needs to be removed when hwpoisoned hugetlb is
> > unpoisoned. And unpoison handler needs to know how many errors there
> > are in the target hugepage. So add them.
> >
> > HPageVmemmapOptimized(hpage) and HPageRawHwpUnreliable(hpage)) can't be
> > unpoisoned, so let's skip them.
> >
> > Signed-off-by: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
> > Reported-by: kernel test robot <lkp@xxxxxxxxx>
> > ---
> > v4 -> v5:
> > - fix type of return value of free_raw_hwp_pages()
> > (found by kernel test robot),
> > - prevent unpoison for HPageVmemmapOptimized and HPageRawHwpUnreliable.
> > ---
...
> > diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> > index 6833c5e4b410..89e74ec8a95f 100644
> > --- a/mm/memory-failure.c
> > +++ b/mm/memory-failure.c
> > @@ -1720,22 +1720,41 @@ static int hugetlb_set_page_hwpoison(struct page *hpage, struct page *page)
> > return ret;
> > }
> >
> > -int hugetlb_clear_page_hwpoison(struct page *hpage)
> > +static long free_raw_hwp_pages(struct page *hpage, bool move_flag)
>
> NO strong opinion: Maybe the return type should be "unsigned" as it always >= 0 ?
Yes, will update.
>
> > {
> > struct llist_head *head;
> > struct llist_node *t, *tnode;
> > + long count = 0;
> >
> > - if (!HPageRawHwpUnreliable(hpage))
> > - ClearPageHWPoison(hpage);
> > + /*
> > + * HPageVmemmapOptimized hugepages can't be unpoisoned because
> > + * struct pages for tail pages are required to free hwpoisoned
> > + * hugepages. HPageRawHwpUnreliable hugepages shouldn't be
> > + * unpoisoned by definition.
> > + */
> > + if (HPageVmemmapOptimized(hpage) || HPageRawHwpUnreliable(hpage))
> > + return 0;
> > head = raw_hwp_list_head(hpage);
> > llist_for_each_safe(tnode, t, head->first) {
> > struct raw_hwp_page *p = container_of(tnode, struct raw_hwp_page, node);
> >
> > - SetPageHWPoison(p->page);
> > + if (move_flag)
> > + SetPageHWPoison(p->page);
> > kfree(p);
> > + count++;
> > }
> > llist_del_all(head);
> > - return 0;
> > + return count;
> > +}
> > +
> > +int hugetlb_clear_page_hwpoison(struct page *hpage)
>
> It seems the return value is unused?
Yes, the return value is not needed now.
>
> > +{
> > + int ret = -EBUSY;
> > +
> > + if (!HPageRawHwpUnreliable(hpage))
> > + ret = !TestClearPageHWPoison(hpage);
> > + free_raw_hwp_pages(hpage, true);
> > + return ret;
> > }
> >
> > /*
> > @@ -1879,6 +1898,10 @@ static inline int try_memory_failure_hugetlb(unsigned long pfn, int flags, int *
> > return 0;
> > }
> >
> > +static inline long free_raw_hwp_pages(struct page *hpage, bool move_flag)
>
> If return type is changed, remember to change here too.
OK.
> > +{
> > + return 0;
> > +}
> > #endif /* CONFIG_HUGETLB_PAGE */
> >
> > static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
> > @@ -2284,6 +2307,7 @@ int unpoison_memory(unsigned long pfn)
> > struct page *p;
> > int ret = -EBUSY;
> > int freeit = 0;
> > + long count = 1;
> > static DEFINE_RATELIMIT_STATE(unpoison_rs, DEFAULT_RATELIMIT_INTERVAL,
> > DEFAULT_RATELIMIT_BURST);
> >
> > @@ -2331,6 +2355,13 @@ int unpoison_memory(unsigned long pfn)
> >
> > ret = get_hwpoison_page(p, MF_UNPOISON);
> > if (!ret) {
> > + if (PageHuge(p)) {
> > + count = free_raw_hwp_pages(page, false);
>
> It seems the current behavior is: if any subpage of a hugetlb page is unpoisoned, then all of the
> hwpoisoned subpages will be unpoisoned. I'm not sure whether this is what we want.
Basically raw_hwp_info is not available to userspace (it might be recorded
in dmesg but not available via /proc/kpageflags), so unpoisoning error
subpages one-by-one is sometimes bothering. If someone would like to
unpoison one-by-one (I expect nobody would), I can do this.
> Thanks.
Thank you!
- Naoya Horiguchi
