Messages in this thread | | | From | Yang Shi <> | Date | Wed, 8 Sep 2021 20:22:14 -0700 | Subject | Re: [PATCH v1] mm, hwpoison: add is_free_buddy_page() in HWPoisonHandlable() |
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On Wed, Sep 8, 2021 at 5:41 PM Naoya Horiguchi <naoya.horiguchi@linux.dev> wrote: > > From: Naoya Horiguchi <naoya.horiguchi@nec.com> > > commit fcc00621d88b ("mm/hwpoison: retry with shake_page() for > unhandlable pages") changes the return value of __get_hwpoison_page() to > retry for transiently unhandlable cases. However, __get_hwpoison_page() > currently fails to properly judge buddy pages as handlable, so hard/soft > offline for buddy pages always fail as "unhandlable page". This is > totally regrettable. > > So let's add is_free_buddy_page() in HWPoisonHandlable(), so that > __get_hwpoison_page() returns different return values between buddy > pages and unhandlable pages as intended. > > Fixes: fcc00621d88b ("mm/hwpoison: retry with shake_page() for unhandlable pages") > Cc: <stable@vger.kernel.org> > Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com> > --- > mm/memory-failure.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git v5.14-rc7-mmotm-2021-08-23-16-42/mm/memory-failure.c v5.14-rc7-mmotm-2021-08-23-16-42_patched/mm/memory-failure.c > index 60df8fcd0444..3416c55be810 100644 > --- v5.14-rc7-mmotm-2021-08-23-16-42/mm/memory-failure.c > +++ v5.14-rc7-mmotm-2021-08-23-16-42_patched/mm/memory-failure.c > @@ -1126,7 +1126,7 @@ static int page_action(struct page_state *ps, struct page *p, > */ > static inline bool HWPoisonHandlable(struct page *page) > { > - return PageLRU(page) || __PageMovable(page); > + return PageLRU(page) || __PageMovable(page) || is_free_buddy_page(page);
It seems to work. Although this may change the return value of get_any_page() to 1 when MF_COUNT_INCREASED is set. This may cause soft offline to mishandle free buddy page, but MF_COUNT_INCREASED is only set when madvise is used, and madvise definitely can't soft offline free buddy page. It did take me a while to figure out this trick. Maybe need some refactor?
Anyway this patch looks fine to me. Reviewed-by: Yang Shi <shy828301@gmail.com>
> } > > static int __get_hwpoison_page(struct page *page) > -- > 2.25.1 >
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