Messages in this thread | | | Date | Fri, 26 Apr 2024 13:33:27 -0700 | Subject | Re: [PATCH] mm/memory-failure: remove shake_page() | From | Jane Chu <> |
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My apology for the gobbled message earlier.
On 4/26/2024 12:52 PM, Jane Chu wrote: > On 4/26/2024 12:05 PM, Matthew Wilcox wrote: > [..] >> That would be unsafe, the safe way would be if we moved page_folio() >> after >>> the call to __get_hw_poison() in get_any_page() and there would >>> still be one >>> remaining user of shake_page() that we can't convert. A safe version >>> of this >>> patch would result in a removal of one use of PageHuge() and two >>> uses of >>> put_page(), would that be worth submitting? >>> >>> get_any_page() >>> if(__get_hwpoison_page()) >>> folio = page_folio() /* folio_try_get() returned 1, safe */ >> I think we should convert __get_hwpoison_page() to return either the >> folio >> or an ERR_PTR or NULL. Also, I think we should delete the "cannot catch >> tail" part and just loop in __get_hwpoison_page() until we do catch it. >> See try_get_folio() in mm/gup.c for inspiration (although you can't use >> it exactly because that code knows that the page is mapped into a page >> table, so has a refcount). >> >> But that's just an immediate assessment; you might find a reason that >> doesn't work. > Besides, in a possible hugetlb demote scenario, it seems to me that we should retry get_hwpoison_hugetlb_folio() instead of falling thru to folio_try_get().
static int __get_hwpoison_page(struct page *page, unsigned long flags) { struct folio *folio = page_folio(page); int ret = 0; bool hugetlb = false;
ret = get_hwpoison_hugetlb_folio(folio, &hugetlb, false); if (hugetlb) { /* Make sure hugetlb demotion did not happen from under us. */ if (folio == page_folio(page)) return ret; if (ret > 0) { <===== still hugetlb, don't fall thru, retry folio_put(folio); folio = page_folio(page); }
}
thanks! -jane
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