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d=arm.com; s=foss; t=1783918869; bh=f9Tys1Cvm6yJflSHdH0xqAExQOs6Nr0MHrCE80JqbDY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IJAmj6OreHuA8GCVfOWOXpQ+RGDdi9qE1KRh3Oz/kBGduz6kKMYeTYffG8IxuCqEf NjBd2C1fNlzbeFWFMxY4kVhB6a5ESW7piA6AG5gkuv5/wbRaJyHwUxC88+bMCSwLaM zBGptXblrb5E7gQvPqfkkCIYAdg9HpciPjjAklhA= From: Dev Jain To: akpm@linux-foundation.org, david@kernel.org, ljs@kernel.org, muchun.song@linux.dev, osalvador@suse.de Cc: Dev Jain , riel@surriel.com, liam@infradead.org, vbabka@kernel.org, harry@kernel.org, jannh@google.com, lance.yang@linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, ryan.roberts@arm.com, anshuman.khandual@arm.com Subject: [PATCH v3 1/5] mm/rmap: convert page -> folio for hwpoison checks Date: Mon, 13 Jul 2026 05:00:44 +0000 Message-ID: <20260713050050.1017741-2-dev.jain@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260713050050.1017741-1-dev.jain@arm.com> References: <20260713050050.1017741-1-dev.jain@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 9A92980006 X-Rspam-User: X-Stat-Signature: i86r7o6a9g163m8mmuwomhn4cx6wutcj X-Rspamd-Server: rspam03 X-HE-Tag: 1783918870-478026 X-HE-Meta: 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 0hccK7cf 761Pbq0mq9AdWHBU6NgqNy/HMtY5WI79BrxP5+Vq2UV4E87rX+RUBU0OTekv9W1gOh8LFJ6yz3G2R29sk8Q9jnt7WeP2Y/eSWwammYOa/+lGbFSox2+JoWyOmqA+XaDTtN2KglpcBb/G69fiVkFJcPt+THs11X65bMeM9Jx2nwi6oua8NHTdSOXb+OeCxTZyS0WrFKb0TJCLKRPZqy/FRKZXongM0VN2I9/1TVgTNU7phtOi0nH95SRxFoO5evSpw35+3wAHM6LjDw88= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: try_to_unmap() receives hugetlb folios only from the hwpoison path. hugetlb_update_hwpoison() sets the hugetlb folio's head-page hwpoison bit, and page_vma_mapped_walk() reports the hugetlb mapping at the head PFN, so the previous PageHWPoison(subpage) check happened to work for hugetlb. For non-hugetlb folios, unmap_poisoned_folio() currently rejects large folios before calling try_to_unmap(). Hence it is always the case that if try_to_unmap_one() handles an hwpoisoned folio, then the head page is marked with the poison bit. Therefore, convert the poisoned subpage checks to folio_test_hwpoison(). No functional change intended, except that, while at it, convert VM_BUG_* to VM_WARN_*. Acked-by: David Hildenbrand (Arm) Signed-off-by: Dev Jain --- mm/rmap.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/mm/rmap.c b/mm/rmap.c index 26166a6b8cb9b..2b74668f356d6 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -2122,10 +2122,11 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, bool anon = folio_test_anon(folio); /* - * The try_to_unmap() is only passed a hugetlb page - * in the case where the hugetlb page is poisoned. + * The try_to_unmap() is only passed a hugetlb folio + * in the case where the hugetlb folio contains a + * poisoned page. */ - VM_BUG_ON_PAGE(!PageHWPoison(subpage), subpage); + VM_WARN_ON_FOLIO(!folio_test_hwpoison(folio), folio); /* * huge_pmd_unshare may unmap an entire PMD page. * There is no way of knowing exactly which PMDs may @@ -2204,7 +2205,11 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, /* Update high watermark before we lower rss */ update_hiwater_rss(mm); - if (PageHWPoison(subpage) && (flags & TTU_HWPOISON)) { + /* + * With TTU_HWPOISON, we only expect small folios or hugetlb + * folios here for now. + */ + if (folio_test_hwpoison(folio) && (flags & TTU_HWPOISON)) { pteval = swp_entry_to_pte(make_hwpoison_entry(subpage)); if (folio_test_hugetlb(folio)) { hugetlb_count_sub(folio_nr_pages(folio), mm); -- 2.43.0