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bh=74HpFWRFRTO3Ef08AiFl7DxF5dkmm6WMDaEm4lC7tlk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=m8MH6uHr6tfyXXYzpTwtFTbAt9HftVJg17b7MOHYYx5/i1m3s5xfWGbo6deU1DvSF 0rceOxATmMECerhpnDm+D3ndcUnsYHzacEUENhw9iqNQK1Ky3d7EVpDf5ij2y/63yz p3KD/1kdLi03SpQ1Ho1ShGAr48Kwhu0DZ74pLvwg= 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 v2 1/5] mm/rmap: convert page -> folio for hwpoison checks Date: Fri, 10 Jul 2026 05:59:10 +0000 Message-ID: <20260710055915.638659-2-dev.jain@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260710055915.638659-1-dev.jain@arm.com> References: <20260710055915.638659-1-dev.jain@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 82460100004 X-Stat-Signature: r615ht8bgm7gttdd9yypd8ndiqr3p9zq X-HE-Tag: 1783663171-980283 X-HE-Meta: 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 UnfwHKWH yzUSsFZ0ljYiLSX7yY7W5Um+MX4tlKI+0wUQkFgqccwCnhZe17ho74LeYR+q1jdY1ElPrJjqZCFYEV8RWoE8GvhDhqfth/mGlroJ13j7pTT52fEB8DbQ1LoqqaZBitmlYkQ9xWf4xmv94GYOKXOl4Jz1S4jZJ+HampBSHHwZWC5ws4zWQFhos/svjF7HMqXu90MVBC5V8pexPaNxnA65UXRoHyuV/hah51wYgbATnAlELDW3AasZ/xynjk4gaI+DGg6+CAXMF8QuerEc= 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 9939400e77c79..dbb077f8443e3 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