From mboxrd@z Thu Jan 1 00:00:00 1970 From: Doug Berger Subject: [PATCH 03/21] mm/hugetlb: correct demote page offset logic Date: Tue, 13 Sep 2022 12:54:50 -0700 Message-ID: <20220913195508.3511038-4-opendmb@gmail.com> References: <20220913195508.3511038-1-opendmb@gmail.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date; bh=dgAC9wdSWdNnQd7c6lUo6ch6gbgfZ8Ik+m13B5omrFE=; b=pgU7qB1cfn3bbb6aqaPKVsP0QULztBXM6ZTdmlLajCShk8VBE78cxzG8Cv0iNse9pr raJ8GgLPcDyEkXzvMHViIvbgw2EPxCCCxmBWVydWXsbvHPXhV9LnTIQcxrhx+uvf4Xru 5WYEg1qQVSMXl/Ik2LXwDiiTB+uN5XnQ7jp32HYymQ2HZJZADmguB3tnteKHk9qIukRc jpn8LdBlaPcxTkVAmOKzkV+NLvIVifwROYLBZ5KLKak/eoCCJdA+KloOJgYdmZJeYMVG xPc5vPtISXEXXxdKiktdhoBVSWbwV6cguyuU1u/JwyBG7hVEPpa11URawNPjZH6cK9Db YImw== In-Reply-To: <20220913195508.3511038-1-opendmb-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> List-ID: Content-Type: text/plain; charset="us-ascii" To: Andrew Morton Cc: Jonathan Corbet , Rob Herring , Krzysztof Kozlowski , Frank Rowand , Mike Kravetz , Muchun Song , Mike Rapoport , Christoph Hellwig , Marek Szyprowski , Robin Murphy , Borislav Petkov , "Paul E. McKenney" , Neeraj Upadhyay , Randy Dunlap , Damien Le Moal , Doug Berger , Florian Fainelli , David Hildenbrand , Zi Yan , Oscar Salvador With gigantic pages it may not be true that struct page structures are contiguous across the entire gigantic page. The mem_map_offset function is used here in place of direct pointer arithmetic to correct for this. Fixes: 8531fc6f52f5 ("hugetlb: add hugetlb demote page support") Signed-off-by: Doug Berger --- mm/hugetlb.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 79949893ac12..a1d51a1f0404 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -3420,6 +3420,7 @@ static int demote_free_huge_page(struct hstate *h, struct page *page) { int i, nid = page_to_nid(page); struct hstate *target_hstate; + struct page *subpage; int rc = 0; target_hstate = size_to_hstate(PAGE_SIZE << h->demote_order); @@ -3453,15 +3454,16 @@ static int demote_free_huge_page(struct hstate *h, struct page *page) mutex_lock(&target_hstate->resize_lock); for (i = 0; i < pages_per_huge_page(h); i += pages_per_huge_page(target_hstate)) { + subpage = mem_map_offset(page, i); if (hstate_is_gigantic(target_hstate)) - prep_compound_gigantic_page_for_demote(page + i, + prep_compound_gigantic_page_for_demote(subpage, target_hstate->order); else - prep_compound_page(page + i, target_hstate->order); - set_page_private(page + i, 0); - set_page_refcounted(page + i); - prep_new_huge_page(target_hstate, page + i, nid); - put_page(page + i); + prep_compound_page(subpage, target_hstate->order); + set_page_private(subpage, 0); + set_page_refcounted(subpage); + prep_new_huge_page(target_hstate, subpage, nid); + put_page(subpage); } mutex_unlock(&target_hstate->resize_lock); -- 2.25.1