From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B29B03B6C17 for ; Fri, 17 Jul 2026 06:44:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784270676; cv=none; b=KMn7A2SdB6DxUFD/B84BW2KW/O8jDnLzssxPzvh7ByTbj5bnnLkG1uVHQa320q23PdB3xtk7RmZpC8jIZQzYqVOce6NiDElI4roEp3vx7L2LcXK2iVluHOK2DJuVZ4/ujFRS35ObJhsqSDeyvGkyR81W1sMkIKNHMUL0AsKpEqU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784270676; c=relaxed/simple; bh=sORV0X+F4O0KR4Pc+tiRmUJlRF6pji9/qC/zLQyUz8o=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=khAGScfHuDtCFtbPU4g4cLe9LBSsviVsy9CvZjxmpZAJX+BAu2VqFe9POXXrBrAp9NAfEiGWYJvMuPDzcKUq7vFl7EabApG8wfn1ZQzmMVTHipT0+4S8TGEpnjZAIHhY8VMuTOE1T5wojqC8CFWpVWQY2G+UuAE9C6TRH0o0Deo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=aiPFH63+; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="aiPFH63+" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1784270664; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=MfX3Q3RbVvpkOOQ837KTiogN+xhujAPLrjvpYVR6OyQ=; b=aiPFH63+E26Hc9+cTi0iKpb3WsAlQOby2Wm6AkBY6V7swaUf4M1tT1jLTZjNHhQwof7N7J nayecasg0XSgoY5wGfV4ANlBGWRHTBj+MYOAvmci4YHPPk2PsR00VmXQHbIMNjbxI/SIrU p2/C7YMt/QMLe6jTxdXzo3gbP3hTTc8= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-213-t0hT6U0FPpu1tZ_D-cZpZQ-1; Fri, 17 Jul 2026 02:44:21 -0400 X-MC-Unique: t0hT6U0FPpu1tZ_D-cZpZQ-1 X-Mimecast-MFC-AGG-ID: t0hT6U0FPpu1tZ_D-cZpZQ_1784270658 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 1AB5F18007F5; Fri, 17 Jul 2026 06:44:18 +0000 (UTC) Received: from p1.redhat.com (unknown [10.22.74.7]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 3548E180036E; Fri, 17 Jul 2026 06:44:08 +0000 (UTC) From: Nico Pache To: Barry Song , David Hildenbrand , linux-cxl@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: ljs@kernel.org, willy@infradead.org, Nico Pache , Zi Yan , Oscar Salvador , Andrew Morton , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Gregory Price , Ying Huang , Alistair Popple Subject: [PATCH v2 2/2] mm/migrate: exclude hugetlb folios from MTHP_STAT_NR_ANON accounting Date: Fri, 17 Jul 2026 00:45:00 -0600 Message-ID: <20260717064502.1980173-3-npache@redhat.com> In-Reply-To: <20260717064502.1980173-1-npache@redhat.com> References: <20260717064502.1980173-1-npache@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 __folio_migrate_mapping() increments MTHP_STAT_NR_ANON for the destination folio when `folio_test_anon(folio) && folio_test_large(folio)` is true. However, hugetlb folios satisfy both conditions despite having a completely separate accounting system — they use hugetlb_add_anon_rmap() which does not touch mTHP stats, and their free path also bypasses the mTHP decrement in __free_pages_prepare(). This causes MTHP_STAT_NR_ANON to be incremented on each hugetlb migration without a corresponding decrement, permanently inflating the nr_anon counter. Add a !folio_test_hugetlb() check to __folio_migrate_mapping() so that only actual mTHP folios are counted. Fixes: 5d65c8d758f2 ("mm: count the number of anonymous THPs per size") Reviewed-by: Zi Yan Co-developed-by: David Hildenbrand Signed-off-by: David Hildenbrand Signed-off-by: Nico Pache --- mm/migrate.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/migrate.c b/mm/migrate.c index d9b23909d716..dd15a84b2a52 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -590,7 +590,8 @@ static int __folio_migrate_mapping(struct address_space *mapping, /* No turning back from here */ newfolio->index = folio->index; newfolio->mapping = folio->mapping; - if (folio_test_anon(folio) && folio_test_large(folio)) + if (folio_test_anon(folio) && folio_test_large(folio) && + !folio_test_hugetlb(folio)) mod_mthp_stat(folio_order(folio), MTHP_STAT_NR_ANON, 1); if (folio_test_swapbacked(folio)) __folio_set_swapbacked(newfolio); -- 2.55.0