From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 3EDAE34A303 for ; Mon, 1 Sep 2025 15:07:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756739231; cv=none; b=FWtxuXyU6EUgKZWnDAVIjoKFy6Xq6SQNK6clYkV9E10oWV2fBw6gMT3xQW5VV3gTF94y0hX2Q1hXITIu1xOy/x4UBM4BPzScJc6SixzJq5ZWJf/4iP+UhmSfd87zBbqudhwljFsNF0KO8JSbyorrWY8YYqdEk9ZTQYBS465rEVw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1756739231; c=relaxed/simple; bh=awZ3C2+6gqVSpU2nRz+GoKKKVTF9HKURUj8zg+19qco=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=m0wcQxewjl+tgCkjaWnUt/hxT2FXkYZ+kUE/nuQn4vat0hWARNRYJaA4wKPlGioDERF6UkMRiB0E5Z5vAUk0YURz0Se78RGBlqGRQCAi26a3nN2VkKoAE0LlH/iS3Mr4xEE0h7c1za/GgYf3TMEZrIloi2jsfPHR5l/Dlr/jacc= 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=B0U54YfN; arc=none smtp.client-ip=170.10.133.124 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="B0U54YfN" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1756739227; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=R4lKJy8SBWSrsm7Vh+zb8hrnJCJALrpbQ5NruWVxUgs=; b=B0U54YfNfqSWlMbYFj/yNlKClc4Rz8lUgFP82rq9AHv4+W+zBMoz+K8G778juYWn/YXwjk 7tgo7BI3ddYK/YRC1Cj9LOjVeunT8QxP91ysb8ZKSCsWEem+vsLZsOOZzv4McMXL6EOu2d MHx+4g5NRays42LYGKoA/7PcToAF7a4= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-488-6C4RCufwPEqzyZW8T0eORg-1; Mon, 01 Sep 2025 11:07:06 -0400 X-MC-Unique: 6C4RCufwPEqzyZW8T0eORg-1 X-Mimecast-MFC-AGG-ID: 6C4RCufwPEqzyZW8T0eORg_1756739221 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-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 331CF195C27E; Mon, 1 Sep 2025 15:07:01 +0000 (UTC) Received: from t14s.fritz.box (unknown [10.22.88.45]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 3B7921800447; Mon, 1 Sep 2025 15:06:47 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: David Hildenbrand , "Mike Rapoport (Microsoft)" , Wei Yang , Lorenzo Stoakes , "Liam R. Howlett" , Alexander Potapenko , Andrew Morton , Brendan Jackman , Christoph Lameter , Dennis Zhou , Dmitry Vyukov , dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, iommu@lists.linux.dev, io-uring@vger.kernel.org, Jason Gunthorpe , Jens Axboe , Johannes Weiner , John Hubbard , kasan-dev@googlegroups.com, kvm@vger.kernel.org, Linus Torvalds , linux-arm-kernel@axis.com, linux-arm-kernel@lists.infradead.org, linux-crypto@vger.kernel.org, linux-ide@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mips@vger.kernel.org, linux-mmc@vger.kernel.org, linux-mm@kvack.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-scsi@vger.kernel.org, Marco Elver , Marek Szyprowski , Michal Hocko , Muchun Song , netdev@vger.kernel.org, Oscar Salvador , Peter Xu , Robin Murphy , Suren Baghdasaryan , Tejun Heo , virtualization@lists.linux.dev, Vlastimil Babka , wireguard@lists.zx2c4.com, x86@kernel.org, Zi Yan Subject: [PATCH v2 09/37] mm/mm_init: make memmap_init_compound() look more like prep_compound_page() Date: Mon, 1 Sep 2025 17:03:30 +0200 Message-ID: <20250901150359.867252-10-david@redhat.com> In-Reply-To: <20250901150359.867252-1-david@redhat.com> References: <20250901150359.867252-1-david@redhat.com> Precedence: bulk X-Mailing-List: linux-mips@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 Grepping for "prep_compound_page" leaves on clueless how devdax gets its compound pages initialized. Let's add a comment that might help finding this open-coded prep_compound_page() initialization more easily. Further, let's be less smart about the ordering of initialization and just perform the prep_compound_head() call after all tail pages were initialized: just like prep_compound_page() does. No need for a comment to describe the initialization order: again, just like prep_compound_page(). Reviewed-by: Mike Rapoport (Microsoft) Reviewed-by: Wei Yang Reviewed-by: Lorenzo Stoakes Acked-by: Liam R. Howlett Signed-off-by: David Hildenbrand --- mm/mm_init.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) diff --git a/mm/mm_init.c b/mm/mm_init.c index 5c21b3af216b2..df614556741a4 100644 --- a/mm/mm_init.c +++ b/mm/mm_init.c @@ -1091,6 +1091,12 @@ static void __ref memmap_init_compound(struct page *head, unsigned long pfn, end_pfn = head_pfn + nr_pages; unsigned int order = pgmap->vmemmap_shift; + /* + * We have to initialize the pages, including setting up page links. + * prep_compound_page() does not take care of that, so instead we + * open-code prep_compound_page() so we can take care of initializing + * the pages in the same go. + */ __SetPageHead(head); for (pfn = head_pfn + 1; pfn < end_pfn; pfn++) { struct page *page = pfn_to_page(pfn); @@ -1098,15 +1104,8 @@ static void __ref memmap_init_compound(struct page *head, __init_zone_device_page(page, pfn, zone_idx, nid, pgmap); prep_compound_tail(head, pfn - head_pfn); set_page_count(page, 0); - - /* - * The first tail page stores important compound page info. - * Call prep_compound_head() after the first tail page has - * been initialized, to not have the data overwritten. - */ - if (pfn == head_pfn + 1) - prep_compound_head(head, order); } + prep_compound_head(head, order); } void __ref memmap_init_zone_device(struct zone *zone, -- 2.50.1