From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6293DC2D0C9 for ; Thu, 12 Dec 2019 17:12:42 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 26853205C9 for ; Thu, 12 Dec 2019 17:12:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="A/xMs0Oe" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 26853205C9 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id CDE6D8E0009; Thu, 12 Dec 2019 12:12:41 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id CB4AD8E0006; Thu, 12 Dec 2019 12:12:41 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BA4C18E0009; Thu, 12 Dec 2019 12:12:41 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0179.hostedemail.com [216.40.44.179]) by kanga.kvack.org (Postfix) with ESMTP id A1C968E0006 for ; Thu, 12 Dec 2019 12:12:41 -0500 (EST) Received: from smtpin12.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with SMTP id 404E5181AEF1F for ; Thu, 12 Dec 2019 17:12:41 +0000 (UTC) X-FDA: 76257133722.12.ear53_6eac19a788116 X-HE-Tag: ear53_6eac19a788116 X-Filterd-Recvd-Size: 5202 Received: from us-smtp-delivery-1.mimecast.com (us-smtp-1.mimecast.com [205.139.110.61]) by imf21.hostedemail.com (Postfix) with ESMTP for ; Thu, 12 Dec 2019 17:12:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1576170760; 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=cioP1Au5xwfJCBdcc5XOpwCVArGo5wEcHN4WYiyUNDA=; b=A/xMs0OeYvn3A/CIJdsRru/ijEZeM5kPXJBzpdFZ7QdR6AgAphwH1kDQ7PUGMQYk2VfbTH 4MDkiCpRjnMOKzSHuHOZJsOO+7QhDHMNA8m6vZD6LkQoOpUla0od4HgsKX6e5MBbkwAtgf GyyHyOrXMlCpPhI9d6P0GAMZ8WWSK1Y= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-224-Cq7CVDBDPvKYM77AioR_vg-1; Thu, 12 Dec 2019 12:12:30 -0500 X-MC-Unique: Cq7CVDBDPvKYM77AioR_vg-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 27E901005502; Thu, 12 Dec 2019 17:12:28 +0000 (UTC) Received: from t480s.redhat.com (ovpn-117-65.ams2.redhat.com [10.36.117.65]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9D4E25C1C3; Thu, 12 Dec 2019 17:12:19 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, virtio-dev@lists.oasis-open.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, Michal Hocko , Andrew Morton , "Michael S . Tsirkin" , David Hildenbrand , Michal Hocko , Vlastimil Babka , Oscar Salvador , Mel Gorman , Mike Rapoport , Dan Williams , Alexander Duyck , Pavel Tatashin , Alexander Potapenko Subject: [PATCH RFC v4 04/13] mm: Export alloc_contig_range() / free_contig_range() Date: Thu, 12 Dec 2019 18:11:28 +0100 Message-Id: <20191212171137.13872-5-david@redhat.com> In-Reply-To: <20191212171137.13872-1-david@redhat.com> References: <20191212171137.13872-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: A virtio-mem device wants to allocate memory from the memory region it manages in order to unplug it in the hypervisor - similar to a balloon driver. Also, it might want to plug previously unplugged (allocated) memory and give it back to Linux. alloc_contig_range() / free_contig_range() seem to be the perfect interface for this task. In contrast to existing balloon devices, a virtio-mem device operates on bigger chunks (e.g., 4MB) and only on physical memory it manages. It tracks which chunks (subblocks) are still plugged, so it can go ahead and try to alloc_contig_range()+unplug them on unplug request, or plug+free_contig_range() unplugged chunks on plug requests. A virtio-mem device will use alloc_contig_range() / free_contig_range() only on ranges that belong to the same node/zone in at least MAX(MAX_ORDER - 1, pageblock_order) order granularity - e.g., 4MB on x86-64. The virtio-mem device added that memory, so the memory exists and does not contain any holes. virtio-mem will only try to alloca= te on ZONE_NORMAL, never on ZONE_MOVABLE, just like when allocating gigantic pages (we don't put unmovable data into the movable zone). Cc: Andrew Morton Cc: Michal Hocko Cc: Vlastimil Babka Cc: Oscar Salvador Cc: Mel Gorman Cc: Mike Rapoport Cc: Dan Williams Cc: Alexander Duyck Cc: Pavel Tatashin Cc: Alexander Potapenko Acked-by: Michal Hocko # to export contig range allocat= or API Signed-off-by: David Hildenbrand --- mm/page_alloc.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 62dcd6b76c80..5334decc9e06 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -8494,6 +8494,7 @@ int alloc_contig_range(unsigned long start, unsigne= d long end, pfn_max_align_up(end), migratetype); return ret; } +EXPORT_SYMBOL(alloc_contig_range); =20 static int __alloc_contig_pages(unsigned long start_pfn, unsigned long nr_pages, gfp_t gfp_mask) @@ -8609,6 +8610,7 @@ void free_contig_range(unsigned long pfn, unsigned = int nr_pages) } WARN(count !=3D 0, "%d pages are still in use!\n", count); } +EXPORT_SYMBOL(free_contig_range); =20 /* * The zone indicated has a new number of managed_pages; batch sizes and= percpu --=20 2.23.0