From patchwork Thu Sep 10 09:13:33 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Hildenbrand X-Patchwork-Id: 11767221 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 1BC2D92C for ; Thu, 10 Sep 2020 09:15:32 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D5C472053B for ; Thu, 10 Sep 2020 09:15:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="UUbpsuWs" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D5C472053B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kGIei-0007CS-7e; Thu, 10 Sep 2020 09:14:12 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kGIeh-0007CK-30 for xen-devel@lists.xenproject.org; Thu, 10 Sep 2020 09:14:11 +0000 X-Inumbo-ID: 979ae280-0474-45a1-bb4c-dc08b185a586 Received: from us-smtp-delivery-1.mimecast.com (unknown [205.139.110.120]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTP id 979ae280-0474-45a1-bb4c-dc08b185a586; Thu, 10 Sep 2020 09:14:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1599729249; 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; bh=q+xRLYk6ElaQMFati+s8ZI/gmN1ETJt7O5tUW1WhghI=; b=UUbpsuWspWBy64qJNqR0KQ6hXzfJ2U4HhrstGWZgatVuF/t/43EiKXD7Xt9Mx4x7gB2v95 iw6/6FftSqjpVYyN7RdluG9gNiCASQp7HsW5RO1htuBE+BbLimnoRe/L3eHaY3IbVi8hBu Yfgv5V3T6J+CiY0lsqmu8y+db4MqiR0= 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-308-3iuqD9l8MNi4UpNNbX7W8g-1; Thu, 10 Sep 2020 05:14:07 -0400 X-MC-Unique: 3iuqD9l8MNi4UpNNbX7W8g-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4996418B9F00; Thu, 10 Sep 2020 09:14:01 +0000 (UTC) Received: from t480s.redhat.com (ovpn-113-88.ams2.redhat.com [10.36.113.88]) by smtp.corp.redhat.com (Postfix) with ESMTP id 2A880282CA; Thu, 10 Sep 2020 09:13:41 +0000 (UTC) From: David Hildenbrand To: linux-kernel@vger.kernel.org Cc: virtualization@lists.linux-foundation.org, linux-mm@kvack.org, linux-hyperv@vger.kernel.org, xen-devel@lists.xenproject.org, linux-acpi@vger.kernel.org, linux-nvdimm@lists.01.org, linux-s390@vger.kernel.org, Andrew Morton , David Hildenbrand , Andrew Morton , Anton Blanchard , Ard Biesheuvel , Baoquan He , Benjamin Herrenschmidt , Boris Ostrovsky , Christian Borntraeger , Dan Williams , Dave Jiang , Eric Biederman , Greg Kroah-Hartman , Haiyang Zhang , Heiko Carstens , Jason Gunthorpe , Jason Wang , Juergen Gross , Julien Grall , Kees Cook , "K. Y. Srinivasan" , Len Brown , Leonardo Bras , Libor Pechacek , Michael Ellerman , "Michael S. Tsirkin" , Michal Hocko , Nathan Lynch , "Oliver O'Halloran" , Pankaj Gupta , Paul Mackerras , Pingfan Liu , "Rafael J. Wysocki" , =?utf-8?q?Roger_Pau_Monn=C3=A9?= , Stefano Stabellini , Stephen Hemminger , Thomas Gleixner , Vasily Gorbik , Vishal Verma , Wei Liu , Wei Yang Subject: [PATCH v3 0/7] mm/memory_hotplug: selective merging of system ram resources Date: Thu, 10 Sep 2020 11:13:33 +0200 Message-Id: <20200910091340.8654-1-david@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" Some add_memory*() users add memory in small, contiguous memory blocks. Examples include virtio-mem, hyper-v balloon, and the XEN balloon. This can quickly result in a lot of memory resources, whereby the actual resource boundaries are not of interest (e.g., it might be relevant for DIMMs, exposed via /proc/iomem to user space). We really want to merge added resources in this scenario where possible. Resources are effectively stored in a list-based tree. Having a lot of resources not only wastes memory, it also makes traversing that tree more expensive, and makes /proc/iomem explode in size (e.g., requiring kexec-tools to manually merge resources when creating a kdump header. The current kexec-tools resource count limit does not allow for more than ~100GB of memory with a memory block size of 128MB on x86-64). Let's allow to selectively merge system ram resources by specifying a new flag for add_memory*(). Patch #5 contains a /proc/iomem example. Only tested with virtio-mem. v2 -> v3: - "mm/memory_hotplug: prepare passing flags to add_memory() and friends" -- Use proper __bitwise type for flags -- Use "MHP_NONE" for empty flags - Rebased to latest -next, added rb's v1 -> v2: - I had another look at v1 after vacation and didn't like it - it felt like a hack. So I want forward and added a proper flag to add_memory*(), and introduce a clean (non-racy) way to mark System RAM resources mergeable. - "kernel/resource: move and rename IORESOURCE_MEM_DRIVER_MANAGED" -- Clean that flag up, felt wrong in the PnP section - "mm/memory_hotplug: prepare passing flags to add_memory() and friends" -- Previously sent in other context - decided to keep Wei's ack - "mm/memory_hotplug: MEMHP_MERGE_RESOURCE to specify merging of System RAM resources" -- Cleaner approach to get the job done by using proper flags and only merging the single, specified resource - "virtio-mem: try to merge system ram resources" "xen/balloon: try to merge system ram resources" "hv_balloon: try to merge system ram resources" -- Use the new flag MEMHP_MERGE_RESOURCE, much cleaner RFC -> v1: - Switch from rather generic "merge_child_mem_resources()" where a resource name has to be specified to "merge_system_ram_resources(). - Smaller comment/documentation/patch description changes/fixes David Hildenbrand (7): kernel/resource: make release_mem_region_adjustable() never fail kernel/resource: move and rename IORESOURCE_MEM_DRIVER_MANAGED mm/memory_hotplug: prepare passing flags to add_memory() and friends mm/memory_hotplug: MEMHP_MERGE_RESOURCE to specify merging of System RAM resources virtio-mem: try to merge system ram resources xen/balloon: try to merge system ram resources hv_balloon: try to merge system ram resources arch/powerpc/platforms/powernv/memtrace.c | 2 +- .../platforms/pseries/hotplug-memory.c | 2 +- drivers/acpi/acpi_memhotplug.c | 3 +- drivers/base/memory.c | 3 +- drivers/dax/kmem.c | 2 +- drivers/hv/hv_balloon.c | 2 +- drivers/s390/char/sclp_cmd.c | 2 +- drivers/virtio/virtio_mem.c | 3 +- drivers/xen/balloon.c | 2 +- include/linux/ioport.h | 12 +- include/linux/memory_hotplug.h | 23 +++- kernel/kexec_file.c | 2 +- kernel/resource.c | 109 ++++++++++++++---- mm/memory_hotplug.c | 47 +++----- 14 files changed, 146 insertions(+), 68 deletions(-)