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=-9.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED autolearn=unavailable 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 E5F55C2D0E3 for ; Wed, 16 Sep 2020 12:52:23 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 618C022274 for ; Wed, 16 Sep 2020 12:52:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 618C022274 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id BFED76B005D; Wed, 16 Sep 2020 08:52:22 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id BD6016B0062; Wed, 16 Sep 2020 08:52:22 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AEC256B0068; Wed, 16 Sep 2020 08:52:22 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0196.hostedemail.com [216.40.44.196]) by kanga.kvack.org (Postfix) with ESMTP id 9A4EB6B005D for ; Wed, 16 Sep 2020 08:52:22 -0400 (EDT) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 5D26E1EE6 for ; Wed, 16 Sep 2020 12:52:22 +0000 (UTC) X-FDA: 77268912924.24.drop47_140b88b2711a Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin24.hostedemail.com (Postfix) with ESMTP id 34E9E1A4A5 for ; Wed, 16 Sep 2020 12:52:22 +0000 (UTC) X-HE-Tag: drop47_140b88b2711a X-Filterd-Recvd-Size: 5194 Received: from out30-57.freemail.mail.aliyun.com (out30-57.freemail.mail.aliyun.com [115.124.30.57]) by imf29.hostedemail.com (Postfix) with ESMTP for ; Wed, 16 Sep 2020 12:52:17 +0000 (UTC) X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R931e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04394;MF=richard.weiyang@linux.alibaba.com;NM=1;PH=DS;RN=17;SR=0;TI=SMTPD_---0U97x1KA_1600260734; Received: from localhost(mailfrom:richard.weiyang@linux.alibaba.com fp:SMTPD_---0U97x1KA_1600260734) by smtp.aliyun-inc.com(127.0.0.1); Wed, 16 Sep 2020 20:52:14 +0800 Date: Wed, 16 Sep 2020 20:52:14 +0800 From: Wei Yang To: David Hildenbrand Cc: linux-kernel@vger.kernel.org, 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 , Pankaj Gupta , Michal Hocko , Dan Williams , "Michael S . Tsirkin" , Jason Wang , Baoquan He , Wei Yang Subject: Re: [PATCH v4 6/8] virtio-mem: try to merge system ram resources Message-ID: <20200916125214.GB48039@L-31X9LVDL-1304.local> Reply-To: Wei Yang References: <20200911103459.10306-1-david@redhat.com> <20200911103459.10306-7-david@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200911103459.10306-7-david@redhat.com> X-Rspamd-Queue-Id: 34E9E1A4A5 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam04 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: On Fri, Sep 11, 2020 at 12:34:57PM +0200, David Hildenbrand wrote: >virtio-mem adds memory in memory block granularity, to be able to >remove it in the same granularity again later, and to grow slowly on >demand. This, however, results in quite a lot of resources when >adding a lot of memory. 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 later >when e.g., trying to create a kdump header). > >Before this patch, we get (/proc/iomem) when hotplugging 2G via virtio-mem >on x86-64: > [...] > 100000000-13fffffff : System RAM > 140000000-33fffffff : virtio0 > 140000000-147ffffff : System RAM (virtio_mem) > 148000000-14fffffff : System RAM (virtio_mem) > 150000000-157ffffff : System RAM (virtio_mem) > 158000000-15fffffff : System RAM (virtio_mem) > 160000000-167ffffff : System RAM (virtio_mem) > 168000000-16fffffff : System RAM (virtio_mem) > 170000000-177ffffff : System RAM (virtio_mem) > 178000000-17fffffff : System RAM (virtio_mem) > 180000000-187ffffff : System RAM (virtio_mem) > 188000000-18fffffff : System RAM (virtio_mem) > 190000000-197ffffff : System RAM (virtio_mem) > 198000000-19fffffff : System RAM (virtio_mem) > 1a0000000-1a7ffffff : System RAM (virtio_mem) > 1a8000000-1afffffff : System RAM (virtio_mem) > 1b0000000-1b7ffffff : System RAM (virtio_mem) > 1b8000000-1bfffffff : System RAM (virtio_mem) > 3280000000-32ffffffff : PCI Bus 0000:00 > >With this patch, we get (/proc/iomem): > [...] > fffc0000-ffffffff : Reserved > 100000000-13fffffff : System RAM > 140000000-33fffffff : virtio0 > 140000000-1bfffffff : System RAM (virtio_mem) > 3280000000-32ffffffff : PCI Bus 0000:00 > >Of course, with more hotplugged memory, it gets worse. When unplugging >memory blocks again, try_remove_memory() (via >offline_and_remove_memory()) will properly split the resource up again. > >Reviewed-by: Pankaj Gupta >Cc: Andrew Morton >Cc: Michal Hocko >Cc: Dan Williams >Cc: Michael S. Tsirkin >Cc: Jason Wang >Cc: Pankaj Gupta >Cc: Baoquan He >Signed-off-by: David Hildenbrand Reviewed-by: Wei Yang >--- > drivers/virtio/virtio_mem.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > >diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c >index ed99e43354010..ba4de598f6636 100644 >--- a/drivers/virtio/virtio_mem.c >+++ b/drivers/virtio/virtio_mem.c >@@ -424,7 +424,8 @@ static int virtio_mem_mb_add(struct virtio_mem *vm, unsigned long mb_id) > > dev_dbg(&vm->vdev->dev, "adding memory block: %lu\n", mb_id); > return add_memory_driver_managed(nid, addr, memory_block_size_bytes(), >- vm->resource_name, MHP_NONE); >+ vm->resource_name, >+ MEMHP_MERGE_RESOURCE); > } > > /* >-- >2.26.2 -- Wei Yang Help you, Help me