From patchwork Mon Aug 12 13:12:35 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Nitesh Narayan Lal X-Patchwork-Id: 11089849 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 512426C5 for ; Mon, 12 Aug 2019 13:13:21 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 41D4320072 for ; Mon, 12 Aug 2019 13:13:21 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 36131283E8; Mon, 12 Aug 2019 13:13:21 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8F2B220072 for ; Mon, 12 Aug 2019 13:13:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728927AbfHLNNT (ORCPT ); Mon, 12 Aug 2019 09:13:19 -0400 Received: from mx1.redhat.com ([209.132.183.28]:39050 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728864AbfHLNNR (ORCPT ); Mon, 12 Aug 2019 09:13:17 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 64F01309C387; Mon, 12 Aug 2019 13:13:16 +0000 (UTC) Received: from virtlab605.virt.lab.eng.bos.redhat.com (virtlab605.virt.lab.eng.bos.redhat.com [10.19.152.201]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6F84B5D6A0; Mon, 12 Aug 2019 13:13:14 +0000 (UTC) From: Nitesh Narayan Lal To: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, virtio-dev@lists.oasis-open.org, pbonzini@redhat.com, lcapitulino@redhat.com, pagupta@redhat.com, wei.w.wang@intel.com, yang.zhang.wz@gmail.com, riel@surriel.com, david@redhat.com, mst@redhat.com, dodgen@google.com, konrad.wilk@oracle.com, dhildenb@redhat.com, aarcange@redhat.com, alexander.duyck@gmail.com, john.starks@microsoft.com, dave.hansen@intel.com, mhocko@suse.com, cohuck@redhat.com Subject: [RFC][Patch v12 2/2] virtio-balloon: interface to support free page reporting Date: Mon, 12 Aug 2019 09:12:35 -0400 Message-Id: <20190812131235.27244-3-nitesh@redhat.com> In-Reply-To: <20190812131235.27244-1-nitesh@redhat.com> References: <20190812131235.27244-1-nitesh@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.43]); Mon, 12 Aug 2019 13:13:16 +0000 (UTC) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Enables the kernel to negotiate VIRTIO_BALLOON_F_REPORTING feature with the host. If it is available and page_reporting_flag is set to true, page_reporting is enabled and its callback is configured along with the max_pages count which indicates the maximum number of pages that can be isolated and reported at a time. Currently, only free pages of order >= (MAX_ORDER - 2) are reported. To prevent any false OOM max_pages count is set to 16. By default page_reporting feature is enabled and gets loaded as soon as the virtio-balloon driver is loaded. However, it could be disabled by writing the page_reporting_flag which is a virtio-balloon parameter. Signed-off-by: Nitesh Narayan Lal --- drivers/virtio/Kconfig | 1 + drivers/virtio/virtio_balloon.c | 64 ++++++++++++++++++++++++++++- include/uapi/linux/virtio_balloon.h | 1 + 3 files changed, 65 insertions(+), 1 deletion(-) diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig index 078615cf2afc..4b2dd8259ff5 100644 --- a/drivers/virtio/Kconfig +++ b/drivers/virtio/Kconfig @@ -58,6 +58,7 @@ config VIRTIO_BALLOON tristate "Virtio balloon driver" depends on VIRTIO select MEMORY_BALLOON + select PAGE_REPORTING ---help--- This driver supports increasing and decreasing the amount of memory within a KVM guest. diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index 226fbb995fb0..defec00d4ee2 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -19,6 +19,7 @@ #include #include #include +#include /* * Balloon device works in 4K page units. So each page is pointed to by @@ -46,6 +47,7 @@ enum virtio_balloon_vq { VIRTIO_BALLOON_VQ_DEFLATE, VIRTIO_BALLOON_VQ_STATS, VIRTIO_BALLOON_VQ_FREE_PAGE, + VIRTIO_BALLOON_VQ_REPORTING, VIRTIO_BALLOON_VQ_MAX }; @@ -55,7 +57,8 @@ enum virtio_balloon_config_read { struct virtio_balloon { struct virtio_device *vdev; - struct virtqueue *inflate_vq, *deflate_vq, *stats_vq, *free_page_vq; + struct virtqueue *inflate_vq, *deflate_vq, *stats_vq, *free_page_vq, + *reporting_vq; /* Balloon's own wq for cpu-intensive work items */ struct workqueue_struct *balloon_wq; @@ -113,6 +116,9 @@ struct virtio_balloon { /* To register a shrinker to shrink memory upon memory pressure */ struct shrinker shrinker; + + /* To configure page reporting to report isolated pages */ + struct page_reporting_config page_reporting_conf; }; static struct virtio_device_id id_table[] = { @@ -120,6 +126,10 @@ static struct virtio_device_id id_table[] = { { 0 }, }; +bool page_reporting_flag = true; +module_param(page_reporting_flag, bool, 0644); +MODULE_PARM_DESC(page_reporting_flag, "Enable page reporting"); + static u32 page_to_balloon_pfn(struct page *page) { unsigned long pfn = page_to_pfn(page); @@ -152,6 +162,44 @@ static void tell_host(struct virtio_balloon *vb, struct virtqueue *vq) } +void virtballoon_report_pages(struct page_reporting_config *page_reporting_conf, + unsigned int num_pages) +{ + struct virtio_balloon *vb = container_of(page_reporting_conf, + struct virtio_balloon, + page_reporting_conf); + struct virtqueue *vq = vb->reporting_vq; + int err, unused; + + /* We should always be able to add these buffers to an empty queue. */ + err = virtqueue_add_inbuf(vq, page_reporting_conf->sg, num_pages, vb, + GFP_NOWAIT); + /* We should not report if the guest is low on memory */ + if (unlikely(err)) + return; + virtqueue_kick(vq); + + /* When host has read buffer, this completes via balloon_ack */ + wait_event(vb->acked, virtqueue_get_buf(vq, &unused)); +} + +static void virtballoon_page_reporting_setup(struct virtio_balloon *vb) +{ + struct device *dev = &vb->vdev->dev; + int err; + + vb->page_reporting_conf.report = virtballoon_report_pages; + vb->page_reporting_conf.max_pages = PAGE_REPORTING_MAX_PAGES; + err = page_reporting_enable(&vb->page_reporting_conf); + if (err < 0) { + dev_err(dev, "Failed to enable reporting, err = %d\n", err); + page_reporting_flag = false; + vb->page_reporting_conf.report = NULL; + vb->page_reporting_conf.max_pages = 0; + return; + } +} + static void set_page_pfns(struct virtio_balloon *vb, __virtio32 pfns[], struct page *page) { @@ -476,6 +524,7 @@ static int init_vqs(struct virtio_balloon *vb) names[VIRTIO_BALLOON_VQ_DEFLATE] = "deflate"; names[VIRTIO_BALLOON_VQ_STATS] = NULL; names[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL; + names[VIRTIO_BALLOON_VQ_REPORTING] = NULL; if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) { names[VIRTIO_BALLOON_VQ_STATS] = "stats"; @@ -487,11 +536,18 @@ static int init_vqs(struct virtio_balloon *vb) callbacks[VIRTIO_BALLOON_VQ_FREE_PAGE] = NULL; } + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_REPORTING)) { + names[VIRTIO_BALLOON_VQ_REPORTING] = "reporting_vq"; + callbacks[VIRTIO_BALLOON_VQ_REPORTING] = balloon_ack; + } err = vb->vdev->config->find_vqs(vb->vdev, VIRTIO_BALLOON_VQ_MAX, vqs, callbacks, names, NULL, NULL); if (err) return err; + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_REPORTING)) + vb->reporting_vq = vqs[VIRTIO_BALLOON_VQ_REPORTING]; + vb->inflate_vq = vqs[VIRTIO_BALLOON_VQ_INFLATE]; vb->deflate_vq = vqs[VIRTIO_BALLOON_VQ_DEFLATE]; if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ)) { @@ -924,6 +980,9 @@ static int virtballoon_probe(struct virtio_device *vdev) if (err) goto out_del_balloon_wq; } + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_REPORTING) && + page_reporting_flag) + virtballoon_page_reporting_setup(vb); virtio_device_ready(vdev); if (towards_target(vb)) @@ -971,6 +1030,8 @@ static void virtballoon_remove(struct virtio_device *vdev) destroy_workqueue(vb->balloon_wq); } + if (page_reporting_flag) + page_reporting_disable(&vb->page_reporting_conf); remove_common(vb); #ifdef CONFIG_BALLOON_COMPACTION if (vb->vb_dev_info.inode) @@ -1027,6 +1088,7 @@ static unsigned int features[] = { VIRTIO_BALLOON_F_DEFLATE_ON_OOM, VIRTIO_BALLOON_F_FREE_PAGE_HINT, VIRTIO_BALLOON_F_PAGE_POISON, + VIRTIO_BALLOON_F_REPORTING, }; static struct virtio_driver virtio_balloon_driver = { diff --git a/include/uapi/linux/virtio_balloon.h b/include/uapi/linux/virtio_balloon.h index a1966cd7b677..19974392d324 100644 --- a/include/uapi/linux/virtio_balloon.h +++ b/include/uapi/linux/virtio_balloon.h @@ -36,6 +36,7 @@ #define VIRTIO_BALLOON_F_DEFLATE_ON_OOM 2 /* Deflate balloon on OOM */ #define VIRTIO_BALLOON_F_FREE_PAGE_HINT 3 /* VQ to report free pages */ #define VIRTIO_BALLOON_F_PAGE_POISON 4 /* Guest is using page poisoning */ +#define VIRTIO_BALLOON_F_REPORTING 5 /* Page reporting virtqueue */ /* Size of a PFN in the balloon interface. */ #define VIRTIO_BALLOON_PFN_SHIFT 12