From patchwork Wed Aug 21 15:00:02 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Duyck X-Patchwork-Id: 11107249 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 B2CF414F7 for ; Wed, 21 Aug 2019 15:00:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7D423233FE for ; Wed, 21 Aug 2019 15:00:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="GAQYD4vm" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729675AbfHUPAF (ORCPT ); Wed, 21 Aug 2019 11:00:05 -0400 Received: from mail-pf1-f194.google.com ([209.85.210.194]:41902 "EHLO mail-pf1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729565AbfHUPAE (ORCPT ); Wed, 21 Aug 2019 11:00:04 -0400 Received: by mail-pf1-f194.google.com with SMTP id 196so1597097pfz.8; Wed, 21 Aug 2019 08:00:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:from:to:cc:date:message-id:in-reply-to:references :user-agent:mime-version:content-transfer-encoding; bh=sof0muTDiXKYNM5WhTCBi1PApUlSP0Ym0GyRsBlZ35s=; b=GAQYD4vmtrgEm7ws2DRxh+SFIyTTpZBVKsE3nSoFw8U6EcZeHEc81fbDxOvK54HGJP K1XeL1Rh+F+zBciPVSYMb+MI8zo15QSOUjql8cykOMZPXhN99jUCo5pDjd6ANgXB7GY3 d/roabw+JdHbzC3baQcyjEkqQMWw1tKzELt1LKS6gDJPx/mxsnhjs5oWEgeU2dcHbkT1 /qf3c/+uXO9byajoC5OJcbl648mX7aYxcSKAJxanVcZuoQpDILwad3S5ZcvMZzaWpAIh rSZpt3szQ0OihGuotPqgyfduTo1+oHWxBVpgqRI1JkElUjgVo1GUs6rj7hKa/SQA37h6 DdGg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:from:to:cc:date:message-id:in-reply-to :references:user-agent:mime-version:content-transfer-encoding; bh=sof0muTDiXKYNM5WhTCBi1PApUlSP0Ym0GyRsBlZ35s=; b=lWi6MlEz84QGvW3VDQrPSQhbMbeftBI34Hd6qG/iWMo5lzPf2/tr9hDWHpeW/PQk7G K77mcZOrVEnFnel8ROVawLcLUshibEfh0GHZnu65Va8ry3WlwFmKxEWYJ7H+mJiLZ+DV TAN7ypkd3QgB/GV8yXj1ftv0ZjD9zCXI2PQzIDmvLjfu1XFwdf8xhabTtQx5vO99YjB7 Q6W9kMpblRaBkaPXw/AhQywMQOOK9+p5xZJVMLPT+hv9EYNhZ6UIxpfN8rLm7L6sQ6rJ ekCke+77YmdZF+17Q8GEjdPZXstItposhINb6M9GwRjGBIZLhRAihALLPpxZMaiFwDhI p/pw== X-Gm-Message-State: APjAAAWJdkz0rUuVamJwP6pYBry3bYiNaZgU/0jjAfX5wMtlizVHc3UO B8nXWPtawbMtVkP+f+n1Q6AG6LrN X-Google-Smtp-Source: APXvYqzx28RnVl7NYtT7FqqVGNs2LwfVWPtdlXAL+NVoFazKGeAh28lQdVah7q3QEB4H+/VTTLmUTQ== X-Received: by 2002:aa7:9abc:: with SMTP id x28mr36644210pfi.234.1566399603844; Wed, 21 Aug 2019 08:00:03 -0700 (PDT) Received: from localhost.localdomain ([2001:470:b:9c3:9e5c:8eff:fe4f:f2d0]) by smtp.gmail.com with ESMTPSA id e13sm25636458pff.181.2019.08.21.08.00.02 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 21 Aug 2019 08:00:03 -0700 (PDT) Subject: [PATCH v6 6/6] virtio-balloon: Add support for providing unused page reports to host From: Alexander Duyck To: nitesh@redhat.com, kvm@vger.kernel.org, mst@redhat.com, david@redhat.com, dave.hansen@intel.com, linux-kernel@vger.kernel.org, willy@infradead.org, mhocko@kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, virtio-dev@lists.oasis-open.org, osalvador@suse.de Cc: yang.zhang.wz@gmail.com, pagupta@redhat.com, riel@surriel.com, konrad.wilk@oracle.com, lcapitulino@redhat.com, wei.w.wang@intel.com, aarcange@redhat.com, pbonzini@redhat.com, dan.j.williams@intel.com, alexander.h.duyck@linux.intel.com Date: Wed, 21 Aug 2019 08:00:02 -0700 Message-ID: <20190821150002.20926.6527.stgit@localhost.localdomain> In-Reply-To: <20190821145806.20926.22448.stgit@localhost.localdomain> References: <20190821145806.20926.22448.stgit@localhost.localdomain> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Alexander Duyck Add support for the page reporting feature provided by virtio-balloon. Reporting differs from the regular balloon functionality in that is is much less durable than a standard memory balloon. Instead of creating a list of pages that cannot be accessed the pages are only inaccessible while they are being indicated to the virtio interface. Once the interface has acknowledged them they are placed back into their respective free lists and are once again accessible by the guest system. Signed-off-by: Alexander Duyck --- drivers/virtio/Kconfig | 1 + drivers/virtio/virtio_balloon.c | 65 +++++++++++++++++++++++++++++++++++ include/uapi/linux/virtio_balloon.h | 1 + 3 files changed, 67 insertions(+) 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 2c19457ab573..52f9eeda1877 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 @@ -37,6 +38,9 @@ #define VIRTIO_BALLOON_FREE_PAGE_SIZE \ (1 << (VIRTIO_BALLOON_FREE_PAGE_ORDER + PAGE_SHIFT)) +/* limit on the number of pages that can be on the reporting vq */ +#define VIRTIO_BALLOON_VRING_HINTS_MAX 16 + #ifdef CONFIG_BALLOON_COMPACTION static struct vfsmount *balloon_mnt; #endif @@ -46,6 +50,7 @@ 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 }; @@ -113,6 +118,10 @@ struct virtio_balloon { /* To register a shrinker to shrink memory upon memory pressure */ struct shrinker shrinker; + + /* Unused page reporting device */ + struct virtqueue *reporting_vq; + struct page_reporting_dev_info ph_dev_info; }; static struct virtio_device_id id_table[] = { @@ -152,6 +161,32 @@ static void tell_host(struct virtio_balloon *vb, struct virtqueue *vq) } +void virtballoon_unused_page_report(struct page_reporting_dev_info *ph_dev_info, + unsigned int nents) +{ + struct virtio_balloon *vb = + container_of(ph_dev_info, struct virtio_balloon, ph_dev_info); + struct virtqueue *vq = vb->reporting_vq; + unsigned int unused, err; + + /* We should always be able to add these buffers to an empty queue. */ + err = virtqueue_add_inbuf(vq, ph_dev_info->sg, nents, vb, + GFP_NOWAIT | __GFP_NOWARN); + + /* + * In the extremely unlikely case that something has changed and we + * are able to trigger an error we will simply display a warning + * and exit without actually processing the pages. + */ + if (WARN_ON(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 set_page_pfns(struct virtio_balloon *vb, __virtio32 pfns[], struct page *page) { @@ -476,6 +511,7 @@ 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 +523,19 @@ 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)) { @@ -931,12 +975,30 @@ static int virtballoon_probe(struct virtio_device *vdev) if (err) goto out_del_balloon_wq; } + + vb->ph_dev_info.report = virtballoon_unused_page_report; + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_REPORTING)) { + unsigned int capacity; + + capacity = min_t(unsigned int, + virtqueue_get_vring_size(vb->reporting_vq) - 1, + VIRTIO_BALLOON_VRING_HINTS_MAX); + vb->ph_dev_info.capacity = capacity; + + err = page_reporting_startup(&vb->ph_dev_info); + if (err) + goto out_unregister_shrinker; + } + virtio_device_ready(vdev); if (towards_target(vb)) virtballoon_changed(vdev); return 0; +out_unregister_shrinker: + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM)) + virtio_balloon_unregister_shrinker(vb); out_del_balloon_wq: if (virtio_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT)) destroy_workqueue(vb->balloon_wq); @@ -965,6 +1027,8 @@ static void virtballoon_remove(struct virtio_device *vdev) { struct virtio_balloon *vb = vdev->priv; + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_REPORTING)) + page_reporting_shutdown(&vb->ph_dev_info); if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_DEFLATE_ON_OOM)) virtio_balloon_unregister_shrinker(vb); spin_lock_irq(&vb->stop_update_lock); @@ -1034,6 +1098,7 @@ static int virtballoon_validate(struct virtio_device *vdev) 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