From patchwork Tue Oct 22 22:28:31 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Duyck X-Patchwork-Id: 11205427 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 69BFD13BD for ; Tue, 22 Oct 2019 22:28:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3375420684 for ; Tue, 22 Oct 2019 22:28:39 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="XEOoJjLX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389134AbfJVW2f (ORCPT ); Tue, 22 Oct 2019 18:28:35 -0400 Received: from mail-pl1-f196.google.com ([209.85.214.196]:43648 "EHLO mail-pl1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389125AbfJVW2e (ORCPT ); Tue, 22 Oct 2019 18:28:34 -0400 Received: by mail-pl1-f196.google.com with SMTP id v5so4298246ply.10; Tue, 22 Oct 2019 15:28:33 -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=JJfwPr63Q1M/xjYGQd4hOFUJFA0qW3vXAUWOtzOr/WI=; b=XEOoJjLXjBwFMF9BJSoWwKHMGT7Hyv8wDXVyxnLy3MqM5eSt0W4cs8lc94YWUsZA5B rB2/6Fd3AmyT/OTjU8FF8mZo9kjAYNR1segrfuqX47KmaZssfkrDnXXXJKopExw/G+GP qPNLL+8kD2f9aTRvzp8tPxG3IADYjZ93BsxA/0SJA1WfhVey40wbvMiqFqZbxO2O2g7F D0pcUoAQcrShFci4V39EQ6aIoTgPdynH0k9uetrsnf3iRLabf7Fl2WwQDPo1XdUvGPxJ J4xv9HK4lHbQybJ9NdksPKz5Vu1FZGoQ/TBfF4Ack2Cekeb/tDuMYwp14tlID4+BFPZ/ 35YA== 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=JJfwPr63Q1M/xjYGQd4hOFUJFA0qW3vXAUWOtzOr/WI=; b=DDOuSraeFaLpwzhs0VkERmsxKHFRIbvBgDO84pvByAODpZvGkZd1iHiQbYVkrx8bkK eAbxWyvBCDns15/RNiy6ljpuaqJVKV9YNmdZTXUQtJ4CIZXMcAiscZE0mVopwfIcDJph 5TDX9xUlJnhqBnHEz9qOa3lKdOdIoIgtQmEbQMD9M+DLgmH+j/Qqg2vhwv3QoRV0qB/L tPbDiGFqDivO5NF89nzlAo68MY/ZUyiehSzS79jld+3RoRhK43aqxgkgLp8va/D4Zkud 6L6ca3G/pRakRGEnBSRBIRIR0bsJgiLLqwoE1IJpKjCmLTPliKqDXeP+1lsOHrsck+EV 2Kug== X-Gm-Message-State: APjAAAX6cnb/Oe9DU/mH8r1MZcJgAOH15YLViOTAtOTv0a0HyUofq6XJ MkSOTyc+JaqLooAWfpkPg0c= X-Google-Smtp-Source: APXvYqx1+LBfw8M6XHL5m0irLpA+1EmMLYboLvXMgJUwR0aMF+pvKlK2RHF2T9xaRS/g9C1h5W8oVA== X-Received: by 2002:a17:902:8c96:: with SMTP id t22mr6088677plo.290.1571783313202; Tue, 22 Oct 2019 15:28:33 -0700 (PDT) Received: from localhost.localdomain ([2001:470:b:9c3:9e5c:8eff:fe4f:f2d0]) by smtp.gmail.com with ESMTPSA id ce16sm19296350pjb.29.2019.10.22.15.28.32 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 22 Oct 2019 15:28:32 -0700 (PDT) Subject: [PATCH v12 6/6] virtio-balloon: Add support for providing unused page reports to host From: Alexander Duyck To: kvm@vger.kernel.org, mst@redhat.com, linux-kernel@vger.kernel.org, willy@infradead.org, mhocko@kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, mgorman@techsingularity.net, vbabka@suse.cz Cc: yang.zhang.wz@gmail.com, nitesh@redhat.com, konrad.wilk@oracle.com, david@redhat.com, pagupta@redhat.com, riel@surriel.com, lcapitulino@redhat.com, dave.hansen@intel.com, wei.w.wang@intel.com, aarcange@redhat.com, pbonzini@redhat.com, dan.j.williams@intel.com, alexander.h.duyck@linux.intel.com, osalvador@suse.de Date: Tue, 22 Oct 2019 15:28:31 -0700 Message-ID: <20191022222831.17338.83628.stgit@localhost.localdomain> In-Reply-To: <20191022221223.17338.5860.stgit@localhost.localdomain> References: <20191022221223.17338.5860.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 92099298bc16..b56ca35482bc 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)) { @@ -932,12 +976,30 @@ 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), + VIRTIO_BALLOON_VRING_HINTS_MAX); + vb->ph_dev_info.capacity = capacity; + + err = page_reporting_register(&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); @@ -966,6 +1028,8 @@ 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_unregister(&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); @@ -1038,6 +1102,7 @@ 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