Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757570AbcCCKx2 (ORCPT ); Thu, 3 Mar 2016 05:53:28 -0500 Received: from mga14.intel.com ([192.55.52.115]:17863 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757407AbcCCKxX (ORCPT ); Thu, 3 Mar 2016 05:53:23 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.22,532,1449561600"; d="scan'208";a="663096805" From: Liang Li To: mst@redhat.com, linux-kernel@vger.kernel.org Cc: akpm@linux-foundation.org, pbonzini@redhat.com, rth@twiddle.net, ehabkost@redhat.com, quintela@redhat.com, amit.shah@redhat.com, qemu-devel@nongnu.org, linux-mm@kvack.org, virtualization@lists.linux-foundation.org, kvm@vger.kernel.org, dgilbert@redhat.com, Liang Li Subject: [RFC kernel 2/2] virtio-balloon: extend balloon driver to support a new feature Date: Thu, 3 Mar 2016 18:46:59 +0800 Message-Id: <1457002019-15998-3-git-send-email-liang.z.li@intel.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1457002019-15998-1-git-send-email-liang.z.li@intel.com> References: <1457002019-15998-1-git-send-email-liang.z.li@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6649 Lines: 206 Extend the virio balloon to support the new feature VIRTIO_BALLOON_F_GET_FREE_PAGES, so that we can use it to send the free pages information from guest to QEMU, and then optimize the live migration process. Signed-off-by: Liang Li --- drivers/virtio/virtio_balloon.c | 106 ++++++++++++++++++++++++++++++++++-- include/uapi/linux/virtio_balloon.h | 1 + 2 files changed, 102 insertions(+), 5 deletions(-) diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index 0c3691f..7461d3e 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -45,9 +45,18 @@ static int oom_pages = OOM_VBALLOON_DEFAULT_PAGES; module_param(oom_pages, int, S_IRUSR | S_IWUSR); MODULE_PARM_DESC(oom_pages, "pages to free on OOM"); +extern void get_free_pages(unsigned long *free_page_bitmap, + unsigned long *free_pages_num, + unsigned long lowmem); +extern unsigned long get_total_pages_count(unsigned long lowmem); + +struct mem_layout { + unsigned long low_mem; +}; + struct virtio_balloon { struct virtio_device *vdev; - struct virtqueue *inflate_vq, *deflate_vq, *stats_vq; + struct virtqueue *inflate_vq, *deflate_vq, *stats_vq, *free_pages_vq; /* Where the ballooning thread waits for config to change. */ wait_queue_head_t config_change; @@ -75,6 +84,11 @@ struct virtio_balloon { unsigned int num_pfns; u32 pfns[VIRTIO_BALLOON_ARRAY_PFNS_MAX]; + unsigned long *free_pages; + unsigned long free_pages_len; + unsigned long free_pages_num; + struct mem_layout mem_config; + /* Memory statistics */ int need_stats_update; struct virtio_balloon_stat stats[VIRTIO_BALLOON_S_NR]; @@ -245,6 +259,34 @@ static void update_balloon_stats(struct virtio_balloon *vb) pages_to_bytes(i.totalram)); } +static void update_free_pages_stats(struct virtio_balloon *vb) +{ + unsigned long total_page_count, bitmap_bytes; + + total_page_count = get_total_pages_count(vb->mem_config.low_mem); + bitmap_bytes = ALIGN(total_page_count, BITS_PER_LONG) / 8; + + if (!vb->free_pages) + vb->free_pages = kzalloc(bitmap_bytes, GFP_KERNEL); + else { + if (bitmap_bytes < vb->free_pages_len) + memset(vb->free_pages, 0, bitmap_bytes); + else { + kfree(vb->free_pages); + vb->free_pages = kzalloc(bitmap_bytes, GFP_KERNEL); + } + } + if (!vb->free_pages) { + vb->free_pages_len = 0; + vb->free_pages_num = 0; + return; + } + + vb->free_pages_len = bitmap_bytes; + get_free_pages(vb->free_pages, &vb->free_pages_num, + vb->mem_config.low_mem); +} + /* * While most virtqueues communicate guest-initiated requests to the hypervisor, * the stats queue operates in reverse. The driver initializes the virtqueue @@ -278,6 +320,39 @@ static void stats_handle_request(struct virtio_balloon *vb) virtqueue_kick(vq); } +static void free_pages_handle_rq(struct virtio_balloon *vb) +{ + struct virtqueue *vq; + struct scatterlist sg[3]; + unsigned int len; + struct mem_layout *ptr_mem_layout; + struct scatterlist sg_in; + + vq = vb->free_pages_vq; + ptr_mem_layout = virtqueue_get_buf(vq, &len); + + if (!ptr_mem_layout) + return; + update_free_pages_stats(vb); + sg_init_table(sg, 3); + sg_set_buf(&sg[0], &(vb->free_pages_num), sizeof(vb->free_pages_num)); + sg_set_buf(&sg[1], &(vb->free_pages_len), sizeof(vb->free_pages_len)); + sg_set_buf(&sg[2], vb->free_pages, vb->free_pages_len); + + sg_init_one(&sg_in, &vb->mem_config, sizeof(vb->mem_config)); + + virtqueue_add_outbuf(vq, &sg[0], 3, vb, GFP_KERNEL); + virtqueue_add_inbuf(vq, &sg_in, 1, &vb->mem_config, GFP_KERNEL); + virtqueue_kick(vq); +} + +static void free_pages_rq(struct virtqueue *vq) +{ + struct virtio_balloon *vb = vq->vdev->priv; + + free_pages_handle_rq(vb); +} + static void virtballoon_changed(struct virtio_device *vdev) { struct virtio_balloon *vb = vdev->priv; @@ -386,16 +461,22 @@ static int balloon(void *_vballoon) static int init_vqs(struct virtio_balloon *vb) { - struct virtqueue *vqs[3]; - vq_callback_t *callbacks[] = { balloon_ack, balloon_ack, stats_request }; - static const char * const names[] = { "inflate", "deflate", "stats" }; + struct virtqueue *vqs[4]; + vq_callback_t *callbacks[] = { balloon_ack, balloon_ack, + stats_request, free_pages_rq }; + const char *names[] = { "inflate", "deflate", "stats", "free_pages" }; int err, nvqs; /* * We expect two virtqueues: inflate and deflate, and * optionally stat. */ - nvqs = virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_STATS_VQ) ? 3 : 2; + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_GET_FREE_PAGES)) + nvqs = 4; + else + nvqs = virtio_has_feature(vb->vdev, + VIRTIO_BALLOON_F_STATS_VQ) ? 3 : 2; + err = vb->vdev->config->find_vqs(vb->vdev, nvqs, vqs, callbacks, names); if (err) return err; @@ -416,6 +497,16 @@ static int init_vqs(struct virtio_balloon *vb) BUG(); virtqueue_kick(vb->stats_vq); } + if (virtio_has_feature(vb->vdev, VIRTIO_BALLOON_F_GET_FREE_PAGES)) { + struct scatterlist sg_in; + + vb->free_pages_vq = vqs[3]; + sg_init_one(&sg_in, &vb->mem_config, sizeof(vb->mem_config)); + if (virtqueue_add_inbuf(vb->free_pages_vq, &sg_in, 1, + &vb->mem_config, GFP_KERNEL) < 0) + BUG(); + virtqueue_kick(vb->free_pages_vq); + } return 0; } @@ -505,6 +596,9 @@ static int virtballoon_probe(struct virtio_device *vdev) init_waitqueue_head(&vb->acked); vb->vdev = vdev; vb->need_stats_update = 0; + vb->free_pages_num = 0; + vb->free_pages_len = 0; + vb->free_pages = NULL; balloon_devinfo_init(&vb->vb_dev_info); #ifdef CONFIG_BALLOON_COMPACTION @@ -561,6 +655,7 @@ static void virtballoon_remove(struct virtio_device *vdev) unregister_oom_notifier(&vb->nb); kthread_stop(vb->thread); remove_common(vb); + kfree(vb->free_pages); kfree(vb); } @@ -599,6 +694,7 @@ static unsigned int features[] = { VIRTIO_BALLOON_F_MUST_TELL_HOST, VIRTIO_BALLOON_F_STATS_VQ, VIRTIO_BALLOON_F_DEFLATE_ON_OOM, + VIRTIO_BALLOON_F_GET_FREE_PAGES, }; static struct virtio_driver virtio_balloon_driver = { diff --git a/include/uapi/linux/virtio_balloon.h b/include/uapi/linux/virtio_balloon.h index d7f1cbc..54aaf20 100644 --- a/include/uapi/linux/virtio_balloon.h +++ b/include/uapi/linux/virtio_balloon.h @@ -34,6 +34,7 @@ #define VIRTIO_BALLOON_F_MUST_TELL_HOST 0 /* Tell before reclaiming pages */ #define VIRTIO_BALLOON_F_STATS_VQ 1 /* Memory Stats virtqueue */ #define VIRTIO_BALLOON_F_DEFLATE_ON_OOM 2 /* Deflate balloon on OOM */ +#define VIRTIO_BALLOON_F_GET_FREE_PAGES 3 /* Get free pages bitmap */ /* Size of a PFN in the balloon interface. */ #define VIRTIO_BALLOON_PFN_SHIFT 12 -- 1.8.3.1