On Thu, Mar 03, 2016 at 06:44:26PM +0800, Liang Li wrote: > Extend the virtio balloon device to support a new feature, this > new feature can help to get guest's free pages information, which > can be used for live migration optimzation. > > Signed-off-by: Liang Li <liang.z.li@xxxxxxxxx> I don't understand why we need a new interface. Balloon already sends free pages to host. Just teach host to skip these pages. Maybe instead of starting with code, you should send a high level description to the virtio tc for consideration? You can do it through the mailing list or using the web form: http://www.oasis-open.org/committees/comments/form.php?wg_abbrev=virtio > --- > balloon.c | 30 ++++++++- > hw/virtio/virtio-balloon.c | 81 ++++++++++++++++++++++++- > include/hw/virtio/virtio-balloon.h | 17 +++++- > include/standard-headers/linux/virtio_balloon.h | 1 + > include/sysemu/balloon.h | 10 ++- > 5 files changed, 134 insertions(+), 5 deletions(-) > > diff --git a/balloon.c b/balloon.c > index f2ef50c..a37717e 100644 > --- a/balloon.c > +++ b/balloon.c > @@ -36,6 +36,7 @@ > > static QEMUBalloonEvent *balloon_event_fn; > static QEMUBalloonStatus *balloon_stat_fn; > +static QEMUBalloonFreePages *balloon_free_pages_fn; > static void *balloon_opaque; > static bool balloon_inhibited; > > @@ -65,9 +66,12 @@ static bool have_balloon(Error **errp) > } > > int qemu_add_balloon_handler(QEMUBalloonEvent *event_func, > - QEMUBalloonStatus *stat_func, void *opaque) > + QEMUBalloonStatus *stat_func, > + QEMUBalloonFreePages *free_pages_func, > + void *opaque) > { > - if (balloon_event_fn || balloon_stat_fn || balloon_opaque) { > + if (balloon_event_fn || balloon_stat_fn || balloon_free_pages_fn > + || balloon_opaque) { > /* We're already registered one balloon handler. How many can > * a guest really have? > */ > @@ -75,6 +79,7 @@ int qemu_add_balloon_handler(QEMUBalloonEvent *event_func, > } > balloon_event_fn = event_func; > balloon_stat_fn = stat_func; > + balloon_free_pages_fn = free_pages_func; > balloon_opaque = opaque; > return 0; > } > @@ -86,6 +91,7 @@ void qemu_remove_balloon_handler(void *opaque) > } > balloon_event_fn = NULL; > balloon_stat_fn = NULL; > + balloon_free_pages_fn = NULL; > balloon_opaque = NULL; > } > > @@ -116,3 +122,23 @@ void qmp_balloon(int64_t target, Error **errp) > trace_balloon_event(balloon_opaque, target); > balloon_event_fn(balloon_opaque, target); > } > + > +bool balloon_free_pages_support(void) > +{ > + return balloon_free_pages_fn ? true : false; > +} > + > +int balloon_get_free_pages(unsigned long *free_pages_bitmap, > + unsigned long *free_pages_count) > +{ > + if (!balloon_free_pages_fn) { > + return -1; > + } > + > + if (!free_pages_bitmap || !free_pages_count) { > + return -1; > + } > + > + return balloon_free_pages_fn(balloon_opaque, > + free_pages_bitmap, free_pages_count); > + } > diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c > index e9c30e9..a5b9d08 100644 > --- a/hw/virtio/virtio-balloon.c > +++ b/hw/virtio/virtio-balloon.c > @@ -76,6 +76,12 @@ static bool balloon_stats_supported(const VirtIOBalloon *s) > return virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_STATS_VQ); > } > > +static bool balloon_free_pages_supported(const VirtIOBalloon *s) > +{ > + VirtIODevice *vdev = VIRTIO_DEVICE(s); > + return virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_GET_FREE_PAGES); > +} > + > static bool balloon_stats_enabled(const VirtIOBalloon *s) > { > return s->stats_poll_interval > 0; > @@ -293,6 +299,37 @@ out: > } > } > > +static void virtio_balloon_get_free_pages(VirtIODevice *vdev, VirtQueue *vq) > +{ > + VirtIOBalloon *s = VIRTIO_BALLOON(vdev); > + VirtQueueElement *elem; > + size_t offset = 0; > + uint64_t bitmap_bytes = 0, free_pages_count = 0; > + > + elem = virtqueue_pop(vq, sizeof(VirtQueueElement)); > + if (!elem) { > + return; > + } > + s->free_pages_vq_elem = elem; > + > + if (!elem->out_num) { > + return; > + } > + > + iov_to_buf(elem->out_sg, elem->out_num, offset, > + &free_pages_count, sizeof(uint64_t)); > + > + offset += sizeof(uint64_t); > + iov_to_buf(elem->out_sg, elem->out_num, offset, > + &bitmap_bytes, sizeof(uint64_t)); > + > + offset += sizeof(uint64_t); > + iov_to_buf(elem->out_sg, elem->out_num, offset, > + s->free_pages_bitmap, bitmap_bytes); > + s->req_status = DONE; > + s->free_pages_count = free_pages_count; > +} > + > static void virtio_balloon_get_config(VirtIODevice *vdev, uint8_t *config_data) > { > VirtIOBalloon *dev = VIRTIO_BALLOON(vdev); > @@ -362,6 +399,7 @@ static uint64_t virtio_balloon_get_features(VirtIODevice *vdev, uint64_t f, > VirtIOBalloon *dev = VIRTIO_BALLOON(vdev); > f |= dev->host_features; > virtio_add_feature(&f, VIRTIO_BALLOON_F_STATS_VQ); > + virtio_add_feature(&f, VIRTIO_BALLOON_F_GET_FREE_PAGES); > return f; > } > > @@ -372,6 +410,45 @@ static void virtio_balloon_stat(void *opaque, BalloonInfo *info) > VIRTIO_BALLOON_PFN_SHIFT); > } > > +static int virtio_balloon_free_pages(void *opaque, > + unsigned long *free_pages_bitmap, > + unsigned long *free_pages_count) > +{ > + VirtIOBalloon *s = opaque; > + VirtIODevice *vdev = VIRTIO_DEVICE(s); > + VirtQueueElement *elem = s->free_pages_vq_elem; > + int len; > + > + if (!balloon_free_pages_supported(s)) { > + return -1; > + } > + > + if (s->req_status == NOT_STARTED) { > + s->free_pages_bitmap = free_pages_bitmap; > + s->req_status = STARTED; > + s->mem_layout.low_mem = pc_get_lowmem(PC_MACHINE(current_machine)); > + if (!elem->in_num) { > + elem = virtqueue_pop(s->fvq, sizeof(VirtQueueElement)); > + if (!elem) { > + return 0; > + } > + s->free_pages_vq_elem = elem; > + } > + len = iov_from_buf(elem->in_sg, elem->in_num, 0, &s->mem_layout, > + sizeof(s->mem_layout)); > + virtqueue_push(s->fvq, elem, len); > + virtio_notify(vdev, s->fvq); > + return 0; > + } else if (s->req_status == STARTED) { > + return 0; > + } else if (s->req_status == DONE) { > + *free_pages_count = s->free_pages_count; > + s->req_status = NOT_STARTED; > + } > + > + return 1; > +} > + > static void virtio_balloon_to_target(void *opaque, ram_addr_t target) > { > VirtIOBalloon *dev = VIRTIO_BALLOON(opaque); > @@ -429,7 +506,8 @@ static void virtio_balloon_device_realize(DeviceState *dev, Error **errp) > sizeof(struct virtio_balloon_config)); > > ret = qemu_add_balloon_handler(virtio_balloon_to_target, > - virtio_balloon_stat, s); > + virtio_balloon_stat, > + virtio_balloon_free_pages, s); > > if (ret < 0) { > error_setg(errp, "Only one balloon device is supported"); > @@ -440,6 +518,7 @@ static void virtio_balloon_device_realize(DeviceState *dev, Error **errp) > s->ivq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output); > s->dvq = virtio_add_queue(vdev, 128, virtio_balloon_handle_output); > s->svq = virtio_add_queue(vdev, 128, virtio_balloon_receive_stats); > + s->fvq = virtio_add_queue(vdev, 128, virtio_balloon_get_free_pages); > > reset_stats(s); > > diff --git a/include/hw/virtio/virtio-balloon.h b/include/hw/virtio/virtio-balloon.h > index 35f62ac..fc173e4 100644 > --- a/include/hw/virtio/virtio-balloon.h > +++ b/include/hw/virtio/virtio-balloon.h > @@ -23,6 +23,16 @@ > #define VIRTIO_BALLOON(obj) \ > OBJECT_CHECK(VirtIOBalloon, (obj), TYPE_VIRTIO_BALLOON) > > +typedef enum virtio_req_status { > + NOT_STARTED, > + STARTED, > + DONE, > +} VIRTIO_REQ_STATUS; > + > +typedef struct MemLayout { > + uint64_t low_mem; > +} MemLayout; > + > typedef struct virtio_balloon_stat VirtIOBalloonStat; > > typedef struct virtio_balloon_stat_modern { > @@ -33,16 +43,21 @@ typedef struct virtio_balloon_stat_modern { > > typedef struct VirtIOBalloon { > VirtIODevice parent_obj; > - VirtQueue *ivq, *dvq, *svq; > + VirtQueue *ivq, *dvq, *svq, *fvq; > uint32_t num_pages; > uint32_t actual; > uint64_t stats[VIRTIO_BALLOON_S_NR]; > VirtQueueElement *stats_vq_elem; > + VirtQueueElement *free_pages_vq_elem; > size_t stats_vq_offset; > QEMUTimer *stats_timer; > int64_t stats_last_update; > int64_t stats_poll_interval; > uint32_t host_features; > + uint64_t *free_pages_bitmap; > + uint64_t free_pages_count; > + MemLayout mem_layout; > + VIRTIO_REQ_STATUS req_status; > } VirtIOBalloon; > > #endif > diff --git a/include/standard-headers/linux/virtio_balloon.h b/include/standard-headers/linux/virtio_balloon.h > index 2e2a6dc..95b7d0c 100644 > --- a/include/standard-headers/linux/virtio_balloon.h > +++ b/include/standard-headers/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 the free pages bitmap */ > > /* Size of a PFN in the balloon interface. */ > #define VIRTIO_BALLOON_PFN_SHIFT 12 > diff --git a/include/sysemu/balloon.h b/include/sysemu/balloon.h > index 3f976b4..205b272 100644 > --- a/include/sysemu/balloon.h > +++ b/include/sysemu/balloon.h > @@ -18,11 +18,19 @@ > > typedef void (QEMUBalloonEvent)(void *opaque, ram_addr_t target); > typedef void (QEMUBalloonStatus)(void *opaque, BalloonInfo *info); > +typedef int (QEMUBalloonFreePages)(void *opaque, > + unsigned long *free_pages_bitmap, > + unsigned long *free_pages_count); > > int qemu_add_balloon_handler(QEMUBalloonEvent *event_func, > - QEMUBalloonStatus *stat_func, void *opaque); > + QEMUBalloonStatus *stat_func, > + QEMUBalloonFreePages *free_pages_func, > + void *opaque); > void qemu_remove_balloon_handler(void *opaque); > bool qemu_balloon_is_inhibited(void); > void qemu_balloon_inhibit(bool state); > +bool balloon_free_pages_support(void); > +int balloon_get_free_pages(unsigned long *free_pages_bitmap, > + unsigned long *free_pages_count); > > #endif > -- > 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
