[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [RFC 2/3] virtio-balloon: re-enable balloon stats
From: |
Luiz Capitulino |
Subject: |
Re: [Qemu-devel] [RFC 2/3] virtio-balloon: re-enable balloon stats |
Date: |
Thu, 6 Dec 2012 15:58:49 -0200 |
On Thu, 6 Dec 2012 11:03:21 -0600
mdroth <address@hidden> wrote:
> On Tue, Dec 04, 2012 at 01:04:47PM -0200, Luiz Capitulino wrote:
> > The statistics are now available through device properties via a
> > polling mechanism. First, a client has to enable polling, then it
> > can query the stats.
> >
> > The following control properties are introduced:
> >
> > o stats-polling-interval: a value greater than zero enables polling
> > in the specified interval (in seconds). When value equals zero,
> > polling is disabled. If polling is already enabled and a value
> > greater than zero is written, the polling interval time is changed
> >
> > o stats-last-update: last stats update timestamp, in seconds.
> >
> > The following stats properties are introduced:
> >
> > o stat-swap-in
> > o stat-swap-out
> > o stat-major-faults
> > o stat-minor-faults
> > o stat-free-memory
> > o stat-total-memory
> >
> > All values are in bytes. A value of -1 means that the statistic isn't
> > available right now.
> >
> > FIXME: Can balloon_stats_poll_cb(), balloon_stats_set_poll_interval(),
> > virtio_balloon_handle_output() can run in parallel?
> >
> > XXX: Should we return an error instead of -1? Might require a specific
> > error. Although this is not exactly a failure...
> >
> > Signed-off-by: Luiz Capitulino <address@hidden>
> > ---
> >
> > NOTE: Anthony suggested having a bool to enable/disable polling, but I
> > prefer
> > to let the client specify the polling interval. I can revisit this,
> > though.
> >
> > hw/virtio-balloon.c | 156
> > +++++++++++++++++++++++++++++++++++++++++++++++++++-
> > 1 file changed, 155 insertions(+), 1 deletion(-)
> >
> > diff --git a/hw/virtio-balloon.c b/hw/virtio-balloon.c
> > index 4398025..06af18f 100644
> > --- a/hw/virtio-balloon.c
> > +++ b/hw/virtio-balloon.c
> > @@ -22,6 +22,8 @@
> > #include "virtio-balloon.h"
> > #include "kvm.h"
> > #include "exec-memory.h"
> > +#include "qemu-timer.h"
> > +#include "qapi/qapi-visit-core.h"
> >
> > #if defined(__linux__)
> > #include <sys/mman.h>
> > @@ -36,6 +38,9 @@ typedef struct VirtIOBalloon
> > uint64_t stats[VIRTIO_BALLOON_S_NR];
> > VirtQueueElement stats_vq_elem;
> > size_t stats_vq_offset;
> > + QEMUTimer *stats_timer;
> > + int64_t stats_last_update;
> > + int64_t stats_poll_interval;
> > DeviceState *qdev;
> > } VirtIOBalloon;
> >
> > @@ -53,6 +58,16 @@ static void balloon_page(void *addr, int deflate)
> > #endif
> > }
> >
> > +static const char *balloon_stat_names[] = {
> > + [VIRTIO_BALLOON_S_SWAP_IN] = "stat-swap-in",
> > + [VIRTIO_BALLOON_S_SWAP_OUT] = "stat-swap-out",
> > + [VIRTIO_BALLOON_S_MAJFLT] = "stat-major-faults",
> > + [VIRTIO_BALLOON_S_MINFLT] = "stat-minor-faults",
> > + [VIRTIO_BALLOON_S_MEMFREE] = "stat-free-memory",
> > + [VIRTIO_BALLOON_S_MEMTOT] = "stat-total-memory",
> > + [VIRTIO_BALLOON_S_NR] = NULL
> > +};
> > +
> > /*
> > * reset_stats - Mark all items in the stats array as unset
> > *
> > @@ -67,6 +82,119 @@ static inline void reset_stats(VirtIOBalloon *dev)
> > for (i = 0; i < VIRTIO_BALLOON_S_NR; dev->stats[i++] = -1);
> > }
> >
> > +static bool balloon_stats_supported(const VirtIOBalloon *s)
> > +{
> > + return s->vdev.guest_features & (1 << VIRTIO_BALLOON_F_STATS_VQ);
> > +}
> > +
> > +static bool balloon_stats_enabled(const VirtIOBalloon *s)
> > +{
> > + return s->stats_poll_interval > 0;
> > +}
> > +
> > +static void balloon_stats_disable_timer(VirtIOBalloon *s)
> > +{
> > + if (balloon_stats_enabled(s)) {
> > + qemu_del_timer(s->stats_timer);
> > + qemu_free_timer(s->stats_timer);
> > + s->stats_timer = NULL;
> > + s->stats_poll_interval = 0;
> > + }
> > +}
> > +
> > +static void balloon_stats_change_timer(VirtIOBalloon *s, int secs)
> > +{
> > + qemu_mod_timer(s->stats_timer, qemu_get_clock_ms(vm_clock) + secs *
> > 1000);
> > +}
> > +
> > +static void balloon_stats_poll_cb(void *opaque)
> > +{
> > + VirtIOBalloon *s = opaque;
> > +
> > + virtqueue_push(s->svq, &s->stats_vq_elem, s->stats_vq_offset);
> > + virtio_notify(&s->vdev, s->svq);
>
> I think we'll want to add some logic to avoid the potential for
> re-pushing an elem we've already processed, as I think that violates the
> virtio spec. In the past the monitor blocked us from doing this but with
> timer-driven requests I think it's a possibility now.
I'll check that, thanks for the feedback Mike.
>
> But the general approach seems sane to me and the code looks to
> be in decent shape.
>
> > --
> > 1.8.0
> >
> >
>
- Re: [Qemu-devel] [RFC 3/3] docs: document virtio-balloon stats, (continued)
- Re: [Qemu-devel] [RFC 3/3] docs: document virtio-balloon stats, Luiz Capitulino, 2012/12/07
- Re: [Qemu-devel] [RFC 3/3] docs: document virtio-balloon stats, Dietmar Maurer, 2012/12/07
- Re: [Qemu-devel] [RFC 3/3] docs: document virtio-balloon stats, Luiz Capitulino, 2012/12/07
- Re: [Qemu-devel] [RFC 3/3] docs: document virtio-balloon stats, Dietmar Maurer, 2012/12/08
- Re: [Qemu-devel] [RFC 3/3] docs: document virtio-balloon stats, Luiz Capitulino, 2012/12/10
- Re: [Qemu-devel] [RFC 3/3] docs: document virtio-balloon stats, Dietmar Maurer, 2012/12/10
- Re: [Qemu-devel] [RFC 3/3] docs: document virtio-balloon stats, Alexandre DERUMIER, 2012/12/10
[Qemu-devel] [RFC 1/3] virtio-balloon: drop old stats code, Luiz Capitulino, 2012/12/04
[Qemu-devel] [RFC 2/3] virtio-balloon: re-enable balloon stats, Luiz Capitulino, 2012/12/04