[libvirt] PATCH: 6/25: Avoid event loop wakups in remote driver
Daniel P. Berrange
berrange at redhat.com
Tue Jan 20 12:29:21 UTC 2009
On Thu, Jan 15, 2009 at 03:19:39PM +0100, Jim Meyering wrote:
> "Daniel P. Berrange" <berrange at redhat.com> wrote:
> > When going into the call() method, we temporarily disable the
> > event wakup callback. The call() method is already processing
> > any async messages which arrive, so letting the main event loop
> > wakup here is inefficient, and indeed will block the main event
> > loop on the mutex while the main thread is in call(). We really
> > don't want that !
> >
> > remote_internal.c | 42 ++++++++++++++++++++++++++++++++++--------
> > 1 file changed, 34 insertions(+), 8 deletions(-)
> >
> > Daniel
> >
> > diff --git a/src/remote_internal.c b/src/remote_internal.c
> ...
> > +doCall (virConnectPtr conn, struct private_data *priv,
> ...
> > +static int
> > +call (virConnectPtr conn, struct private_data *priv,
> > + int flags /* if we are in virConnectOpen */,
> > + int proc_nr,
> > + xdrproc_t args_filter, char *args,
> > + xdrproc_t ret_filter, char *ret)
> > +{
> > + int rv;
> > + /*
> > + * Avoid needless wake-ups of the event loop in the
> > + * case where this call is being made from a different
> > + * thread than the event loop. These wake-ups would
> > + * cause the event loop thread to be blocked on the
> > + * mutex for the duration of the call
> > + */
> > + if (priv->watch >= 0)
> > + virEventUpdateHandle(priv->watch, 0);
> > +
> > + rv = doCall(conn, priv,flags, proc_nr,
> > + args_filter, args,
> > + ret_filter, ret);
> > +
> > + if (priv->watch >= 0)
> > + virEventUpdateHandle(priv->watch, VIR_EVENT_HANDLE_READABLE);
>
> Looks fine. ACK.
Comitted this
Daniel
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