[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH MINI-OS v3 2/2] xenbus: workaround oxenstored short-write
On Tue, 2015-10-27 at 16:47 +0100, Samuel Thibault wrote: > Wei Liu, le Tue 27 Oct 2015 15:43:29 +0000, a Ãcrit : > > Oxenstored has a behaviour that it only writes a contiguous piece of > > data. When it writes across ring boundary it will return a short-write > > while there is still room. That leads to mini-os stalling when it sees > > there is not enough data in the ring. > > > > Given that oxenstored is the default xenstored implementation we think > > it would be useful to workaround this for the benefit of running mini- > > os > > (and unikernel based on it) on any Xen installation. > > > > Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx> > > As discussed in the previous thread, this is rather a workaround. Given that I'm in the process of applying "tools/ocaml/xb: Correct calculations of data/space the ring" which I think is the real fix here am unsure if we still want to take this workaround. Any thoughts? > Better > be safe than sorry. > > Acked-by: Samuel Thibault <samuel.thibault@xxxxxxxxxxxx> > > And could too be backported to stable branches. > > > --- > > Âxenbus/xenbus.c | 10 ++++++++-- > > Â1 file changed, 8 insertions(+), 2 deletions(-) > > > > diff --git a/xenbus/xenbus.c b/xenbus/xenbus.c > > index 0ab387a..abf8b1b 100644 > > --- a/xenbus/xenbus.c > > +++ b/xenbus/xenbus.c > > @@ -205,8 +205,11 @@ static void xenbus_thread_func(void *ign) > > ÂÂÂÂÂÂÂÂÂÂÂÂÂprod = xenstore_buf->rsp_prod; > > ÂÂÂÂÂÂÂÂÂÂÂÂÂDEBUG("Rsp_cons %d, rsp_prod %d.\n", xenstore_buf- > > >rsp_cons, > > ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂxenstore_buf->rsp_prod); > > -ÂÂÂÂÂÂÂÂÂÂÂÂif (xenstore_buf->rsp_prod - xenstore_buf->rsp_cons < > > sizeof(msg)) > > +ÂÂÂÂÂÂÂÂÂÂÂÂif (xenstore_buf->rsp_prod - xenstore_buf->rsp_cons < > > sizeof(msg)) { > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ/* Work around oxenstored bug */ > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂnotify_remote_via_evtchn(start_info.store_evtchn); > > ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂbreak; > > +ÂÂÂÂÂÂÂÂÂÂÂÂ} > > ÂÂÂÂÂÂÂÂÂÂÂÂÂrmb(); > > ÂÂÂÂÂÂÂÂÂÂÂÂÂmemcpy_from_ring(xenstore_buf->rsp, > > ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ&msg, > > @@ -217,8 +220,11 @@ static void xenbus_thread_func(void *ign) > > ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂxenstore_buf->rsp_prod - xenstore_buf->rsp_cons, > > ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂmsg.req_id); > > ÂÂÂÂÂÂÂÂÂÂÂÂÂif (xenstore_buf->rsp_prod - xenstore_buf->rsp_cons < > > -ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂsizeof(msg) + msg.len) > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂsizeof(msg) + msg.len) { > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ/* Work around oxenstored bug */ > > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂnotify_remote_via_evtchn(start_info.store_evtchn); > > ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂbreak; > > +ÂÂÂÂÂÂÂÂÂÂÂÂ} > > Â > > ÂÂÂÂÂÂÂÂÂÂÂÂÂDEBUG("Message is good.\n"); > > Â > > -- > > 2.1.4 > > > _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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