Am 05.11.2025 um 18:18 hat Eric Blake geschrieben: > On Tue, Nov 04, 2025 at 12:08:42PM +0100, Kevin Wolf wrote: > > Am 03.11.2025 um 21:10 hat Eric Blake geschrieben: > > > Upcoming patches will adjust how net_listener watches for new client > > > connections; adding trace points now makes it easier to debug that the > > > changes work as intended. For example, adding > > > --trace='qio_net_listener*' to the qemu-storage-daemon command line > > > before --nbd-server will track when the server first starts listening > > > for clients. > > > > > > Signed-off-by: Eric Blake <[email protected]> > > > --- > > > io/net-listener.c | 17 +++++++++++++++++ > > > io/trace-events | 5 +++++ > > > 2 files changed, 22 insertions(+) > > > > > > diff --git a/io/net-listener.c b/io/net-listener.c > > > index 47405965a66..0adbc409cf2 100644 > > > --- a/io/net-listener.c > > > +++ b/io/net-listener.c > > > @@ -23,6 +23,7 @@ > > > #include "io/dns-resolver.h" > > > #include "qapi/error.h" > > > #include "qemu/module.h" > > > +#include "trace.h" > > > > > > QIONetListener *qio_net_listener_new(void) > > > { > > > @@ -50,6 +51,7 @@ static gboolean > > > qio_net_listener_channel_func(QIOChannel *ioc, > > > return TRUE; > > > } > > > > > > + trace_qio_net_listener_callback(listener, listener->io_func); > > > if (listener->io_func) { > > > listener->io_func(listener, sioc, listener->io_data); > > > } > > > > Not necessarily a problem, but I wonder why you decided to have the > > trace point unconditional here... > > > > > @@ -143,6 +147,9 @@ void > > > qio_net_listener_set_client_func_full(QIONetListener *listener, > > > { > > > size_t i; > > > > > > + if (listener->io_func) { > > > + trace_qio_net_listener_watch_disabled(listener, > > > "set_client_func"); > > > + } > > > if (listener->io_notify) { > > > listener->io_notify(listener->io_data); > > > } > > > > ...while everywhere else you only call it with a non-NULL > > listener->io_func. > > In the former, the trace is printing out the address of which io_func > (including NULL) is currently registered when the callback is reached. > In the case where a single NetListener registers more than one socket > address, but the user uninstalls their callback after the first client > to connect, it is still possible that other pending connections have > still raced, at which point the qio_net_listener_channel_func can > still fire on those later connections even though there is no longer > an io_func from the user. In all the latter cases, I was merely > tracing when state transitioned between the user installing a handler > or removing one. > > Unless you think it would be to noisy, I'm game for changing this in > v2 to have all of the traces be unconditional. It is potentially > noisier, but also would aid in spotting how many times a client > requests no change to the current io_func or lack thereof.
I think being noisy in traces is okay. It's easy enough to filter the output for non-NULL instances if that's what you need. In debugging I usually want more data, having too much data is rarely a problem. > Also worth thinking about: in this patch, I added new traces under the > names enabled/disabled, with the trace points being reacable from > multiple locations. Then in 4/8, when refactoring to consolidate > duplicate code, the trace points are reduced to a single usage in > functions named watch/unwatch. It may be worth rethinking naming to > have the tracepoint and function names share the same terminology. Yes, that's a good idea. Kevin
