From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Mon, 28 Jan 2019 11:43:25 +0300 From: Vladimir Davydov Subject: Re: [PATCH v5 1/3] box: implement on_shutdown triggers Message-ID: <20190128084325.2f2a6j6nyykjzkhl@esperanza> References: <9c7b6a71c1092f04c4538fddc1b08199e01dd995.1548430046.git.sergepetrenko@tarantool.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9c7b6a71c1092f04c4538fddc1b08199e01dd995.1548430046.git.sergepetrenko@tarantool.org> To: Serge Petrenko Cc: kostja@tarantool.org, tarantool-patches@freelists.org List-ID: The patch is generally OK. See a few really minor comments below. On Fri, Jan 25, 2019 at 06:41:32PM +0300, Serge Petrenko wrote: > diff --git a/src/main.cc b/src/main.cc > index 993355ac4..96df9e851 100644 > --- a/src/main.cc > +++ b/src/main.cc > @@ -89,6 +89,12 @@ static const int ev_sig_count = sizeof(ev_sigs)/sizeof(*ev_sigs); > > static double start_time; > > +/** A preallocated fiber to run on_shutdown triggers. */ > +static struct fiber *on_shutdown_fiber = NULL; > +static bool is_shutting_down = false; Missing comment. > +/** A trigger which will break the event loop on shutdown. */ > +static struct trigger shutdown_trig; IMO break_loop_trigger would be a more appropriate name. > + > double > tarantool_uptime(void) > { > @@ -119,9 +125,33 @@ sig_checkpoint(ev_loop * /* loop */, struct ev_signal * /* w */, > fiber_wakeup(f); > } > > +static int > +on_shutdown_f(va_list ap) > +{ > + (void) ap; > + trigger_run(&box_on_shutdown, NULL); > + return 0; > +} > + > +void > +tarantool_exit(void) Should be static. > +{ > + if (is_shutting_down) { > + /* > + * We are already running on_shutdown triggers, > + * and will exit as soon as they'll finish. > + * Do not execute them twice. > + */ > + return; > + } > + is_shutting_down = true; > + fiber_wakeup(on_shutdown_fiber); > +} > + > static void > signal_cb(ev_loop *loop, struct ev_signal *w, int revents) > { > + (void) loop; > (void) w; > (void) revents; > > @@ -135,8 +165,7 @@ signal_cb(ev_loop *loop, struct ev_signal *w, int revents) > if (pid_file) > say_crit("got signal %d - %s", w->signum, strsignal(w->signum)); > start_loop = false; > - /* Terminate the main event loop */ > - ev_break(loop, EVBREAK_ALL); > + tarantool_exit(); > } > > static void > @@ -628,6 +657,12 @@ print_help(const char *program) > puts("to see online documentation, submit bugs or contribute a patch."); > } > > +static void > +break_loop(struct trigger *, void *) > +{ > + ev_break(loop(), EVBREAK_ALL); > +} > + > int > main(int argc, char **argv) > { > @@ -751,6 +786,17 @@ main(int argc, char **argv) > try { > box_init(); > box_lua_init(tarantool_L); > + /* Reserve a fiber to run on_shutdown triggers. */ > + on_shutdown_fiber = fiber_new("on_exit", on_shutdown_f); > + if (on_shutdown_fiber == NULL) > + diag_raise(); I guess the fiber should be made non-cancellable so that it couldn't be occasionally woken up from Lua. > + /* > + * Register a on_shutdown trigger which will break the > + * main event loop. The trigger will be the last to run > + * since it's the first one we register. > + */ > + trigger_create(&shutdown_trig, break_loop, NULL, NULL); > + trigger_add(&box_on_shutdown, &shutdown_trig); > > /* main core cleanup routine */ > atexit(tarantool_free);