From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:39059) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f1Vxe-0005H1-Jn for qemu-devel@nongnu.org; Thu, 29 Mar 2018 07:43:19 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1f1Vxb-0007YJ-CT for qemu-devel@nongnu.org; Thu, 29 Mar 2018 07:43:18 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:47434 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1f1Vxb-0007Y6-6i for qemu-devel@nongnu.org; Thu, 29 Mar 2018 07:43:15 -0400 Date: Thu, 29 Mar 2018 13:43:03 +0200 From: Igor Mammedov Message-ID: <20180329134303.548a864b@redhat.com> In-Reply-To: <20180328192148.GR5046@localhost.localdomain> References: <1520860275-101576-1-git-send-email-imammedo@redhat.com> <1520860275-101576-4-git-send-email-imammedo@redhat.com> <20180323212508.GF28161@localhost.localdomain> <20180327170541.295fc29a@redhat.com> <20180328134835.04f95535@redhat.com> <20180328192148.GR5046@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v4 3/9] cli: add -preconfig option List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eduardo Habkost Cc: peter.maydell@linaro.org, pkrempa@redhat.com, cohuck@redhat.com, qemu-devel@nongnu.org, armbru@redhat.com, pbonzini@redhat.com, david@gibson.dropbear.id.au On Wed, 28 Mar 2018 16:21:48 -0300 Eduardo Habkost wrote: > On Wed, Mar 28, 2018 at 01:48:35PM +0200, Igor Mammedov wrote: > > On Tue, 27 Mar 2018 17:05:41 +0200 > > Igor Mammedov wrote: > > > > > On Fri, 23 Mar 2018 18:25:08 -0300 > > > Eduardo Habkost wrote: > > > > > > > On Mon, Mar 12, 2018 at 02:11:09PM +0100, Igor Mammedov wrote: > > > [...] > > [...] > > > > > @@ -1886,6 +1895,13 @@ static bool main_loop_should_exit(void) > > > > > RunState r; > > > > > ShutdownCause request; > > > > > > > > > > + if (preconfig_exit_requested) { > > > > > + if (runstate_check(RUN_STATE_PRECONFIG)) { > > > > > > > > Is it possible to have preconfig_exit_request set outside of > > > > RUN_STATE_PRECONFIG? When and why? > > > preconfig_exit_requested is initialized with TRUE and > > > in combo with '-inmigrate' we need this runstate check. > > > it's the same as it was with > > > { RUN_STATE_PRELAUNCH, RUN_STATE_INMIGRATE }, > > > which I probably should remove (I need to check it though) > > [...] > > > > > > > @@ -4594,6 +4623,10 @@ int main(int argc, char **argv, char **envp) > > > > > } > > > > > parse_numa_opts(current_machine); > > > > > > > > > > + /* do monitor/qmp handling at preconfig state if requested */ > > > > > + main_loop(); > > > > > > > > Wouldn't it be simpler to do "if (!preconfig) { main_loop(); }" > > > > instead of entering main_loop() just to exit immediately? > > > The thought didn't cross my mind, it might work and more readable > > > as one doesn't have to jump into main_loop() to find out that > > > it would exit immediately. > > > I'll try to it on respin. > > Well doing as suggested end ups more messy: > > > > @@static bool main_loop_should_exit(void) > > ... > > if (preconfig_exit_requested) { > > runstate_set(RUN_STATE_PRELAUNCH); > > return true; > > } > > > > @@main > > /* do monitor/qmp handling at preconfig state if requested */ > > if (!preconfig_exit_requested) { > > main_loop(); > > } else if (runstate_check(RUN_STATE_PRECONFIG)) { > > runstate_set(RUN_STATE_PRELAUNCH); > > } > > This doesn't make sense to me. Why would we enter > RUN_STATE_PRECONFIG state if -preconfig is not used at all? because of RUN_STATE_PRECONFIG becomes new initial state of our state machine where we start of (used to be RUN_STATE_PRELAUNCH) Lets call it variant 1: with this we have 2 possible transitions: RUN_STATE_PRECONFIG -> RUN_STATE_PRELAUNCH (machine_init) and RUN_STATE_PRECONFIG -> RUN_STATE_INMIGRATE ugly but it was the same with RUN_STATE_PRELAUNCH initial transition Another variant 2, in case we switch to RUN_STATE_PRECONFIG only on -preconfig transitions would be RUN_STATE_PRELAUNCH -> RUN_STATE_PRECONFIG (allow switch from initial to -preconfig) RUN_STATE_PRECONFIG -> RUN_STATE_PRELAUNCH while the last is valid transition, the 1st one isn't really valid because of (beside of switching from initial state) it allows bouncing back to RUN_STATE_PRECONFIG later. If we consider only state machine transitions, I think it's cleaner to start with variant 1 with the same -inmigrate hack we already have (which potentially could be fixed later), than allowing arbitrary bouncing to RUN_STATE_PRECONFIG at later stage. With this approach all processing before machine_init() would run at RUN_STATE_PRECONFIG and then we would switch to RUN_STATE_PRELAUNCH. Even though it is far reaching goal but at least that's where we should be moving to have sane initialization flow in vl.c > > preconfig_exit_requested = false; > > ... > > > > I'd prefer original v4 approach, where only main_loop_should_exit() > > has to deal with state transitions and book-keeping. > > If the above is unavoidable, I agree. But I still don't > understand we have to enter PRECONFIG state if the user didn't > specify -preconfig. >