From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists1p.gnu.org (lists1p.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 70809F34C5C for ; Mon, 13 Apr 2026 15:23:55 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wCJ7y-0005R7-Kd; Mon, 13 Apr 2026 11:23:06 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wCJ7w-0005Qg-32; Mon, 13 Apr 2026 11:23:04 -0400 Received: from mx.treblig.org ([2a00:1098:5b::1]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wCJ7q-0008Nk-9D; Mon, 13 Apr 2026 11:23:00 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=treblig.org ; s=bytemarkmx; h=Content-Type:MIME-Version:Message-ID:Subject:From:Date:From :Subject; bh=tTucvl7BRw4RPnkprViEL7BGBp/YOb1uNjVLYq4B8/I=; b=W3K0d5ASN7fSLnbj PMttQ8+ms2o3DC22evWol+o/MQefT1QAXn46q4S5KlbTLYxTzKufE8kXxDUr/QZQyIdbprPIDiemC /wwe2GsfzEk6gO6GYwXI1SJ+c/EGRjzpQD6Ob8JFIuQLAlVvKOZqAsztDxMC+fdLvWGRTqBA23Xsz q/cAmu7w7Bzi4OO+e8BuzC4lGomMlsKlZ1I1A8tlVtgY7VQ3y1mjUTeMZBrQSR1MENIE7kW/8tseN 5sxZsyTqPn8xq9TmFzWNXlv0FsOuOAUjdnH560+Kr5b1TLdTaxH6qg3urJesO2MLV+tkiTGZgP2LA riQFQdVEH8kZ/81a9Q==; Received: from dg by mx.treblig.org with local (Exim 4.98.2) (envelope-from ) id 1wCJ7m-000000081Ul-1xVC; Mon, 13 Apr 2026 15:22:54 +0000 Date: Mon, 13 Apr 2026 15:22:54 +0000 From: "Dr. David Alan Gilbert" To: Daniel =?iso-8859-1?Q?P=2E_Berrang=E9?= Cc: qemu-devel@nongnu.org, Paolo Bonzini , Markus Armbruster , Christian Brauner , Alex =?iso-8859-1?Q?Benn=E9e?= , Philippe =?iso-8859-1?Q?Mathieu-Daud=E9?= , Fabiano Rosas , =?iso-8859-1?Q?Marc-Andr=E9?= Lureau , Peter Xu , Kevin Wolf , qemu-block@nongnu.org, Eric Blake Subject: Re: [PATCH 05/17] monitor: remove 'skip_flush' field Message-ID: References: <20260410160458.3778874-1-berrange@redhat.com> <20260410160458.3778874-6-berrange@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Chocolate: 70 percent or better cocoa solids preferably X-Operating-System: Linux/6.12.74+deb13+1-amd64 (x86_64) X-Uptime: 15:22:46 up 31 days, 16:36, 2 users, load average: 0.02, 0.05, 0.01 User-Agent: Mutt/2.2.13 (2024-03-09) Received-SPF: pass client-ip=2a00:1098:5b::1; envelope-from=dg@treblig.org; helo=mx.treblig.org X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org * Daniel P. Berrangé (berrange@redhat.com) wrote: > On Mon, Apr 13, 2026 at 01:28:13AM +0000, Dr. David Alan Gilbert wrote: > > * Daniel P. Berrangé (berrange@redhat.com) wrote: > > > The 'skip_flush' field is set on the dummy throwaway HMP monitor > > > object created by QMP's 'human-monitor-command', as an indication > > > not to try to write data to the chardev. Instead the QMP command > > > impl will grab the data straight out of the in-memory buffer. > > > > > > The flag is redundant, however, as the monitor code could instead > > > simply check the 'fe_is_open' field on the CharFrontend, which > > > will be false in the same scenarios that 'skip_flush' is true. > > > > For monitors on sockets where the other end isn't connected, does that > > change the behaviour? Does that also have !fe_is_open and can that hit this > > case? > > The only place that sets fe_is_open is qemu_chr_fe_set_open, > which is called by qemu_chr_fe_set_handlers_full. > > IOW, it merely reflects the fact that some frontend (the > monitor in this case) and configured the chardev for use, > and is separate from any notion of whether the chardev > backend is open/connected. Ah ok, in which case, Reviewed-by: Dr. David Alan Gilbert > > > > > > > Dave > > > > > Signed-off-by: Daniel P. Berrangé > > > --- > > > monitor/hmp.c | 2 +- > > > monitor/monitor-internal.h | 4 +--- > > > monitor/monitor.c | 11 +++++++---- > > > monitor/qmp-cmds.c | 2 +- > > > monitor/qmp.c | 2 +- > > > 5 files changed, 11 insertions(+), 10 deletions(-) > > > > > > diff --git a/monitor/hmp.c b/monitor/hmp.c > > > index 614d9a3707..72f8303662 100644 > > > --- a/monitor/hmp.c > > > +++ b/monitor/hmp.c > > > @@ -1539,7 +1539,7 @@ void monitor_new_hmp(Chardev *chr, bool use_readline, Error **errp) > > > return; > > > } > > > > > > - monitor_data_init(&mon->parent, false, false, false); > > > + monitor_data_init(&mon->parent, false, false); > > > > > > mon->use_readline = use_readline; > > > if (mon->use_readline) { > > > diff --git a/monitor/monitor-internal.h b/monitor/monitor-internal.h > > > index 25320928a7..84117805b7 100644 > > > --- a/monitor/monitor-internal.h > > > +++ b/monitor/monitor-internal.h > > > @@ -102,7 +102,6 @@ struct Monitor { > > > CharFrontend chr; > > > int suspend_cnt; /* Needs to be accessed atomically */ > > > bool is_qmp; > > > - bool skip_flush; > > > bool use_io_thread; > > > > > > char *mon_cpu_path; > > > @@ -183,8 +182,7 @@ extern QmpCommandList qmp_commands, qmp_cap_negotiation_commands; > > > extern QemuMutex monitor_lock; > > > extern MonitorList mon_list; > > > > > > -void monitor_data_init(Monitor *mon, bool is_qmp, bool skip_flush, > > > - bool use_io_thread); > > > +void monitor_data_init(Monitor *mon, bool is_qmp, bool use_io_thread); > > > void monitor_data_destroy(Monitor *mon); > > > int monitor_can_read(void *opaque); > > > void monitor_list_append(Monitor *mon); > > > diff --git a/monitor/monitor.c b/monitor/monitor.c > > > index 7936e2ab22..f7e3708d2f 100644 > > > --- a/monitor/monitor.c > > > +++ b/monitor/monitor.c > > > @@ -167,7 +167,12 @@ void monitor_flush_locked(Monitor *mon) > > > size_t len; > > > const char *buf; > > > > > > - if (mon->skip_flush) { > > > + /* > > > + * When used by QMP human-monitor-command, no chardev > > > + * will be connected, as we want to just collect the > > > + * output in the buffer > > > + */ > > > + if (!mon->chr.fe_is_open) { > > > return; > > > } > > > > > > @@ -621,8 +626,7 @@ static void monitor_iothread_init(void) > > > mon_iothread = iothread_create("mon_iothread", &error_abort); > > > } > > > > > > -void monitor_data_init(Monitor *mon, bool is_qmp, bool skip_flush, > > > - bool use_io_thread) > > > +void monitor_data_init(Monitor *mon, bool is_qmp, bool use_io_thread) > > > { > > > if (use_io_thread && !mon_iothread) { > > > monitor_iothread_init(); > > > @@ -630,7 +634,6 @@ void monitor_data_init(Monitor *mon, bool is_qmp, bool skip_flush, > > > qemu_mutex_init(&mon->mon_lock); > > > mon->is_qmp = is_qmp; > > > mon->outbuf = g_string_new(NULL); > > > - mon->skip_flush = skip_flush; > > > mon->use_io_thread = use_io_thread; > > > } > > > > > > diff --git a/monitor/qmp-cmds.c b/monitor/qmp-cmds.c > > > index d0ed241d6a..be2bd985b7 100644 > > > --- a/monitor/qmp-cmds.c > > > +++ b/monitor/qmp-cmds.c > > > @@ -168,7 +168,7 @@ char *qmp_human_monitor_command(const char *command_line, bool has_cpu_index, > > > char *output = NULL; > > > MonitorHMP *hmp = MONITOR_HMP(object_new(TYPE_MONITOR_HMP)); > > > > > > - monitor_data_init(&hmp->parent, false, true, false); > > > + monitor_data_init(&hmp->parent, false, false); > > > > > > if (has_cpu_index) { > > > int ret = monitor_set_cpu(&hmp->parent, cpu_index); > > > diff --git a/monitor/qmp.c b/monitor/qmp.c > > > index 36cb078f30..fe2aec9ce9 100644 > > > --- a/monitor/qmp.c > > > +++ b/monitor/qmp.c > > > @@ -538,7 +538,7 @@ void monitor_new_qmp(Chardev *chr, bool pretty, Error **errp) > > > qemu_chr_fe_set_echo(&mon->parent.chr, true); > > > > > > /* Note: we run QMP monitor in I/O thread when @chr supports that */ > > > - monitor_data_init(&mon->parent, true, false, > > > + monitor_data_init(&mon->parent, true, > > > qemu_chr_has_feature(chr, QEMU_CHAR_FEATURE_GCONTEXT)); > > > > > > mon->pretty = pretty; > > > -- > > > 2.53.0 > > > > > -- > > -----Open up your eyes, open up your mind, open up your code ------- > > / Dr. David Alan Gilbert | Running GNU/Linux | Happy \ > > \ dave @ treblig.org | | In Hex / > > \ _________________________|_____ http://www.treblig.org |_______/ > > > > With regards, > Daniel > -- > |: https://berrange.com ~~ https://hachyderm.io/@berrange :| > |: https://libvirt.org ~~ https://entangle-photo.org :| > |: https://pixelfed.art/berrange ~~ https://fstop138.berrange.com :| > -- -----Open up your eyes, open up your mind, open up your code ------- / Dr. David Alan Gilbert | Running GNU/Linux | Happy \ \ dave @ treblig.org | | In Hex / \ _________________________|_____ http://www.treblig.org |_______/