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 lists.gnu.org (lists.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 6BE88D2D0E0 for ; Tue, 13 Jan 2026 12:03:35 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vfd0i-0006HJ-WA; Tue, 13 Jan 2026 06:56:33 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vfd0Y-0006As-NN for qemu-rust@nongnu.org; Tue, 13 Jan 2026 06:56:23 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vfd0U-0006gZ-CL for qemu-rust@nongnu.org; Tue, 13 Jan 2026 06:56:20 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1768305376; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=AceUXHTl+ZnYM6QlCLoO/rXHTCu2lYmMUrjaVdxnwO4=; b=K+fqt/Ux0TWVZZpOaZtErrbVhybbRz8GoFSWWbSD/tuxTDyCq9mUvIDWGXGMkIOTLh0eT1 KThYVzqWJJIKtD41ZcGXxsxsaDM4MPfblwqetZ08fa664w3OU0RFpvHZ+xaUyI4nYKowCl 50/VbKkgUL7R3Jkgtx0bQ0nfFJgbXHI= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-541-9pNpgyPoMEO7fDWyKF-6nw-1; Tue, 13 Jan 2026 06:56:13 -0500 X-MC-Unique: 9pNpgyPoMEO7fDWyKF-6nw-1 X-Mimecast-MFC-AGG-ID: 9pNpgyPoMEO7fDWyKF-6nw_1768305371 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 3DD6418005B8; Tue, 13 Jan 2026 11:56:11 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.87]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 91EA830001A2; Tue, 13 Jan 2026 11:56:06 +0000 (UTC) Date: Tue, 13 Jan 2026 11:56:03 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Markus Armbruster Cc: qemu-devel@nongnu.org, Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , Manos Pitsidianakis , Hanna Reitz , Gerd Hoffmann , Paolo Bonzini , Christian Schoenebeck , "Dr. David Alan Gilbert" , =?utf-8?Q?Marc-Andr=C3=A9?= Lureau , devel@lists.libvirt.org, qemu-block@nongnu.org, qemu-rust@nongnu.org, Stefan Weil , Kevin Wolf , Richard Henderson Subject: Re: [PATCH v5 10/24] util: avoid repeated prefix on incremental qemu_log calls Message-ID: References: <20260108170338.2693853-1-berrange@redhat.com> <20260108170338.2693853-11-berrange@redhat.com> <87h5spak7y.fsf@pond.sub.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <87h5spak7y.fsf@pond.sub.org> User-Agent: Mutt/2.2.14 (2025-02-20) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com 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, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-rust@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: QEMU Rust-related patches and discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-rust-bounces+qemu-rust=archiver.kernel.org@nongnu.org Sender: qemu-rust-bounces+qemu-rust=archiver.kernel.org@nongnu.org On Tue, Jan 13, 2026 at 11:19:13AM +0100, Markus Armbruster wrote: > Daniel P. Berrangé writes: > > > There are three general patterns to QEMU log output > > > > 1. Single complete message calls > > > > qemu_log("Some message\n"); > > > > 2. Direct use of fprintf > > > > FILE *f = qemu_log_trylock() > > fprintf(f, "..."); > > fprintf(f, "..."); > > fprintf(f, "...\n"); > > qemu_log_unlock(f) > > > > 3. Mixed use of qemu_log_trylock/qemu_log() > > > > FILE *f = qemu_log_trylock() > > qemu_log("...."); > > qemu_log("...."); > > qemu_log("....\n"); > > qemu_log_unlock(f) > > Fixes: 012842c07552 (log: make '-msg timestamp=on' apply to all qemu_log usage) > > Reported-by: Richard Henderson > > Signed-off-by: Daniel P. Berrangé > > --- > > include/qemu/log.h | 7 +++++++ > > util/log.c | 49 ++++++++++++++++++++++++++-------------------- > > 2 files changed, 35 insertions(+), 21 deletions(-) > > > > diff --git a/include/qemu/log.h b/include/qemu/log.h > > index e9d3c6806b..95f417c2b7 100644 > > --- a/include/qemu/log.h > > +++ b/include/qemu/log.h > > @@ -69,6 +69,13 @@ bool qemu_log_separate(void); > > */ > > FILE *qemu_log_trylock(void) G_GNUC_WARN_UNUSED_RESULT; > > > > +/** > > + * As qemu_log_trylock(), but will also print the message > > + * context, if any is configured and this caused the > > + * acquisition of the FILE lock > > + */ > > +FILE *qemu_log_trylock_context(void) G_GNUC_WARN_UNUSED_RESULT; > > This is used just once, in qemu_log(). Could be inlined into > qemu_log(). > > If you prefer to keep it as a function, you could make it static. The intent was that some, but not all, places which currently use qemu_log_trylock() really ought to be including configured message prefix, and hence would need to call this method. No such updates of callers are done in this series though. > I wouldn't guess that this prints from the function name. Dunno, > qemu_log_start_line()? Might want to pair it with a qemu_log_end_line() > then. > > Telling function name is less important if it's static. Personally the inclusion of "log" in its filename is sufficiently suggestive. I'll rename it to qemu_log_trylock_with_context which is the name Richard originally requested. > > diff --git a/util/log.c b/util/log.c > > index c44d66b5ce..2ce7286f31 100644 > > --- a/util/log.c > > +++ b/util/log.c > > @@ -127,13 +127,39 @@ static FILE *qemu_log_trylock_with_err(Error **errp) > > Not this patch's fault, but here goes anyway: > > static FILE *qemu_log_trylock_with_err(Error **errp) > { > FILE *logfile; > > logfile = thread_file; > if (!logfile) { > if (log_per_thread) { > g_autofree char *filename > = g_strdup_printf(global_filename, log_thread_id()); > logfile = fopen(filename, "w"); > if (!logfile) { > error_setg_errno(errp, errno, > "Error opening logfile %s for thread %d", > filename, log_thread_id()); > return NULL; > } > thread_file = logfile; > qemu_log_thread_cleanup_notifier.notify = qemu_log_thread_cleanup; > qemu_thread_atexit_add(&qemu_log_thread_cleanup_notifier); > } else { > rcu_read_lock(); > /* > * FIXME: typeof_strip_qual, as used by qatomic_rcu_read, > * does not work with pointers to undefined structures, > * such as we have with struct _IO_FILE and musl libc. > * Since all we want is a read of a pointer, cast to void**, > * which does work with typeof_strip_qual. > */ > logfile = qatomic_rcu_read((void **)&global_file); > if (!logfile) { > rcu_read_unlock(); > return NULL; > > Fails without setting @errp. Trivial to fix, I'll include a patch for that in next posting. > > } > } > } > > qemu_flockfile(logfile); > > return logfile; > > } > > +FILE *qemu_log_trylock_context(void) > > +{ > > + FILE *f = qemu_log_trylock(); > > This can fail, and if it does... > > > + if (log_depth == 1 && message_with_timestamp) { > > + g_autofree const char *timestr = NULL; > > + g_autoptr(GDateTime) dt = g_date_time_new_now_utc(); > > + timestr = g_date_time_format_iso8601(dt); > > + fprintf(f, "%s ", timestr); > > ... we crash here. Opps, yes will fix. With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|