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 1FAEECAC59A for ; Fri, 19 Sep 2025 11:36:32 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1uzZOs-0003OB-9r; Fri, 19 Sep 2025 07:35:38 -0400 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 1uzZOi-0003MZ-Pl for qemu-devel@nongnu.org; Fri, 19 Sep 2025 07:35:32 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1uzZOc-00056A-PK for qemu-devel@nongnu.org; Fri, 19 Sep 2025 07:35:28 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1758281719; h=from:from: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=741sIxHsT13C6H6nJWliu6nYEPxwVGA7QOsTdTIN/zU=; b=UJG7FApFfVmDECSAln0MXx4ISNwDZcBfHYnzyfhBFITsd0P2f/rGpEcgxizNxjHj66jQu9 xu246fD74HeyRMWX6jGHF9bfihl1kpigg4oUe3LmL6FnU+2MV/+rXkaevKLzt9xHYk/RlW pr+2F/6eeiNFGqCnm7tTCyomfmDqnow= Received: from mx-prod-mc-08.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-450-lIqGPDsjOBGZKCY0kiPflw-1; Fri, 19 Sep 2025 07:35:10 -0400 X-MC-Unique: lIqGPDsjOBGZKCY0kiPflw-1 X-Mimecast-MFC-AGG-ID: lIqGPDsjOBGZKCY0kiPflw_1758281708 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (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-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id AB43E18002C4; Fri, 19 Sep 2025 11:35:08 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.45.242.33]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 356B91956045; Fri, 19 Sep 2025 11:35:08 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 6BD2121E6A27; Fri, 19 Sep 2025 13:35:05 +0200 (CEST) From: Markus Armbruster To: Daniel P. =?utf-8?Q?Berrang=C3=A9?= Cc: qemu-devel@nongnu.org, qemu-block@nongnu.org, Hanna Reitz , Kevin Wolf , =?utf-8?Q?Marc-Andr?= =?utf-8?Q?=C3=A9?= Lureau , Christian Schoenebeck , Richard Henderson , Manos Pitsidianakis , Stefan Weil , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , Gerd Hoffmann , Paolo Bonzini , "Dr. David Alan Gilbert" Subject: Re: [PATCH v3 07/20] util: add API to fetch the current thread name In-Reply-To: ("Daniel P. =?utf-8?Q?Berrang?= =?utf-8?Q?=C3=A9=22's?= message of "Fri, 19 Sep 2025 10:05:21 +0100") References: <20250910180357.320297-1-berrange@redhat.com> <20250910180357.320297-8-berrange@redhat.com> <87y0qa4y3d.fsf@pond.sub.org> Date: Fri, 19 Sep 2025 13:35:05 +0200 Message-ID: <878qia3cba.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 Received-SPF: pass client-ip=170.10.133.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.105, 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_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_PASS=-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: 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. Berrang=C3=A9 writes: > On Fri, Sep 19, 2025 at 10:59:18AM +0200, Markus Armbruster wrote: >> Daniel P. Berrang=C3=A9 writes: >>=20 >> > This will be used to include the thread name in error reports >> > in a later patch. It returns a const string stored in a thread >> > local to avoid memory allocation when it is called repeatedly >> > in a single thread. This makes the assumption that the thread >> > name is set at the very start of the thread, which is the case >> > when using qemu_thread_create. >>=20 >> What happens when the assumption is violated? > > You will get an operating system default thread name, > which on Linux will default to the unqualified binary > name based on argv[0] Suggest something like "The thread name should be set at the very start of the thread, which is the case when using qemu_thread_create." >> > Signed-off-by: Daniel P. Berrang=C3=A9 >> > --- >> > include/qemu/thread.h | 1 + >> > meson.build | 21 +++++++++++++++++ >> > util/qemu-thread-posix.c | 28 ++++++++++++++++++++++- >> > util/qemu-thread-win32.c | 49 ++++++++++++++++++++++++++++++++++++---- >> > 4 files changed, 94 insertions(+), 5 deletions(-) > > >> > diff --git a/util/qemu-thread-posix.c b/util/qemu-thread-posix.c >> > index 275445ed94..fbb94ca97b 100644 >> > --- a/util/qemu-thread-posix.c >> > +++ b/util/qemu-thread-posix.c >> > @@ -18,7 +18,7 @@ >> > #include "qemu/tsan.h" >> > #include "qemu/bitmap.h" >> >=20=20 >> > -#ifdef CONFIG_PTHREAD_SET_NAME_NP >> > +#if defined(CONFIG_PTHREAD_SET_NAME_NP) || defined(CONFIG_PTHREAD_GET= _NAME_NP) >> > #include >> > #endif >> >=20=20 >> > @@ -532,3 +532,29 @@ void *qemu_thread_join(QemuThread *thread) >> > } >> > return ret; >> > } >> > + >> > +#ifndef PTHREAD_MAX_NAMELEN_NP >> > +#define PTHREAD_MAX_NAMELEN_NP 16 >>=20 >> Feels a bit tight. 32? > > On Linux this constant is not defined, but the manpage says > > The thread name is a meaningful C language string, whose length is > restricted to 16 characters, including the terminating null byte ('\0') > > so I defined the constant to match the non-Linux constant > name, but with the Linux documented max length. I see. Maybe mention in a comment or the commit message? [...]