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 B84DFC61DC2 for ; Wed, 26 Aug 2026 06:51:47 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wz7U3-000650-Oe; Wed, 26 Aug 2026 02:51:39 -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 1wz7U1-00064s-Cb for qemu-devel@nongnu.org; Wed, 26 Aug 2026 02:51:37 -0400 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 1wz7Tz-0000DW-KH for qemu-devel@nongnu.org; Wed, 26 Aug 2026 02:51:37 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1787727094; 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=bgPm9jSR+mQX8cCodBAjyTmKYIDhZ/I1V+riNvmqwjY=; b=D9fD78sb56PCNfRLNfYBrdPgNQNU5ruM2tE5w0f4RlI2LkjLGHvhmy73MFT1ezWiOZtKY9 qvs49oqdW8nYtuu3OVRX7MtzvhIH0rgyO15aT4UUVhhkXAkJzmTVnS+2JQD84DVm4OfVDH qkWY23UljC0Oj/k8FLtWJiUElduflFc= 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-203-93JndsYmMkKDwnCxRs-61Q-1; Wed, 26 Aug 2026 02:51:31 -0400 X-MC-Unique: 93JndsYmMkKDwnCxRs-61Q-1 X-Mimecast-MFC-AGG-ID: 93JndsYmMkKDwnCxRs-61Q_1787727090 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (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 594A818C1062; Wed, 26 Aug 2026 06:51:30 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.44.22.2]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id EB0E91803A4D; Wed, 26 Aug 2026 06:51:29 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 74B1821E6920; Wed, 26 Aug 2026 08:51:27 +0200 (CEST) From: Markus Armbruster To: Zhang Chen Cc: qemu-devel , Eric Blake , "Michael S . Tsirkin" , Stefan Hajnoczi , Paolo Bonzini , Daniel P . =?utf-8?Q?Berrang=C3=A9?= , Jason Wang Subject: Re: [PATCH V13 02/15] iothread: introduce holder tracking In-Reply-To: (Zhang Chen's message of "Tue, 25 Aug 2026 21:50:43 +0800") References: <20260822213343.661939-1-zhangckid@gmail.com> <20260822213343.661939-3-zhangckid@gmail.com> <874igipqbu.fsf@pond.sub.org> Date: Wed, 26 Aug 2026 08:51:27 +0200 Message-ID: <87wltdidcg.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 3.4.1 on 10.30.177.111 Received-SPF: pass client-ip=170.10.129.124; envelope-from=armbru@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, 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: 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 Zhang Chen writes: > On Tue, Aug 25, 2026 at 4:17=E2=80=AFPM Markus Armbruster wrote: >> >> Zhang Chen writes: >> >> > IOThreads do not record the QOM objects and block exports that use >> > them, making runtime introspection and hotplug debugging difficult. >> > >> > Add: >> > >> > - holders: a list describing what is holding an iothread >> > - iothread_ref(): add a holder to the list >> > - iothread_unref(): remove a holder from the list >> > >> > A holder can identify either a QOM object or a block export. A later >> > patch will expose this information through query-iothreads. >> > >> > Signed-off-by: Zhang Chen >> > Reviewed-by: Stefan Hajnoczi >> > Reviewed-by: Markus Armbruster >> >> I'm suspending my R-by, see below why. I'm now reinstating it. >> [...] >> >> > diff --git a/iothread.c b/iothread.c >> > index 3558535b40..66dfde626e 100644 >> > --- a/iothread.c >> > +++ b/iothread.c >> > @@ -21,10 +21,71 @@ >> > #include "system/iothread.h" >> > #include "qapi/error.h" >> > #include "qapi/qapi-commands-misc.h" >> > +#include "qapi/clone-visitor.h" >> > +#include "qapi/qapi-visit-misc.h" >> > #include "qemu/error-report.h" >> > #include "qemu/rcu.h" >> > #include "qemu/main-loop.h" >> > >> > +/* Add a deep copy of @holder to @iothread's list of holders. */ >> > +void iothread_ref(IOThread *iothread, const IOThreadHolder *holder) >> > +{ >> > + assert(holder); >> > + >> > + QAPI_LIST_PREPEND(iothread->holders, QAPI_CLONE(IOThreadHolder, h= older)); >> > +} >> > + >> > +static int iothread_holder_compare(const IOThreadHolder *holder_a, >> > + const IOThreadHolder *holder_b) >> > +{ >> > + const char *name_a, *name_b; >> > + >> > + if (holder_a->type !=3D holder_b->type) { >> > + return holder_a->type - holder_b->type; >> >> Why did you swap the operands in v13? Not mentioned in the cover >> letter's change log. I requested the other order in review of v8[*] and >> v9, and you complied in v10. Unless you have a compelling reason, swap >> them right back, please. >> >> In general, rocking the boat like this when you're at v13 is >> inadvisable. It risks delaying the series even more and annoying >> reviewers. > > Please allow me to explain the details, I have always respected the > opinions of the community. > Yes, I remember your comments in V9 and I fixed it. This change wasn't > something I made secretly or accidentally. > However, Stefan gave the opposite opinion in the V12, and I see you > didn't object, I didn't see it. Sadly, I can't follow the entire discussion of every version of every series I comment on. When reviewer A asks you to change something, and reviewer B later asks you to change it again, there's a conflict. If A is aware and remains silent, that may be taken as assent. But is A aware? Better ask to make sure. > so it was changed according to his suggestion. This might be a misunderst= anding. It is. Go with your current version. > https://lists.gnu.org/archive/html/qemu-devel/2026-08/msg05089.html > > I look forward to your reply so we can discuss this issue clearly. > > Thanks > Chen [...]