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 7C1DAC61DB6 for ; Tue, 25 Aug 2026 08:17:46 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wymLD-0000Js-8b; Tue, 25 Aug 2026 04:17:07 -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 1wymLB-0000Jd-LQ for qemu-devel@nongnu.org; Tue, 25 Aug 2026 04:17:05 -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 1wymLA-0002F9-1b for qemu-devel@nongnu.org; Tue, 25 Aug 2026 04:17:05 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1787645820; 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: in-reply-to:in-reply-to:references:references; bh=YLxEHNEb8QwCgk/DLTCRXq7gC4OckZkBoij29RBa9bU=; b=W1aaSqByCZlJYgJnB4sJGDT0KrdgYJvrkTIKjYzWTZixpMJGPEqJ7Oj2nde+mp0oH2HFSU iJC9uc4kmtASM+ZZJmtJYDjw9Me162oQMnLj3B60lO+Ph0PDrQNGKAnVa+GDgKViExUQUA rr89zFN6oBrB/lAcAUveaioHYj6BeXY= 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-35-tnoNNsTDO_mMbS3u1eLl6w-1; Tue, 25 Aug 2026 04:16:57 -0400 X-MC-Unique: tnoNNsTDO_mMbS3u1eLl6w-1 X-Mimecast-MFC-AGG-ID: tnoNNsTDO_mMbS3u1eLl6w_1787645816 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (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 64C65186A6E1; Tue, 25 Aug 2026 08:16:56 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.44.22.12]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id DD652195604A; Tue, 25 Aug 2026 08:16:55 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 5293921E6920; Tue, 25 Aug 2026 10:16:53 +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: <20260822213343.661939-3-zhangckid@gmail.com> (Zhang Chen's message of "Sun, 23 Aug 2026 05:33:25 +0800") References: <20260822213343.661939-1-zhangckid@gmail.com> <20260822213343.661939-3-zhangckid@gmail.com> Date: Tue, 25 Aug 2026 10:16:53 +0200 Message-ID: <874igipqbu.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 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: > 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. [...] > 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, holder)); > +} > + > +static int iothread_holder_compare(const IOThreadHolder *holder_a, > + const IOThreadHolder *holder_b) > +{ > + const char *name_a, *name_b; > + > + if (holder_a->type != 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. > + } > + > + switch (holder_a->type) { > + case IO_THREAD_HOLDER_KIND_QOM_OBJECT: > + name_a = holder_a->u.qom_object.qom_path; > + name_b = holder_b->u.qom_object.qom_path; > + break; > + case IO_THREAD_HOLDER_KIND_BLOCK_EXPORT: > + name_a = holder_a->u.block_export.export_id; > + name_b = holder_b->u.block_export.export_id; > + break; > + default: > + g_assert_not_reached(); > + } > + > + return strcmp(name_a, name_b); > +} [...] [*] Here's my review of v8: Date: Tue, 02 Jun 2026 13:29:19 +0200 Message-ID: <87tsrl2nao.fsf@pond.sub.org> https://lore.kernel.org/qemu-devel/87tsrl2nao.fsf@pond.sub.org