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 34001C4332F for ; Fri, 11 Nov 2022 09:34:37 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1otQQW-00026B-AN; Fri, 11 Nov 2022 04:34:20 -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 1otQQT-00021m-Or for qemu-devel@nongnu.org; Fri, 11 Nov 2022 04:34:17 -0500 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 1otQQS-00040S-1r for qemu-devel@nongnu.org; Fri, 11 Nov 2022 04:34:17 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1668159254; 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=AvcYP2cIY2OkqaJn/h4ppD3BPnevV1wj+dJSx9KvoWg=; b=PNWIJruMW66FmdiwPszeDqWIDT8F/ED+6xHsMt9/k1/+ddqnMuJLd2SOkc15uaTVuRvLQI /fl28Xw2guIKaiFbNmJdJJJfZFRWHVYLFD8ixDBDHFR16S9fIWJTB6p9VXUiNNQvK5sj5c BueS7NXHubmLhOOsm9FBuqYMtHewkvY= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-288-jMyfg9phO-qNXhzND3yc_A-1; Fri, 11 Nov 2022 04:34:13 -0500 X-MC-Unique: jMyfg9phO-qNXhzND3yc_A-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 9EA80382F654; Fri, 11 Nov 2022 09:34:12 +0000 (UTC) Received: from [10.67.24.81] (unknown [10.67.24.81]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E75081401C29; Fri, 11 Nov 2022 09:34:08 +0000 (UTC) Subject: Re: [PATCH v3] qapi/qom: Memory backend property prealloc-threads doc fix To: Igor Mammedov , Markus Armbruster Cc: Zhenyu Zhang , qemu-devel@nongnu.org, philmd@linaro.org, shan.gavin@gmail.com, eric.auger@redhat.com, lijin@redhat.com References: <20221111030541.191186-1-zhenyzha@redhat.com> <87bkpedm2z.fsf@pond.sub.org> <20221111101310.47bdced9@imammedo.users.ipa.redhat.com> From: Gavin Shan Message-ID: <98a4d569-b81e-b3e3-f011-82ef19eeb5df@redhat.com> Date: Fri, 11 Nov 2022 17:34:04 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.0 MIME-Version: 1.0 In-Reply-To: <20221111101310.47bdced9@imammedo.users.ipa.redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 3.1 on 10.11.54.7 Received-SPF: pass client-ip=170.10.133.124; envelope-from=gshan@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, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, 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: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Gavin Shan Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 11/11/22 5:13 PM, Igor Mammedov wrote: > On Fri, 11 Nov 2022 07:47:16 +0100 > Markus Armbruster wrote: >> Gavin Shan writes: >>> On 11/11/22 11:05 AM, Zhenyu Zhang wrote: >>>> Commit ffac16fab3 "hostmem: introduce "prealloc-threads" property" >>>> (v5.0.0) changed the default number of threads from number of CPUs >>>> to 1. This was deemed a regression, and fixed in commit f8d426a685 >>>> "hostmem: default the amount of prealloc-threads to smp-cpus". >>>> Except the documentation remained unchanged. Update it now. >>>> Signed-off-by: Zhenyu Zhang >>>> --- >>>> v3: Covers historical descriptions (Markus) >>>> v2: The property is changed to smp-cpus since 5.0 (Phild) >>>> --- >>>> qapi/qom.json | 2 +- >>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>> >>> >>> With the following comments addressed: >>> >>> Reviewed-by: Gavin Shan >>> >>> --- >>> >>> Please consider amending the commit log to something like below. >>> >>> The default "prealloc-threads" value is set to 1 when the property is >>> added by commit ffac16fab33b ("hostmem: introduce "prealloc-threads" >>> property") in v5.0.0. The default value is conflicting with the sugar >>> property as the value provided by the sugar property is number of CPUs. >> >> What is the sugar property? Can you explain the conflict in a bit more >> detail? > > my guess is that Gavin means mem_prealloc compat glue in qemu_process_sugar_options() > > property value should be set according to following order > default -> compat -> explicit value > so I don't see any conflict here. > > PS: > if it we up to me, default would have stayed 1, > and prealloc-threads fixup to vCPUs number would happen in vl.c > similar to what is done in qemu_process_sugar_options(), > keeping backend clean of external dependencies. > Yes, it's the sugar property I was talking about. I'm not sure if we have a more popular name for this property: compat property or sugar property. When 'mem-prealloc=on' and 'prealloc-threads=xxx' aren't provided, the value is 1 before commit f8d426a6852c is applied. It's not inconsistent with 'mem-prealloc=on'. It's the conflict I was talking about and it's fixed by commit f8d426a6852c >> >>> The conflict has been fixed by commit f8d426a6852c ("hostmem: default >>> the amount of prealloc-threads to smp-cpus"). However, 'qapi/qom.json' >>> was missed to be updated accordingly in the commit. >>> >>> Update 'qapi/qom.json' to reflect the change in commit f8d426a6852c. >>> >>> Signed-off-by: Zhenyu Zhang >>> >>> When a specific commit is mentioned in the commit log, we usually have >>> fixed format like below. >>> >>> commit ffac16fab33b ("hostmem: introduce "prealloc-threads" property") >>> commit f8d426a6852c ("hostmem: default the amount of prealloc-threads to smp-cpus") >> >> This is certainly a common format, but the other one is also in use. >> >>>> diff --git a/qapi/qom.json b/qapi/qom.json >>>> index 30e76653ad..dfd89bc6d4 100644 >>>> --- a/qapi/qom.json >>>> +++ b/qapi/qom.json >>>> @@ -576,7 +576,7 @@ >>>> # >>>> # @prealloc: if true, preallocate memory (default: false) >>>> # >>>> -# @prealloc-threads: number of CPU threads to use for prealloc (default: 1) >>>> +# @prealloc-threads: number of CPU threads to use for prealloc (default: number of CPUs) (since 5.0) >>>> # >>>> # @prealloc-context: thread context to use for creation of preallocation threads >>>> # (default: none) (since 7.2) >>>> >>> >>> The line seems exceeding 80 characters. It'd better to limit each line in 75 characters. >>> So you probably need: >>> >>> # @prealloc-threads: number of CPU threads to use for prealloc (default: number of CPUs) >>> # (since 5.0) >> >> Still exceeds :) >> >> I suggested >> >> # @prealloc-threads: number of CPU threads to use for prealloc >> # (default: number of CPUs) (since 5.0) >> > Markus's suggestion works :) Thanks, Gavin