Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <49006cf2-1f54-d53d-4f8a-0c1dfae9aa28@huawei.com>
Date:   Sun, 13 Nov 2022 21:49:32 +0800
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101
 Thunderbird/91.7.0
Subject: Re: [RFC 0/4] pci/sriov: support VFs dynamic addition
To:     Bjorn Helgaas <helgaas@kernel.org>
CC:     <bhelgaas@google.com>, <linux-pci@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <jianjay.zhou@huawei.com>,
        <zhuangshengen@huawei.com>, <arei.gonglei@huawei.com>,
        <yechuan@huawei.com>, <huangzhichao@huawei.com>,
        <xiehong@huawei.com>
References: <20221111230703.GA759162@bhelgaas>
From:   "Longpeng (Mike, Cloud Infrastructure Service Product Dept.)" 
        <longpeng2@huawei.com>
In-Reply-To: <20221111230703.GA759162@bhelgaas>
Content-Type: text/plain; charset="UTF-8"; format=flowed
Content-Transfer-Encoding: 8bit
Precedence: bulk


在 2022/11/12 7:07, Bjorn Helgaas 写道:
> On Fri, Nov 11, 2022 at 10:27:18PM +0800, Longpeng(Mike) wrote:
>> From: Longpeng <longpeng2@huawei.com>
>>
>> We can enable SRIOV and add VFs by /sys/bus/pci/devices/..../sriov_numvfs, but
>> this operation needs to spend lots of time if there has a large amount of VFs.
>>                                                              
>> For example, if the machine has 10 PFs and 250 VFs per-PF, enable all the VFs
>> concurrently would cost about 200-250ms. However most of them are not need to be
>> used at the moment, so we can enable SRIOV first but add VFs on demand.
>>
>> This series introduces two interfaces:
>> 1. sriov_numvfs_no_scan: enable SRIOV without add the VFs.
>> 2. sriov_scan_vf_id: add a specific VF.
>>
>> Longpeng (4):
>>    pci/sriov: extract sriov_numvfs common helper
>>    pci/sriov: add vf_bitmap to mark the vf id allocation
>>    pci/sriov: add sriov_numfs_no_scan interface
>>    pci/sriov: add sriov_scan_vf_id interface
> 
> When you respond to Leon's questions, please also spend a little time
> to look at the iov.c history and coding style and follow it, so we
> don't have to waste time commenting on or fixing trivial things.
> 
Okay, thanks for your valuable suggestions.

> For example, there are no previous subject lines for that file that
> start with "pci/sriov".  Don't make up a new prefix; use what's been
> done in the past.  And follow the style of capitalizing the first word
> after the prefix.
> 
> There are a few comments that look like they are more than 80 columns.
> Again unlike everything else in the file.
> 
> The PCIe spec spells it "SR-IOV", not "sriov".  Do the same in your
> commit logs and comments.
> 
> Capitalize "VF" consistently.  I see "VF" and "vf" used randomly.
> 
> Sysfs changes require documention updates, e.g., in
> Documentation/ABI/testing/sysfs-bus-pci.
> .