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From:   Coiby Xu <coiby.xu@gmail.com>
Date:   Tue, 22 Jun 2021 19:36:49 +0800
To:     Dan Carpenter <dan.carpenter@oracle.com>
Cc:     linux-staging@lists.linux.dev, netdev@vger.kernel.org,
        Benjamin Poirier <benjamin.poirier@gmail.com>,
        Shung-Hsi Yu <shung-hsi.yu@suse.com>,
        Manish Chopra <manishc@marvell.com>,
        "supporter:QLOGIC QLGE 10Gb ETHERNET DRIVER" 
        <GR-Linux-NIC-Dev@marvell.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        open list <linux-kernel@vger.kernel.org>
Subject: Re: [RFC 01/19] staging: qlge: fix incorrect truesize accounting
Message-ID: <20210622113649.vm2hfh2veqr4dq6y@Rk>
References: <20210621134902.83587-1-coiby.xu@gmail.com>
 <20210621134902.83587-2-coiby.xu@gmail.com>
 <20210621141027.GJ1861@kadam>
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On Mon, Jun 21, 2021 at 05:10:27PM +0300, Dan Carpenter wrote:
>On Mon, Jun 21, 2021 at 09:48:44PM +0800, Coiby Xu wrote:
>> Commit 7c734359d3504c869132166d159c7f0649f0ab34 ("qlge: Size RX buffers
>> based on MTU") introduced page_chunk structure. We should add
>> qdev->lbq_buf_size to skb->truesize after __skb_fill_page_desc.
>>
>
>Add a Fixes tag.

I will fix it in next version, thanks!

>
>The runtime impact of this is just that ethtool will report things
>incorrectly, right?  It's not 100% from the commit message.  Could you
>please edit the commit message so that an ignoramous like myself can
>understand it?

I'm not sure how it would affect ethtool. But according to "git log
--grep=truesize", it affects coalescing SKBs. Btw, I fixed the issue
according to the definition of truesize which according to Linux Kernel
Network by Rami Rosen, it's defined as follows,
> The total memory allocated for the SKB (including the SKB structure itself 
> and the size of the allocated data block).

I'll edit the commit message to include it, thanks!

>
>Why is this an RFC instead of just a normal patch which we can apply?

After doing the tests mentioned in the cover letter, I found Red Hat's 
network QE team has quite a rigorous test suite. But I needed to return 
the machine before having the time to learn about the test suite and run 
it by myself. So I mark it as an RFC before I borrow the machine again to 
run the test suite.

>
>regards,
>dan carpenter
>

-- 
Best regards,
Coiby