linux-kernel - Re: [PATCH RFC v3 03/15] md: fix mssing blktrace bio split events

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Message-ID: <0431e4f2-5e9a-b172-bb65-3d355232e831@huaweicloud.com>
Date: Mon, 1 Sep 2025 15:53:43 +0800
From: Yu Kuai <yukuai1@...weicloud.com>
To: Damien Le Moal <dlemoal@...nel.org>, Yu Kuai <yukuai1@...weicloud.com>,
 hch@...radead.org, colyli@...nel.org, hare@...e.de, tieren@...as.com,
 axboe@...nel.dk, tj@...nel.org, josef@...icpanda.com, song@...nel.org,
 kmo@...erainc.com, satyat@...gle.com, ebiggers@...gle.com, neil@...wn.name,
 akpm@...ux-foundation.org
Cc: linux-block@...r.kernel.org, linux-kernel@...r.kernel.org,
 cgroups@...r.kernel.org, linux-raid@...r.kernel.org, yi.zhang@...wei.com,
 yangerkun@...wei.com, johnny.chenyi@...wei.com,
 "yukuai (C)" <yukuai3@...wei.com>
Subject: Re: [PATCH RFC v3 03/15] md: fix mssing blktrace bio split events

Hi,

在 2025/09/01 14:30, Damien Le Moal 写道:
> On 9/1/25 12:32 PM, Yu Kuai wrote:
>> From: Yu Kuai <yukuai3@...wei.com>
>>
>> If bio is split by internal chunksize of badblocks, the corresponding
> 
> badblocks ? Unclear.

This is due to raid1/10/5 internal processing, if read/write range
contain badblocks that are recorded in rdev, this bio will be split to
bypass the badblocks range, an example from raid1 is choose_bb_rdev()
will update max_sectors from read_balance(), and caller will split bio
by max_sectors.
> 
>> trace_block_split() is missing, causing blktrace can't catch the split
>> events and make it hader to analyze IO behavior.
> 
> maybe:
> 
> trace_block_split() is missing, resulting in blktrace inability to catch BIO
> split events and making it harder to analyze the BIO sequence.
> 
> would be better.
> 
OK,

>>
>> Fixes: 4b1faf931650 ("block: Kill bio_pair_split()")
> 
> Missing Cc: stable@...r.kernel.org
> 
>> Signed-off-by: Yu Kuai <yukuai3@...wei.com>
> 
> With that,
> 
> Reviewed-by: Damien Le Moal <dlemoal@...nel.org>
> 
> (maybe drop the RFC on this patch series ? Sending a review tag for RFC patches
> is odd...)

Yes, I'll send the next version without RFC now. :)

Thanks,
Kuai

>