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Subject: Re: [PATCH v8] bio: limit bio max size
To:     Changheun Lee <nanich.lee@samsung.com>, Johannes.Thumshirn@wdc.com,
        asml.silence@gmail.com, axboe@kernel.dk, damien.lemoal@wdc.com,
        gregkh@linuxfoundation.org, hch@infradead.org,
        linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
        ming.lei@redhat.com, osandov@fb.com, patchwork-bot@kernel.org,
        tj@kernel.org, tom.leiming@gmail.com
Cc:     jisoo2146.oh@samsung.com, junho89.kim@samsung.com,
        mj0123.lee@samsung.com, seunghwan.hyun@samsung.com,
        sookwan7.kim@samsung.com, woosung2.lee@samsung.com,
        yt0928.kim@samsung.com
References: <CGME20210421100544epcas1p13c2c86e84102f0955dd591f72e45756a@epcas1p1.samsung.com>
 <20210421094745.29660-1-nanich.lee@samsung.com>
From:   Bart Van Assche <bvanassche@acm.org>
Message-ID: <8799c4da-a07f-1837-2fa8-f968469742f0@acm.org>
Date:   Thu, 22 Apr 2021 13:33:10 -0700
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On 4/21/21 2:47 AM, Changheun Lee wrote:
> bio size can grow up to 4GB when muli-page bvec is enabled.
> but sometimes it would lead to inefficient behaviors.
> in case of large chunk direct I/O, - 32MB chunk read in user space -
> all pages for 32MB would be merged to a bio structure if the pages
> physical addresses are contiguous. it makes some delay to submit
> until merge complete. bio max size should be limited to a proper size.

Hi Christoph, Ming and Damien,

Can one of you take a look at this patch?

Thanks,

Bart.