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Date:   Wed, 6 Dec 2023 23:47:13 -0800
From:   Christoph Hellwig <hch@infradead.org>
To:     Sergei Shtepa <sergei.shtepa@linux.dev>
Cc:     axboe@kernel.dk, hch@infradead.org, corbet@lwn.net,
        snitzer@kernel.org, mingo@redhat.com, peterz@infradead.org,
        juri.lelli@redhat.com, viro@zeniv.linux.org.uk, brauner@kernel.org,
        linux-block@vger.kernel.org, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        Sergei Shtepa <sergei.shtepa@veeam.com>
Subject: Re: [PATCH v6 10/11] blksnap: Kconfig and Makefile
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References: <20231124165933.27580-1-sergei.shtepa@linux.dev>
 <20231124165933.27580-11-sergei.shtepa@linux.dev>
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Precedence: bulk

> +config BLKSNAP_DIFF_BLKDEV
> +	bool "Use an optimized algorithm to store difference on a block device"
> +	depends on BLKSNAP
> +	default y
> +	help
> +	  The difference storage for a snapshot can be a regular file or a
> +	  block device. We can work with a block device through the interface
> +	  of a regular file. However, direct management of I/O units should
> +	  allow for higher performance.

Is there much of a point in making this option?

Btw, Linus hates defaul y, so we should not have one in there.

> +config BLKSNAP_CHUNK_DIFF_BIO_SYNC
> +	bool "Use a synchronous I/O unit processing algorithm for the snapshot image"
> +	depends on BLKSNAP
> +	default n

n the default default, so no need to add it.  But unless there is a
really good reason to have two different bio submission mechanisms
upstream I'd strongly suggest dropping one of them and this option.