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Sender: Tejun Heo <htejun@gmail.com>
Date: Wed, 1 May 2024 06:49:53 -1000
From: Tejun Heo <tj@kernel.org>
To: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: willy@infradead.org, akpm@linux-foundation.org, jack@suse.cz,
	linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 02/10] writeback: add general function domain_dirty_avail
 to calculate dirty and avail of domain
Message-ID: <ZjJysTZO6IOpe4BT@slm.duckdns.org>
References: <20240429034738.138609-1-shikemeng@huaweicloud.com>
 <20240429034738.138609-3-shikemeng@huaweicloud.com>
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In-Reply-To: <20240429034738.138609-3-shikemeng@huaweicloud.com>

Hello,

On Mon, Apr 29, 2024 at 11:47:30AM +0800, Kemeng Shi wrote:
> +/*
> + * Dirty background will ignore pages being written as we're trying to
> + * decide whether to put more under writeback.
> + */
> +static void domain_dirty_avail(struct dirty_throttle_control *dtc, bool bg)

I wonder whether it'd be better if the bool arg is flipped to something like
`bool include_writeback` so that it's clear what the difference is between
the two. Also, do global_domain_dirty_avail() and wb_domain_dirty_avail()
have to be separate functions? They seem trivial enough to include into the
body of domain_dirty_avail(). Are they used directly elsewhere?

> +{
> +	struct dirty_throttle_control *gdtc = mdtc_gdtc(dtc);
> +
> +	if (gdtc)

I know this test is used elsewhere but it isn't the most intuitive. Would it
make sense to add dtc_is_global() (or dtc_is_gdtc()) helper instead?

> +		wb_domain_dirty_avail(dtc, bg);
> +	else
> +		global_domain_dirty_avail(dtc, bg);
> +}

Thanks.

-- 
tejun