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Subject: Re: [PATCH 02/10] writeback: add general function domain_dirty_avail
 to calculate dirty and avail of domain
To: Tejun Heo <tj@kernel.org>
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
References: <20240429034738.138609-1-shikemeng@huaweicloud.com>
 <20240429034738.138609-3-shikemeng@huaweicloud.com>
 <ZjJysTZO6IOpe4BT@slm.duckdns.org>
From: Kemeng Shi <shikemeng@huaweicloud.com>
Message-ID: <d69093d9-0786-b16f-1ed9-7cc5e37791d9@huaweicloud.com>
Date: Mon, 6 May 2024 09:32:41 +0800
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on 5/2/2024 12:49 AM, Tejun Heo wrote:
> 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
Sure, I rename 'bool bg' to 'bool include_writeback'.
> 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?
I will fold global_domain_dirty_avail() and wb_domain_dirty_avail() and
just use domain_dirty_avail.
> 
>> +{
>> +	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?
Will add helper dtc_is_global().

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