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Subject: Re: [f2fs-dev] [PATCH] f2fs: introduce sysfs/data_io_flag to attach
 REQ_META/FUA
To:     Jaegeuk Kim <jaegeuk@kernel.org>
CC:     <linux-kernel@vger.kernel.org>,
        <linux-f2fs-devel@lists.sourceforge.net>, <kernel-team@android.com>
References: <20200403161249.68385-1-jaegeuk@kernel.org>
 <0e627c29-7fb0-5bd6-c1d9-b96a94df62ae@huawei.com>
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 <2ca452cd-073a-29fa-1884-99ad1199bb97@huawei.com>
 <20200409022005.GA110440@google.com>
 <69df999a-1df2-595e-579d-a8c3fc700d7b@huawei.com>
 <20200409022802.GC110440@google.com>
From:   Chao Yu <yuchao0@huawei.com>
Message-ID: <edf76981-d427-bea7-81c5-531878112443@huawei.com>
Date:   Thu, 9 Apr 2020 10:31:48 +0800
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On 2020/4/9 10:28, Jaegeuk Kim wrote:
> On 04/09, Chao Yu wrote:
>> On 2020/4/9 10:20, Jaegeuk Kim wrote:
>>> On 04/07, Chao Yu wrote:
>>>> On 2020/4/7 10:59, Jaegeuk Kim wrote:
>>>>> On 04/07, Chao Yu wrote:
>>>>>> On 2020/4/4 0:12, Jaegeuk Kim wrote:
>>>>>>> This patch introduces a way to attach REQ_META/FUA explicitly
>>>>>>> to all the data writes given temperature.
>>>>>>>
>>>>>>> -> attach REQ_FUA to Hot Data writes
>>>>>>>
>>>>>>> -> attach REQ_FUA to Hot|Warm Data writes
>>>>>>>
>>>>>>> -> attach REQ_FUA to Hot|Warm|Cold Data writes
>>>>>>>
>>>>>>> -> attach REQ_FUA to Hot|Warm|Cold Data writes as well as
>>>>>>>           REQ_META to Hot Data writes
>>>>>>
>>>>>> Out of curiosity, what scenario it is used for?
>>>>>
>>>>> It's testing purpose to compare the bandwidths per different IO flags.
>>>>
>>>> Thanks for the hint. :)
>>>>
>>>> As nobarrier was set in Android, so REQ_PREFLUSH will not be considered in
>>>> this sysfs interface?
>>>
>>> I don't see any diff on performance, so not interesting. :)
>>
>> I doubt it may has diff on non-ufs/emmc device? just guess.
> 
> I don't have any data on emmc, so maybe. Which case do we send REQ_PREFLUSH?

fsync w/ barrier mount option.

> 
>>
>> Thanks,
>>
>>>
>>>>
>>>> Thanks,
>>>>
>>>>>
>>>>>>
>>>>>> Thanks,
>>>>> .
>>>>>
>>> .
>>>
> .
>