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Date:   Wed, 8 Apr 2020 19:28:02 -0700
From:   Jaegeuk Kim <jaegeuk@kernel.org>
To:     Chao Yu <yuchao0@huawei.com>
Cc:     linux-kernel@vger.kernel.org,
        linux-f2fs-devel@lists.sourceforge.net, kernel-team@android.com
Subject: Re: [f2fs-dev] [PATCH] f2fs: introduce sysfs/data_io_flag to attach
 REQ_META/FUA
Message-ID: <20200409022802.GC110440@google.com>
References: <20200403161249.68385-1-jaegeuk@kernel.org>
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 <2ca452cd-073a-29fa-1884-99ad1199bb97@huawei.com>
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 <69df999a-1df2-595e-579d-a8c3fc700d7b@huawei.com>
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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?

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