Date:   Wed, 10 Nov 2021 11:08:54 -0800
From:   Jaegeuk Kim <jaegeuk@kernel.org>
To:     Jens Axboe <axboe@kernel.dk>
Cc:     Christoph Hellwig <hch@infradead.org>,
        linux-kernel@vger.kernel.org,
        linux-f2fs-devel@lists.sourceforge.net,
        linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH] f2fs: provide a way to attach HIPRI for Direct IO
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On 11/09, Jens Axboe wrote:
> On 11/9/21 9:39 AM, Christoph Hellwig wrote:
> > On Mon, Nov 08, 2021 at 06:13:36PM -0800, Jaegeuk Kim wrote:
> >> This patch adds a way to attach HIPRI by expanding the existing sysfs's
> >> data_io_flag. User can measure IO performance by enabling it.
> > 
> > NAK.  This flag should only be used when explicitly specified by
> > the submitter of the I/O.
> 
> Yes, this cannot be set in the middle for a multitude of reasons. I wonder
> if we should add a comment to that effect near the definition of it.

Not surprising. I was wondering we can add this for testing purpose only.
Btw, is there a reasonable way that filesystem can use IO polling?

> 
> -- 
> Jens Axboe