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Date: Wed, 2 Oct 2024 17:19:49 +0200
From: Christoph Hellwig <hch@lst.de>
To: Keith Busch <kbusch@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
	Kanchan Joshi <joshi.k@samsung.com>, hare@suse.de, sagi@grimberg.me,
	martin.petersen@oracle.com, brauner@kernel.org,
	viro@zeniv.linux.org.uk, jack@suse.cz, jaegeuk@kernel.org,
	bcrl@kvack.org, dhowells@redhat.com, bvanassche@acm.org,
	asml.silence@gmail.com, linux-nvme@lists.infradead.org,
	linux-fsdevel@vger.kernel.org, io-uring@vger.kernel.org,
	linux-block@vger.kernel.org, linux-aio@kvack.org,
	gost.dev@samsung.com, vishak.g@samsung.com, javier.gonz@samsung.com
Subject: Re: [PATCH v7 0/3] FDP and per-io hints
Message-ID: <20241002151949.GA20877@lst.de>
References: <CGME20240930182052epcas5p37edefa7556b87c3fbb543275756ac736@epcas5p3.samsung.com> <20240930181305.17286-1-joshi.k@samsung.com> <20241001092047.GA23730@lst.de> <99c95f26-d6fb-4354-822d-eac94fdba765@kernel.dk> <20241002075140.GB20819@lst.de> <f14a246b-10bf-40c1-bf8f-19101194a6dc@kernel.dk> <20241002151344.GA20364@lst.de> <Zv1kD8iLeu0xd7eP@kbusch-mbp.dhcp.thefacebook.com>
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User-Agent: Mutt/1.5.17 (2007-11-01)

On Wed, Oct 02, 2024 at 09:17:35AM -0600, Keith Busch wrote:
> On Wed, Oct 02, 2024 at 05:13:44PM +0200, Christoph Hellwig wrote:
> > 
> > Well, he finally started on the right approach and gave it up after the
> > first round of feedback.  That's just a bit weird.
> 
> Nothing prevents future improvements in that direction. It just seems
> out of scope for what Kanchan is trying to enable for his customer use
> cases. This patch looks harmless.

It's not really.  Once we wire it up like this we mess up the ability
to use the feature in other ways.  Additionally the per-I/O hints are
simply broken if you want a file system in the way as last time,
and if I don't misremember you acknowledged in person last week.