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Date: Mon, 4 Mar 2024 16:38:31 +0100
From: "Pankaj Raghav (Samsung)" <kernel@pankajraghav.com>
To: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Matthew Wilcox <willy@infradead.org>, linux-fsdevel@vger.kernel.org, 
	linux-xfs@vger.kernel.org, djwong@kernel.org, mcgrof@kernel.org, linux-mm@kvack.org, 
	hare@suse.de, david@fromorbit.com, akpm@linux-foundation.org, 
	gost.dev@samsung.com, linux-kernel@vger.kernel.org, chandan.babu@oracle.com, 
	Pankaj Raghav <p.raghav@samsung.com>
Subject: Re: [PATCH v2 03/13] filemap: align the index to mapping_min_order
 in the page cache
Message-ID: <mu5ajujhqqlriqow5nehawhtr2ywqi67xjisgcxd5p2lacmsrp@jurev3lqvopc>
References: <20240301164444.3799288-1-kernel@pankajraghav.com>
 <20240301164444.3799288-4-kernel@pankajraghav.com>
 <ZeIr_2fiEpWLgmsv@casper.infradead.org>
 <c5rw63nyg2tdkgeuvriu74jjv2vszy2luorhmv3gb4uz2z4msz@2ktshazjwc2n>
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In-Reply-To: <c5rw63nyg2tdkgeuvriu74jjv2vszy2luorhmv3gb4uz2z4msz@2ktshazjwc2n>

On Fri, Mar 01, 2024 at 03:04:33PM -0500, Kent Overstreet wrote:
> On Fri, Mar 01, 2024 at 07:26:55PM +0000, Matthew Wilcox wrote:
> > On Fri, Mar 01, 2024 at 05:44:34PM +0100, Pankaj Raghav (Samsung) wrote:
> > > +#define DEFINE_READAHEAD_ALIGNED(ractl, f, r, m, i)			\
> > > +	struct readahead_control ractl = {				\
> > > +		.file = f,						\
> > > +		.mapping = m,						\
> > > +		.ra = r,						\
> > > +		._index = mapping_align_start_index(m, i),		\
> > > +	}
> > 
> > My point was that you didn't need to do any of this.
> > 
> > Look, I've tried to give constructive review, but I feel like I'm going
> > to have to be blunt.  There is no evidence of design or understanding
> > in these patches or their commit messages.  You don't have a coherent
> > message about "These things have to be aligned; these things can be at
> > arbitrary alignment".  If you have thought about it, it doesn't show.
> 
> Don't you think you might be going off a bit much? I looked over these
> patches after we talked privately, and they looked pretty sensible to
> me...
> 
> Yes, we _always_ want more thorough commit messages that properly
> explain the motivations for changes, but in my experience that's the
> thing that takes the longest to learn how to do well as an engineer...
> ease up abit.
> 
> > So, let's start off: Is the index in ractl aligned or not, and why do
> > you believe that's the right approach?  And review each of the patches
> > in this series with the answer to that question in mind because you are
> > currently inconsistent.
> 
> ^ this is a real point though, DEFINE_READAHEAD_ALIGNED() feels off to
> me.

Thanks Kent. I am going over the patches again and changing it based on
the feedback.