Re: Convert write_cache_pages() to an iterator v3

From: Dave Chinner <david@fromorbit.com>
To: Christoph Hellwig <hch@lst.de>
Cc: linux-mm@kvack.org,
	"Matthew Wilcox (Oracle)" <willy@infradead.org>,
	Jan Kara <jack@suse.com>, David Howells <dhowells@redhat.com>,
	Brian Foster <bfoster@redhat.com>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: Convert write_cache_pages() to an iterator v3
Date: Tue, 19 Dec 2023 08:00:52 +1100	[thread overview]
Message-ID: <ZYCzBCqetc+tLmq+@dread.disaster.area> (raw)
In-Reply-To: <20231218153553.807799-1-hch@lst.de>

On Mon, Dec 18, 2023 at 04:35:36PM +0100, Christoph Hellwig wrote:
> Hi all,
> 
> this is basically a evolution of the series Matthew Wilcox originally
> set in June.  Based on comments from Jan a Brian this now actually
> untangles some of the more confusing conditional in the writeback code
> before refactoring it into the iterator.  Because of that all the
> later patches need a fair amount of rebasing and I've not carried any
> reviewed-by over.
> 
> The original cover letter is below:
> 
> Dave Howells doesn't like the indirect function call imposed by
> write_cache_pages(), so refactor it into an iterator.  I took the
> opportunity to add the ability to iterate a folio_batch without having
> an external variable.
> 
> This is against next-20230623.  If you try to apply it on top of a tree
> which doesn't include the pagevec removal series, IT WILL CRASH because
> it won't reinitialise folio_batch->i and the iteration will index out
> of bounds.
> 
> I have a feeling the 'done' parameter could have a better name, but I
> can't think what it might be.
> 
> Diffstat:
>  include/linux/pagevec.h   |   18 ++
>  include/linux/writeback.h |   19 ++
>  mm/page-writeback.c       |  333 +++++++++++++++++++++++++---------------------
>  3 files changed, 220 insertions(+), 150 deletions(-)

I've just done a quick scan of the code - nothing stands out to me
as problematic, and I like how much cleaner the result is.

Acked-by: Dave Chinner <dchinner@redhat.com>

-- 
Dave Chinner
david@fromorbit.com