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From: Matthew Wilcox <willy@infradead.org>
To: David Howells <dhowells@redhat.com>
Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 0/7] mm: Make more use of readahead_control
Date: Tue, 1 Sep 2020 17:48:27 +0100	[thread overview]
Message-ID: <20200901164827.GQ14765@casper.infradead.org> (raw)
In-Reply-To: <159897769535.405783.17587409235571100774.stgit@warthog.procyon.org.uk>

On Tue, Sep 01, 2020 at 05:28:15PM +0100, David Howells wrote:
> Here's a set of patches to expand the use of the readahead_control struct,
> essentially from do_sync_mmap_readahead() down.

I like this.

> Note that I've been
> passing the number of pages to read in rac->_nr_pages, and then saving it
> and changing it certain points, e.g. page_cache_readahead_unbounded().

I do not like this.  You're essentially mutating the meaning of _nr_pages
as the ractl moves down the stack, and that's going to lead to bugs.
I'd keep it as a separate argument.

> Also there's an apparent minor bug in khugepaged.c that I've included a
> patch for: page_cache_sync_readahead() looks to be given the wrong size in
> collapse_file().

This needs to go in as an independent fix.  But you didn't actually cc Song.

  parent reply	other threads:[~2020-09-01 16:48 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-01 16:28 [RFC PATCH 0/7] mm: Make more use of readahead_control David Howells
2020-09-01 16:28 ` [RFC PATCH 1/7] Fix khugepaged's request size in collapse_file() David Howells
2020-09-01 18:06   ` Song Liu
2020-09-01 16:28 ` [RFC PATCH 2/7] mm: Make ondemand_readahead() take a readahead_control struct David Howells
2020-09-01 16:28 ` [RFC PATCH 3/7] mm: Push readahead_control down into force_page_cache_readahead() David Howells
2020-09-01 16:28 ` [RFC PATCH 4/7] mm: Pass readahead_control into page_cache_{sync,async}_readahead() David Howells
2020-09-01 16:28 ` [RFC PATCH 5/7] mm: Make __do_page_cache_readahead() use rac->_nr_pages David Howells
2020-09-01 16:28 ` [RFC PATCH 6/7] mm: Fold ra_submit() into do_sync_mmap_readahead() David Howells
2020-09-01 16:29 ` [RFC PATCH 7/7] mm: Pass a file_ra_state struct into force_page_cache_readahead() David Howells
2020-09-01 16:41 ` [RFC PATCH 0/7] mm: Make more use of readahead_control Eric Biggers
2020-09-01 16:45   ` Matthew Wilcox
2020-09-02 15:42   ` David Howells
2020-09-01 16:48 ` Matthew Wilcox [this message]
2020-09-01 19:40 ` David Howells
2020-09-01 19:44 ` David Howells
2020-09-01 22:33   ` Matthew Wilcox

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