From: Matthew Wilcox <willy@infradead.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org, Jeff Layton <jlayton@kernel.org>,
Chris Mason <clm@fb.com>
Subject: Re: [PATCH v2 6/9] iomap,xfs: Convert from readpages to readahead
Date: Fri, 24 Jan 2020 14:53:21 -0800 [thread overview]
Message-ID: <20200124225321.GM4675@bombadil.infradead.org> (raw)
In-Reply-To: <20200115074243.GA31744@bombadil.infradead.org>
On Tue, Jan 14, 2020 at 11:42:43PM -0800, Matthew Wilcox wrote:
> On Tue, Jan 14, 2020 at 11:16:28PM -0800, Christoph Hellwig wrote:
> > On Tue, Jan 14, 2020 at 06:38:40PM -0800, Matthew Wilcox wrote:
> > > +iomap_readahead(struct address_space *mapping, pgoff_t start,
> > > unsigned nr_pages, const struct iomap_ops *ops)
> > > {
> > > struct iomap_readpage_ctx ctx = {
> > > - .pages = pages,
> > > .is_readahead = true,
> > > };
> > > - loff_t pos = page_offset(list_entry(pages->prev, struct page, lru));
> > > - loff_t last = page_offset(list_entry(pages->next, struct page, lru));
> > > - loff_t length = last - pos + PAGE_SIZE, ret = 0;
> > > + loff_t pos = start * PAGE_SIZE;
> > > + loff_t length = nr_pages * PAGE_SIZE;
> >
> > Any good reason not to pass byte offsets for start and length?
> >
> > > + return length / PAGE_SIZE;
> >
> > Same for the return value?
> >
> > For the file systems that would usually be a more natural interface than
> > a page index and number of pages.
>
> That seems to depend on the filesystem. iomap definitely would be happier
> with loff_t, but cifs prefers pgoff_t. I should probably survey a few
> more filesystems and see if there's a strong lean in one direction or
> the other.
I've converted all the filesystems now except for those that use fscache.
http://git.infradead.org/users/willy/linux-dax.git/shortlog/refs/heads/readahead
iomap is the only one for which an loff_t makes sense as an argument.
fscache will also prefer page index & count once Dave's conversion series
lands:
https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/commit/?h=fscache-iter&id=ae317744dfb9732123e554467a9f6d93733e8a5b
I'll prep a serious conversion series for 5.6 soon (skipping cifs, but
converting all the non-fscache filesystems).
next prev parent reply other threads:[~2020-01-24 22:53 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-15 2:38 [RFC v2 0/9] Replacing the readpages a_op Matthew Wilcox
2020-01-15 2:38 ` [PATCH v2 1/9] mm: Fix the return type of __do_page_cache_readahead Matthew Wilcox
2020-01-15 2:38 ` [PATCH v2 2/9] readahead: Ignore return value of ->readpages Matthew Wilcox
2020-01-15 2:38 ` [PATCH v2 3/9] XArray: Add xarray_for_each_range Matthew Wilcox
2020-01-15 2:38 ` [PATCH v2 4/9] readahead: Put pages in cache earlier Matthew Wilcox
2020-01-15 2:38 ` [PATCH v2 5/9] mm: Add readahead address space operation Matthew Wilcox
2020-01-15 2:38 ` [PATCH v2 6/9] iomap,xfs: Convert from readpages to readahead Matthew Wilcox
2020-01-15 7:16 ` Christoph Hellwig
2020-01-15 7:42 ` Matthew Wilcox
2020-01-24 22:53 ` Matthew Wilcox [this message]
2020-01-15 2:38 ` [PATCH v2 7/9] cifs: " Matthew Wilcox
2020-01-15 2:38 ` [PATCH v2 8/9] mm: Remove add_to_page_cache_locked Matthew Wilcox
2020-01-15 2:38 ` [PATCH v2 9/9] mm: Unify all add_to_page_cache variants Matthew Wilcox
2020-01-15 7:20 ` Christoph Hellwig
2020-01-15 7:44 ` Matthew Wilcox
2020-01-18 23:13 ` [RFC v2 0/9] Replacing the readpages a_op Matthew Wilcox
2020-01-21 11:36 ` Jan Kara
2020-01-21 21:48 ` Matthew Wilcox
2020-01-22 9:44 ` Jan Kara
2020-01-23 10:31 ` Jan Kara
2020-01-22 23:47 ` Dave Chinner
2020-01-23 10:21 ` Jan Kara
2020-01-23 22:29 ` Dave Chinner
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