From: Matthew Wilcox <willy@infradead.org>
To: "Pankaj Raghav (Samsung)" <kernel@pankajraghav.com>
Cc: david@fromorbit.com, djwong@kernel.org, hch@lst.de,
Keith Busch <kbusch@kernel.org>,
mcgrof@kernel.org, akpm@linux-foundation.org, brauner@kernel.org,
chandan.babu@oracle.com, gost.dev@samsung.com, hare@suse.de,
john.g.garry@oracle.com, linux-block@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
linux-xfs@vger.kernel.org, p.raghav@samsung.com,
ritesh.list@gmail.com, ziy@nvidia.com
Subject: Re: [RFC] iomap: use huge zero folio in iomap_dio_zero
Date: Wed, 15 May 2024 19:03:20 +0100 [thread overview]
Message-ID: <ZkT46AsZ3WghOArL@casper.infradead.org> (raw)
In-Reply-To: <20240515155943.2uaa23nvddmgtkul@quentin>
On Wed, May 15, 2024 at 03:59:43PM +0000, Pankaj Raghav (Samsung) wrote:
> static int __init iomap_init(void)
> {
> + void *addr = kzalloc(16 * PAGE_SIZE, GFP_KERNEL);
Don't use XFS coding style outside XFS.
kzalloc() does not guarantee page alignment much less alignment to
a folio. It happens to work today, but that is an implementation
artefact.
> +
> + if (!addr)
> + return -ENOMEM;
> +
> + zero_fsb_folio = virt_to_folio(addr);
We also don't guarantee that calling kzalloc() gives you a virtual
address that can be converted to a folio. You need to allocate a folio
to be sure that you get a folio.
Of course, you don't actually need a folio. You don't need any of the
folio metadata and can just use raw pages.
> + /*
> + * The zero folio used is 64k.
> + */
> + WARN_ON_ONCE(len > (16 * PAGE_SIZE));
PAGE_SIZE is not necessarily 4KiB.
> + bio = iomap_dio_alloc_bio(iter, dio, BIO_MAX_VECS,
> + REQ_OP_WRITE | REQ_SYNC | REQ_IDLE);
The point was that we now only need one biovec, not MAX.
next prev parent reply other threads:[~2024-05-15 18:03 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-03 9:53 [PATCH v5 00/11] enable bs > ps in XFS Luis Chamberlain
2024-05-03 9:53 ` [PATCH v5 01/11] readahead: rework loop in page_cache_ra_unbounded() Luis Chamberlain
2024-05-03 9:53 ` [PATCH v5 02/11] fs: Allow fine-grained control of folio sizes Luis Chamberlain
2024-05-03 9:53 ` [PATCH v5 03/11] filemap: allocate mapping_min_order folios in the page cache Luis Chamberlain
2024-05-03 9:53 ` [PATCH v5 04/11] readahead: allocate folios with mapping_min_order in readahead Luis Chamberlain
2024-05-03 14:32 ` Hannes Reinecke
2024-05-03 9:53 ` [PATCH v5 05/11] mm: split a folio in minimum folio order chunks Luis Chamberlain
2024-05-03 14:53 ` Zi Yan
2024-05-15 15:32 ` Matthew Wilcox
2024-05-16 14:56 ` Pankaj Raghav (Samsung)
2024-05-03 9:53 ` [PATCH v5 06/11] filemap: cap PTE range to be created to allowed zero fill in folio_map_range() Luis Chamberlain
2024-05-03 9:53 ` [PATCH v5 07/11] iomap: fix iomap_dio_zero() for fs bs > system page size Luis Chamberlain
2024-05-07 14:58 ` [RFC] iomap: use huge zero folio in iomap_dio_zero Pankaj Raghav (Samsung)
2024-05-07 15:11 ` Zi Yan
2024-05-07 16:11 ` Christoph Hellwig
2024-05-08 11:39 ` Pankaj Raghav (Samsung)
2024-05-08 11:43 ` Christoph Hellwig
2024-05-09 12:31 ` Pankaj Raghav (Samsung)
2024-05-09 12:46 ` Christoph Hellwig
2024-05-09 12:55 ` Pankaj Raghav (Samsung)
2024-05-09 12:58 ` Christoph Hellwig
2024-05-09 14:32 ` Darrick J. Wong
2024-05-09 15:05 ` Christoph Hellwig
2024-05-09 15:08 ` Darrick J. Wong
2024-05-09 15:09 ` Christoph Hellwig
2024-05-15 0:50 ` Matthew Wilcox
2024-05-15 2:34 ` Keith Busch
2024-05-15 4:04 ` Matthew Wilcox
2024-05-15 15:59 ` Pankaj Raghav (Samsung)
2024-05-15 18:03 ` Matthew Wilcox [this message]
2024-05-16 15:02 ` Pankaj Raghav (Samsung)
2024-05-17 12:36 ` Hannes Reinecke
2024-05-17 12:56 ` Hannes Reinecke
2024-05-17 13:30 ` Matthew Wilcox
2024-05-15 11:48 ` Christoph Hellwig
2024-05-07 16:00 ` [PATCH v5 07/11] iomap: fix iomap_dio_zero() for fs bs > system page size Matthew Wilcox
2024-05-07 16:10 ` Christoph Hellwig
2024-05-07 16:11 ` Matthew Wilcox
2024-05-07 16:13 ` Christoph Hellwig
2024-05-08 4:24 ` Matthew Wilcox
2024-05-08 11:22 ` Pankaj Raghav (Samsung)
2024-05-08 11:36 ` Christoph Hellwig
2024-05-08 11:20 ` Pankaj Raghav (Samsung)
2024-05-03 9:53 ` [PATCH v5 08/11] xfs: use kvmalloc for xattr buffers Luis Chamberlain
2024-05-03 9:53 ` [PATCH v5 09/11] xfs: expose block size in stat Luis Chamberlain
2024-05-03 9:53 ` [PATCH v5 10/11] xfs: make the calculation generic in xfs_sb_validate_fsb_count() Luis Chamberlain
2024-05-07 8:40 ` John Garry
2024-05-07 21:13 ` Darrick J. Wong
2024-05-08 11:28 ` Pankaj Raghav (Samsung)
2024-05-03 9:53 ` [PATCH v5 11/11] xfs: enable block size larger than page size support Luis Chamberlain
2024-05-07 0:05 ` Dave Chinner
-- strict thread matches above, loose matches on Subject: below --
2024-05-07 18:38 [RFC] iomap: use huge zero folio in iomap_dio_zero Ritesh Harjani
2024-05-08 11:42 ` Christoph Hellwig
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