From: Dave Chinner <david@fromorbit.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 14/36] iomap: Support large pages in iomap_adjust_read_range
Date: Fri, 22 May 2020 08:24:38 +1000 [thread overview]
Message-ID: <20200521222438.GT2005@dread.disaster.area> (raw)
In-Reply-To: <20200515131656.12890-15-willy@infradead.org>
On Fri, May 15, 2020 at 06:16:34AM -0700, Matthew Wilcox wrote:
> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
>
> Pass the struct page instead of the iomap_page so we can determine the
> size of the page. Use offset_in_thp() instead of offset_in_page() and use
> thp_size() instead of PAGE_SIZE.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---
> fs/iomap/buffered-io.c | 15 ++++++++-------
> 1 file changed, 8 insertions(+), 7 deletions(-)
>
> diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
> index 4a79061073eb..423ffc9d4a97 100644
> --- a/fs/iomap/buffered-io.c
> +++ b/fs/iomap/buffered-io.c
> @@ -83,15 +83,16 @@ iomap_page_release(struct page *page)
> * Calculate the range inside the page that we actually need to read.
> */
> static void
> -iomap_adjust_read_range(struct inode *inode, struct iomap_page *iop,
> +iomap_adjust_read_range(struct inode *inode, struct page *page,
> loff_t *pos, loff_t length, unsigned *offp, unsigned *lenp)
> {
> + struct iomap_page *iop = to_iomap_page(page);
> loff_t orig_pos = *pos;
> loff_t isize = i_size_read(inode);
> unsigned block_bits = inode->i_blkbits;
> unsigned block_size = (1 << block_bits);
> - unsigned poff = offset_in_page(*pos);
> - unsigned plen = min_t(loff_t, PAGE_SIZE - poff, length);
> + unsigned poff = offset_in_thp(page, *pos);
> + unsigned plen = min_t(loff_t, thp_size(page) - poff, length);
> unsigned first = poff >> block_bits;
> unsigned last = (poff + plen - 1) >> block_bits;
>
> @@ -129,7 +130,7 @@ iomap_adjust_read_range(struct inode *inode, struct iomap_page *iop,
> * page cache for blocks that are entirely outside of i_size.
> */
> if (orig_pos <= isize && orig_pos + length > isize) {
> - unsigned end = offset_in_page(isize - 1) >> block_bits;
> + unsigned end = offset_in_thp(page, isize - 1) >> block_bits;
>
> if (first <= end && last > end)
> plen -= (last - end) * block_size;
> @@ -256,7 +257,7 @@ iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
> }
>
> /* zero post-eof blocks as the page may be mapped */
> - iomap_adjust_read_range(inode, iop, &pos, length, &poff, &plen);
> + iomap_adjust_read_range(inode, page, &pos, length, &poff, &plen);
> if (plen == 0)
> goto done;
>
> @@ -571,7 +572,6 @@ static int
> __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, int flags,
> struct page *page, struct iomap *srcmap)
> {
> - struct iomap_page *iop = iomap_page_create(inode, page);
> loff_t block_size = i_blocksize(inode);
> loff_t block_start = pos & ~(block_size - 1);
> loff_t block_end = (pos + len + block_size - 1) & ~(block_size - 1);
> @@ -580,9 +580,10 @@ __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, int flags,
>
> if (PageUptodate(page))
> return 0;
> + iomap_page_create(inode, page);
What problem does this fix? i.e. if we can get here with an
uninitialised page, why isn't this a separate bug fix. I don't see
anything in this patch that actually changes behaviour, and there's
nothing in the commit description to tell me why this is here,
so... ???
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2020-05-21 22:24 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-15 13:16 [PATCH v4 00/36] Large pages in the page cache Matthew Wilcox
2020-05-15 13:16 ` [PATCH v4 01/36] mm: Move PageDoubleMap bit Matthew Wilcox
2020-05-15 13:16 ` [PATCH v4 02/36] mm: Simplify PageDoubleMap with PF_SECOND policy Matthew Wilcox
2020-05-15 13:16 ` [PATCH v4 03/36] mm: Allow hpages to be arbitrary order Matthew Wilcox
2020-05-28 14:19 ` Zi Yan
2020-05-15 13:16 ` [PATCH v4 04/36] mm: Introduce thp_size Matthew Wilcox
2020-05-15 13:38 ` David Hildenbrand
2020-05-15 13:16 ` [PATCH v4 05/36] mm: Introduce thp_order Matthew Wilcox
2020-05-15 13:16 ` [PATCH v4 06/36] mm: Introduce offset_in_thp Matthew Wilcox
2020-05-15 13:39 ` David Hildenbrand
2020-05-22 17:15 ` Kirill A. Shutemov
2020-05-29 12:59 ` Matthew Wilcox
2020-05-15 13:16 ` [PATCH v4 07/36] fs: Add a filesystem flag for large pages Matthew Wilcox
2020-05-21 21:55 ` Dave Chinner
2020-05-21 23:29 ` Matthew Wilcox
2020-05-15 13:16 ` [PATCH v4 08/36] fs: Do not update nr_thps for large page mappings Matthew Wilcox
2020-05-15 13:16 ` [PATCH v4 09/36] fs: Introduce i_blocks_per_page Matthew Wilcox
2020-05-15 13:16 ` [PATCH v4 10/36] fs: Make page_mkwrite_check_truncate thp-aware Matthew Wilcox
2020-05-21 22:01 ` Dave Chinner
2020-05-21 23:30 ` Matthew Wilcox
2020-05-15 13:16 ` [PATCH v4 11/36] fs: Support THPs in zero_user_segments Matthew Wilcox
2020-05-25 4:55 ` Kirill A. Shutemov
2020-05-15 13:16 ` [PATCH v4 12/36] bio: Add bio_for_each_thp_segment_all Matthew Wilcox
2020-05-15 13:16 ` [PATCH v4 13/36] iomap: Support arbitrarily many blocks per page Matthew Wilcox
2020-05-15 13:16 ` [PATCH v4 14/36] iomap: Support large pages in iomap_adjust_read_range Matthew Wilcox
2020-05-21 22:24 ` Dave Chinner [this message]
2020-05-21 23:39 ` Matthew Wilcox
2020-05-15 13:16 ` [PATCH v4 15/36] iomap: Support large pages in read paths Matthew Wilcox
2020-05-15 13:16 ` [PATCH v4 16/36] iomap: Support large pages in write paths Matthew Wilcox
2020-05-15 13:16 ` [PATCH v4 17/36] iomap: Inline data shouldn't see large pages Matthew Wilcox
2020-05-15 13:16 ` [PATCH v4 18/36] iomap: Handle tail pages in iomap_page_mkwrite Matthew Wilcox
2020-05-15 13:16 ` [PATCH v4 19/36] xfs: Support large pages Matthew Wilcox
2020-05-15 13:16 ` [PATCH v4 20/36] mm: Make prep_transhuge_page return its argument Matthew Wilcox
2020-05-15 13:16 ` [PATCH v4 21/36] mm: Add __page_cache_alloc_order Matthew Wilcox
2020-05-15 13:16 ` [PATCH v4 22/36] mm: Allow large pages to be added to the page cache Matthew Wilcox
2020-05-15 13:16 ` [PATCH v4 23/36] mm: Allow large pages to be removed from " Matthew Wilcox
2020-05-15 13:16 ` [PATCH v4 24/36] mm: Remove page fault assumption of compound page size Matthew Wilcox
2020-05-25 4:59 ` Kirill A. Shutemov
2020-05-15 13:16 ` [PATCH v4 25/36] mm: Fix total_mapcount assumption of " Matthew Wilcox
2020-05-15 13:16 ` [PATCH v4 26/36] mm: Avoid splitting large pages Matthew Wilcox
2020-05-15 13:16 ` [PATCH v4 27/36] mm: Fix truncation for pages of arbitrary size Matthew Wilcox
2020-05-15 13:16 ` [PATCH v4 28/36] mm: Support storing shadow entries for large pages Matthew Wilcox
2020-05-15 13:16 ` [PATCH v4 29/36] mm: Support retrieving tail pages from the page cache Matthew Wilcox
2020-05-15 13:16 ` [PATCH v4 30/36] mm: Support tail pages in wait_for_stable_page Matthew Wilcox
2020-05-15 13:16 ` [PATCH v4 31/36] mm: Add DEFINE_READAHEAD Matthew Wilcox
2020-05-15 13:16 ` [PATCH v4 32/36] mm: Make page_cache_readahead_unbounded take a readahead_control Matthew Wilcox
2020-05-15 13:16 ` [PATCH v4 33/36] mm: Make __do_page_cache_readahead " Matthew Wilcox
2020-05-15 13:16 ` [PATCH v4 34/36] mm: Allow PageReadahead to be set on head pages Matthew Wilcox
2020-05-15 13:16 ` [PATCH v4 35/36] mm: Add large page readahead Matthew Wilcox
2020-05-15 13:16 ` [PATCH v4 36/36] mm: Align THP mappings for non-DAX Matthew Wilcox
2020-05-26 22:05 ` William Kucharski
2020-05-26 22:20 ` Matthew Wilcox
2020-05-21 22:49 ` [PATCH v4 00/36] Large pages in the page cache Dave Chinner
2020-05-22 0:04 ` Matthew Wilcox
2020-05-22 2:57 ` Dave Chinner
2020-05-22 3:05 ` Matthew Wilcox
2020-05-25 23:07 ` Dave Chinner
2020-05-26 1:21 ` Matthew Wilcox
2020-05-28 11:00 ` William Kucharski
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