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| author | Matthew Wilcox (Oracle) <willy@infradead.org> | 2020-09-21 18:58:40 +0300 |
|---|---|---|
| committer | Darrick J. Wong <darrick.wong@oracle.com> | 2020-09-21 18:59:26 +0300 |
| commit | 0a195b91e8991367a94ee199f3af7faa7607e7db (patch) | |
| tree | 25e7c055e0621e64a0e09479cd505dd1a6083168 /fs | |
| parent | b21866f514cb50bd75614851a8d066398a114cab (diff) | |
| download | linux-0a195b91e8991367a94ee199f3af7faa7607e7db.tar.xz | |
iomap: Support arbitrarily many blocks per page
Size the uptodate array dynamically to support larger pages in the
page cache. With a 64kB page, we're only saving 8 bytes per page today,
but with a 2MB maximum page size, we'd have to allocate more than 4kB
per page. Add a few debugging assertions.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/iomap/buffered-io.c | 22 |
1 files changed, 17 insertions, 5 deletions
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index eab839b2be33..9f0fa495ab69 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -22,18 +22,25 @@ #include "../internal.h" /* - * Structure allocated for each page when block size < PAGE_SIZE to track - * sub-page uptodate status and I/O completions. + * Structure allocated for each page or THP when block size < page size + * to track sub-page uptodate status and I/O completions. */ struct iomap_page { atomic_t read_count; atomic_t write_count; spinlock_t uptodate_lock; - DECLARE_BITMAP(uptodate, PAGE_SIZE / 512); + unsigned long uptodate[]; }; static inline struct iomap_page *to_iomap_page(struct page *page) { + /* + * per-block data is stored in the head page. Callers should + * not be dealing with tail pages (and if they are, they can + * call thp_head() first. + */ + VM_BUG_ON_PGFLAGS(PageTail(page), page); + if (page_has_private(page)) return (struct iomap_page *)page_private(page); return NULL; @@ -45,11 +52,13 @@ static struct iomap_page * iomap_page_create(struct inode *inode, struct page *page) { struct iomap_page *iop = to_iomap_page(page); + unsigned int nr_blocks = i_blocks_per_page(inode, page); - if (iop || i_blocks_per_page(inode, page) <= 1) + if (iop || nr_blocks <= 1) return iop; - iop = kzalloc(sizeof(*iop), GFP_NOFS | __GFP_NOFAIL); + iop = kzalloc(struct_size(iop, uptodate, BITS_TO_LONGS(nr_blocks)), + GFP_NOFS | __GFP_NOFAIL); spin_lock_init(&iop->uptodate_lock); attach_page_private(page, iop); return iop; @@ -59,11 +68,14 @@ static void iomap_page_release(struct page *page) { struct iomap_page *iop = detach_page_private(page); + unsigned int nr_blocks = i_blocks_per_page(page->mapping->host, page); if (!iop) return; WARN_ON_ONCE(atomic_read(&iop->read_count)); WARN_ON_ONCE(atomic_read(&iop->write_count)); + WARN_ON_ONCE(bitmap_full(iop->uptodate, nr_blocks) != + PageUptodate(page)); kfree(iop); } |