If we have a large folio, we can copy in larger chunks than PAGE_SIZE.
Start at the maximum page cache size and shrink by half every time we
hit the "we are short on memory" problem.
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
---
fs/iomap/buffered-io.c | 32 +++++++++++++++++---------------
1 file changed, 17 insertions(+), 15 deletions(-)
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 2d3e90f4d16e..f21f1f641c4a 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -769,6 +769,7 @@ static size_t iomap_write_end(struct iomap_iter *iter, loff_t pos, size_t len,
static loff_t iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i)
{
loff_t length = iomap_length(iter);
+ size_t chunk = PAGE_SIZE << MAX_PAGECACHE_ORDER;
loff_t pos = iter->pos;
ssize_t written = 0;
long status = 0;
@@ -777,15 +778,12 @@ static loff_t iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i)
do {
struct folio *folio;
- struct page *page;
- unsigned long offset; /* Offset into pagecache page */
- unsigned long bytes; /* Bytes to write to page */
+ size_t offset; /* Offset into folio */
+ size_t bytes; /* Bytes to write to folio */
size_t copied; /* Bytes copied from user */
- offset = offset_in_page(pos);
- bytes = min_t(unsigned long, PAGE_SIZE - offset,
- iov_iter_count(i));
-again:
+ offset = pos & (chunk - 1);
+ bytes = min(chunk - offset, iov_iter_count(i));
status = balance_dirty_pages_ratelimited_flags(mapping,
bdp_flags);
if (unlikely(status))
@@ -815,12 +813,14 @@ static loff_t iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i)
if (iter->iomap.flags & IOMAP_F_STALE)
break;
- page = folio_file_page(folio, pos >> PAGE_SHIFT);
- if (mapping_writably_mapped(mapping))
- flush_dcache_page(page);
+ offset = offset_in_folio(folio, pos);
+ if (bytes > folio_size(folio) - offset)
+ bytes = folio_size(folio) - offset;
- copied = copy_page_from_iter_atomic(page, offset, bytes, i);
+ if (mapping_writably_mapped(mapping))
+ flush_dcache_folio(folio);
+ copied = copy_folio_from_iter_atomic(folio, offset, bytes, i);
status = iomap_write_end(iter, pos, bytes, copied, folio);
if (unlikely(copied != status))
@@ -836,11 +836,13 @@ static loff_t iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i)
*/
if (copied)
bytes = copied;
- goto again;
+ if (chunk > PAGE_SIZE)
+ chunk /= 2;
+ } else {
+ pos += status;
+ written += status;
+ length -= status;
}
- pos += status;
- written += status;
- length -= status;
} while (iov_iter_count(i) && length);
if (status == -EAGAIN) {
--
2.39.2
