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filemap: Convert generic_perform_write() to support large folios

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Modelled after the loop in iomap_write_iter(), copy larger chunks from
userspace if the filesystem has created large folios.

[hch: use mapping_max_folio_size to keep supporting file systems that do
 not support large folios]

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Tested-by: Shaun Tancheff <shaun.tancheff@hpe.com>
Tested-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
This commit is contained in:
Matthew Wilcox (Oracle) 2024-05-27 18:36:08 +02:00 committed by Anna Schumaker
parent 146a99aefe
commit 9aac777aaf
1 changed files with 26 additions and 16 deletions
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42
mm/filemap.c
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@ -3981,21 +3981,24 @@ ssize_t generic_perform_write(struct kiocb *iocb, struct iov_iter *i)
loff_t pos = iocb->ki_pos;
struct address_space *mapping = file->f_mapping;
const struct address_space_operations *a_ops = mapping->a_ops;
size_t chunk = mapping_max_folio_size(mapping);
long status = 0;
ssize_t written = 0;
do {
struct page *page;
unsigned long offset; /* Offset into pagecache page */
unsigned long bytes; /* Bytes to write to page */
struct folio *folio;
size_t offset; /* Offset into folio */
size_t bytes; /* Bytes to write to folio */
size_t copied; /* Bytes copied from user */
void *fsdata = NULL;
offset = (pos & (PAGE_SIZE - 1));
bytes = min_t(unsigned long, PAGE_SIZE - offset,
iov_iter_count(i));
bytes = iov_iter_count(i);
retry:
offset = pos & (chunk - 1);
bytes = min(chunk - offset, bytes);
balance_dirty_pages_ratelimited(mapping);
again:
/*
* Bring in the user page that we will copy from _first_.
* Otherwise there's a nasty deadlock on copying from the
@ -4017,11 +4020,16 @@ again:
if (unlikely(status < 0))
break;
if (mapping_writably_mapped(mapping))
flush_dcache_page(page);
folio = page_folio(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);
flush_dcache_page(page);
if (mapping_writably_mapped(mapping))
flush_dcache_folio(folio);
copied = copy_folio_from_iter_atomic(folio, offset, bytes, i);
flush_dcache_folio(folio);
status = a_ops->write_end(file, mapping, pos, bytes, copied,
page, fsdata);
@ -4039,14 +4047,16 @@ again:
* halfway through, might be a race with munmap,
* might be severe memory pressure.
*/
if (copied)
if (chunk > PAGE_SIZE)
chunk /= 2;
if (copied) {
bytes = copied;
goto again;
goto retry;
}
} else {
pos += status;
written += status;
}
pos += status;
written += status;
balance_dirty_pages_ratelimited(mapping);
} while (iov_iter_count(i));
if (!written)