The tmpfs supports large folio, but there is some configurable options
to enable/disable large folio allocation, and for huge=within_size,
large folio only allowabled if it fully within i_size, so there is
performance issue when perform write without large folio, the issue is
similar to commit 4e527d5841e2 ("iomap: fault in smaller chunks for
non-large folio mappings").
Fix it by checking whether it allows large folio allocation or not
before perform write.
Fixes: 9aac777aaf94 ("filemap: Convert generic_perform_write() to support large folios")
Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
---
v2:
- Don't use IOCB flags
mm/filemap.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/mm/filemap.c b/mm/filemap.c
index 3e46ca45e13d..b33f260fa32f 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -4126,13 +4126,28 @@ generic_file_direct_write(struct kiocb *iocb, struct iov_iter *from)
}
EXPORT_SYMBOL(generic_file_direct_write);
+static size_t generic_mapping_max_folio_size(struct address_space *mapping,
+ loff_t pos)
+{
+ struct inode *inode = mapping->host;
+ pgoff_t index = pos >> PAGE_SHIFT;
+
+ if (!shmem_mapping(mapping))
+ goto out;
+
+ if (!shmem_allowable_huge_orders(inode, NULL, index, 0, false))
+ return PAGE_SIZE;
+out:
+ return mapping_max_folio_size(mapping);
+}
+
ssize_t generic_perform_write(struct kiocb *iocb, struct iov_iter *i)
{
struct file *file = iocb->ki_filp;
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);
+ size_t chunk = generic_mapping_max_folio_size(mapping, pos);
long status = 0;
ssize_t written = 0;
--
2.27.0
