Increasing the batch size runs into diminishing returns. It's probably
better to make, eg, three calls to filemap_get_pages() than it is to
call into kmalloc().
Signed-off-by: Matthew Wilcox (Oracle) <wi...@infradead.org>
Reviewed-by: Christoph Hellwig <h...@lst.de>
Reviewed-by: Miaohe Lin <linmia...@huawei.com>
---
mm/filemap.c | 15 ++-------------
1 file changed, 2 insertions(+), 13 deletions(-)
diff --git a/mm/filemap.c b/mm/filemap.c
index afc0f674f2242..a5c4f7ddfc40c 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2444,8 +2444,8 @@ ssize_t generic_file_buffered_read(struct kiocb *iocb,
struct file_ra_state *ra = &filp->f_ra;
struct address_space *mapping = filp->f_mapping;
struct inode *inode = mapping->host;
- struct page *pages_onstack[PAGEVEC_SIZE], **pages = NULL;
- unsigned int nr_pages = min_t(unsigned int, 512,
+ struct page *pages[PAGEVEC_SIZE];
+ unsigned int nr_pages = min_t(unsigned int, PAGEVEC_SIZE,
((iocb->ki_pos + iter->count + PAGE_SIZE - 1) >>
PAGE_SHIFT) -
(iocb->ki_pos >> PAGE_SHIFT));
int i, pg_nr, error = 0;
@@ -2459,14 +2459,6 @@ ssize_t generic_file_buffered_read(struct kiocb *iocb,
iov_iter_truncate(iter, inode->i_sb->s_maxbytes);
- if (nr_pages > ARRAY_SIZE(pages_onstack))
- pages = kmalloc_array(nr_pages, sizeof(void *), GFP_KERNEL);
-
- if (!pages) {
- pages = pages_onstack;
- nr_pages = min_t(unsigned int, nr_pages,
ARRAY_SIZE(pages_onstack));
- }
-
do {
cond_resched();
@@ -2551,9 +2543,6 @@ ssize_t generic_file_buffered_read(struct kiocb *iocb,
file_accessed(filp);
- if (pages != pages_onstack)
- kfree(pages);
-
return written ? written : error;
}
EXPORT_SYMBOL_GPL(generic_file_buffered_read);
--
2.29.2
