mm,tmpfs: consider end of file write in shmem_is_huge

Take the end of a file write into consideration when deciding whether or
not to use huge pages for tmpfs files when the tmpfs filesystem is mounted
with huge=within_size

This allows large writes that append to the end of a file to automatically
use large pages.

Doing 4MB sequential writes without fallocate to a 16GB tmpfs file with
fio.  The numbers without THP or with huge=always stay the same, but the
performance with huge=within_size now matches that of huge=always.

huge		before		after
4kB pages	1560 MB/s	1560 MB/s
within_size	1560 MB/s	4720 MB/s
always:		4720 MB/s	4720 MB/s

[[email protected]: coding-style cleanups]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Rik van Riel <[email protected]>
Reviewed-by: Baolin Wang <[email protected]>
Tested-by: Baolin Wang <[email protected]>
Cc: Darrick J. Wong <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

1 files changed, 4 insertions, 4 deletions

diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h
index 1564d7d3ca61..515a9a6a3c6f 100644
--- a/include/linux/shmem_fs.h
+++ b/include/linux/shmem_fs.h
@@ -113,11 +113,11 @@ int shmem_unuse(unsigned int type);
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 unsigned long shmem_allowable_huge_orders(struct inode *inode,
 				struct vm_area_struct *vma, pgoff_t index,
-				bool shmem_huge_force);
+				loff_t write_end, bool shmem_huge_force);
 #else
 static inline unsigned long shmem_allowable_huge_orders(struct inode *inode,
 				struct vm_area_struct *vma, pgoff_t index,
-				bool shmem_huge_force)
+				loff_t write_end, bool shmem_huge_force)
 {
 	return 0;
 }
@@ -143,8 +143,8 @@ enum sgp_type {
 	SGP_FALLOC,	/* like SGP_WRITE, but make existing page Uptodate */
 };
 
-int shmem_get_folio(struct inode *inode, pgoff_t index, struct folio **foliop,
-		enum sgp_type sgp);
+int shmem_get_folio(struct inode *inode, pgoff_t index, loff_t write_end,
+		struct folio **foliop, enum sgp_type sgp);
 struct folio *shmem_read_folio_gfp(struct address_space *mapping,
 		pgoff_t index, gfp_t gfp);