From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
The page cache needs to know whether the filesystem supports THPs.
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
fs/inode.c | 2 ++
include/linux/fs.h | 1 +
include/linux/pagemap.h | 6 ++++++
mm/shmem.c | 2 +-
4 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/fs/inode.c b/fs/inode.c
index 72c4c347afb7..9d78c37b00b8 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -181,6 +181,8 @@ int inode_init_always(struct super_block *sb, struct inode *inode)
mapping->a_ops = &empty_aops;
mapping->host = inode;
mapping->flags = 0;
+ if (sb->s_type->fs_flags & FS_THP_SUPPORT)
+ __set_bit(AS_THP_SUPPORT, &mapping->flags);
mapping->wb_err = 0;
atomic_set(&mapping->i_mmap_writable, 0);
#ifdef CONFIG_READ_ONLY_THP_FOR_FS
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 19ef6c88c152..ac411a08f83c 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2241,6 +2241,7 @@ struct file_system_type {
#define FS_HAS_SUBTYPE 4
#define FS_USERNS_MOUNT 8 /* Can be mounted by userns root */
#define FS_DISALLOW_NOTIFY_PERM 16 /* Disable fanotify permission events */
+#define FS_THP_SUPPORT 8192 /* Remove once all fs converted */
#define FS_RENAME_DOES_D_MOVE 32768 /* FS will handle d_move() during rename() internally. */
int (*init_fs_context)(struct fs_context *);
const struct fs_parameter_spec *parameters;
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 484a36185bb5..8a45b572bcf1 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -29,6 +29,7 @@ enum mapping_flags {
AS_EXITING = 4, /* final truncate in progress */
/* writeback related tags are not used */
AS_NO_WRITEBACK_TAGS = 5,
+ AS_THP_SUPPORT = 6, /* THPs supported */
};
/**
@@ -119,6 +120,11 @@ static inline void mapping_set_gfp_mask(struct address_space *m, gfp_t mask)
m->gfp_mask = mask;
}
+static inline bool mapping_thp_support(struct address_space *mapping)
+{
+ return test_bit(AS_THP_SUPPORT, &mapping->flags);
+}
+
void release_pages(struct page **pages, int nr);
/*
diff --git a/mm/shmem.c b/mm/shmem.c
index a0dbe62f8042..a05d129a45e9 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -3854,7 +3854,7 @@ static struct file_system_type shmem_fs_type = {
.parameters = shmem_fs_parameters,
#endif
.kill_sb = kill_litter_super,
- .fs_flags = FS_USERNS_MOUNT,
+ .fs_flags = FS_USERNS_MOUNT | FS_THP_SUPPORT,
};
int __init shmem_init(void)
--
2.26.2
