khugepaged: add support of collapse for tmpfs/shmem pages

[cascardo/linux.git] / include / linux / shmem_fs.h

diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h
index 94eaaa2..0890f70 100644 (file)
--- a/include/linux/shmem_fs.h
+++ b/include/linux/shmem_fs.h
@@ -54,6 +54,7 @@ extern unsigned long shmem_get_unmapped_area(struct file *, unsigned long addr,
                unsigned long len, unsigned long pgoff, unsigned long flags);
 extern int shmem_lock(struct file *file, int lock, struct user_struct *user);
 extern bool shmem_mapping(struct address_space *mapping);
+extern bool shmem_huge_enabled(struct vm_area_struct *vma);
 extern void shmem_unlock_mapping(struct address_space *mapping);
 extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
                                        pgoff_t index, gfp_t gfp_mask);
@@ -64,6 +65,19 @@ extern unsigned long shmem_swap_usage(struct vm_area_struct *vma);
 extern unsigned long shmem_partial_swap_usage(struct address_space *mapping,
                                                pgoff_t start, pgoff_t end);
 
+/* Flag allocation requirements to shmem_getpage */
+enum sgp_type {
+       SGP_READ,       /* don't exceed i_size, don't allocate page */
+       SGP_CACHE,      /* don't exceed i_size, may allocate page */
+       SGP_NOHUGE,     /* like SGP_CACHE, but no huge pages */
+       SGP_HUGE,       /* like SGP_CACHE, huge pages preferred */
+       SGP_WRITE,      /* may exceed i_size, may allocate !Uptodate page */
+       SGP_FALLOC,     /* like SGP_WRITE, but make existing page Uptodate */
+};
+
+extern int shmem_getpage(struct inode *inode, pgoff_t index,
+               struct page **pagep, enum sgp_type sgp);
+
 static inline struct page *shmem_read_mapping_page(
                                struct address_space *mapping, pgoff_t index)
 {
@@ -71,6 +85,15 @@ static inline struct page *shmem_read_mapping_page(
                                        mapping_gfp_mask(mapping));
 }
 
+static inline bool shmem_file(struct file *file)
+{
+       if (!IS_ENABLED(CONFIG_SHMEM))
+               return false;
+       if (!file || !file->f_mapping)
+               return false;
+       return shmem_mapping(file->f_mapping);
+}
+
 extern bool shmem_charge(struct inode *inode, long pages);
 extern void shmem_uncharge(struct inode *inode, long pages);