shmem: split huge pages beyond i_size under memory pressure

[karo-tx-linux.git] / include / linux / shmem_fs.h

diff --git a/include/linux/shmem_fs.h b/include/linux/shmem_fs.h
index 4d4780c00d345e9e5fd50f5394b89d93c57c966b..ff078e7043b6908ce5ca96c16eaf83e4fbfbd980 100644 (file)
--- a/include/linux/shmem_fs.h
+++ b/include/linux/shmem_fs.h
@@ -16,8 +16,9 @@ struct shmem_inode_info {
        unsigned long           flags;
        unsigned long           alloced;        /* data pages alloced to file */
        unsigned long           swapped;        /* subtotal assigned to swap */
-       struct shared_policy    policy;         /* NUMA memory alloc policy */
+       struct list_head        shrinklist;     /* shrinkable hpage inodes */
        struct list_head        swaplist;       /* chain of maybes on swap */
+       struct shared_policy    policy;         /* NUMA memory alloc policy */
        struct simple_xattrs    xattrs;         /* list of xattrs */
        struct inode            vfs_inode;
 };
@@ -28,10 +29,14 @@ struct shmem_sb_info {
        unsigned long max_inodes;   /* How many inodes are allowed */
        unsigned long free_inodes;  /* How many are left for allocation */
        spinlock_t stat_lock;       /* Serialize shmem_sb_info changes */
+       umode_t mode;               /* Mount mode for root directory */
+       unsigned char huge;         /* Whether to try for hugepages */
        kuid_t uid;                 /* Mount uid for root directory */
        kgid_t gid;                 /* Mount gid for root directory */
-       umode_t mode;               /* Mount mode for root directory */
        struct mempolicy *mpol;     /* default memory policy for mappings */
+       spinlock_t shrinklist_lock;   /* Protects shrinklist */
+       struct list_head shrinklist;  /* List of shinkable inodes */
+       unsigned long shrinklist_len; /* Length of shrinklist */
 };
 
 static inline struct shmem_inode_info *SHMEM_I(struct inode *inode)
@@ -49,6 +54,8 @@ extern struct file *shmem_file_setup(const char *name,
 extern struct file *shmem_kernel_file_setup(const char *name, loff_t size,
                                            unsigned long flags);
 extern int shmem_zero_setup(struct vm_area_struct *);
+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 void shmem_unlock_mapping(struct address_space *mapping);
@@ -61,6 +68,19 @@ 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)
 {
@@ -68,6 +88,18 @@ 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);
+
 #ifdef CONFIG_TMPFS
 
 extern int shmem_add_seals(struct file *file, unsigned int seals);
@@ -83,4 +115,13 @@ static inline long shmem_fcntl(struct file *f, unsigned int c, unsigned long a)
 
 #endif
 
+#ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
+extern bool shmem_huge_enabled(struct vm_area_struct *vma);
+#else
+static inline bool shmem_huge_enabled(struct vm_area_struct *vma)
+{
+       return false;
+}
+#endif
+
 #endif