linux_dsm_epyc7002/include/linux/shmem_fs.h
Hugh Dickins d9d90e5eb7 tmpfs: add shmem_read_mapping_page_gfp
Although it is used (by i915) on nothing but tmpfs, read_cache_page_gfp()
is unsuited to tmpfs, because it inserts a page into pagecache before
calling the filesystem's ->readpage: tmpfs may have pages in swapcache
which only it knows how to locate and switch to filecache.

At present tmpfs provides a ->readpage method, and copes with this by
copying pages; but soon we can simplify it by removing its ->readpage.
Provide shmem_read_mapping_page_gfp() now, ready for that transition,

Export shmem_read_mapping_page_gfp() and add it to list in shmem_fs.h,
with shmem_read_mapping_page() inline for the common mapping_gfp case.

(shmem_read_mapping_page_gfp or shmem_read_cache_page_gfp? Generally the
read_mapping_page functions use the mapping's ->readpage, and the
read_cache_page functions use the supplied filler, so I think
read_cache_page_gfp was slightly misnamed.)

Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-06-27 18:00:12 -07:00

73 lines
2.6 KiB
C

#ifndef __SHMEM_FS_H
#define __SHMEM_FS_H
#include <linux/swap.h>
#include <linux/mempolicy.h>
#include <linux/pagemap.h>
#include <linux/percpu_counter.h>
/* inode in-kernel data */
#define SHMEM_NR_DIRECT 16
#define SHMEM_SYMLINK_INLINE_LEN (SHMEM_NR_DIRECT * sizeof(swp_entry_t))
struct shmem_inode_info {
spinlock_t lock;
unsigned long flags;
unsigned long alloced; /* data pages alloced to file */
unsigned long swapped; /* subtotal assigned to swap */
unsigned long next_index; /* highest alloced index + 1 */
struct shared_policy policy; /* NUMA memory alloc policy */
struct page *i_indirect; /* top indirect blocks page */
union {
swp_entry_t i_direct[SHMEM_NR_DIRECT]; /* first blocks */
char inline_symlink[SHMEM_SYMLINK_INLINE_LEN];
};
struct list_head swaplist; /* chain of maybes on swap */
struct list_head xattr_list; /* list of shmem_xattr */
struct inode vfs_inode;
};
struct shmem_sb_info {
unsigned long max_blocks; /* How many blocks are allowed */
struct percpu_counter used_blocks; /* How many are allocated */
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 */
uid_t uid; /* Mount uid for root directory */
gid_t gid; /* Mount gid for root directory */
mode_t mode; /* Mount mode for root directory */
struct mempolicy *mpol; /* default memory policy for mappings */
};
static inline struct shmem_inode_info *SHMEM_I(struct inode *inode)
{
return container_of(inode, struct shmem_inode_info, vfs_inode);
}
/*
* Functions in mm/shmem.c called directly from elsewhere:
*/
extern int init_tmpfs(void);
extern int shmem_fill_super(struct super_block *sb, void *data, int silent);
extern struct file *shmem_file_setup(const char *name,
loff_t size, unsigned long flags);
extern int shmem_zero_setup(struct vm_area_struct *);
extern int shmem_lock(struct file *file, int lock, struct user_struct *user);
extern struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
pgoff_t index, gfp_t gfp_mask);
extern void shmem_truncate_range(struct inode *inode, loff_t start, loff_t end);
extern int shmem_unuse(swp_entry_t entry, struct page *page);
extern void mem_cgroup_get_shmem_target(struct inode *inode, pgoff_t pgoff,
struct page **pagep, swp_entry_t *ent);
static inline struct page *shmem_read_mapping_page(
struct address_space *mapping, pgoff_t index)
{
return shmem_read_mapping_page_gfp(mapping, index,
mapping_gfp_mask(mapping));
}
#endif