linux-sg2042/include/linux/shmem_fs.h

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#ifndef __SHMEM_FS_H
#define __SHMEM_FS_H
#include <linux/swap.h>
#include <linux/mempolicy.h>
/* inode in-kernel data */
#define SHMEM_NR_DIRECT 16
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 */
swp_entry_t i_direct[SHMEM_NR_DIRECT]; /* first blocks */
struct list_head swaplist; /* chain of maybes on swap */
struct inode vfs_inode;
#ifdef CONFIG_TMPFS_POSIX_ACL
struct posix_acl *i_acl;
struct posix_acl *i_default_acl;
#endif
};
struct shmem_sb_info {
unsigned long max_blocks; /* How many blocks are allowed */
unsigned long free_blocks; /* How many are left for allocation */
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 */
unsigned short policy; /* Default NUMA memory alloc policy */
mempolicy: support optional mode flags With the evolution of mempolicies, it is necessary to support mempolicy mode flags that specify how the policy shall behave in certain circumstances. The most immediate need for mode flag support is to suppress remapping the nodemask of a policy at the time of rebind. Both the mempolicy mode and flags are passed by the user in the 'int policy' formal of either the set_mempolicy() or mbind() syscall. A new constant, MPOL_MODE_FLAGS, represents the union of legal optional flags that may be passed as part of this int. Mempolicies that include illegal flags as part of their policy are rejected as invalid. An additional member to struct mempolicy is added to support the mode flags: struct mempolicy { ... unsigned short policy; unsigned short flags; } The splitting of the 'int' actual passed by the user is done in sys_set_mempolicy() and sys_mbind() for their respective syscalls. This is done by intersecting the actual with MPOL_MODE_FLAGS, rejecting the syscall of there are additional flags, and storing it in the new 'flags' member of struct mempolicy. The intersection of the actual with ~MPOL_MODE_FLAGS is stored in the 'policy' member of the struct and all current users of pol->policy remain unchanged. The union of the policy mode and optional mode flags is passed back to the user in get_mempolicy(). This combination of mode and flags within the same actual does not break userspace code that relies on get_mempolicy(&policy, ...) and either switch (policy) { case MPOL_BIND: ... case MPOL_INTERLEAVE: ... }; statements or if (policy == MPOL_INTERLEAVE) { ... } statements. Such applications would need to use optional mode flags when calling set_mempolicy() or mbind() for these previously implemented statements to stop working. If an application does start using optional mode flags, it will need to mask the optional flags off the policy in switch and conditional statements that only test mode. An additional member is also added to struct shmem_sb_info to store the optional mode flags. [hugh@veritas.com: shmem mpol: fix build warning] Cc: Paul Jackson <pj@sgi.com> Cc: Christoph Lameter <clameter@sgi.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Andi Kleen <ak@suse.de> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-28 17:12:25 +08:00
unsigned short flags; /* Optional mempolicy flags */
nodemask_t policy_nodes; /* nodemask for preferred and bind */
};
static inline struct shmem_inode_info *SHMEM_I(struct inode *inode)
{
return container_of(inode, struct shmem_inode_info, vfs_inode);
}
#ifdef CONFIG_TMPFS_POSIX_ACL
int shmem_permission(struct inode *, int, struct nameidata *);
int shmem_acl_init(struct inode *, struct inode *);
void shmem_acl_destroy_inode(struct inode *);
extern struct xattr_handler shmem_xattr_acl_access_handler;
extern struct xattr_handler shmem_xattr_acl_default_handler;
extern struct generic_acl_operations shmem_acl_ops;
#else
static inline int shmem_acl_init(struct inode *inode, struct inode *dir)
{
return 0;
}
static inline void shmem_acl_destroy_inode(struct inode *inode)
{
}
#endif /* CONFIG_TMPFS_POSIX_ACL */
#endif