028fec414d
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>
68 lines
2.1 KiB
C
68 lines
2.1 KiB
C
#ifndef __SHMEM_FS_H
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#define __SHMEM_FS_H
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#include <linux/swap.h>
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#include <linux/mempolicy.h>
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/* inode in-kernel data */
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#define SHMEM_NR_DIRECT 16
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struct shmem_inode_info {
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spinlock_t lock;
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unsigned long flags;
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unsigned long alloced; /* data pages alloced to file */
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unsigned long swapped; /* subtotal assigned to swap */
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unsigned long next_index; /* highest alloced index + 1 */
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struct shared_policy policy; /* NUMA memory alloc policy */
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struct page *i_indirect; /* top indirect blocks page */
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swp_entry_t i_direct[SHMEM_NR_DIRECT]; /* first blocks */
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struct list_head swaplist; /* chain of maybes on swap */
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struct inode vfs_inode;
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#ifdef CONFIG_TMPFS_POSIX_ACL
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struct posix_acl *i_acl;
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struct posix_acl *i_default_acl;
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#endif
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};
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struct shmem_sb_info {
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unsigned long max_blocks; /* How many blocks are allowed */
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unsigned long free_blocks; /* How many are left for allocation */
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unsigned long max_inodes; /* How many inodes are allowed */
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unsigned long free_inodes; /* How many are left for allocation */
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spinlock_t stat_lock; /* Serialize shmem_sb_info changes */
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uid_t uid; /* Mount uid for root directory */
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gid_t gid; /* Mount gid for root directory */
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mode_t mode; /* Mount mode for root directory */
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unsigned short policy; /* Default NUMA memory alloc policy */
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unsigned short flags; /* Optional mempolicy flags */
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nodemask_t policy_nodes; /* nodemask for preferred and bind */
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};
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static inline struct shmem_inode_info *SHMEM_I(struct inode *inode)
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{
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return container_of(inode, struct shmem_inode_info, vfs_inode);
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}
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#ifdef CONFIG_TMPFS_POSIX_ACL
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int shmem_permission(struct inode *, int, struct nameidata *);
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int shmem_acl_init(struct inode *, struct inode *);
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void shmem_acl_destroy_inode(struct inode *);
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extern struct xattr_handler shmem_xattr_acl_access_handler;
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extern struct xattr_handler shmem_xattr_acl_default_handler;
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extern struct generic_acl_operations shmem_acl_ops;
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#else
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static inline int shmem_acl_init(struct inode *inode, struct inode *dir)
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{
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return 0;
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}
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static inline void shmem_acl_destroy_inode(struct inode *inode)
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{
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}
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#endif /* CONFIG_TMPFS_POSIX_ACL */
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#endif
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