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6164281ab7
Currently on 64-bit arch the user_namespace is 2096 and when being kmalloc-ed it resides on a 4k slab wasting 2003 bytes. If we allocate a separate cache for it and reduce the hash size from 128 to 64 chains the packaging becomes *much* better - the struct is 1072 bytes and the hole between is 98 bytes. [akpm@linux-foundation.org: s/__initcall/module_init/] Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Acked-by: Serge E. Hallyn <serge@hallyn.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
72 lines
1.5 KiB
C
72 lines
1.5 KiB
C
#ifndef _LINUX_USER_NAMESPACE_H
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#define _LINUX_USER_NAMESPACE_H
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#include <linux/kref.h>
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#include <linux/nsproxy.h>
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#include <linux/sched.h>
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#include <linux/err.h>
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#define UIDHASH_BITS (CONFIG_BASE_SMALL ? 3 : 7)
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#define UIDHASH_SZ (1 << UIDHASH_BITS)
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struct user_namespace {
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struct kref kref;
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struct hlist_head uidhash_table[UIDHASH_SZ];
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struct user_struct *creator;
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struct work_struct destroyer;
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};
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extern struct user_namespace init_user_ns;
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#ifdef CONFIG_USER_NS
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static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
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{
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if (ns)
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kref_get(&ns->kref);
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return ns;
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}
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extern int create_user_ns(struct cred *new);
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extern void free_user_ns(struct kref *kref);
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static inline void put_user_ns(struct user_namespace *ns)
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{
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if (ns)
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kref_put(&ns->kref, free_user_ns);
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}
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uid_t user_ns_map_uid(struct user_namespace *to, const struct cred *cred, uid_t uid);
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gid_t user_ns_map_gid(struct user_namespace *to, const struct cred *cred, gid_t gid);
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#else
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static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
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{
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return &init_user_ns;
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}
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static inline int create_user_ns(struct cred *new)
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{
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return -EINVAL;
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}
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static inline void put_user_ns(struct user_namespace *ns)
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{
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}
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static inline uid_t user_ns_map_uid(struct user_namespace *to,
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const struct cred *cred, uid_t uid)
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{
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return uid;
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}
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static inline gid_t user_ns_map_gid(struct user_namespace *to,
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const struct cred *cred, gid_t gid)
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{
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return gid;
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}
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#endif
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#endif /* _LINUX_USER_H */
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