kernel_optimize_test/security/selinux/ss/avtab.h
Yuichi Nakamura 3232c110b5 SELinux: tune avtab to reduce memory usage
This patch reduces memory usage of SELinux by tuning avtab. Number of hash
slots in avtab was 32768. Unused slots used memory when number of rules is
fewer. This patch decides number of hash slots dynamically based on number
of rules. (chain length)^2 is also printed out in avtab_hash_eval to see
standard deviation of avtab hash table.

Signed-off-by: Yuichi Nakamura<ynakam@hitachisoft.jp>
Acked-by:  Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
2007-10-17 08:59:30 +10:00

91 lines
2.8 KiB
C

/*
* An access vector table (avtab) is a hash table
* of access vectors and transition types indexed
* by a type pair and a class. An access vector
* table is used to represent the type enforcement
* tables.
*
* Author : Stephen Smalley, <sds@epoch.ncsc.mil>
*/
/* Updated: Frank Mayer <mayerf@tresys.com> and Karl MacMillan <kmacmillan@tresys.com>
*
* Added conditional policy language extensions
*
* Copyright (C) 2003 Tresys Technology, LLC
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, version 2.
*
* Updated: Yuichi Nakamura <ynakam@hitachisoft.jp>
* Tuned number of hash slots for avtab to reduce memory usage
*/
#ifndef _SS_AVTAB_H_
#define _SS_AVTAB_H_
struct avtab_key {
u16 source_type; /* source type */
u16 target_type; /* target type */
u16 target_class; /* target object class */
#define AVTAB_ALLOWED 1
#define AVTAB_AUDITALLOW 2
#define AVTAB_AUDITDENY 4
#define AVTAB_AV (AVTAB_ALLOWED | AVTAB_AUDITALLOW | AVTAB_AUDITDENY)
#define AVTAB_TRANSITION 16
#define AVTAB_MEMBER 32
#define AVTAB_CHANGE 64
#define AVTAB_TYPE (AVTAB_TRANSITION | AVTAB_MEMBER | AVTAB_CHANGE)
#define AVTAB_ENABLED_OLD 0x80000000 /* reserved for used in cond_avtab */
#define AVTAB_ENABLED 0x8000 /* reserved for used in cond_avtab */
u16 specified; /* what field is specified */
};
struct avtab_datum {
u32 data; /* access vector or type value */
};
struct avtab_node {
struct avtab_key key;
struct avtab_datum datum;
struct avtab_node *next;
};
struct avtab {
struct avtab_node **htable;
u32 nel; /* number of elements */
u32 nslot; /* number of hash slots */
u16 mask; /* mask to compute hash func */
};
int avtab_init(struct avtab *);
int avtab_alloc(struct avtab *, u32);
struct avtab_datum *avtab_search(struct avtab *h, struct avtab_key *k);
void avtab_destroy(struct avtab *h);
void avtab_hash_eval(struct avtab *h, char *tag);
int avtab_read_item(void *fp, uint32_t vers, struct avtab *a,
int (*insert)(struct avtab *a, struct avtab_key *k,
struct avtab_datum *d, void *p),
void *p);
int avtab_read(struct avtab *a, void *fp, u32 vers);
struct avtab_node *avtab_insert_nonunique(struct avtab *h, struct avtab_key *key,
struct avtab_datum *datum);
struct avtab_node *avtab_search_node(struct avtab *h, struct avtab_key *key);
struct avtab_node *avtab_search_node_next(struct avtab_node *node, int specified);
void avtab_cache_init(void);
void avtab_cache_destroy(void);
#define MAX_AVTAB_HASH_BITS 13
#define MAX_AVTAB_HASH_BUCKETS (1 << MAX_AVTAB_HASH_BITS)
#define MAX_AVTAB_HASH_MASK (MAX_AVTAB_HASH_BUCKETS-1)
#define MAX_AVTAB_SIZE MAX_AVTAB_HASH_BUCKETS
#endif /* _SS_AVTAB_H_ */