54b27f9287
Move (most of) the definitions of hashtab_search() and hashtab_insert()
to the header file. In combination with the previous patch, this avoids
calling the callbacks indirectly by function pointers and allows for
better optimization, leading to a drastic performance improvement of
these operations.
With this patch, I measured a speed up in the following areas (measured
on x86_64 F32 VM with 4 CPUs):
1. Policy load (`load_policy`) - takes ~150 ms instead of ~230 ms.
2. `chcon -R unconfined_u:object_r:user_tmp_t:s0:c381,c519 /tmp/linux-src`
where /tmp/linux-src is an extracted linux-5.7 source tarball -
takes ~522 ms instead of ~576 ms. This is because of many
symtab_search() calls in string_to_context_struct() when there are
many categories specified in the context.
3. `stress-ng --msg 1 --msg-ops 10000000` - takes 12.41 s instead of
13.95 s (consumes 18.6 s of kernel CPU time instead of 21.6 s).
This is thanks to security_transition_sid() being ~43% faster after
this patch.
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Acked-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
143 lines
3.4 KiB
C
143 lines
3.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* A hash table (hashtab) maintains associations between
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* key values and datum values. The type of the key values
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* and the type of the datum values is arbitrary. The
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* functions for hash computation and key comparison are
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* provided by the creator of the table.
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*
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* Author : Stephen Smalley, <sds@tycho.nsa.gov>
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*/
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#ifndef _SS_HASHTAB_H_
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#define _SS_HASHTAB_H_
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#include <linux/types.h>
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#include <linux/errno.h>
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#include <linux/sched.h>
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#define HASHTAB_MAX_NODES U32_MAX
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struct hashtab_key_params {
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u32 (*hash)(const void *key); /* hash function */
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int (*cmp)(const void *key1, const void *key2);
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/* key comparison function */
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};
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struct hashtab_node {
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void *key;
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void *datum;
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struct hashtab_node *next;
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};
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struct hashtab {
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struct hashtab_node **htable; /* hash table */
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u32 size; /* number of slots in hash table */
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u32 nel; /* number of elements in hash table */
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};
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struct hashtab_info {
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u32 slots_used;
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u32 max_chain_len;
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};
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/*
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* Initializes a new hash table with the specified characteristics.
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*
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* Returns -ENOMEM if insufficient space is available or 0 otherwise.
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*/
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int hashtab_init(struct hashtab *h, u32 nel_hint);
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int __hashtab_insert(struct hashtab *h, struct hashtab_node **dst,
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void *key, void *datum);
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/*
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* Inserts the specified (key, datum) pair into the specified hash table.
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*
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* Returns -ENOMEM on memory allocation error,
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* -EEXIST if there is already an entry with the same key,
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* -EINVAL for general errors or
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0 otherwise.
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*/
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static inline int hashtab_insert(struct hashtab *h, void *key, void *datum,
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struct hashtab_key_params key_params)
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{
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u32 hvalue;
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struct hashtab_node *prev, *cur;
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cond_resched();
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if (!h->size || h->nel == HASHTAB_MAX_NODES)
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return -EINVAL;
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hvalue = key_params.hash(key) & (h->size - 1);
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prev = NULL;
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cur = h->htable[hvalue];
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while (cur) {
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int cmp = key_params.cmp(key, cur->key);
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if (cmp == 0)
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return -EEXIST;
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if (cmp < 0)
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break;
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prev = cur;
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cur = cur->next;
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}
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return __hashtab_insert(h, prev ? &prev->next : &h->htable[hvalue],
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key, datum);
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}
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/*
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* Searches for the entry with the specified key in the hash table.
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*
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* Returns NULL if no entry has the specified key or
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* the datum of the entry otherwise.
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*/
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static inline void *hashtab_search(struct hashtab *h, const void *key,
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struct hashtab_key_params key_params)
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{
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u32 hvalue;
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struct hashtab_node *cur;
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if (!h->size)
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return NULL;
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hvalue = key_params.hash(key) & (h->size - 1);
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cur = h->htable[hvalue];
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while (cur) {
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int cmp = key_params.cmp(key, cur->key);
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if (cmp == 0)
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return cur->datum;
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if (cmp < 0)
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break;
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cur = cur->next;
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}
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return NULL;
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}
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/*
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* Destroys the specified hash table.
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*/
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void hashtab_destroy(struct hashtab *h);
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/*
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* Applies the specified apply function to (key,datum,args)
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* for each entry in the specified hash table.
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*
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* The order in which the function is applied to the entries
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* is dependent upon the internal structure of the hash table.
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*
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* If apply returns a non-zero status, then hashtab_map will cease
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* iterating through the hash table and will propagate the error
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* return to its caller.
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*/
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int hashtab_map(struct hashtab *h,
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int (*apply)(void *k, void *d, void *args),
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void *args);
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/* Fill info with some hash table statistics */
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void hashtab_stat(struct hashtab *h, struct hashtab_info *info);
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#endif /* _SS_HASHTAB_H */
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