Commit 54b27f92 authored by Ondrej Mosnacek's avatar Ondrej Mosnacek Committed by Paul Moore
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selinux: complete the inlining of hashtab functions 



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: default avatarOndrej Mosnacek <omosnace@redhat.com>
Acked-by: default avatarStephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: default avatarPaul Moore <paul@paul-moore.com>
parent 24def7bb

security/selinux/ss/hashtab.c

+5 −54
Original line number Diff line number Diff line
@@ -7,7 +7,6 @@ 
#include <linux/kernel.h>

#include <linux/slab.h>

#include <linux/errno.h>

#include <linux/sched.h>

#include "hashtab.h"



static struct kmem_cache *hashtab_node_cachep;
@@ -40,71 +39,23 @@ int hashtab_init(struct hashtab *h, u32 nel_hint) 
	return h->htable ? 0 : -ENOMEM;

}



int hashtab_insert(struct hashtab *h, void *key, void *datum,

		   struct hashtab_key_params key_params)

int __hashtab_insert(struct hashtab *h, struct hashtab_node **dst,

		     void *key, void *datum)

{

	u32 hvalue;

	struct hashtab_node *prev, *cur, *newnode;



	cond_resched();



	if (!h->size || h->nel == HASHTAB_MAX_NODES)

		return -EINVAL;



	hvalue = key_params.hash(key) & (h->size - 1);

	prev = NULL;

	cur = h->htable[hvalue];

	while (cur) {

		int cmp = key_params.cmp(key, cur->key);



		if (cmp == 0)

			return -EEXIST;

		if (cmp < 0)

			break;

		prev = cur;

		cur = cur->next;

	}

	struct hashtab_node *newnode;



	newnode = kmem_cache_zalloc(hashtab_node_cachep, GFP_KERNEL);

	if (!newnode)

		return -ENOMEM;

	newnode->key = key;

	newnode->datum = datum;

	if (prev) {

		newnode->next = prev->next;

		prev->next = newnode;

	} else {

		newnode->next = h->htable[hvalue];

		h->htable[hvalue] = newnode;

	}

	newnode->next = *dst;

	*dst = newnode;



	h->nel++;

	return 0;

}



void *hashtab_search(struct hashtab *h, const void *key,

		     struct hashtab_key_params key_params)

{

	u32 hvalue;

	struct hashtab_node *cur;



	if (!h->size)

		return NULL;



	hvalue = key_params.hash(key) & (h->size - 1);

	cur = h->htable[hvalue];

	while (cur) {

		int cmp = key_params.cmp(key, cur->key);



		if (cmp == 0)

			return cur->datum;

		if (cmp < 0)

			break;

		cur = cur->next;

	}

	return NULL;

}



void hashtab_destroy(struct hashtab *h)

{

	u32 i;

security/selinux/ss/hashtab.h

+58 −5
Original line number Diff line number Diff line
@@ -11,7 +11,11 @@ 
#ifndef _SS_HASHTAB_H_

#define _SS_HASHTAB_H_



#define HASHTAB_MAX_NODES	0xffffffff

#include <linux/types.h>

#include <linux/errno.h>

#include <linux/sched.h>



#define HASHTAB_MAX_NODES	U32_MAX



struct hashtab_key_params {

	u32 (*hash)(const void *key);	/* hash function */
@@ -43,6 +47,9 @@ struct hashtab_info { 
 */

int hashtab_init(struct hashtab *h, u32 nel_hint);



int __hashtab_insert(struct hashtab *h, struct hashtab_node **dst,

		     void *key, void *datum);



/*

 * Inserts the specified (key, datum) pair into the specified hash table.

 *
@@ -51,8 +58,34 @@ int hashtab_init(struct hashtab *h, u32 nel_hint); 
 * -EINVAL for general errors or

  0 otherwise.

 */

int hashtab_insert(struct hashtab *h, void *k, void *d,

		   struct hashtab_key_params key_params);

static inline int hashtab_insert(struct hashtab *h, void *key, void *datum,

				 struct hashtab_key_params key_params)

{

	u32 hvalue;

	struct hashtab_node *prev, *cur;



	cond_resched();



	if (!h->size || h->nel == HASHTAB_MAX_NODES)

		return -EINVAL;



	hvalue = key_params.hash(key) & (h->size - 1);

	prev = NULL;

	cur = h->htable[hvalue];

	while (cur) {

		int cmp = key_params.cmp(key, cur->key);



		if (cmp == 0)

			return -EEXIST;

		if (cmp < 0)

			break;

		prev = cur;

		cur = cur->next;

	}



	return __hashtab_insert(h, prev ? &prev->next : &h->htable[hvalue],

				key, datum);

}



/*

 * Searches for the entry with the specified key in the hash table.
@@ -60,8 +93,28 @@ int hashtab_insert(struct hashtab *h, void *k, void *d, 
 * Returns NULL if no entry has the specified key or

 * the datum of the entry otherwise.

 */

void *hashtab_search(struct hashtab *h, const void *k,

		     struct hashtab_key_params key_params);

static inline void *hashtab_search(struct hashtab *h, const void *key,

				   struct hashtab_key_params key_params)

{

	u32 hvalue;

	struct hashtab_node *cur;



	if (!h->size)

		return NULL;



	hvalue = key_params.hash(key) & (h->size - 1);

	cur = h->htable[hvalue];

	while (cur) {

		int cmp = key_params.cmp(key, cur->key);



		if (cmp == 0)

			return cur->datum;

		if (cmp < 0)

			break;

		cur = cur->next;

	}

	return NULL;

}



/*

 * Destroys the specified hash table.

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