[thirdparty/squid.git] / src / repl / lru / store_repl_lru.cc


/*
 * $Id: store_repl_lru.cc,v 1.13 2003/01/23 00:38:29 robertc Exp $
 *
 * DEBUG: section ?     LRU Removal policy
 * AUTHOR: Henrik Nordstrom
 *
 * SQUID Web Proxy Cache          http://www.squid-cache.org/
 * ----------------------------------------------------------
 *
 *  Squid is the result of efforts by numerous individuals from
 *  the Internet community; see the CONTRIBUTORS file for full
 *  details.   Many organizations have provided support for Squid's
 *  development; see the SPONSORS file for full details.  Squid is
 *  Copyrighted (C) 2001 by the Regents of the University of
 *  California; see the COPYRIGHT file for full details.  Squid
 *  incorporates software developed and/or copyrighted by other
 *  sources; see the CREDITS file for full details.
 *
 *  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; either version 2 of the License, or
 *  (at your option) any later version.
 *  
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *  
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
 *
 */

#include "squid.h"
#include "Store.h"
#include "MemObject.h"

REMOVALPOLICYCREATE createRemovalPolicy_lru;

struct LruPolicyData {
    void setPolicyNode (StoreEntry *, void *) const;
    RemovalPolicy *policy;
    dlink_list list;
    int count;
    int nwalkers;
    enum heap_entry_type {
	TYPE_UNKNOWN = 0, TYPE_STORE_ENTRY, TYPE_STORE_MEM
    } type;
};

/* Hack to avoid having to remember the RemovalPolicyNode location.
 * Needed by the purge walker to clear the policy information
 */
static enum LruPolicyData::heap_entry_type
repl_guessType(StoreEntry * entry, RemovalPolicyNode * node)
{
    if (node == &entry->repl)
	return LruPolicyData::TYPE_STORE_ENTRY;
    if (entry->mem_obj && node == &entry->mem_obj->repl)
	return LruPolicyData::TYPE_STORE_MEM;
    fatal("Heap Replacement: Unknown StoreEntry node type");
    return LruPolicyData::TYPE_UNKNOWN;
}

void
LruPolicyData::setPolicyNode (StoreEntry *entry, void *value) const
{
    switch (type) {
        case TYPE_STORE_ENTRY: entry->repl.data = value; break ;
	case TYPE_STORE_MEM: entry->mem_obj->repl.data = value ; break ;
	default: break;
    }
}

typedef struct _LruNode LruNode;
struct _LruNode {
    /* Note: the dlink_node MUST be the first member of the LruNode
     * structure. This member is later pointer typecasted to LruNode *.
     */
    dlink_node node;
};

static MemPool *lru_node_pool = NULL;
static int nr_lru_policies = 0;

static void
lru_add(RemovalPolicy * policy, StoreEntry * entry, RemovalPolicyNode * node)
{
    LruPolicyData *lru = (LruPolicyData *)policy->_data;
    LruNode *lru_node;
    assert(!node->data);
    node->data = lru_node = (LruNode *)memPoolAlloc(lru_node_pool);
    dlinkAddTail(entry, &lru_node->node, &lru->list);
    lru->count += 1;
    if (!lru->type)
	lru->type = repl_guessType(entry, node);
}

static void
lru_remove(RemovalPolicy * policy, StoreEntry * entry, RemovalPolicyNode * node)
{
    LruPolicyData *lru = (LruPolicyData *)policy->_data;
    LruNode *lru_node = (LruNode *)node->data;
    if (!lru_node)
	return;
    /*
     * It seems to be possible for an entry to exist in the hash
     * but not be in the LRU list, so check for that case rather
     * than suffer a NULL pointer access.
     */
    if (NULL == lru_node->node.data)
	return;
    assert(lru_node->node.data == entry);
    node->data = NULL;
    dlinkDelete(&lru_node->node, &lru->list);
    memPoolFree(lru_node_pool, lru_node);
    lru->count -= 1;
}

static void
lru_referenced(RemovalPolicy * policy, const StoreEntry * entry,
    RemovalPolicyNode * node)
{
    LruPolicyData *lru = (LruPolicyData *)policy->_data;
    LruNode *lru_node = (LruNode *)node->data;
    if (!lru_node)
	return;
    dlinkDelete(&lru_node->node, &lru->list);
    dlinkAddTail((void *) entry, &lru_node->node, &lru->list);
}

/** RemovalPolicyWalker **/

typedef struct _LruWalkData LruWalkData;
struct _LruWalkData {
    LruNode *current;
};

static const StoreEntry *
lru_walkNext(RemovalPolicyWalker * walker)
{
    LruWalkData *lru_walk = (LruWalkData *)walker->_data;
    LruNode *lru_node = lru_walk->current;
    if (!lru_node)
	return NULL;
    lru_walk->current = (LruNode *) lru_node->node.next;
    return (StoreEntry *) lru_node->node.data;
}

static void
lru_walkDone(RemovalPolicyWalker * walker)
{
    RemovalPolicy *policy = walker->_policy;
    LruPolicyData *lru = (LruPolicyData *)policy->_data;
    assert(strcmp(policy->_type, "lru") == 0);
    assert(lru->nwalkers > 0);
    lru->nwalkers -= 1;
    safe_free(walker->_data);
    cbdataFree(walker);
}

static RemovalPolicyWalker *
lru_walkInit(RemovalPolicy * policy)
{
    LruPolicyData *lru = (LruPolicyData *)policy->_data;
    RemovalPolicyWalker *walker;
    LruWalkData *lru_walk;
    lru->nwalkers += 1;
    walker = cbdataAlloc(RemovalPolicyWalker);
    lru_walk = (LruWalkData *)xcalloc(1, sizeof(*lru_walk));
    walker->_policy = policy;
    walker->_data = lru_walk;
    walker->Next = lru_walkNext;
    walker->Done = lru_walkDone;
    lru_walk->current = (LruNode *) lru->list.head;
    return walker;
}

/** RemovalPurgeWalker **/

typedef struct _LruPurgeData LruPurgeData;
struct _LruPurgeData {
    LruNode *current;
    LruNode *start;
};

static StoreEntry *
lru_purgeNext(RemovalPurgeWalker * walker)
{
    LruPurgeData *lru_walker = (LruPurgeData *)walker->_data;
    RemovalPolicy *policy = walker->_policy;
    LruPolicyData *lru = (LruPolicyData *)policy->_data;
    LruNode *lru_node;
    StoreEntry *entry;
  try_again:
    lru_node = lru_walker->current;
    if (!lru_node || walker->scanned >= walker->max_scan)
	return NULL;
    walker->scanned += 1;
    lru_walker->current = (LruNode *) lru_node->node.next;
    if (lru_walker->current == lru_walker->start) {
	/* Last node found */
	lru_walker->current = NULL;
    }
    entry = (StoreEntry *) lru_node->node.data;
    dlinkDelete(&lru_node->node, &lru->list);
    if (storeEntryLocked(entry)) {
	/* Shit, it is locked. we can't return this one */
	walker->locked++;
	dlinkAddTail(entry, &lru_node->node, &lru->list);
	goto try_again;
    }
    memPoolFree(lru_node_pool, lru_node);
    lru->count -= 1;
    lru->setPolicyNode(entry, NULL);
    return entry;
}

static void
lru_purgeDone(RemovalPurgeWalker * walker)
{
    RemovalPolicy *policy = walker->_policy;
    LruPolicyData *lru = (LruPolicyData *)policy->_data;
    assert(strcmp(policy->_type, "lru") == 0);
    assert(lru->nwalkers > 0);
    lru->nwalkers -= 1;
    safe_free(walker->_data);
    cbdataFree(walker);
}

static RemovalPurgeWalker *
lru_purgeInit(RemovalPolicy * policy, int max_scan)
{
    LruPolicyData *lru = (LruPolicyData *)policy->_data;
    RemovalPurgeWalker *walker;
    LruPurgeData *lru_walk;
    lru->nwalkers += 1;
    walker = cbdataAlloc(RemovalPurgeWalker);
    lru_walk = (LruPurgeData *)xcalloc(1, sizeof(*lru_walk));
    walker->_policy = policy;
    walker->_data = lru_walk;
    walker->max_scan = max_scan;
    walker->Next = lru_purgeNext;
    walker->Done = lru_purgeDone;
    lru_walk->start = lru_walk->current = (LruNode *) lru->list.head;
    return walker;
}

static void
lru_stats(RemovalPolicy * policy, StoreEntry * sentry)
{
    LruPolicyData *lru = (LruPolicyData *)policy->_data;
    LruNode *lru_node = (LruNode *) lru->list.head;

  again:
    if (lru_node) {
	StoreEntry *entry = (StoreEntry *) lru_node->node.data;
	if (storeEntryLocked(entry)) {
	    lru_node = (LruNode *) lru_node->node.next;
	    goto again;
	}
	storeAppendPrintf(sentry, "LRU reference age: %.2f days\n", (double) (squid_curtime - entry->lastref) / (double) (24 * 60 * 60));
    }
}

static void
lru_free(RemovalPolicy * policy)
{
    LruPolicyData *lru = (LruPolicyData *)policy->_data;
    /* Make some verification of the policy state */
    assert(strcmp(policy->_type, "lru") == 0);
    assert(lru->nwalkers);
    assert(lru->count);
    /* Ok, time to destroy this policy */
    safe_free(policy->_data);
    memset(policy, 0, sizeof(*policy));
    cbdataFree(policy);
}

RemovalPolicy *
createRemovalPolicy_lru(wordlist * args)
{
    RemovalPolicy *policy;
    LruPolicyData *lru_data;
    /* no arguments expected or understood */
    assert(!args);
    /* Initialize */
    if (!lru_node_pool) {
	lru_node_pool = memPoolCreate("LRU policy node", sizeof(LruNode));
	memPoolSetChunkSize(lru_node_pool, 512 * 1024);
    }
    /* Allocate the needed structures */
    lru_data = (LruPolicyData *)xcalloc(1, sizeof(*lru_data));
    policy = cbdataAlloc(RemovalPolicy);
    /* Initialize the URL data */
    lru_data->policy = policy;
    /* Populate the policy structure */
    policy->_type = "lru";
    policy->_data = lru_data;
    policy->Free = lru_free;
    policy->Add = lru_add;
    policy->Remove = lru_remove;
    policy->Referenced = lru_referenced;
    policy->Dereferenced = lru_referenced;
    policy->WalkInit = lru_walkInit;
    policy->PurgeInit = lru_purgeInit;
    policy->Stats = lru_stats;
    /* Increase policy usage count */
    nr_lru_policies += 0;
    return policy;
}
Commit	Line	Data
6a566b9c	1
6a566b9c	2	/*
528b2c61	3	* $Id: store_repl_lru.cc,v 1.13 2003/01/23 00:38:29 robertc Exp $
6a566b9c	4	*
	5	* DEBUG: section ? LRU Removal policy
	6	* AUTHOR: Henrik Nordstrom
	7	*
2b6662ba	8	* SQUID Web Proxy Cache http://www.squid-cache.org/
6a566b9c	9	* ----------------------------------------------------------
6a566b9c	10	*
2b6662ba	11	* Squid is the result of efforts by numerous individuals from
	12	* the Internet community; see the CONTRIBUTORS file for full
	13	* details. Many organizations have provided support for Squid's
	14	* development; see the SPONSORS file for full details. Squid is
	15	* Copyrighted (C) 2001 by the Regents of the University of
	16	* California; see the COPYRIGHT file for full details. Squid
	17	* incorporates software developed and/or copyrighted by other
	18	* sources; see the CREDITS file for full details.
6a566b9c	19	*
	20	* This program is free software; you can redistribute it and/or modify
	21	* it under the terms of the GNU General Public License as published by
	22	* the Free Software Foundation; either version 2 of the License, or
	23	* (at your option) any later version.
	24	*
	25	* This program is distributed in the hope that it will be useful,
	26	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	27	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	28	* GNU General Public License for more details.
	29	*
	30	* You should have received a copy of the GNU General Public License
	31	* along with this program; if not, write to the Free Software
	32	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
	33	*
	34	*/
	35
	36	#include "squid.h"
e6ccf245	37	#include "Store.h"
528b2c61	38	#include "MemObject.h"
6a566b9c	39
	40	REMOVALPOLICYCREATE createRemovalPolicy_lru;
	41
e6ccf245	42	struct LruPolicyData {
e6ccf245	43	void setPolicyNode (StoreEntry , void ) const;
6a566b9c	44	RemovalPolicy *policy;
	45	dlink_list list;
	46	int count;
	47	int nwalkers;
9f913cf1	48	enum heap_entry_type {
	49	TYPE_UNKNOWN = 0, TYPE_STORE_ENTRY, TYPE_STORE_MEM
	50	} type;
6a566b9c	51	};
	52
	53	/* Hack to avoid having to remember the RemovalPolicyNode location.
	54	* Needed by the purge walker to clear the policy information
	55	*/
e6ccf245	56	static enum LruPolicyData::heap_entry_type
6a566b9c	57	repl_guessType(StoreEntry * entry, RemovalPolicyNode * node)
	58	{
	59	if (node == &entry->repl)
e6ccf245	60	return LruPolicyData::TYPE_STORE_ENTRY;
6a566b9c	61	if (entry->mem_obj && node == &entry->mem_obj->repl)
e6ccf245	62	return LruPolicyData::TYPE_STORE_MEM;
6a566b9c	63	fatal("Heap Replacement: Unknown StoreEntry node type");
e6ccf245	64	return LruPolicyData::TYPE_UNKNOWN;
6a566b9c	65	}
e6ccf245	66
	67	void
	68	LruPolicyData::setPolicyNode (StoreEntry entry, void value) const
	69	{
	70	switch (type) {
	71	case TYPE_STORE_ENTRY: entry->repl.data = value; break ;
	72	case TYPE_STORE_MEM: entry->mem_obj->repl.data = value ; break ;
	73	default: break;
6a566b9c	74	}
e6ccf245	75	}
6a566b9c	76
6a566b9c	77	typedef struct _LruNode LruNode;
9f913cf1	78	struct _LruNode {
6a566b9c	79	/* Note: the dlink_node MUST be the first member of the LruNode
	80	* structure. This member is later pointer typecasted to LruNode *.
	81	*/
	82	dlink_node node;
	83	};
	84
	85	static MemPool *lru_node_pool = NULL;
	86	static int nr_lru_policies = 0;
	87
	88	static void
	89	lru_add(RemovalPolicy * policy, StoreEntry * entry, RemovalPolicyNode * node)
	90	{
e6ccf245	91	LruPolicyData lru = (LruPolicyData )policy->_data;
6a566b9c	92	LruNode *lru_node;
6a566b9c	93	assert(!node->data);
e6ccf245	94	node->data = lru_node = (LruNode *)memPoolAlloc(lru_node_pool);
6a566b9c	95	dlinkAddTail(entry, &lru_node->node, &lru->list);
	96	lru->count += 1;
	97	if (!lru->type)
	98	lru->type = repl_guessType(entry, node);
	99	}
	100
	101	static void
	102	lru_remove(RemovalPolicy * policy, StoreEntry * entry, RemovalPolicyNode * node)
	103	{
e6ccf245	104	LruPolicyData lru = (LruPolicyData )policy->_data;
e6ccf245	105	LruNode lru_node = (LruNode )node->data;
6a566b9c	106	if (!lru_node)
6a566b9c	107	return;
75240ca9	108	/*
	109	* It seems to be possible for an entry to exist in the hash
	110	* but not be in the LRU list, so check for that case rather
	111	* than suffer a NULL pointer access.
	112	*/
	113	if (NULL == lru_node->node.data)
	114	return;
6a566b9c	115	assert(lru_node->node.data == entry);
	116	node->data = NULL;
	117	dlinkDelete(&lru_node->node, &lru->list);
	118	memPoolFree(lru_node_pool, lru_node);
	119	lru->count -= 1;
	120	}
	121
	122	static void
	123	lru_referenced(RemovalPolicy * policy, const StoreEntry * entry,
	124	RemovalPolicyNode * node)
	125	{
e6ccf245	126	LruPolicyData lru = (LruPolicyData )policy->_data;
e6ccf245	127	LruNode lru_node = (LruNode )node->data;
6a566b9c	128	if (!lru_node)
	129	return;
	130	dlinkDelete(&lru_node->node, &lru->list);
	131	dlinkAddTail((void *) entry, &lru_node->node, &lru->list);
	132	}
	133
	134	/ RemovalPolicyWalker /
	135
	136	typedef struct _LruWalkData LruWalkData;
9f913cf1	137	struct _LruWalkData {
6a566b9c	138	LruNode *current;
	139	};
	140
2d72d4fd	141	static const StoreEntry *
6a566b9c	142	lru_walkNext(RemovalPolicyWalker * walker)
6a566b9c	143	{
e6ccf245	144	LruWalkData lru_walk = (LruWalkData )walker->_data;
6a566b9c	145	LruNode *lru_node = lru_walk->current;
	146	if (!lru_node)
	147	return NULL;
	148	lru_walk->current = (LruNode *) lru_node->node.next;
	149	return (StoreEntry *) lru_node->node.data;
	150	}
	151
	152	static void
	153	lru_walkDone(RemovalPolicyWalker * walker)
	154	{
	155	RemovalPolicy *policy = walker->_policy;
e6ccf245	156	LruPolicyData lru = (LruPolicyData )policy->_data;
6a566b9c	157	assert(strcmp(policy->_type, "lru") == 0);
	158	assert(lru->nwalkers > 0);
	159	lru->nwalkers -= 1;
	160	safe_free(walker->_data);
	161	cbdataFree(walker);
	162	}
	163
	164	static RemovalPolicyWalker *
	165	lru_walkInit(RemovalPolicy * policy)
	166	{
e6ccf245	167	LruPolicyData lru = (LruPolicyData )policy->_data;
6a566b9c	168	RemovalPolicyWalker *walker;
	169	LruWalkData *lru_walk;
	170	lru->nwalkers += 1;
72711e31	171	walker = cbdataAlloc(RemovalPolicyWalker);
e6ccf245	172	lru_walk = (LruWalkData )xcalloc(1, sizeof(lru_walk));
6a566b9c	173	walker->_policy = policy;
	174	walker->_data = lru_walk;
	175	walker->Next = lru_walkNext;
	176	walker->Done = lru_walkDone;
	177	lru_walk->current = (LruNode *) lru->list.head;
6a566b9c	178	return walker;
	179	}
	180
	181	/ RemovalPurgeWalker /
	182
	183	typedef struct _LruPurgeData LruPurgeData;
9f913cf1	184	struct _LruPurgeData {
6a566b9c	185	LruNode *current;
	186	LruNode *start;
	187	};
	188
	189	static StoreEntry *
	190	lru_purgeNext(RemovalPurgeWalker * walker)
	191	{
e6ccf245	192	LruPurgeData lru_walker = (LruPurgeData )walker->_data;
6a566b9c	193	RemovalPolicy *policy = walker->_policy;
e6ccf245	194	LruPolicyData lru = (LruPolicyData )policy->_data;
6a566b9c	195	LruNode *lru_node;
	196	StoreEntry *entry;
	197	try_again:
	198	lru_node = lru_walker->current;
	199	if (!lru_node \|\| walker->scanned >= walker->max_scan)
	200	return NULL;
	201	walker->scanned += 1;
	202	lru_walker->current = (LruNode *) lru_node->node.next;
	203	if (lru_walker->current == lru_walker->start) {
	204	/* Last node found */
	205	lru_walker->current = NULL;
	206	}
	207	entry = (StoreEntry *) lru_node->node.data;
	208	dlinkDelete(&lru_node->node, &lru->list);
	209	if (storeEntryLocked(entry)) {
	210	/* Shit, it is locked. we can't return this one */
	211	walker->locked++;
	212	dlinkAddTail(entry, &lru_node->node, &lru->list);
	213	goto try_again;
	214	}
	215	memPoolFree(lru_node_pool, lru_node);
	216	lru->count -= 1;
e6ccf245	217	lru->setPolicyNode(entry, NULL);
6a566b9c	218	return entry;
	219	}
	220
	221	static void
	222	lru_purgeDone(RemovalPurgeWalker * walker)
	223	{
	224	RemovalPolicy *policy = walker->_policy;
e6ccf245	225	LruPolicyData lru = (LruPolicyData )policy->_data;
6a566b9c	226	assert(strcmp(policy->_type, "lru") == 0);
	227	assert(lru->nwalkers > 0);
	228	lru->nwalkers -= 1;
	229	safe_free(walker->_data);
	230	cbdataFree(walker);
	231	}
	232
	233	static RemovalPurgeWalker *
	234	lru_purgeInit(RemovalPolicy * policy, int max_scan)
	235	{
e6ccf245	236	LruPolicyData lru = (LruPolicyData )policy->_data;
6a566b9c	237	RemovalPurgeWalker *walker;
	238	LruPurgeData *lru_walk;
	239	lru->nwalkers += 1;
72711e31	240	walker = cbdataAlloc(RemovalPurgeWalker);
e6ccf245	241	lru_walk = (LruPurgeData )xcalloc(1, sizeof(lru_walk));
6a566b9c	242	walker->_policy = policy;
	243	walker->_data = lru_walk;
	244	walker->max_scan = max_scan;
	245	walker->Next = lru_purgeNext;
	246	walker->Done = lru_purgeDone;
	247	lru_walk->start = lru_walk->current = (LruNode *) lru->list.head;
6a566b9c	248	return walker;
	249	}
	250
8a3e7d9e	251	static void
	252	lru_stats(RemovalPolicy * policy, StoreEntry * sentry)
	253	{
e6ccf245	254	LruPolicyData lru = (LruPolicyData )policy->_data;
b671cc68	255	LruNode lru_node = (LruNode ) lru->list.head;
8a3e7d9e	256
b671cc68	257	again:
8a3e7d9e	258	if (lru_node) {
b671cc68	259	StoreEntry entry = (StoreEntry ) lru_node->node.data;
8a3e7d9e	260	if (storeEntryLocked(entry)) {
b671cc68	261	lru_node = (LruNode *) lru_node->node.next;
8a3e7d9e	262	goto again;
	263	}
	264	storeAppendPrintf(sentry, "LRU reference age: %.2f days\n", (double) (squid_curtime - entry->lastref) / (double) (24 * 60 * 60));
	265	}
	266	}
	267
6a566b9c	268	static void
	269	lru_free(RemovalPolicy * policy)
	270	{
e6ccf245	271	LruPolicyData lru = (LruPolicyData )policy->_data;
6a566b9c	272	/* Make some verification of the policy state */
	273	assert(strcmp(policy->_type, "lru") == 0);
	274	assert(lru->nwalkers);
	275	assert(lru->count);
	276	/* Ok, time to destroy this policy */
	277	safe_free(policy->_data);
	278	memset(policy, 0, sizeof(*policy));
	279	cbdataFree(policy);
	280	}
	281
	282	RemovalPolicy *
9f913cf1	283	createRemovalPolicy_lru(wordlist * args)
6a566b9c	284	{
	285	RemovalPolicy *policy;
	286	LruPolicyData *lru_data;
	287	/* no arguments expected or understood */
	288	assert(!args);
	289	/* Initialize */
d96ceb8e	290	if (!lru_node_pool) {
6a566b9c	291	lru_node_pool = memPoolCreate("LRU policy node", sizeof(LruNode));
d96ceb8e	292	memPoolSetChunkSize(lru_node_pool, 512 * 1024);
d96ceb8e	293	}
6a566b9c	294	/* Allocate the needed structures */
e6ccf245	295	lru_data = (LruPolicyData )xcalloc(1, sizeof(lru_data));
72711e31	296	policy = cbdataAlloc(RemovalPolicy);
6a566b9c	297	/* Initialize the URL data */
	298	lru_data->policy = policy;
	299	/* Populate the policy structure */
	300	policy->_type = "lru";
	301	policy->_data = lru_data;
	302	policy->Free = lru_free;
	303	policy->Add = lru_add;
	304	policy->Remove = lru_remove;
	305	policy->Referenced = lru_referenced;
	306	policy->Dereferenced = lru_referenced;
	307	policy->WalkInit = lru_walkInit;
	308	policy->PurgeInit = lru_purgeInit;
8a3e7d9e	309	policy->Stats = lru_stats;
6a566b9c	310	/* Increase policy usage count */
	311	nr_lru_policies += 0;
	312	return policy;
	313	}