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active memory defragmentation

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This commit is contained in:
oranagra 2016-12-30 03:37:52 +02:00
parent 6712bce92c
commit 7aa9e6d2ae
13 changed files with 755 additions and 8 deletions
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32
deps/jemalloc/src/jemalloc.c vendored
View File

@ -2591,3 +2591,35 @@ jemalloc_postfork_child(void)
}
/******************************************************************************/
/* Helps the application decide if a pointer is worth re-allocating in order to reduce fragmentation.
* returns 0 if the allocation is in the currently active run,
* or when it is not causing any frag issue (large or huge bin)
* returns the bin utilization and run utilization both in fixed point 16:16.
* If the application decides to re-allocate it should use MALLOCX_TCACHE_NONE when doing so. */
JEMALLOC_EXPORT int JEMALLOC_NOTHROW
je_get_defrag_hint(void* ptr, int *bin_util, int *run_util) {
int defrag = 0;
arena_chunk_t *chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(ptr);
if (likely(chunk != ptr)) { /* indication that this is not a HUGE alloc */
size_t pageind = ((uintptr_t)ptr - (uintptr_t)chunk) >> LG_PAGE;
size_t mapbits = arena_mapbits_get(chunk, pageind);
if (likely((mapbits & CHUNK_MAP_LARGE) == 0)) { /* indication that this is not a LARGE alloc */
arena_t *arena = extent_node_arena_get(&chunk->node);
size_t rpages_ind = pageind - arena_mapbits_small_runind_get(chunk, pageind);
arena_run_t *run = &arena_miscelm_get(chunk, rpages_ind)->run;
arena_bin_t *bin = &arena->bins[run->binind];
malloc_mutex_lock(&bin->lock);
/* runs that are in the same chunk in as the current chunk, are likely to be the next currun */
if (chunk != (arena_chunk_t *)CHUNK_ADDR2BASE(bin->runcur)) {
arena_bin_info_t *bin_info = &arena_bin_info[run->binind];
size_t availregs = bin_info->nregs * bin->stats.curruns;
*bin_util = (bin->stats.curregs<<16) / availregs;
*run_util = ((bin_info->nregs - run->nfree)<<16) / bin_info->nregs;
defrag = 1;
}
malloc_mutex_unlock(&bin->lock);
}
}
return defrag;
}

20
redis.conf
View File

@ -1228,3 +1228,23 @@ aof-rewrite-incremental-fsync yes
#
# lfu-log-factor 10
# lfu-decay-time 1
########################### ACTIVE DEFRAGMENTATION #######################
# enabled active defragmentation
# activedefrag yes
# minimum amount of fragmentation waste to start active defrag
# active-defrag-ignore-bytes 100mb
# minimum percentage of fragmentation to start active defrag
# active-defrag-threshold-lower 10
# maximum percentage of fragmentation at which we use maximum effort
# active-defrag-threshold-upper 100
# minimal effort for defrag in CPU percentage
# active-defrag-cycle-min 25
# maximal effort for defrag in CPU percentage
# active-defrag-cycle-max 75

2
src/Makefile
View File

@ -128,7 +128,7 @@ endif
REDIS_SERVER_NAME=redis-server
REDIS_SENTINEL_NAME=redis-sentinel
REDIS_SERVER_OBJ=adlist.o quicklist.o ae.o anet.o dict.o server.o sds.o zmalloc.o lzf_c.o lzf_d.o pqsort.o zipmap.o sha1.o ziplist.o release.o networking.o util.o object.o db.o replication.o rdb.o t_string.o t_list.o t_set.o t_zset.o t_hash.o config.o aof.o pubsub.o multi.o debug.o sort.o intset.o syncio.o cluster.o crc16.o endianconv.o slowlog.o scripting.o bio.o rio.o rand.o memtest.o crc64.o bitops.o sentinel.o notify.o setproctitle.o blocked.o hyperloglog.o latency.o sparkline.o redis-check-rdb.o geo.o lazyfree.o module.o evict.o expire.o geohash.o geohash_helper.o childinfo.o
REDIS_SERVER_OBJ=adlist.o quicklist.o ae.o anet.o dict.o server.o sds.o zmalloc.o lzf_c.o lzf_d.o pqsort.o zipmap.o sha1.o ziplist.o release.o networking.o util.o object.o db.o replication.o rdb.o t_string.o t_list.o t_set.o t_zset.o t_hash.o config.o aof.o pubsub.o multi.o debug.o sort.o intset.o syncio.o cluster.o crc16.o endianconv.o slowlog.o scripting.o bio.o rio.o rand.o memtest.o crc64.o bitops.o sentinel.o notify.o setproctitle.o blocked.o hyperloglog.o latency.o sparkline.o redis-check-rdb.o geo.o lazyfree.o module.o evict.o expire.o geohash.o geohash_helper.o childinfo.o defrag.o
REDIS_CLI_NAME=redis-cli
REDIS_CLI_OBJ=anet.o adlist.o redis-cli.o zmalloc.o release.o anet.o ae.o crc64.o
REDIS_BENCHMARK_NAME=redis-benchmark

58
src/config.c
View File

@ -423,6 +423,10 @@ void loadServerConfigFromString(char *config) {
if ((server.repl_slave_lazy_flush = yesnotoi(argv[1])) == -1) {
err = "argument must be 'yes' or 'no'"; goto loaderr;
}
} else if (!strcasecmp(argv[0],"activedefrag") && argc == 2) {
if ((server.active_defrag_enabled = yesnotoi(argv[1])) == -1) {
err = "argument must be 'yes' or 'no'"; goto loaderr;
}
} else if (!strcasecmp(argv[0],"daemonize") && argc == 2) {
if ((server.daemonize = yesnotoi(argv[1])) == -1) {
err = "argument must be 'yes' or 'no'"; goto loaderr;
@ -499,6 +503,36 @@ void loadServerConfigFromString(char *config) {
}
zfree(server.rdb_filename);
server.rdb_filename = zstrdup(argv[1]);
} else if (!strcasecmp(argv[0],"active-defrag-threshold-lower") && argc == 2) {
server.active_defrag_threshold_lower = atoi(argv[1]);
if (server.active_defrag_threshold_lower < 0) {
err = "active-defrag-threshold-lower must be 0 or greater";
goto loaderr;
}
} else if (!strcasecmp(argv[0],"active-defrag-threshold-upper") && argc == 2) {
server.active_defrag_threshold_upper = atoi(argv[1]);
if (server.active_defrag_threshold_upper < 0) {
err = "active-defrag-threshold-upper must be 0 or greater";
goto loaderr;
}
} else if (!strcasecmp(argv[0],"active-defrag-ignore-bytes") && argc == 2) {
server.active_defrag_ignore_bytes = memtoll(argv[1], NULL);
if (server.active_defrag_ignore_bytes <= 0) {
err = "active-defrag-ignore-bytes must above 0";
goto loaderr;
}
} else if (!strcasecmp(argv[0],"active-defrag-cycle-min") && argc == 2) {
server.active_defrag_cycle_min = atoi(argv[1]);
if (server.active_defrag_cycle_min < 1 || server.active_defrag_cycle_min > 99) {
err = "active-defrag-cycle-min must be between 1 and 99";
goto loaderr;
}
} else if (!strcasecmp(argv[0],"active-defrag-cycle-max") && argc == 2) {
server.active_defrag_cycle_max = atoi(argv[1]);
if (server.active_defrag_cycle_max < 1 || server.active_defrag_cycle_max > 99) {
err = "active-defrag-cycle-max must be between 1 and 99";
goto loaderr;
}
} else if (!strcasecmp(argv[0],"hash-max-ziplist-entries") && argc == 2) {
server.hash_max_ziplist_entries = memtoll(argv[1], NULL);
} else if (!strcasecmp(argv[0],"hash-max-ziplist-value") && argc == 2) {
@ -971,6 +1005,8 @@ void configSetCommand(client *c) {
"slave-read-only",server.repl_slave_ro) {
} config_set_bool_field(
"activerehashing",server.activerehashing) {
} config_set_bool_field(
"activedefrag",server.active_defrag_enabled) {
} config_set_bool_field(
"protected-mode",server.protected_mode) {
} config_set_bool_field(
@ -998,6 +1034,16 @@ void configSetCommand(client *c) {
"lfu-decay-time",server.lfu_decay_time,0,LLONG_MAX) {
} config_set_numerical_field(
"timeout",server.maxidletime,0,LONG_MAX) {
} config_set_numerical_field(
"active-defrag-threshold-lower",server.active_defrag_threshold_lower,0,1000) {
} config_set_numerical_field(
"active-defrag-threshold-upper",server.active_defrag_threshold_upper,0,1000) {
} config_set_memory_field(
"active-defrag-ignore-bytes",server.active_defrag_ignore_bytes) {
} config_set_numerical_field(
"active-defrag-cycle-min",server.active_defrag_cycle_min,1,99) {
} config_set_numerical_field(
"active-defrag-cycle-max",server.active_defrag_cycle_max,1,99) {
} config_set_numerical_field(
"auto-aof-rewrite-percentage",server.aof_rewrite_perc,0,LLONG_MAX){
} config_set_numerical_field(
@ -1166,6 +1212,11 @@ void configGetCommand(client *c) {
config_get_numerical_field("maxmemory",server.maxmemory);
config_get_numerical_field("maxmemory-samples",server.maxmemory_samples);
config_get_numerical_field("timeout",server.maxidletime);
config_get_numerical_field("active-defrag-threshold-lower",server.active_defrag_threshold_lower);
config_get_numerical_field("active-defrag-threshold-upper",server.active_defrag_threshold_upper);
config_get_numerical_field("active-defrag-ignore-bytes",server.active_defrag_ignore_bytes);
config_get_numerical_field("active-defrag-cycle-min",server.active_defrag_cycle_min);
config_get_numerical_field("active-defrag-cycle-max",server.active_defrag_cycle_max);
config_get_numerical_field("auto-aof-rewrite-percentage",
server.aof_rewrite_perc);
config_get_numerical_field("auto-aof-rewrite-min-size",
@ -1230,6 +1281,7 @@ void configGetCommand(client *c) {
config_get_bool_field("rdbcompression", server.rdb_compression);
config_get_bool_field("rdbchecksum", server.rdb_checksum);
config_get_bool_field("activerehashing", server.activerehashing);
config_get_bool_field("activedefrag", server.active_defrag_enabled);
config_get_bool_field("protected-mode", server.protected_mode);
config_get_bool_field("repl-disable-tcp-nodelay",
server.repl_disable_tcp_nodelay);
@ -1930,6 +1982,11 @@ int rewriteConfig(char *path) {
rewriteConfigBytesOption(state,"maxmemory",server.maxmemory,CONFIG_DEFAULT_MAXMEMORY);
rewriteConfigEnumOption(state,"maxmemory-policy",server.maxmemory_policy,maxmemory_policy_enum,CONFIG_DEFAULT_MAXMEMORY_POLICY);
rewriteConfigNumericalOption(state,"maxmemory-samples",server.maxmemory_samples,CONFIG_DEFAULT_MAXMEMORY_SAMPLES);
rewriteConfigNumericalOption(state,"active-defrag-threshold-lower",server.active_defrag_threshold_lower,CONFIG_DEFAULT_DEFRAG_THRESHOLD_LOWER);
rewriteConfigNumericalOption(state,"active-defrag-threshold-upper",server.active_defrag_threshold_upper,CONFIG_DEFAULT_DEFRAG_THRESHOLD_UPPER);
rewriteConfigBytesOption(state,"active-defrag-ignore-bytes",server.active_defrag_ignore_bytes,CONFIG_DEFAULT_DEFRAG_IGNORE_BYTES);
rewriteConfigNumericalOption(state,"active-defrag-cycle-min",server.active_defrag_cycle_min,CONFIG_DEFAULT_DEFRAG_CYCLE_MIN);
rewriteConfigNumericalOption(state,"active-defrag-cycle-max",server.active_defrag_cycle_max,CONFIG_DEFAULT_DEFRAG_CYCLE_MAX);
rewriteConfigYesNoOption(state,"appendonly",server.aof_state != AOF_OFF,0);
rewriteConfigStringOption(state,"appendfilename",server.aof_filename,CONFIG_DEFAULT_AOF_FILENAME);
rewriteConfigEnumOption(state,"appendfsync",server.aof_fsync,aof_fsync_enum,CONFIG_DEFAULT_AOF_FSYNC);
@ -1956,6 +2013,7 @@ int rewriteConfig(char *path) {
rewriteConfigNumericalOption(state,"zset-max-ziplist-value",server.zset_max_ziplist_value,OBJ_ZSET_MAX_ZIPLIST_VALUE);
rewriteConfigNumericalOption(state,"hll-sparse-max-bytes",server.hll_sparse_max_bytes,CONFIG_DEFAULT_HLL_SPARSE_MAX_BYTES);
rewriteConfigYesNoOption(state,"activerehashing",server.activerehashing,CONFIG_DEFAULT_ACTIVE_REHASHING);
rewriteConfigYesNoOption(state,"activedefrag",server.active_defrag_enabled,CONFIG_DEFAULT_ACTIVE_DEFRAG);
rewriteConfigYesNoOption(state,"protected-mode",server.protected_mode,CONFIG_DEFAULT_PROTECTED_MODE);
rewriteConfigClientoutputbufferlimitOption(state);
rewriteConfigNumericalOption(state,"hz",server.hz,CONFIG_DEFAULT_HZ);

2
src/db.c
View File

@ -665,7 +665,7 @@ void scanGenericCommand(client *c, robj *o, unsigned long cursor) {
privdata[0] = keys;
privdata[1] = o;
do {
cursor = dictScan(ht, cursor, scanCallback, privdata);
cursor = dictScan(ht, cursor, scanCallback, NULL, privdata);
} while (cursor &&
maxiterations-- &&
listLength(keys) < (unsigned long)count);

15
src/debug.c
View File

@ -282,7 +282,7 @@ void debugCommand(client *c) {
blen++; addReplyStatus(c,
"ziplist <key> -- Show low level info about the ziplist encoding.");
blen++; addReplyStatus(c,
"populate <count> [prefix] -- Create <count> string keys named key:<num>. If a prefix is specified is used instead of the 'key' prefix.");
"populate <count> [prefix] [size] -- Create <count> string keys named key:<num>. If a prefix is specified is used instead of the 'key' prefix.");
blen++; addReplyStatus(c,
"digest -- Outputs an hex signature representing the current DB content.");
blen++; addReplyStatus(c,
@ -433,7 +433,7 @@ void debugCommand(client *c) {
addReplyStatus(c,"Ziplist structure printed on stdout");
}
} else if (!strcasecmp(c->argv[1]->ptr,"populate") &&
(c->argc == 3 || c->argc == 4)) {
c->argc >= 3 && c->argc <= 5) {
long keys, j;
robj *key, *val;
char buf[128];
@ -442,15 +442,24 @@ void debugCommand(client *c) {
return;
dictExpand(c->db->dict,keys);
for (j = 0; j < keys; j++) {
long valsize = 0;
snprintf(buf,sizeof(buf),"%s:%lu",
(c->argc == 3) ? "key" : (char*)c->argv[3]->ptr, j);
key = createStringObject(buf,strlen(buf));
if (c->argc == 5)
if (getLongFromObjectOrReply(c, c->argv[4], &valsize, NULL) != C_OK)
return;
if (lookupKeyWrite(c->db,key) != NULL) {
decrRefCount(key);
continue;
}
snprintf(buf,sizeof(buf),"value:%lu",j);
val = createStringObject(buf,strlen(buf));
if (valsize==0)
val = createStringObject(buf,strlen(buf));
else {
val = createStringObject(NULL,valsize);
memset(val->ptr, 0, valsize);
}
dbAdd(c->db,key,val);
signalModifiedKey(c->db,key);
decrRefCount(key);

527
src/defrag.c Normal file
View File

@ -0,0 +1,527 @@
/*
* Active memory defragmentation
* Try to find key / value allocations that need to be re-allocated in order
* to reduce external fragmentation.
* We do that by scanning the keyspace and for each pointer we have, we can try to
* ask the allocator if moving it to a new address will help reduce fragmentation.
*
* Copyright (c) 2017, Oran Agra
* Copyright (c) 2017, Redis Labs, Inc
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of Redis nor the names of its contributors may be used
* to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include "server.h"
#include <time.h>
#include <assert.h>
#include <stddef.h>
#if defined(USE_JEMALLOC) && defined(MALLOCX_TCACHE_NONE)
/* this method was added to jemalloc in order to help us understand which
* pointers are worthwhile moving and which aren't */
int je_get_defrag_hint(void* ptr, int *bin_util, int *run_util);
/* Defrag helper for generic allocations.
*
* returns NULL in case the allocatoin wasn't moved.
* when it returns a non-null value, the old pointer was already released
* and should NOT be accessed. */
void* activeDefragAlloc(void *ptr) {
int bin_util, run_util;
size_t size;
void *newptr;
if(!je_get_defrag_hint(ptr, &bin_util, &run_util)) {
server.stat_active_defrag_misses++;
return NULL;
}
/* if this run is more utilized than the average utilization in this bin (or it is full), skip it.
* this will eventually move all the allocations from relatively empty runs into relatively full runs. */
if (run_util > bin_util || run_util == 1<<16) {
server.stat_active_defrag_misses++;
return NULL;
}
/* move this allocation to a new allocation.
* make sure not to use the thread cache. so that we don't get back the same pointers we try to free */
size = zmalloc_size(ptr);
newptr = zmalloc_no_tcache(size);
memcpy(newptr, ptr, size);
zfree_no_tcache(ptr);
return newptr;
}
/*Defrag helper for sds strings
*
* returns NULL in case the allocatoin wasn't moved.
* when it returns a non-null value, the old pointer was already released
* and should NOT be accessed. */
sds activeDefragSds(sds sdsptr) {
void* ptr = sdsAllocPtr(sdsptr);
void* newptr = activeDefragAlloc(ptr);
if (newptr) {
size_t offset = sdsptr - (char*)ptr;
sdsptr = (char*)newptr + offset;
return sdsptr;
}
return NULL;
}
/* Defrag helper for robj and/or string objects
*
* returns NULL in case the allocatoin wasn't moved.
* when it returns a non-null value, the old pointer was already released
* and should NOT be accessed. */
robj *activeDefragStringOb(robj* ob) {
robj *ret = NULL;
if (ob->refcount!=1)
return NULL;
/* try to defrag robj (only if not an EMBSTR type (handled below) */
if (ob->type!=OBJ_STRING || ob->encoding!=OBJ_ENCODING_EMBSTR) {
if ((ret = activeDefragAlloc(ob)))
ob = ret;
}
/* try to defrag string object */
if (ob->type == OBJ_STRING) {
if(ob->encoding==OBJ_ENCODING_RAW) {
sds newsds = activeDefragSds((sds)ob->ptr);
if (newsds) {
ob->ptr = newsds;
/* we don't need to change the return value here.
* we can return NULL if 'ret' is still NULL (since the object pointer itself wasn't changed).
* but we set return value to ob as an indication that we defragged a pointer (for stats).
* NOTE: if ret is already set and the robj was moved, then our stats will be a bit off
* since two pointers were moved, but we show only one in the stats */
ret = ob;
}
} else if (ob->encoding==OBJ_ENCODING_EMBSTR) {
/* the sds is embedded in the object allocation, calculate the offset and update the pointer in the new allocation */
long ofs = (intptr_t)ob->ptr - (intptr_t)ob;
if ((ret = activeDefragAlloc(ob))) {
ret->ptr = (void*)((intptr_t)ret + ofs);
}
} else if (ob->encoding!=OBJ_ENCODING_INT) {
serverPanic("Unknown string encoding");
}
}
return ret;
}
/* Defrag helper for dictEntries to be used during dict iteration (called on each step).
* returns a stat of how many pointers were moved. */
int dictIterDefragEntry(dictIterator *iter) {
/* This function is a little bit dirty since it messes with the internals of the dict and it's iterator,
* but the benefit is that it is very easy to use, and require no other chagnes in the dict. */
int defragged = 0;
dictht *ht;
/* handle the next entry (if there is one), and update the pointer in the current entry. */
if (iter->nextEntry) {
dictEntry *newde = activeDefragAlloc(iter->nextEntry);
if (newde) {
defragged++;
iter->nextEntry = newde;
iter->entry->next = newde;
}
}
/* handle the case of the first entry in the hash bucket. */
ht = &iter->d->ht[iter->table];
if (ht->table[iter->index] == iter->entry) {
dictEntry *newde = activeDefragAlloc(iter->entry);
if (newde) {
iter->entry = newde;
ht->table[iter->index] = newde;
defragged++;
}
}
return defragged;
}
/* Defrag helper for dict main allocations (dict struct, and hash tables).
* receives a pointer to the dict* and implicitly updates it when the dict struct itself was moved.
* returns a stat of how many pointers were moved. */
int dictDefragTables(dict** dictRef) {
dict *d = *dictRef;
dictEntry **newtable;
int defragged = 0;
/* handle the dict struct */
dict *newd = activeDefragAlloc(d);
if (newd)
defragged++, *dictRef = d = newd;
/* handle the first hash table */
newtable = activeDefragAlloc(d->ht[0].table);
if (newtable)
defragged++, d->ht[0].table = newtable;
/* handle the second hash table */
if (d->ht[1].table) {
newtable = activeDefragAlloc(d->ht[1].table);
if (newtable)
defragged++, d->ht[1].table = newtable;
}
return defragged;
}
/* Internal function used by zslDefrag */
void zslUpdateNode(zskiplist *zsl, zskiplistNode *oldnode, zskiplistNode *newnode, zskiplistNode **update) {
int i;
for (i = 0; i < zsl->level; i++) {
if (update[i]->level[i].forward == oldnode)
update[i]->level[i].forward = newnode;
}
if (zsl->header==oldnode)
zsl->header = newnode;
if (zsl->tail==oldnode)
zsl->tail = newnode;
if (newnode->level[0].forward) {
serverAssert(newnode->level[0].forward->backward==oldnode);
newnode->level[0].forward->backward = newnode;
}
}
/* Defrag helper for sorted set.
* Update the robj pointer, defrag the struct and return the new score reference.
* we may not access oldele pointer (not even the pointer stored in the skiplist), as it was already freed.
* newele may be null, in which case we only need to defrag the skiplist, but not update the obj pointer.
* when return value is non-NULL, it is the score reference that must be updated in the dict record. */
double *zslDefrag(zskiplist *zsl, double score, sds oldele, sds newele) {
zskiplistNode *update[ZSKIPLIST_MAXLEVEL], *x, *newx;
int i;
sds ele = newele? newele: oldele;
/* find the skiplist node referring to the object that was moved,
* and all pointers that need to be updated if we'll end up moving the skiplist node. */
x = zsl->header;
for (i = zsl->level-1; i >= 0; i--) {
while (x->level[i].forward &&
x->level[i].forward->ele != oldele && /* make sure not to access the ->obj pointer if it matches oldele */
(x->level[i].forward->score < score ||
(x->level[i].forward->score == score &&
sdscmp(x->level[i].forward->ele,ele) < 0)))
x = x->level[i].forward;
update[i] = x;
}
/* update the robj pointer inside the skip list record. */
x = x->level[0].forward;
serverAssert(x && score == x->score && x->ele==oldele);
if (newele)
x->ele = newele;
/* try to defrag the skiplist record itself */
newx = activeDefragAlloc(x);
if (newx) {
zslUpdateNode(zsl, x, newx, update);
return &newx->score;
}
return NULL;
}
/* for each key we scan in the main dict, this function will attempt to defrag all the various pointers it has.
* returns a stat of how many pointers were moved. */
int defargKey(redisDb *db, dictEntry *de) {
sds keysds = dictGetKey(de);
robj *newob, *ob;
unsigned char *newzl;
dict *d;
dictIterator *di;
int defragged = 0;
sds newsds;
/* try to defrag the key name */
newsds = activeDefragSds(keysds);
if (newsds) {
de->key = newsds;
if (dictSize(db->expires)) {
/* Dirty code:
* i can't search in db->expires for that key after i already released the pointer it holds
* it won't be able to do the string compare */
unsigned int hash = dictGetHash(db->dict, newsds);
dictReplaceKeyPtr(db->expires, keysds, newsds, hash);
}
defragged++;
}
/* try to defrag robj and / or string value */
ob = dictGetVal(de);
if ((newob = activeDefragStringOb(ob))) {
de->v.val = newob;
ob = newob;
defragged++;
}
if (ob->type == OBJ_STRING) {
/* already handled in activeDefragStringOb */
} else if (ob->type == OBJ_LIST) {
if (ob->encoding == OBJ_ENCODING_QUICKLIST) {
quicklist *ql = ob->ptr, *newql;
quicklistNode *node = ql->head, *newnode;
if ((newql = activeDefragAlloc(ql)))
defragged++, ob->ptr = ql = newql;
do {
if ((newnode = activeDefragAlloc(node))) {
if (newnode->prev)
newnode->prev->next = newnode;
else
ql->head = newnode;
if (newnode->next)
newnode->next->prev = newnode;
else
ql->tail = newnode;
node = newnode;
defragged++;
}
if ((newzl = activeDefragAlloc(node->zl)))
defragged++, node->zl = newzl;
} while ((node = node->next));
} else if (ob->encoding == OBJ_ENCODING_ZIPLIST) {
if ((newzl = activeDefragAlloc(ob->ptr)))
defragged++, ob->ptr = newzl;
} else {
serverPanic("Unknown list encoding");
}
} else if (ob->type == OBJ_SET) {
if (ob->encoding == OBJ_ENCODING_HT) {
d = ob->ptr;
di = dictGetIterator(d);
while((de = dictNext(di)) != NULL) {
sds sdsele = dictGetKey(de);
if ((newsds = activeDefragSds(sdsele)))
defragged++, de->key = newsds;
defragged += dictIterDefragEntry(di);
}
dictReleaseIterator(di);
dictDefragTables((dict**)&ob->ptr);
} else if (ob->encoding == OBJ_ENCODING_INTSET) {
intset *is = ob->ptr;
intset *newis = activeDefragAlloc(is);
if (newis)
defragged++, ob->ptr = newis;
} else {
serverPanic("Unknown set encoding");
}
} else if (ob->type == OBJ_ZSET) {
if (ob->encoding == OBJ_ENCODING_ZIPLIST) {
if ((newzl = activeDefragAlloc(ob->ptr)))
defragged++, ob->ptr = newzl;
} else if (ob->encoding == OBJ_ENCODING_SKIPLIST) {
zset *zs = (zset*)ob->ptr;
zset *newzs = activeDefragAlloc(zs);
zskiplist *newzsl;
if (newzs)
defragged++, ob->ptr = zs = newzs;
newzsl = activeDefragAlloc(zs->zsl);
if (newzsl)
defragged++, zs->zsl = newzsl;
d = zs->dict;
di = dictGetIterator(d);
while((de = dictNext(di)) != NULL) {
double* newscore;
sds sdsele = dictGetKey(de);
if ((newsds = activeDefragSds(sdsele)))
defragged++, de->key = newsds;
newscore = zslDefrag(zs->zsl, *(double*)dictGetVal(de), sdsele, newsds);
if (newscore) {
dictSetVal(d, de, newscore);
defragged++;
}
defragged += dictIterDefragEntry(di);
}
dictReleaseIterator(di);
dictDefragTables(&zs->dict);
} else {
serverPanic("Unknown sorted set encoding");
}
} else if (ob->type == OBJ_HASH) {
if (ob->encoding == OBJ_ENCODING_ZIPLIST) {
if ((newzl = activeDefragAlloc(ob->ptr)))
defragged++, ob->ptr = newzl;
} else if (ob->encoding == OBJ_ENCODING_HT) {
d = ob->ptr;
di = dictGetIterator(d);
while((de = dictNext(di)) != NULL) {
sds sdsele = dictGetKey(de);
if ((newsds = activeDefragSds(sdsele)))
defragged++, de->key = newsds;
sdsele = dictGetVal(de);
if ((newsds = activeDefragSds(sdsele)))
defragged++, de->v.val = newsds;
defragged += dictIterDefragEntry(di);
}
dictReleaseIterator(di);
dictDefragTables((dict**)&ob->ptr);
} else {
serverPanic("Unknown hash encoding");
}
} else {
serverPanic("Unknown object type");
}
return defragged;
}
/* defrag scan callback for the main db dictionary */
void defragScanCallback(void *privdata, const dictEntry *de) {
/* TODO: defrag the dictEntry (and also the entriy in expire dict). */
int defragged = defargKey((redisDb*)privdata, (dictEntry*)de);
server.stat_active_defrag_hits += defragged;
if(defragged)
server.stat_active_defrag_key_hits++;
else
server.stat_active_defrag_key_misses++;
}
/* defrag scan callback for for each hash table bicket,
* used in order to defrag the dictEntry allocations */
void defragDictBucketCallback(void *privdata, dictEntry **bucketref) {
UNUSED(privdata);
while(*bucketref) {
dictEntry *de = *bucketref, *newde;
if ((newde = activeDefragAlloc(de))) {
*bucketref = newde;
}
bucketref = &(*bucketref)->next;
}
}
/* Utility function to get the fragmentation ratio from jemalloc.
* it is critical to do that by comparing only heap maps that belown to jemalloc, and skip ones the jemalloc keeps as spare.
* since we use this fragmentation ratio in order to decide if a defrag action should be taken or not,
* a false detection can cause the defragmenter to waste a lot of CPU without the possibility of getting any results. */
float getAllocatorFragmentation(size_t *out_frag_bytes) {
size_t epoch = 1, allocated = 0, resident = 0, active = 0, sz = sizeof(size_t);
je_mallctl("epoch", &epoch, &sz, &epoch, sz); /* Update the statistics cached by mallctl. */
je_mallctl("stats.resident", &resident, &sz, NULL, 0); /* unlike RSS, this does not include RSS from shared libraries and other non heap mappings */
je_mallctl("stats.active", &active, &sz, NULL, 0); /* unlike resident, this doesn't not include the pages jemalloc reserves for re-use (purge will clean that) */
je_mallctl("stats.allocated", &allocated, &sz, NULL, 0); /* unlike zmalloc_used_memory, this matches the stats.resident by taking into account all allocations done by this process (not only zmalloc) */
float frag_pct = ((float)active / allocated)*100 - 100;
size_t frag_bytes = active - allocated;
float rss_pct = ((float)resident / allocated)*100 - 100;
size_t rss_bytes = resident - allocated;
if(out_frag_bytes)
*out_frag_bytes = frag_bytes;
serverLog(LL_DEBUG,
"allocated=%zu, active=%zu, resident=%zu, frag=%.0f%% (%.0f%% rss), frag_bytes=%zu (%zu%% rss)",
allocated, active, resident, frag_pct, rss_pct, frag_bytes, rss_bytes);
return frag_pct;
}
#define INTERPOLATE(x, x1, x2, y1, y2) ( (y1) + ((x)-(x1)) * ((y2)-(y1)) / ((x2)-(x1)) )
#define LIMIT(y, min, max) ((y)<(min)? min: ((y)>(max)? max: (y)))
/* Perform incremental defragmentation work from the serverCron.
* This works in a similar way to activeExpireCycle, in the sense that
* we do incremental work across calls. */
void activeDefragCycle(void) {
static int current_db = -1;
static unsigned long cursor = 0;
static redisDb *db = NULL;
static long long start_scan, start_stat;
unsigned int iterations = 0;
unsigned long long defragged = server.stat_active_defrag_hits;
long long start, timelimit;
if (server.aof_child_pid!=-1 || server.rdb_child_pid!=-1)
return; /* defragging memory while there's a fork will just do damage. */
/* once a second, check if we the fragmentation justfies starting a scan or making it more aggressive */
run_with_period(1000) {
size_t frag_bytes;
float frag_pct = getAllocatorFragmentation(&frag_bytes);
/* if we're not already running, and below the threshold, exit. */
if (!server.active_defrag_running) {
if(frag_pct < server.active_defrag_threshold_lower || frag_bytes < server.active_defrag_ignore_bytes)
return;
}
/* calculate the adaptive aggressiveness of the defrag */
int cpu_pct = INTERPOLATE(frag_pct, server.active_defrag_threshold_lower, server.active_defrag_threshold_upper,
server.active_defrag_cycle_min, server.active_defrag_cycle_max);
cpu_pct = LIMIT(cpu_pct, server.active_defrag_cycle_min, server.active_defrag_cycle_max);
/* we allow increasing the aggressiveness during a scan, but don't reduce it */
if (!server.active_defrag_running || cpu_pct > server.active_defrag_running) {
server.active_defrag_running = cpu_pct;
serverLog(LL_VERBOSE,
"Starting active defrag, frag=%.0f%%, frag_bytes=%zu, cpu=%d%%",
frag_pct, frag_bytes, cpu_pct);
}
}
if (!server.active_defrag_running)
return;
/* See activeExpireCycle for how timelimit is handled. */
start = ustime();
timelimit = 1000000*server.active_defrag_running/server.hz/100;
if (timelimit <= 0) timelimit = 1;
do {
if (!cursor) {
/* Move on to next database, and stop if we reached the last one */
if (++current_db >= server.dbnum) {
long long now = ustime();
size_t frag_bytes;
float frag_pct = getAllocatorFragmentation(&frag_bytes);
serverLog(LL_VERBOSE,
"Active defrag done in %dms, reallocated=%d, frag=%.0f%%, frag_bytes=%zu",
(int)((now - start_scan)/1000), (int)(server.stat_active_defrag_hits - start_stat), frag_pct, frag_bytes);
start_scan = now;
current_db = -1;
cursor = 0;
db = NULL;
server.active_defrag_running = 0;
return;
}
else if (current_db==0) {
/* start a scan from the first database */
start_scan = ustime();
start_stat = server.stat_active_defrag_hits;
}
db = &server.db[current_db];
cursor = 0;
}
do {
cursor = dictScan(db->dict, cursor, defragScanCallback, defragDictBucketCallback, db);
/* once in 16 scan iterations, or 1000 pointer reallocations (if we have a lot of pointers in one hash bucket),
* check if we reached the tiem limit */
if (cursor && (++iterations > 16 || server.stat_active_defrag_hits - defragged > 1000)) {
if ((ustime() - start) > timelimit) {
return;
}
iterations = 0;
defragged = server.stat_active_defrag_hits;
}
} while(cursor);
} while(1);
}
#else /* USE_JEMALLOC */
void activeDefragCycle(void) {
/* not implemented yet*/
}
#endif

33
src/dict.c
View File

@ -885,6 +885,7 @@ static unsigned long rev(unsigned long v) {
unsigned long dictScan(dict *d,
unsigned long v,
dictScanFunction *fn,
dictScanBucketFunction* bucketfn,
void *privdata)
{
dictht *t0, *t1;
@ -898,6 +899,7 @@ unsigned long dictScan(dict *d,
m0 = t0->sizemask;
/* Emit entries at cursor */
if (bucketfn) bucketfn(privdata, &t0->table[v & m0]);
de = t0->table[v & m0];
while (de) {
next = de->next;
@ -919,6 +921,7 @@ unsigned long dictScan(dict *d,
m1 = t1->sizemask;
/* Emit entries at cursor */
if (bucketfn) bucketfn(privdata, &t0->table[v & m0]);
de = t0->table[v & m0];
while (de) {
next = de->next;
@ -930,6 +933,7 @@ unsigned long dictScan(dict *d,
* of the index pointed to by the cursor in the smaller table */
do {
/* Emit entries at cursor */
if (bucketfn) bucketfn(privdata, &t1->table[v & m1]);
de = t1->table[v & m1];
while (de) {
next = de->next;
@ -1040,6 +1044,35 @@ void dictDisableResize(void) {
dict_can_resize = 0;
}
unsigned int dictGetHash(dict *d, const void *key) {
return dictHashKey(d, key);
}
/* Replace an old key pointer in the dictionary with a new pointer.
* oldkey is a dead pointer and should not be accessed.
* the hash value should be provided using dictGetHash.
* no string / key comparison is performed.
* return value is the dictEntry if found, or NULL if not found. */
dictEntry *dictReplaceKeyPtr(dict *d, const void *oldptr, void *newptr, unsigned int hash) {
dictEntry *he;
unsigned int idx, table;
if (d->ht[0].used + d->ht[1].used == 0) return NULL; /* dict is empty */
for (table = 0; table <= 1; table++) {
idx = hash & d->ht[table].sizemask;
he = d->ht[table].table[idx];
while(he) {
if (oldptr==he->key) {
he->key = newptr;
return he;
}
he = he->next;
}
if (!dictIsRehashing(d)) return NULL;
}
return NULL;
}
/* ------------------------------- Debugging ---------------------------------*/
#define DICT_STATS_VECTLEN 50

5
src/dict.h
View File

@ -95,6 +95,7 @@ typedef struct dictIterator {
} dictIterator;
typedef void (dictScanFunction)(void *privdata, const dictEntry *de);
typedef void (dictScanBucketFunction)(void *privdata, dictEntry **bucketref);
/* This is the initial size of every hash table */
#define DICT_HT_INITIAL_SIZE 4
@ -176,7 +177,9 @@ int dictRehash(dict *d, int n);
int dictRehashMilliseconds(dict *d, int ms);
void dictSetHashFunctionSeed(unsigned int initval);
unsigned int dictGetHashFunctionSeed(void);
unsigned long dictScan(dict *d, unsigned long v, dictScanFunction *fn, void *privdata);
unsigned long dictScan(dict *d, unsigned long v, dictScanFunction *fn, dictScanBucketFunction *bucketfn, void *privdata);
unsigned int dictGetHash(dict *d, const void *key);
dictEntry *dictReplaceKeyPtr(dict *d, const void *oldptr, void *newptr, unsigned int hash);
/* Hash table types */
extern dictType dictTypeHeapStringCopyKey;

29
src/server.c
View File

@ -876,6 +876,10 @@ void databasesCron(void) {
expireSlaveKeys();
}
/* Defrag keys gradually. */
if (server.active_defrag_enabled)
activeDefragCycle();
/* Perform hash tables rehashing if needed, but only if there are no
* other processes saving the DB on disk. Otherwise rehashing is bad
* as will cause a lot of copy-on-write of memory pages. */
@ -1332,6 +1336,12 @@ void initServerConfig(void) {
server.maxidletime = CONFIG_DEFAULT_CLIENT_TIMEOUT;
server.tcpkeepalive = CONFIG_DEFAULT_TCP_KEEPALIVE;
server.active_expire_enabled = 1;
server.active_defrag_enabled = CONFIG_DEFAULT_ACTIVE_DEFRAG;
server.active_defrag_ignore_bytes = CONFIG_DEFAULT_DEFRAG_IGNORE_BYTES;
server.active_defrag_threshold_lower = CONFIG_DEFAULT_DEFRAG_THRESHOLD_LOWER;
server.active_defrag_threshold_upper = CONFIG_DEFAULT_DEFRAG_THRESHOLD_UPPER;
server.active_defrag_cycle_min = CONFIG_DEFAULT_DEFRAG_CYCLE_MIN;
server.active_defrag_cycle_max = CONFIG_DEFAULT_DEFRAG_CYCLE_MAX;
server.client_max_querybuf_len = PROTO_MAX_QUERYBUF_LEN;
server.saveparams = NULL;
server.loading = 0;
@ -1368,6 +1378,7 @@ void initServerConfig(void) {
server.rdb_checksum = CONFIG_DEFAULT_RDB_CHECKSUM;
server.stop_writes_on_bgsave_err = CONFIG_DEFAULT_STOP_WRITES_ON_BGSAVE_ERROR;
server.activerehashing = CONFIG_DEFAULT_ACTIVE_REHASHING;
server.active_defrag_running = 0;
server.notify_keyspace_events = 0;
server.maxclients = CONFIG_DEFAULT_MAX_CLIENTS;
server.bpop_blocked_clients = 0;
@ -1718,6 +1729,10 @@ void resetServerStats(void) {
server.stat_evictedkeys = 0;
server.stat_keyspace_misses = 0;
server.stat_keyspace_hits = 0;
server.stat_active_defrag_hits = 0;
server.stat_active_defrag_misses = 0;
server.stat_active_defrag_key_hits = 0;
server.stat_active_defrag_key_misses = 0;
server.stat_fork_time = 0;
server.stat_fork_rate = 0;
server.stat_rejected_conn = 0;
@ -2873,6 +2888,7 @@ sds genRedisInfoString(char *section) {
"maxmemory_policy:%s\r\n"
"mem_fragmentation_ratio:%.2f\r\n"
"mem_allocator:%s\r\n"
"active_defrag_running:%d\r\n"
"lazyfree_pending_objects:%zu\r\n",
zmalloc_used,
hmem,
@ -2894,6 +2910,7 @@ sds genRedisInfoString(char *section) {
evict_policy,
mh->fragmentation,
ZMALLOC_LIB,
server.active_defrag_running,
lazyfreeGetPendingObjectsCount()
);
freeMemoryOverheadData(mh);
@ -3013,7 +3030,11 @@ sds genRedisInfoString(char *section) {
"pubsub_patterns:%lu\r\n"
"latest_fork_usec:%lld\r\n"
"migrate_cached_sockets:%ld\r\n"
"slave_expires_tracked_keys:%zu\r\n",
"slave_expires_tracked_keys:%zu\r\n"
"active_defrag_hits:%lld\r\n"
"active_defrag_misses:%lld\r\n"
"active_defrag_key_hits:%lld\r\n"
"active_defrag_key_misses:%lld\r\n",
server.stat_numconnections,
server.stat_numcommands,
getInstantaneousMetric(STATS_METRIC_COMMAND),
@ -3033,7 +3054,11 @@ sds genRedisInfoString(char *section) {
listLength(server.pubsub_patterns),
server.stat_fork_time,
dictSize(server.migrate_cached_sockets),
getSlaveKeyWithExpireCount());
getSlaveKeyWithExpireCount(),
server.stat_active_defrag_hits,
server.stat_active_defrag_misses,
server.stat_active_defrag_key_hits,
server.stat_active_defrag_key_misses);
}
/* Replication */

18
src/server.h
View File

@ -152,6 +152,12 @@ typedef long long mstime_t; /* millisecond time type. */
#define CONFIG_DEFAULT_LAZYFREE_LAZY_EXPIRE 0
#define CONFIG_DEFAULT_LAZYFREE_LAZY_SERVER_DEL 0
#define CONFIG_DEFAULT_ALWAYS_SHOW_LOGO 0
#define CONFIG_DEFAULT_ACTIVE_DEFRAG 1
#define CONFIG_DEFAULT_DEFRAG_THRESHOLD_LOWER 10 /* don't defrag when fragmentation is below 10% */
#define CONFIG_DEFAULT_DEFRAG_THRESHOLD_UPPER 100 /* maximum defrag force at 100% fragmentation */
#define CONFIG_DEFAULT_DEFRAG_IGNORE_BYTES (100<<20) /* don't defrag if frag overhead is below 100mb */
#define CONFIG_DEFAULT_DEFRAG_CYCLE_MIN 25 /* 25% CPU min (at lower threshold) */
#define CONFIG_DEFAULT_DEFRAG_CYCLE_MAX 75 /* 75% CPU max (at upper threshold) */
#define ACTIVE_EXPIRE_CYCLE_LOOKUPS_PER_LOOP 20 /* Loopkups per loop. */
#define ACTIVE_EXPIRE_CYCLE_FAST_DURATION 1000 /* Microseconds */
@ -857,6 +863,7 @@ struct redisServer {
unsigned lruclock:LRU_BITS; /* Clock for LRU eviction */
int shutdown_asap; /* SHUTDOWN needed ASAP */
int activerehashing; /* Incremental rehash in serverCron() */
int active_defrag_running; /* Active defragmentation running (holds current scan aggressiveness) */
char *requirepass; /* Pass for AUTH command, or NULL */
char *pidfile; /* PID file path */
int arch_bits; /* 32 or 64 depending on sizeof(long) */
@ -908,6 +915,10 @@ struct redisServer {
long long stat_evictedkeys; /* Number of evicted keys (maxmemory) */
long long stat_keyspace_hits; /* Number of successful lookups of keys */
long long stat_keyspace_misses; /* Number of failed lookups of keys */
long long stat_active_defrag_hits; /* number of allocations moved */
long long stat_active_defrag_misses; /* number of allocations scanned but not moved */
long long stat_active_defrag_key_hits; /* number of keys with moved allocations */
long long stat_active_defrag_key_misses;/* number of keys scanned and not moved */
size_t stat_peak_memory; /* Max used memory record */
long long stat_fork_time; /* Time needed to perform latest fork() */
double stat_fork_rate; /* Fork rate in GB/sec. */
@ -937,6 +948,12 @@ struct redisServer {
int maxidletime; /* Client timeout in seconds */
int tcpkeepalive; /* Set SO_KEEPALIVE if non-zero. */
int active_expire_enabled; /* Can be disabled for testing purposes. */
int active_defrag_enabled;
size_t active_defrag_ignore_bytes; /* minimum amount of fragmentation waste to start active defrag */
int active_defrag_threshold_lower; /* minimum percentage of fragmentation to start active defrag */
int active_defrag_threshold_upper; /* maximum percentage of fragmentation at which we use maximum effort */
int active_defrag_cycle_min; /* minimal effort for defrag in CPU percentage */
int active_defrag_cycle_max; /* maximal effort for defrag in CPU percentage */
size_t client_max_querybuf_len; /* Limit for client query buffer length */
int dbnum; /* Total number of configured DBs */
int supervised; /* 1 if supervised, 0 otherwise. */
@ -1576,6 +1593,7 @@ void adjustOpenFilesLimit(void);
void closeListeningSockets(int unlink_unix_socket);
void updateCachedTime(void);
void resetServerStats(void);
void activeDefragCycle(void);
unsigned int getLRUClock(void);
const char *evictPolicyToString(void);
struct redisMemOverhead *getMemoryOverheadData(void);

20
src/zmalloc.c
View File

@ -66,6 +66,8 @@ void zlibc_free(void *ptr) {
#define calloc(count,size) je_calloc(count,size)
#define realloc(ptr,size) je_realloc(ptr,size)
#define free(ptr) je_free(ptr)
#define mallocx(size,flags) je_mallocx(size,flags)
#define dallocx(ptr,flags) je_dallocx(ptr,flags)
#endif
#define update_zmalloc_stat_alloc(__n) do { \
@ -115,6 +117,24 @@ void *zmalloc(size_t size) {
#endif
}
/* Allocation and free functions that bypass the thread cache
* and go straight to the allocator arena bins.
* Currently implemented only for jemalloc */
#if defined(USE_JEMALLOC) && defined(MALLOCX_TCACHE_NONE)
void *zmalloc_no_tcache(size_t size) {
void *ptr = mallocx(size+PREFIX_SIZE, MALLOCX_TCACHE_NONE);
if (!ptr) zmalloc_oom_handler(size);
update_zmalloc_stat_alloc(zmalloc_size(ptr));
return ptr;
}
void zfree_no_tcache(void *ptr) {
if (ptr == NULL) return;
update_zmalloc_stat_free(zmalloc_size(ptr));
dallocx(ptr, MALLOCX_TCACHE_NONE);
}
#endif
void *zcalloc(size_t size) {
void *ptr = calloc(1, size+PREFIX_SIZE);

2
src/zmalloc.h
View File

@ -69,6 +69,8 @@ void *zmalloc(size_t size);
void *zcalloc(size_t size);
void *zrealloc(void *ptr, size_t size);
void zfree(void *ptr);
void zfree_no_tcache(void *ptr);
void *zmalloc_no_tcache(size_t size);
char *zstrdup(const char *s);
size_t zmalloc_used_memory(void);
void zmalloc_enable_thread_safeness(void);