zmalloc.h
/* zmalloc - total amount of allocated memory aware version of malloc()
*
* Copyright (c) 2009-2010, Salvatore Sanfilippo <antirez at gmail dot com>
* 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.
*/
#ifndef __ZMALLOC_H
#define __ZMALLOC_H
/* Double expansion needed for stringification of macro values. */
#define __xstr(s) __str(s)
#define __str(s) #s
//TCMALLOC内存分配器
#if defined(USE_TCMALLOC)
#define ZMALLOC_LIB ("tcmalloc-" __xstr(TC_VERSION_MAJOR) "." __xstr(TC_VERSION_MINOR))
#include <google/tcmalloc.h>
#if (TC_VERSION_MAJOR == 1 && TC_VERSION_MINOR >= 6) || (TC_VERSION_MAJOR > 1)//版本号要求
#define HAVE_MALLOC_SIZE 1 //TCMALLOC内置获取分配内存空间大小的函数
#define zmalloc_size(p) tc_malloc_size(p)
#else //编译出错处理
#error "Newer version of tcmalloc required"
#endif
#elif defined(USE_JEMALLOC)
#define ZMALLOC_LIB ("jemalloc-" __xstr(JEMALLOC_VERSION_MAJOR) "." __xstr(JEMALLOC_VERSION_MINOR) "." __xstr(JEMALLOC_VERSION_BUGFIX))
#include <jemalloc/jemalloc.h>
#if (JEMALLOC_VERSION_MAJOR == 2 && JEMALLOC_VERSION_MINOR >= 1) || (JEMALLOC_VERSION_MAJOR > 2)
#define HAVE_MALLOC_SIZE 1
#define zmalloc_size(p) je_malloc_usable_size(p)
#else
#error "Newer version of jemalloc required"
#endif
#elif defined(__APPLE__)
#include <malloc/malloc.h>
#define HAVE_MALLOC_SIZE 1
#define zmalloc_size(p) malloc_size(p)
#endif
//使用默认libc分配器
#ifndef ZMALLOC_LIB
#define ZMALLOC_LIB "libc"
#endif
void *zmalloc(size_t size);
void *zcalloc(size_t size);
void *zrealloc(void *ptr, size_t size);
void zfree(void *ptr);
char *zstrdup(const char *s);
size_t zmalloc_used_memory(void);
void zmalloc_enable_thread_safeness(void);
void zmalloc_set_oom_handler(void (*oom_handler)(size_t));
float zmalloc_get_fragmentation_ratio(size_t rss);
size_t zmalloc_get_rss(void);
size_t zmalloc_get_private_dirty(void);
size_t zmalloc_get_smap_bytes_by_field(char *field);
void zlibc_free(void *ptr);
#ifndef HAVE_MALLOC_SIZE
size_t zmalloc_size(void *ptr);
#endif
#endif /* __ZMALLOC_H */
zmalloc.c
/* zmalloc - total amount of allocated memory aware version of malloc()
*
* Copyright (c) 2009-2010, Salvatore Sanfilippo <antirez at gmail dot com>
* 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 <stdio.h>
#include <stdlib.h>
/* This function provide us access to the original libc free(). This is useful
* for instance to free results obtained by backtrace_symbols(). We need
* to define this function before including zmalloc.h that may shadow the
* free implementation if we use jemalloc or another non standard allocator. */
//保留了libc的free()接口。用于释放backtrace_symbols()获取的结果
void zlibc_free(void *ptr) {
free(ptr);
}
#include <string.h>
#include <pthread.h>
#include "config.h"
#include "zmalloc.h"
#ifdef HAVE_MALLOC_SIZE //tc_malloc,je_malloc,Mac平台
#define PREFIX_SIZE (0)
#else
/*其它平台内存分配
**内存模型：data_size(PREFIX_SIZE)+data
**前面PREFIX_SIZE字节存储申请空间大小。后面空间为申请的内存
*/
#if defined(__sun) || defined(__sparc) || defined(__sparc__)
#define PREFIX_SIZE (sizeof(long long))
#else //linux
#define PREFIX_SIZE (sizeof(size_t))
#endif
#endif
/* Explicitly override malloc/free etc when using tcmalloc. */
#if defined(USE_TCMALLOC)
#define malloc(size) tc_malloc(size)
#define calloc(count,size) tc_calloc(count,size)
#define realloc(ptr,size) tc_realloc(ptr,size)
#define free(ptr) tc_free(ptr)
#elif defined(USE_JEMALLOC)
#define malloc(size) je_malloc(size)
#define calloc(count,size) je_calloc(count,size)
#define realloc(ptr,size) je_realloc(ptr,size)
#define free(ptr) je_free(ptr)
#endif
//原子操作改动总共使用内存
#if defined(__ATOMIC_RELAXED)
#define update_zmalloc_stat_add(__n) __atomic_add_fetch(&used_memory, (__n), __ATOMIC_RELAXED)
#define update_zmalloc_stat_sub(__n) __atomic_sub_fetch(&used_memory, (__n), __ATOMIC_RELAXED)
#elif defined(HAVE_ATOMIC)
#define update_zmalloc_stat_add(__n) __sync_add_and_fetch(&used_memory, (__n))
#define update_zmalloc_stat_sub(__n) __sync_sub_and_fetch(&used_memory, (__n))
#else
#define update_zmalloc_stat_add(__n) do {
pthread_mutex_lock(&used_memory_mutex);
used_memory += (__n);
pthread_mutex_unlock(&used_memory_mutex);
} while(0)
#define update_zmalloc_stat_sub(__n) do {
pthread_mutex_lock(&used_memory_mutex);
used_memory -= (__n);
pthread_mutex_unlock(&used_memory_mutex);
} while(0)
#endif
//__n是分配的内存字节。更新used_memory的值，注意long型对齐
#define update_zmalloc_stat_alloc(__n) do {
size_t _n = (__n);
if (_n&(sizeof(long)-1)) _n += sizeof(long)-(_n&(sizeof(long)-1)); //分配字节不到long型的整数倍添加至整数倍
if (zmalloc_thread_safe) { //线程安全模式
update_zmalloc_stat_add(_n);
} else { //非线程安全模式
used_memory += _n;
}
} while(0)
//__n是释放的内存字节，更新used_memory的值，注意long型对齐
#define update_zmalloc_stat_free(__n) do {
size_t _n = (__n);
if (_n&(sizeof(long)-1)) _n += sizeof(long)-(_n&(sizeof(long)-1));
if (zmalloc_thread_safe) {
update_zmalloc_stat_sub(_n);
} else {
used_memory -= _n;
}
} while(0)
static size_t used_memory = 0; //初始时总共使用内存空间为0
static int zmalloc_thread_safe = 0; //默认不启动线程安全模式
pthread_mutex_t used_memory_mutex = PTHREAD_MUTEX_INITIALIZER; //定义并初始化一个相互排斥量
//内存不足默认处理函数
static void zmalloc_default_oom(size_t size) {
fprintf(stderr, "zmalloc: Out of memory trying to allocate %zu bytes
",
size);
fflush(stderr);
abort();
}
//内存不足处理函数指针。初始为默认函数
static void (*zmalloc_oom_handler)(size_t) = zmalloc_default_oom;
//malloc实现内存申请函数
void *zmalloc(size_t size) {
void *ptr = malloc(size+PREFIX_SIZE);
if (!ptr) zmalloc_oom_handler(size); //申请失败调用内存不足处理函数，终止程序
#ifdef HAVE_MALLOC_SIZE //tc_malloc,je_malloc,Mac平台
update_zmalloc_stat_alloc(zmalloc_size(ptr));
return ptr;
#else //其它平台
*((size_t*)ptr) = size;
update_zmalloc_stat_alloc(size+PREFIX_SIZE);
return (char*)ptr+PREFIX_SIZE;
#endif
}
//calloc实现内存释放函数
void *zcalloc(size_t size) {
void *ptr = calloc(1, size+PREFIX_SIZE);
if (!ptr) zmalloc_oom_handler(size);
#ifdef HAVE_MALLOC_SIZE
update_zmalloc_stat_alloc(zmalloc_size(ptr));
return ptr;
#else
*((size_t*)ptr) = size;
update_zmalloc_stat_alloc(size+PREFIX_SIZE);
return (char*)ptr+PREFIX_SIZE;
#endif
}
void *zrealloc(void *ptr, size_t size) {
#ifndef HAVE_MALLOC_SIZE
void *realptr;
#endif
size_t oldsize;
void *newptr;
if (ptr == NULL) return zmalloc(size);
#ifdef HAVE_MALLOC_SIZE
oldsize = zmalloc_size(ptr);
newptr = realloc(ptr,size);
if (!newptr) zmalloc_oom_handler(size);
update_zmalloc_stat_free(oldsize);
update_zmalloc_stat_alloc(zmalloc_size(newptr));
return newptr;
#else
realptr = (char*)ptr-PREFIX_SIZE;
oldsize = *((size_t*)realptr);
newptr = realloc(realptr,size+PREFIX_SIZE);
if (!newptr) zmalloc_oom_handler(size);
*((size_t*)newptr) = size;
update_zmalloc_stat_free(oldsize);
update_zmalloc_stat_alloc(size);
return (char*)newptr+PREFIX_SIZE;
#endif
}
/* Provide zmalloc_size() for systems where this function is not provided by
* malloc itself, given that in that case we store a header with this
* information as the first bytes of every allocation. */
#ifndef HAVE_MALLOC_SIZE
size_t zmalloc_size(void *ptr) {
void *realptr = (char*)ptr-PREFIX_SIZE;
size_t size = *((size_t*)realptr);
/* Assume at least that all the allocations are padded at sizeof(long) by
* the underlying allocator. */
//如果全部分配器分配时均使用long型对齐
if (size&(sizeof(long)-1)) size += sizeof(long)-(size&(sizeof(long)-1));
return size+PREFIX_SIZE;
}
#endif
//释放ptr指向的内存空间
void zfree(void *ptr) {
#ifndef HAVE_MALLOC_SIZE
void *realptr;
size_t oldsize;
#endif
if (ptr == NULL) return;
#ifdef HAVE_MALLOC_SIZE
update_zmalloc_stat_free(zmalloc_size(ptr));
free(ptr);
#else
realptr = (char*)ptr-PREFIX_SIZE;
oldsize = *((size_t*)realptr);
update_zmalloc_stat_free(oldsize+PREFIX_SIZE);
free(realptr);
#endif
}
char *zstrdup(const char *s) {
size_t l = strlen(s)+1;
char *p = zmalloc(l);
memcpy(p,s,l);
return p;
}
//返回总共的使用内存
size_t zmalloc_used_memory(void) {
size_t um;
if (zmalloc_thread_safe) {
#if defined(__ATOMIC_RELAXED) || defined(HAVE_ATOMIC)
um = update_zmalloc_stat_add(0);
#else
pthread_mutex_lock(&used_memory_mutex);
um = used_memory;
pthread_mutex_unlock(&used_memory_mutex);
#endif
}
else {
um = used_memory;
}
return um;
}
//设置安全线程模式
void zmalloc_enable_thread_safeness(void) {
zmalloc_thread_safe = 1;
}
//设置内存不足处理函数
void zmalloc_set_oom_handler(void (*oom_handler)(size_t)) {
zmalloc_oom_handler = oom_handler;
}
/* Get the RSS information in an OS-specific way.
*
* WARNING: the function zmalloc_get_rss() is not designed to be fast
* and may not be called in the busy loops where Redis tries to release
* memory expiring or swapping out objects.
*
* For this kind of "fast RSS reporting" usages use instead the
* function RedisEstimateRSS() that is a much faster (and less precise)
* version of the function. */
#if defined(HAVE_PROC_STAT)
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
//获取当前进程的驻留集大小
size_t zmalloc_get_rss(void) {
int page = sysconf(_SC_PAGESIZE); //获取page大小
size_t rss;
char buf[4096];
char filename[256];
int fd, count;
char *p, *x;
snprintf(filename,256,"/proc/%d/stat",getpid());
if ((fd = open(filename,O_RDONLY)) == -1) return 0;
if (read(fd,buf,4096) <= 0) {
close(fd);
return 0;
}
close(fd);
p = buf;
count = 23; /* RSS is the 24th field in /proc/<pid>/stat */
while(p && count--) {
p = strchr(p,' ');
if (p) p++;
}
if (!p) return 0;
x = strchr(p,' ');
if (!x) return 0;
*x = ' ';
rss = strtoll(p,NULL,10);
rss *= page;
return rss;
}
#elif defined(HAVE_TASKINFO)
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/sysctl.h>
#include <mach/task.h>
#include <mach/mach_init.h>
size_t zmalloc_get_rss(void) {
task_t task = MACH_PORT_NULL;
struct task_basic_info t_info;
mach_msg_type_number_t t_info_count = TASK_BASIC_INFO_COUNT;
if (task_for_pid(current_task(), getpid(), &task) != KERN_SUCCESS)
return 0;
task_info(task, TASK_BASIC_INFO, (task_info_t)&t_info, &t_info_count);
return t_info.resident_size;
}
#else
size_t zmalloc_get_rss(void) {
/* If we can't get the RSS in an OS-specific way for this system just
* return the memory usage we estimated in zmalloc()..
*
* Fragmentation will appear to be always 1 (no fragmentation)
* of course... */
return zmalloc_used_memory();
}
#endif
/* Fragmentation = RSS / allocated-bytes */
//计算碎片率
float zmalloc_get_fragmentation_ratio(size_t rss) {
return (float)rss/zmalloc_used_memory();
}
/* Get the sum of the specified field (converted form kb to bytes) in
* /proc/self/smaps. The field must be specified with trailing ":" as it
* apperas in the smaps output.
*
* Example: zmalloc_get_smap_bytes_by_field("Rss:");
*/
#if defined(HAVE_PROC_SMAPS)
size_t zmalloc_get_smap_bytes_by_field(char *field) {
char line[1024];
size_t bytes = 0;
FILE *fp = fopen("/proc/self/smaps","r");
int flen = strlen(field);
if (!fp) return 0;
while(fgets(line,sizeof(line),fp) != NULL) {
if (strncmp(line,field,flen) == 0) {
char *p = strchr(line,'k');
if (p) {
*p = ' ';
bytes += strtol(line+flen,NULL,10) * 1024;
}
}
}
fclose(fp);
return bytes;
}
#else
size_t zmalloc_get_smap_bytes_by_field(char *field) {
((void) field);
return 0;
}
#endif
//获取Private_Dirty大小，RSS=Shared_Clean+Shared_Dirty+Private_Clean+Private_Dirty
//Shared_Clean：引用大于1，未被改动
//Shared_Dirty：引用大于1，被改动
//Private_Clean：引用等于1，未被改动
//Private_Dirty：引用等于1，被改动
size_t zmalloc_get_private_dirty(void) {
return zmalloc_get_smap_bytes_by_field("Private_Dirty:");
}
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