#if IS_IN (libc) void * __libc_malloc (size_t bytes) { ... victim = _int_malloc (ar_ptr, bytes); /* Retry with another arena only if we were able to find a usable arena before. */ if (!victim && ar_ptr != NULL) { LIBC_PROBE (memory_malloc_retry, 1, bytes); ar_...
INTERNAL_SIZE_T mchunk_prev_size; /* Size of previous chunk, if it is free. */ INTERNAL_SIZE_T mchunk_size; /* Size in bytes, including overhead. */ struct malloc_chunk* fd; /* double links -- used only if this chunk is free. */ struct malloc_chunk* bk; /* Only used for...
if it is free. */ INTERNAL_SIZE_T mchunk_size; /* Size in bytes, including overhead. */ struct malloc_chunk* fd; /* double links -- used only if this chunk is free. */ struct malloc_chunk* bk; /* Only used for large blocks: pointer to next larger size. */ struct malloc_...
size_t len=21;size_t size;char*buf;buf=malloc(len);if(!buf){perror("malloc");return-1;}size=malloc_usable_size(buf);/* we can actually use 'size' bytes of 'buf' ... */ 则我们可用过malloc_usable_size( )这个函数得到ptr指向的内存中实际可用大小。 malloc_trim( ): 该函数允许程序...
+-+-+-+-+|Userdata starts here...(malloc_usable_size()bytes)..|nextchunk->+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+|Sizeof chunk|+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Bins...
int *c = malloc(8); free(a); free(b);//Pass the free check free(a); unsigned long long *d = malloc(8); malloc(8);//Now the fastbin list has only a left stack_var[1] = 0x20; fprintf(stderr, "Now, we overwrite the first 8 bytes of the data at %p to point right befor...
char *p = xxxx;if(p)printf("%d\n",strlen(p));我这里是把指针当做指向字符串的格式。注意，一定要测 p是否NULL，否则没意义了
size_t malloc_usable_size(void *ptr); 查询一块已分配内存中有多少可用字节。 int malloc_trim(size_t padding); 调用malloc_trim()成功时,强制glibc归还所有的可释放的动态内存给内核。数据段会尽可能地收缩,但是填充字节被保留下来。然后返回1。失败时,返回0。
1330: 0000000000409000 52 FUNC WEAK DEFAULT 6 malloc_usable_size 1331: 0000000000424b30 143 FUNC GLOBAL DEFAULT 6 __sscanf 1332: 000000000047ad90 16 FUNC GLOBAL DEFAULT 6 __strtold_internal 1333: 000000000044e600 103 FUNC WEAK DEFAULT 6 tdestroy 1334: 0000000000448f80 495 FUNC GLOBAL DEFAULT 6 ...
除此以外, PMDK 还提供了其他编程库, 比如 libpmemobj,libpmemlog,libvmmalloc 等。感兴趣可以访问其主页获取更多信息。 结语 至此,对于NVDIMM硬件和软件上的不同, 大家都有了一个大致的认识。Intel 在2018年5月发布了基于3D XPoint™ 技术的Intel® Optane™ DC Persistent Memory,引发了NVDIMM爆点。