复制 intget_or_create_shared_memory(key_t key,int size,int flag){int shmid=shmget(key,size,flag);//成功返回共享内存标识符,失败返回-1if(shmid==-1){cout<<"共享内存创建失败,原因是:"<<strerror(errno)<<endl;exit(2);}returnshmid;}intcreate_shared_memory(key_t key,int size){returnget_...
int get_or_create_shared_memory(key_t key, int size, int flag){int shmid = shmget(key, size, flag);//成功返回共享内存标识符,失败返回-1if(shmid == -1){cout << "共享内存创建失败,原因是:" << strerror(errno) << endl;exit(2);}return shmid;}int create_shared_memory(key_t key, ...
/* sync */ NULL, /* advise */ shm_nopage, /* nopage */ NULL, /* wppage ...
将内存中数据强制先刷新到磁盘中: sync; sleep 3; sync 清理缓存: echo 3 > /proc/sys/vm/drop_caches 表示清除pagecache和slab分配器中的缓存对象 echo 1 > /proc/sys/vm/drop_caches:表示清除pagecache。 echo 2 > /proc/sys/vm/drop_caches:表示清除回收slab分配器中的对象(包括目录项缓存和inode缓存...
* (2) shared memory(only posix here): * fd = shm_open(shm_name...); * ptr = mmap(); * * Now, we show (2) * * Also, we will use named semaphore to sync multiple processes. */ #include <stdio.h> #include <unistd.h> ...
staticstruct vm_operations_struct shm_vm_ops = {shm_open, /*open- callbackfora new vm-areaopen*/shm_close, /*close- callbackforwhenthe vm-areaisreleased */NULL, /*noneedtosync pagesatunmap */NULL, /* protect */NULL, /* sync */NULL, /* advise */shm_nopage, /* nopage */NU...
linux有一个守护进程定期清空缓冲内容(即写如磁盘),也可以通过sync命令手动清空缓冲。举个例子吧:我这里有一个ext2的U盘,我往里面cp一个3M的MP3,但U盘的灯没有跳动,过了一会儿(或者手动输入sync)U盘的灯就跳动起来了。卸载设备时会清空缓冲,所以有些时候卸载一个设备时要等上几秒钟。
NULL, /* sync */NULL, /* advise */shm_nopage, /* nopage */NULL, /* wppage */shm_swapout /* swapout */}; shm_vm_ops的nopage回调为shm_nopage()函数,也就是说,当发生页缺失异常时将会调用此函数来恢复内存的映射。 从上面的代码可看出,shmat()函数只是申请了进程的虚拟内存空间,而共享...
2.How to Check Shared Memory on Linux ByGarrett Genet,eHow Contributor updated: August 11, 2010 Shared memory is responsible for the smooth operation of your system; it acts as a space that multiple programs can access at once. This enables those programs to communicate in sync, while avoidin...
staticstructvm_operations_structshm_vm_ops={shm_open,/*open-callbackforanewvm-areaopen*/shm_close,/*close-callbackforwhenthevm-areaisreleased*/NULL,/*noneedtosyncpagesatunmap*/NULL,/*protect*/NULL,/*sync*/NULL,/*advise*/shm_nopage,/*nopage*/NULL,/*wppage*/shm_swapout/*swapout*/...