2. 初始化completion init_completion(&my_completion); or DECLARE_COMPLETION(my_completion); 3. 等待完成量 下面函数用于等待一个完成量被唤醒 void wait_for_completion(struct completion *c); 4. 唤醒完成量 void completion(struct comple
信号量(semaphore)与自旋锁相同,只有得到信号量才能执行临界区代码,但,当获取不到信号量时,进程不会原地打转而是进入休眠等待状态。 相同点:只有得到信号量的进程才能执行临界区的代码。(linux自旋锁和信号量锁采用的都是“获得锁-访问临界区-释放锁”,可以称为“互斥三部曲”,实际存在于几乎所有多任务操作系统中)...
信号量用于同步时只能唤醒一个执行单元,而完成量(completion)用于同步时可以唤醒所有等待的执行单元。 自旋锁与互斥锁的选择 当锁 不能被获取到时,使用信号量的开销是进程上下文切换时间Tsw,使用自旋锁的开始是等待获取自旋锁的时间Tcs,若Tcs比较小,则应使用自旋锁,否则应使用信号量 信号量锁保护的临界区可以包含引起...
1、PAS(进程地址空间):指进程可寻址的虚拟地址空间 2、内核描述符mm_struct A、task_struct(进程描述符)内核对应源码分析如下: B.VMA管理(vm_area_struct) 三、malloc系统调用 Linux内核面试常见高频问题如下: 高速侧信道攻击的原理机制? CPU熔断漏洞攻击? CPU“幽灵”漏洞变体攻击原理机制? 一、CPU熔断/幽灵漏洞...
static noinline void __down(struct semaphore *sem); static noinline int __down_interruptible(struct semaphore *sem); static noinline int __down_killable(struct semaphore *sem); static noinline int __down_timeout(struct semaphore *sem, long jiffies); ...
*/struct list_head ptraced;struct list_head ptrace_entry;/* PID/PID hash table linkage. */struct pid*thread_pid;struct hlist_node pid_links[PIDTYPE_MAX];struct list_head thread_group;struct list_head thread_node;struct completion*vfork_done;/* CLONE_CHILD_SETTID: */int __user*set_chil...
static noinline void __up(struct semaphore *sem); #define DEFINE_SEMAPHORE(name) \ struct semaphore name = __SEMAPHORE_INITIALIZER(name, 1) static inline void sema_init(struct semaphore *sem, int val) { static struct lock_class_key __key; ...
Of course the windows trace looks very different as it uses IOCompletion I ran some tests using a similarly spec'd windows 10 hyper-v VM and got pretty lousy numbers. Both Synchronous and Async used about 50% of the cpu (4 hyper-v cpus on a 5700g) and only got up to about 600mbps...
struct usb_wireless_ep_comp_descriptor { __u8 bLength; __u8 bDescriptorType; __u8 bMaxBurst; __u8 bMaxSequence; __le16 wMaxStreamDelay; __le16 wOverTheAirPacketSize; __u8 bOverTheAirInterval; __u8 bmCompAttributes; #define USB_ENDPOINT_SWITCH_MASK 0x03 /* in bmCompAttributes */ ...
Serial is like running the playbook for each host in turn, waiting for completion of the complete playbook before moving on to the next host. forks=1 means run the first task in a play on one host before running the same task on the next host, so the first task will be run for each...