内核使用了arch/arm/configs/s3c2410_defconfig作为默认的配置文件,Code maturity level options 选项下没有设置CONFIG_LOCK_KERNEL项.所以在这里lock_kernel应该就是do { } while(0) 的空操作. 搞清楚了,但还是要看一下CONFIG_LOCK_KERNEL定义的情况下lock_kernel的情况:lib/kernel_lock.c中有定义也是要根据宏的...
spin_release(&lock->dep_map, _RET_IP_); do_raw_spin_unlock(lock); preempt_enable(); } static inline void __raw_spin_lock(raw_spinlock_t *lock) { preempt_disable(); spin_acquire(&lock->dep_map, 0, 0, _RET_IP_); LOCK_CONTENDED(lock, do_raw_spin_trylock, do_raw_spin_lock)...
#define lock_kernel() \ do { \ preempt_disable(); \ __acquire( &kernel_lock ); \ } while (0) /* 释放BKL */ #define unlock_kernel() \ do { \ __release( &kernel_lock ); \ preempt_enable(); \ } while (0) #include <linux/module.h> #include <linux/kernel.h> #include <...
所以应该是该锁被其他人长时间占用,到了调用栈所示的调用时一直无法获取锁导致的,死等20多秒超时导致该CPU的watchdog发现(watchdog是IRQ所以不会因为死等锁而不能调度),同时可以确定用户态死锁不会导致soft lockup。
lock_map_acquire(&wq->lockdep_map); lock_map_release(&wq->lockdep_map); for_each_cpu(cpu, cpu_map) flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu)); } 回到state_store 函数。 我们发现函数中最初有个判断,如果设置的状态为 "disk" ,则调用函数 hibernate 。
deadlock 比如几个threads在互相等待,因为需要获得一部分data,否则不能进行下一步,但是这部分data分别被彼此锁定了,因此互相僵持,形成了deadlock(如下图)。其中一个例子就是self-lock。The simplest example of a deadlock is the self-deadlock: 4 If a thread of execution attempts to acquire a lock it al...
{//acquirelock 7. AutoMutex_l(mLock); 8. dispatchOnceInnerLocked(keyRepeatTimeout,keyRepeatDelay,&nextWakeupTime); 9. 10. if(runCommandsLockedInterruptible()){ 11. nextWakeupTime=LONG_LONG_MIN;//forcenextpolltowakeupimmediately 12. } 13. }//releaselock 14. 15. //Waitforcallbackortimeout...
If a process attempts to acquire a spinlock and it is unavailable, the process will keep trying (spinning) until it can acquire the lock. This simplicity creates a small and fast lock. The basic use of the spinlock is: spinlock_t mr_lock = SPIN_LOCK_UNLOCKED; unsigned long flags; spin...
if (kernfs_lockdep(kn)) { rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_); if (atomic_read(&kn->active) != KN_DEACTIVATED_BIAS) lock_contended(&kn->dep_map, _RET_IP_); } /* but everyone should wait for draining */ wait_event(root->deactivate_waitq, ...
...The Big Kernel Lock Linux contains a global kernel lock, kernel_flag, that was originally introduced...The global kernel lock is called the big kernel lock or BKL...Call lock_kernel() to acquire the lock and unlock_kernel() to release it. ...