test_and_set_bit()函数定义在include/asm-generic/bitops/atomic.h文件中,实现如下。 BIT_MASK将 1 左移 nr 位获得 mask,再与(maskp->bits)相与。若为 1 则返回直接返回1; 不为1 则需要修改 cpumask。因此调用atomic_long_fetch_or()函数将 cpumask 与 mask 相或置位,并返回原 cpumask 给 old 变量...
atomic_fetch_{add,sub,inc,dec}{,_relaxed,_acquire,_release}() Bitwise位运算: atomic_{and,or,xor,andnot}() atomic_fetch_{and,or,xor,andnot}{,_relaxed,_acquire,_release}() Swap 交换: atomic_xchg{,_relaxed,_acquire,_release}() atomic_cmpxchg{,_relaxed,_acquire,_release}() atomic_tr...
CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */inc_preempt_count();// 如果页框不属于高端内存,直接返回线性地址if(!PageHighMem(page))returnpage_address(page);// 通过 type 与 cpu 标识符 找到临时内存映射的偏移量idx = type + KM_TYPE_NR*smp_processor_id(); /// 通过偏移量 ...
ATOMIC_LONG_FETCH_OP(or, ) ATOMIC_LONG_FETCH_OP(or, _relaxed) ATOMIC_LONG_FETCH_OP(or, _acquire) ATOMIC_LONG_FETCH_OP(or, _release) ATOMIC_LONG_FETCH_OP(xor, ) ATOMIC_LONG_FETCH_OP(xor, _relaxed) ATOMIC_LONG_FETCH_OP(xor, _acquire) ATOMIC_LONG_FETCH_OP(xor, _release) #define ...
oflags = atomic_fetch_or(IRQ_WORK_CLAIMED, &work->flags); oflags = atomic_fetch_or(IRQ_WORK_CLAIMED | CSD_TYPE_IRQ_WORK, &work->flags); /* * If the work is already pending, no need to raise the IPI. * The pairing atomic_fetch_andnot() in irq_work_run() makes sure @@ -...
__sync_fetch_and_add系列的命令,发现这个系列命令讲的最好的一篇文章,英文好的同学可以直接去看原文。Multithreaded simple data type access and atomic variables __sync_fetch_and_add系列一共有十二个函数,有加/减/与/或/异或/等函数的原子性操作函数,__sync_fetch_and_add,顾名思义,先fetch,然后自加,...
__sync_fetch_and_add系列的命令,发现这个系列命令讲的最好的一篇文章,英文好的同学可以直接去看原文。Multithreaded simple data type access and atomic variables __sync_fetch_and_add系列一共有十二个函数,有加/减/与/或/异或/等函数的原子性操作函数,__sync_fetch_and_add,顾名思义,先fetch,然后自加,...
atomic_inc(&skb->users); returnpt_prev->func(skb, skb->dev, pt_prev, orig_dev); } TC 参考[7],暂时不做源码分析。 ip_rcv 到了这里就是网络层的处理了 intip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev) ...
GFP_KERNEL和GFP_ATOMIC, GFP_ATOMIC:用来从中断处理和进程上下文之外的其他代码中分配内存. 从不睡眠 GFP_KERNEL:内核内存的正常分配. 可能睡眠 分配请求队列示例: struct request_queue *queue= =blk_alloc_queue(GFP_KERNEL); 卸载驱动时,可以通过kfree释放空间。...
if (__atomic_sub_fetch(count_, 1, __ATOMIC_SEQ_CST) == 0) { delete ptr_; //释放 delete count_; } ptr_ = nullptr; count_ = nullptr; } } void swap(counted_ptr& rhs) noexcept { T* tp = ptr_; ptr_ = rhs.ptr_; /*tp是临时变量,所以退出swap函数的时候rhs.ptr_变成指向Null....