linux system, compiler or processor will optimize the code, will lead to the implementation of the code running on the same CPU / thread order changes, can cause some oops occurs when the code before and after the strong dependence of execution.
The solution: increase the memory barrier. This ensures that the code before the memory barrier to the implementation of the (same CPU / on the thread) in code memory barrier. So the kernel to make sure the timing of the code, to add memory barrier to ensure.
function:
| Function name | Features |
|---|---|
| smp_mb () | Suitable for multi-processor memory barriers |
| smp_rmb () | For multi-processor read memory barrier |
| smp_wmb () | For multi-processor write memory barrier |
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