我曾经写过一个内核模块，用于处理10Gbs链路上的数据包.我使用vmalloc分配了大约1GB的连续(虚拟)内存，将静态大小的哈希表放入其中以执行连接跟踪(

I once wrote a kernel module processing packets on a 10Gbs link. I used vmalloc to allocate about 1GByte of continuous (virtual) memory to put a static size hash table into it to perform connection tracking (code).

如果您知道需要多少内存，建议您对其进行预分配.这有两个优点

If you know how much memory you need, I recommend to pre-allocate it. This has two advantages

• 速度快(运行时不进行分配/释放)
• 如果kmalloc(_, GFP_ATOMIC)无法返回内存，则无需考虑策略.实际上，在重负载下，这种情况实际上经常会发生.

• It is fast (no mallocing/freeing at runtime)
• You don't have to think of a strategy if kmalloc(_, GFP_ATOMIC) can not return you memory. This can actually happen quite often under heavy load.

缺点

• 您可能需要分配更多的内存.

因此，要编写特殊用途的内核模块，请预先分配尽可能多的内存；)

So, for writing a special-purpose kernel module, please pre-allocate as much memory as you can get ;)

如果您为许多新手用户使用的商品硬件编写内核模块，***按需分配内存(并且浪费更少的内存).

If you write a kernel module for commodity hardware used by many novice users, it would be nice to allocate memory on demand (and waste less memory).

您在哪里分配内存? GFP_ATOMIC只能返回非常少量的内存，并且仅在内存分配无法休眠时才应使用.您可以在安全进入睡眠状态时使用GFP_KERNEL，例如，不在中断上下文中.有关更多信息，请参见此问题.在模块初始化期间使用vmalloc来预分配所有内存是安全的.

Where do you allocate memory? GFP_ATOMIC can only return a very small amount of memory and should only be used if your memory allocation cannot sleep. You can use GFP_KERNEL when it is safe to sleep, e.g., not in interrupt context. See this question for more. It is safe to use vmalloc during module initialization to pre-allocate all you memory.