小弟对于linux kernel算初心者，关于vmalloc的解释有些地方不懂，还请高手解释
void * vmalloc(unsigned long size)
The function returns a pointer to at least size bytes of virtually contiguous
memory. On error, the function returns NULL. The function might sleep, and
thus cannot be called from interrupt context or other situations where
blocking is not permissible.
我的问题是
为什么这个function会sleep? 什么样的情况会导致vmalloc进行sleep?
谢谢!