Libbpf eBPF macro barrier
The barrier macro is used to prevent the compiler from reordering memory operations.
Definition
#define barrier() asm volatile("" ::: "memory")
Usage
This macro inserts what is referred to as a "full memory barrier". Compilers such as GCC and Clang will sometimes reorder memory operations to optimize code, so your actual program may not execute in the order you wrote it. If the order of memory operations is important, you can use the barrier macro to tell the compiler to not reorder memory operations across the barrier.
This is a very specialized tool which you will likely not use often.
Example
Docs could be improved
This part of the docs is incomplete, contributions are very welcome