This patch set removes two dependencies on Linux kernel headers from the XDP socket code in libbpf. A number of people have pointed out that these two dependencies make it hard to build the XDP socket part of libbpf without any kernel header dependencies. The two removed dependecies are: * Remove the usage of likely and unlikely (compiler.h) in xsk.h. It has been reported that the use of these actually decreases the performance of the ring access code due to an increase in instruction cache misses, so let us just remove these. * Remove the dependency on barrier.h as it brings in a lot of kernel headers. As the XDP socket code only uses two simple functions from it, we can reimplement these. As a bonus, the new implementation is faster as it uses the same barrier primitives as the kernel does when the same code is compiled there. Without this patch, the user land code uses lfence and sfence on x86, which are unecessarily harsh/thorough. Do the ARM barriers look sane? Have not tested these. /Magnus Magnus Karlsson (2): libbpf: remove likely/unlikely in xsk.h libbpf: remove dependency on barrier.h in xsk.h tools/lib/bpf/xsk.h | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) -- 2.7.4
