[dpdk-dev] [PATCH v9 1/1] net/af_xdp: introduce AF XDP PMD driver

[Bruce Richardson]

On Wed, Apr 03, 2019 at 11:14:58PM +0800, Ye Xiaolong wrote:
> On 04/03, Luca Boccassi wrote:
> >On Wed, 2019-04-03 at 22:43 +0800, Ye Xiaolong wrote:
> >> On 04/03, Luca Boccassi wrote:
> >> [snip]
> >> > > Got it.
> >> > > 
> >> > > In above steps, 'libbpf' also build from kernel source tree, will
> >> > > it
> >> > > be problem
> >> > > in you builds to not have it build from source?
> >> > > 
> >> > > If not, taking into account that xsk.h also will be fixed, only
> >> > > 'tools/include/asm/barrier.h' remains the problem, and it looks
> >> > > like
> >> > > it can be
> >> > > solved, please check above.
> >> > 
> >> > libbpf is already packaged separately in Debian and I think other
> >> > distros will follow soon, so it's all good for me once the barrier
> >> > issue is solved.
> >> > 
> >> > https://packages.debian.org/buster/libbpf-dev
> >> > 
> >> > 
> >> > From the makefile's perspective it should not matter where it comes
> >> > from - the headers should be expected to be in /usr/include and the
> >> > library in /usr/lib* - and pkg-config can help with that if
> >> > available.
> >> > And if a user wants to use a custom path, then it's no different
> >> > than
> >> > any of the other dependencies on other external libraries
> >> 
> >> From tools/lib/bpf/Makefile, after make install_lib and make
> >> install_headers,
> >> the headers and library would be put in /usr/local/include/bpf and
> >> /usr/local/lib*,
> >> Is it ok?
> >
> >Yes certainly that's fine, that's expected for local installations, and
> >users can specify a prefix with the upstream's makefile if they want to
> >install somewhere else.
> 
> In my local test, if I run `make install_lib` to install the libbpf.so to 
> /usr/local/lib64, `-lbpf` specified in af_xdp pmd still fails to find the library,
> the build would end up with a lot of undefined references which are defined in libbpf.
> It means during dpdk compilation, it won't search libraries in /usr/local/lib*, right?
> 
> Install the libbpf to /usr/lib64 via `make install_lib prefix=/usr` doesn't have 
> this issue, so shall I just document it in af_xdp.rst or there is other proper
> way to do it?
> 
At a guess I'd say you are using Fedora Linux, right? Fedora is unusual in
that it doesn't by default add /usr/local to the library and header search
paths so you need to explicitly add them to your environment. Other distros
should work fine for this.

/Bruce