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path: root/tools/lib/bpf/xsk.h
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2019-08-31libbpf: add flags to umem configKevin Laatz
This patch adds a 'flags' field to the umem_config and umem_reg structs. This will allow for more options to be added for configuring umems. The first use for the flags field is to add a flag for unaligned chunks mode. These flags can either be user-provided or filled with a default. Since we change the size of the xsk_umem_config struct, we need to version the ABI. This patch includes the ABI versioning for xsk_umem__create. The Makefile was also updated to handle multiple function versions in check-abi. Signed-off-by: Kevin Laatz <kevin.laatz@intel.com> Signed-off-by: Ciara Loftus <ciara.loftus@intel.com> Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-08-17libbpf: add support for need_wakeup flag in AF_XDP partMagnus Karlsson
This commit adds support for the new need_wakeup flag in AF_XDP. The xsk_socket__create function is updated to handle this and a new function is introduced called xsk_ring_prod__needs_wakeup(). This function can be used by the application to check if Rx and/or Tx processing needs to be explicitly woken up. Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-06-27xsk: Change the default frame size to 4096 and allow controlling itMaxim Mikityanskiy
The typical XDP memory scheme is one packet per page. Change the AF_XDP frame size in libbpf to 4096, which is the page size on x86, to allow libbpf to be used with the drivers with the packet-per-page scheme. Add a command line option -f to xdpsock to allow to specify a custom frame size. Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com> Signed-off-by: Tariq Toukan <tariqt@mellanox.com> Acked-by: Saeed Mahameed <saeedm@mellanox.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-04-16libbpf: optimize barrier for XDP socket ringsMagnus Karlsson
The full memory barrier in the XDP socket rings on the consumer side between the load of the data and the store of the consumer ring is there to protect the store from being executed before the load of the data. If this was allowed to happen, the producer might overwrite the data field with a new entry before the consumer got the chance to read it. On x86, stores are guaranteed not to be reordered with older loads, so it does not need a full memory barrier here. A compile time barrier would be enough. This patch introdcues a new primitive in libbpf_util.h that implements a new barrier type (libbpf_smp_rwmb) hindering stores to be reordered with older loads. It is then used in the XDP socket ring access code in libbpf to improve performance. Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-04-16libbpf: remove dependency on barrier.h in xsk.hMagnus Karlsson
The use of smp_rmb() and smp_wmb() creates a Linux header dependency on barrier.h that is unnecessary in most parts. This patch implements the two small defines that are needed from barrier.h. As a bonus, the new implementations are faster than the default ones as they default to sfence and lfence for x86, while we only need a compiler barrier in our case. Just as it is when the same ring access code is compiled in the kernel. Fixes: 1cad07884239 ("libbpf: add support for using AF_XDP sockets") Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-04-16libbpf: remove likely/unlikely in xsk.hMagnus Karlsson
This patch removes the use of likely and unlikely in xsk.h since they create a dependency on Linux headers as reported by several users. There have also been reports that the use of these decreases performance as the compiler puts the code on two different cache lines instead of on a single one. All in all, I think we are better off without them. Fixes: 1cad07884239 ("libbpf: add support for using AF_XDP sockets") Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-04-16libbpf: fix XDP socket ring buffer memory orderingMagnus Karlsson
The ring buffer code of XDP sockets is missing a memory barrier on the consumer side between the load of the data and the write that signals that it is ok for the producer to put new data into the buffer. On architectures that does not guarantee that stores are not reordered with older loads, the producer might put data into the ring before the consumer had the chance to read it. As IA does guarantee this ordering, it would only need a compiler barrier here, but there are no primitives in barrier.h for this specific case (hinder writes to be ordered before older reads) so I had to add a smp_mb() here which will translate into a run-time synch operation on IA. Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2019-02-25libbpf: add support for using AF_XDP socketsMagnus Karlsson
This commit adds AF_XDP support to libbpf. The main reason for this is to facilitate writing applications that use AF_XDP by offering higher-level APIs that hide many of the details of the AF_XDP uapi. This is in the same vein as libbpf facilitates XDP adoption by offering easy-to-use higher level interfaces of XDP functionality. Hopefully this will facilitate adoption of AF_XDP, make applications using it simpler and smaller, and finally also make it possible for applications to benefit from optimizations in the AF_XDP user space access code. Previously, people just copied and pasted the code from the sample application into their application, which is not desirable. The interface is composed of two parts: * Low-level access interface to the four rings and the packet * High-level control plane interface for creating and setting up umems and af_xdp sockets as well as a simple XDP program. Tested-by: Björn Töpel <bjorn.topel@intel.com> Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>