wireguard-linux/net/xdp/xsk_queue.h, branch jd/orphan-parallel

xsk: Introduce padding between ring pointers

2020-10-09T14:35:01Z

Introduce one cache line worth of padding between the producer and consumer pointers in all the lockless rings. This so that the HW adjacency prefetcher will not prefetch the consumer pointer when the producer pointer is used and vice versa. This improves throughput performance for the l2fwd sample app with 2% on my machine with HW prefetching turned on. Signed-off-by: Magnus Karlsson Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/1602166338-21378-1-git-send-email-magnus.karlsson@gmail.com

xsk: Fix a documentation mistake in xsk_queue.h

2020-09-29T18:25:56Z

After 'peeking' the ring, the consumer, not the producer, reads the data. Fix this mistake in the comments. Fixes: 15d8c9162ced ("xsk: Add function naming comments and reorder functions") Signed-off-by: Ciara Loftus Signed-off-by: Alexei Starovoitov Acked-by: Magnus Karlsson Link: https://lore.kernel.org/bpf/20200928082344.17110-1-ciara.loftus@intel.com

xsk: Create and free buffer pool independently from umem

2020-08-31T19:15:04Z

Create and free the buffer pool independently from the umem. Move these operations that are performed on the buffer pool from the umem create and destroy functions to new create and destroy functions just for the buffer pool. This so that in later commits we can instantiate multiple buffer pools per umem when sharing a umem between HW queues and/or devices. We also erradicate the back pointer from the umem to the buffer pool as this will not work when we introduce the possibility to have multiple buffer pools per umem. Signed-off-by: Magnus Karlsson Signed-off-by: Daniel Borkmann Acked-by: Björn Töpel Link: https://lore.kernel.org/bpf/1598603189-32145-4-git-send-email-magnus.karlsson@intel.com

xsk: Add new statistics

2020-07-13T22:32:56Z

It can be useful for the user to know the reason behind a dropped packet. Introduce new counters which track drops on the receive path caused by: 1. rx ring being full 2. fill ring being empty Also, on the tx path introduce a counter which tracks the number of times we attempt pull from the tx ring when it is empty. Signed-off-by: Ciara Loftus Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200708072835.4427-2-ciara.loftus@intel.com

xsk: Explicitly inline functions and move definitions

2020-05-22T00:31:27Z

In order to reduce the number of function calls, the struct xsk_buff_pool definition is moved to xsk_buff_pool.h. The functions xp_get_dma(), xp_dma_sync_for_cpu(), xp_dma_sync_for_device(), xp_validate_desc() and various helper functions are explicitly inlined. Further, move xp_get_handle() and xp_release() to xsk.c, to allow for the compiler to perform inlining. rfc->v1: Make sure xp_validate_desc() is inlined for Tx perf. (Maxim) Signed-off-by: Björn Töpel Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200520192103.355233-15-bjorn.topel@gmail.com

xsk: Remove MEM_TYPE_ZERO_COPY and corresponding code

2020-05-22T00:31:27Z

There are no users of MEM_TYPE_ZERO_COPY. Remove all corresponding code, including the "handle" member of struct xdp_buff. rfc->v1: Fixed spelling in commit message. (Björn) Signed-off-by: Björn Töpel Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200520192103.355233-13-bjorn.topel@gmail.com

xsk: Introduce AF_XDP buffer allocation API

2020-05-22T00:31:26Z

In order to simplify AF_XDP zero-copy enablement for NIC driver developers, a new AF_XDP buffer allocation API is added. The implementation is based on a single core (single producer/consumer) buffer pool for the AF_XDP UMEM. A buffer is allocated using the xsk_buff_alloc() function, and returned using xsk_buff_free(). If a buffer is disassociated with the pool, e.g. when a buffer is passed to an AF_XDP socket, a buffer is said to be released. Currently, the release function is only used by the AF_XDP internals and not visible to the driver. Drivers using this API should register the XDP memory model with the new MEM_TYPE_XSK_BUFF_POOL type. The API is defined in net/xdp_sock_drv.h. The buffer type is struct xdp_buff, and follows the lifetime of regular xdp_buffs, i.e. the lifetime of an xdp_buff is restricted to a NAPI context. In other words, the API is not replacing xdp_frames. In addition to introducing the API and implementations, the AF_XDP core is migrated to use the new APIs. rfc->v1: Fixed build errors/warnings for m68k and riscv. (kbuild test robot) Added headroom/chunk size getter. (Maxim/Björn) v1->v2: Swapped SoBs. (Maxim) v2->v3: Initialize struct xdp_buff member frame_sz. (Björn) Add API to query the DMA address of a frame. (Maxim) Do DMA sync for CPU till the end of the frame to handle possible growth (frame_sz). (Maxim) Signed-off-by: Björn Töpel Signed-off-by: Maxim Mikityanskiy Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200520192103.355233-6-bjorn.topel@gmail.com

xsk: Move defines only used by AF_XDP internals to xsk.h

2020-05-22T00:31:26Z

Move the XSK_NEXT_PG_CONTIG_{MASK,SHIFT}, and XDP_UMEM_USES_NEED_WAKEUP defines from xdp_sock.h to the AF_XDP internal xsk.h file. Also, start using the BIT{,_ULL} macro instead of explicit shifts. Signed-off-by: Björn Töpel Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200520192103.355233-5-bjorn.topel@gmail.com

xsk: Change two variable names for increased clarity

2020-05-04T20:56:26Z

Change two variables names so that it is clearer what they represent. The first one is xsk_list that in fact only contains the list of AF_XDP sockets with a Tx component. Change this to xsk_tx_list for improved clarity. The second variable is size in the ring structure. One might think that this is the size of the ring, but it is in fact the size of the umem, copied into the ring structure to improve performance. Rename this variable umem_size to avoid any confusion. Signed-off-by: Magnus Karlsson Signed-off-by: Daniel Borkmann Acked-by: Jonathan Lemon Link: https://lore.kernel.org/bpf/1588599232-24897-2-git-send-email-magnus.karlsson@intel.com

xdp: Replace zero-length array with flexible-array member

2020-02-28T20:08:37Z

The current codebase makes use of the zero-length array language extension to the C90 standard, but the preferred mechanism to declare variable-length types such as these ones is a flexible array member[1][2], introduced in C99: struct foo { int stuff; struct boo array[]; }; By making use of the mechanism above, we will get a compiler warning in case the flexible array does not occur last in the structure, which will help us prevent some kind of undefined behavior bugs from being inadvertently introduced[3] to the codebase from now on. Also, notice that, dynamic memory allocations won't be affected by this change: "Flexible array members have incomplete type, and so the sizeof operator may not be applied. As a quirk of the original implementation of zero-length arrays, sizeof evaluates to zero."[1] This issue was found with the help of Coccinelle. [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html [2] https://github.com/KSPP/linux/issues/21 [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour") Signed-off-by: Gustavo A. R. Silva Acked-by: Jonathan Lemon Acked-by: Björn Töpel Signed-off-by: David S. Miller