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164 lines
7.2 KiB
164 lines
7.2 KiB
From d1ac1b641ea39e946e94c155520c590a5a27e23a Mon Sep 17 00:00:00 2001
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From: Jiri Benc <jbenc@redhat.com>
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Date: Wed, 22 Apr 2020 18:18:11 -0400
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Subject: [PATCH 006/312] [netdrv] mlx5e: Allow XSK frames smaller than a page
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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Message-id: <5c0604430537e1022e4424f8683b5611f3ccceb3.1587578778.git.jbenc@redhat.com>
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Patchwork-id: 304531
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Patchwork-instance: patchwork
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O-Subject: [RHEL8.3 net 20/46] net/mlx5e: Allow XSK frames smaller than a page
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Bugzilla: 1819630
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RH-Acked-by: Hangbin Liu <haliu@redhat.com>
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RH-Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
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RH-Acked-by: Ivan Vecera <ivecera@redhat.com>
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Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1819630
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commit 282c0c798f8ec883c2ac2f1ce2dc06ef9421731c
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Author: Maxim Mikityanskiy <maximmi@mellanox.com>
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Date: Tue Aug 27 02:25:26 2019 +0000
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net/mlx5e: Allow XSK frames smaller than a page
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Relax the requirements to the XSK frame size to allow it to be smaller
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than a page and even not a power of two. The current implementation can
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work in this mode, both with Striding RQ and without it.
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The code that checks `mtu + headroom <= XSK frame size` is modified
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accordingly. Any frame size between 2048 and PAGE_SIZE is accepted.
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Functions that worked with pages only now work with XSK frames, even if
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their size is different from PAGE_SIZE.
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With XSK queues, regardless of the frame size, Striding RQ uses the
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stride size of PAGE_SIZE, and UMR MTTs are posted using starting
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addresses of frames, but PAGE_SIZE as page size. MTU guarantees that no
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packet data will overlap with other frames. UMR MTT size is made equal
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to the stride size of the RQ, because UMEM frames may come in random
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order, and we need to handle them one by one. PAGE_SIZE is just a power
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of two that is bigger than any allowed XSK frame size, and also it
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doesn't require making additional changes to the code.
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Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
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Reviewed-by: Saeed Mahameed <saeedm@mellanox.com>
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Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
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Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
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Signed-off-by: Jiri Benc <jbenc@redhat.com>
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Signed-off-by: Timothy Redaelli <tredaelli@redhat.com>
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Signed-off-by: Frantisek Hrbata <fhrbata@redhat.com>
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---
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.../net/ethernet/mellanox/mlx5/core/en/params.c | 23 ++++++++++++++++++----
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.../net/ethernet/mellanox/mlx5/core/en/params.h | 2 ++
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.../net/ethernet/mellanox/mlx5/core/en/xsk/rx.c | 2 +-
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.../net/ethernet/mellanox/mlx5/core/en/xsk/setup.c | 15 +++++++++-----
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4 files changed, 32 insertions(+), 10 deletions(-)
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diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/params.c b/drivers/net/ethernet/mellanox/mlx5/core/en/params.c
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index 79301d116667..eb2e1f2138e4 100644
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--- a/drivers/net/ethernet/mellanox/mlx5/core/en/params.c
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+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/params.c
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@@ -25,18 +25,33 @@ u16 mlx5e_get_linear_rq_headroom(struct mlx5e_params *params,
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return headroom;
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}
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-u32 mlx5e_rx_get_linear_frag_sz(struct mlx5e_params *params,
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- struct mlx5e_xsk_param *xsk)
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+u32 mlx5e_rx_get_min_frag_sz(struct mlx5e_params *params,
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+ struct mlx5e_xsk_param *xsk)
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{
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u32 hw_mtu = MLX5E_SW2HW_MTU(params, params->sw_mtu);
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u16 linear_rq_headroom = mlx5e_get_linear_rq_headroom(params, xsk);
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- u32 frag_sz = linear_rq_headroom + hw_mtu;
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+
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+ return linear_rq_headroom + hw_mtu;
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+}
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+
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+u32 mlx5e_rx_get_linear_frag_sz(struct mlx5e_params *params,
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+ struct mlx5e_xsk_param *xsk)
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+{
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+ u32 frag_sz = mlx5e_rx_get_min_frag_sz(params, xsk);
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/* AF_XDP doesn't build SKBs in place. */
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if (!xsk)
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frag_sz = MLX5_SKB_FRAG_SZ(frag_sz);
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- /* XDP in mlx5e doesn't support multiple packets per page. */
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+ /* XDP in mlx5e doesn't support multiple packets per page. AF_XDP is a
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+ * special case. It can run with frames smaller than a page, as it
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+ * doesn't allocate pages dynamically. However, here we pretend that
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+ * fragments are page-sized: it allows to treat XSK frames like pages
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+ * by redirecting alloc and free operations to XSK rings and by using
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+ * the fact there are no multiple packets per "page" (which is a frame).
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+ * The latter is important, because frames may come in a random order,
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+ * and we will have trouble assemblying a real page of multiple frames.
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+ */
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if (mlx5e_rx_is_xdp(params, xsk))
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frag_sz = max_t(u32, frag_sz, PAGE_SIZE);
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diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/params.h b/drivers/net/ethernet/mellanox/mlx5/core/en/params.h
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index 3a615d663d84..989d8f429438 100644
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--- a/drivers/net/ethernet/mellanox/mlx5/core/en/params.h
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+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/params.h
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@@ -76,6 +76,8 @@ static inline bool mlx5e_qid_validate(const struct mlx5e_profile *profile,
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u16 mlx5e_get_linear_rq_headroom(struct mlx5e_params *params,
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struct mlx5e_xsk_param *xsk);
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+u32 mlx5e_rx_get_min_frag_sz(struct mlx5e_params *params,
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+ struct mlx5e_xsk_param *xsk);
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u32 mlx5e_rx_get_linear_frag_sz(struct mlx5e_params *params,
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struct mlx5e_xsk_param *xsk);
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u8 mlx5e_mpwqe_log_pkts_per_wqe(struct mlx5e_params *params,
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diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/rx.c b/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/rx.c
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index 6a55573ec8f2..3783776b6d70 100644
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--- a/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/rx.c
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+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/rx.c
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@@ -104,7 +104,7 @@ struct sk_buff *mlx5e_xsk_skb_from_cqe_mpwrq_linear(struct mlx5e_rq *rq,
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/* head_offset is not used in this function, because di->xsk.data and
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* di->addr point directly to the necessary place. Furthermore, in the
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- * current implementation, one page = one packet = one frame, so
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+ * current implementation, UMR pages are mapped to XSK frames, so
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* head_offset should always be 0.
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*/
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WARN_ON_ONCE(head_offset);
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diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/setup.c b/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/setup.c
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index d3a173e88e24..81efd2fbc75d 100644
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--- a/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/setup.c
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+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/setup.c
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@@ -4,18 +4,23 @@
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#include "setup.h"
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#include "en/params.h"
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+/* It matches XDP_UMEM_MIN_CHUNK_SIZE, but as this constant is private and may
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+ * change unexpectedly, and mlx5e has a minimum valid stride size for striding
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+ * RQ, keep this check in the driver.
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+ */
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+#define MLX5E_MIN_XSK_CHUNK_SIZE 2048
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+
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bool mlx5e_validate_xsk_param(struct mlx5e_params *params,
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struct mlx5e_xsk_param *xsk,
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struct mlx5_core_dev *mdev)
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{
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- /* AF_XDP doesn't support frames larger than PAGE_SIZE, and the current
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- * mlx5e XDP implementation doesn't support multiple packets per page.
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- */
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- if (xsk->chunk_size != PAGE_SIZE)
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+ /* AF_XDP doesn't support frames larger than PAGE_SIZE. */
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+ if (xsk->chunk_size > PAGE_SIZE ||
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+ xsk->chunk_size < MLX5E_MIN_XSK_CHUNK_SIZE)
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return false;
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/* Current MTU and XSK headroom don't allow packets to fit the frames. */
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- if (mlx5e_rx_get_linear_frag_sz(params, xsk) > xsk->chunk_size)
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+ if (mlx5e_rx_get_min_frag_sz(params, xsk) > xsk->chunk_size)
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return false;
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/* frag_sz is different for regular and XSK RQs, so ensure that linear
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--
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2.13.6
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