6.12-stable review patch. If anyone has any objections, please let me know.
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From: Carolina Jubran cjubran@nvidia.com
[ Upstream commit b66b76a82c8879d764ab89adc21ee855ffd292d5 ]
CONFIG_INIT_STACK_ALL_ZERO introduces a performance cost by zero-initializing all stack variables on function entry. The mlx5 XDP RX path previously allocated a struct mlx5e_xdp_buff on the stack per received CQE, resulting in measurable performance degradation under this config.
This patch reuses a mlx5e_xdp_buff stored in the mlx5e_rq struct, avoiding per-CQE stack allocations and repeated zeroing.
With this change, XDP_DROP and XDP_TX performance matches that of kernels built without CONFIG_INIT_STACK_ALL_ZERO.
Performance was measured on a ConnectX-6Dx using a single RX channel (1 CPU at 100% usage) at ~50 Mpps. The baseline results were taken from net-next-6.15.
Stack zeroing disabled: - XDP_DROP: * baseline: 31.47 Mpps * baseline + per-RQ allocation: 32.31 Mpps (+2.68%)
- XDP_TX: * baseline: 12.41 Mpps * baseline + per-RQ allocation: 12.95 Mpps (+4.30%)
Stack zeroing enabled: - XDP_DROP: * baseline: 24.32 Mpps * baseline + per-RQ allocation: 32.27 Mpps (+32.7%)
- XDP_TX: * baseline: 11.80 Mpps * baseline + per-RQ allocation: 12.24 Mpps (+3.72%)
Reported-by: Sebastiano Miano mianosebastiano@gmail.com Reported-by: Samuel Dobron sdobron@redhat.com Link: https://lore.kernel.org/all/CAMENy5pb8ea+piKLg5q5yRTMZacQqYWAoVLE1FE9WhQPq92... Signed-off-by: Carolina Jubran cjubran@nvidia.com Reviewed-by: Dragos Tatulea dtatulea@nvidia.com Signed-off-by: Tariq Toukan tariqt@nvidia.com Acked-by: Jesper Dangaard Brouer hawk@kernel.org Link: https://patch.msgid.link/1747253032-663457-1-git-send-email-tariqt@nvidia.co... Signed-off-by: Jakub Kicinski kuba@kernel.org Stable-dep-of: afd5ba577c10 ("net/mlx5e: RX, Fix generating skb from non-linear xdp_buff for legacy RQ") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/mellanox/mlx5/core/en.h | 7 ++ .../net/ethernet/mellanox/mlx5/core/en/xdp.h | 6 -- .../net/ethernet/mellanox/mlx5/core/en_rx.c | 81 ++++++++++--------- 3 files changed, 51 insertions(+), 43 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en.h b/drivers/net/ethernet/mellanox/mlx5/core/en.h index e048a667e0758..f2952a6b0db73 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en.h +++ b/drivers/net/ethernet/mellanox/mlx5/core/en.h @@ -512,6 +512,12 @@ struct mlx5e_xdpsq { struct mlx5e_channel *channel; } ____cacheline_aligned_in_smp;
+struct mlx5e_xdp_buff { + struct xdp_buff xdp; + struct mlx5_cqe64 *cqe; + struct mlx5e_rq *rq; +}; + struct mlx5e_ktls_resync_resp;
struct mlx5e_icosq { @@ -710,6 +716,7 @@ struct mlx5e_rq { struct mlx5e_xdpsq *xdpsq; DECLARE_BITMAP(flags, 8); struct page_pool *page_pool; + struct mlx5e_xdp_buff mxbuf;
/* AF_XDP zero-copy */ struct xsk_buff_pool *xsk_pool; diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.h b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.h index e054db1e10f8a..75256cf978c86 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.h +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xdp.h @@ -45,12 +45,6 @@ (MLX5E_XDP_INLINE_WQE_MAX_DS_CNT * MLX5_SEND_WQE_DS - \ sizeof(struct mlx5_wqe_inline_seg))
-struct mlx5e_xdp_buff { - struct xdp_buff xdp; - struct mlx5_cqe64 *cqe; - struct mlx5e_rq *rq; -}; - /* XDP packets can be transmitted in different ways. On completion, we need to * distinguish between them to clean up things in a proper way. */ diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c index 673043d9ed11a..f072b21eb610d 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c @@ -1691,17 +1691,17 @@ mlx5e_skb_from_cqe_linear(struct mlx5e_rq *rq, struct mlx5e_wqe_frag_info *wi,
prog = rcu_dereference(rq->xdp_prog); if (prog) { - struct mlx5e_xdp_buff mxbuf; + struct mlx5e_xdp_buff *mxbuf = &rq->mxbuf;
net_prefetchw(va); /* xdp_frame data area */ mlx5e_fill_mxbuf(rq, cqe, va, rx_headroom, rq->buff.frame0_sz, - cqe_bcnt, &mxbuf); - if (mlx5e_xdp_handle(rq, prog, &mxbuf)) + cqe_bcnt, mxbuf); + if (mlx5e_xdp_handle(rq, prog, mxbuf)) return NULL; /* page/packet was consumed by XDP */
- rx_headroom = mxbuf.xdp.data - mxbuf.xdp.data_hard_start; - metasize = mxbuf.xdp.data - mxbuf.xdp.data_meta; - cqe_bcnt = mxbuf.xdp.data_end - mxbuf.xdp.data; + rx_headroom = mxbuf->xdp.data - mxbuf->xdp.data_hard_start; + metasize = mxbuf->xdp.data - mxbuf->xdp.data_meta; + cqe_bcnt = mxbuf->xdp.data_end - mxbuf->xdp.data; } frag_size = MLX5_SKB_FRAG_SZ(rx_headroom + cqe_bcnt); skb = mlx5e_build_linear_skb(rq, va, frag_size, rx_headroom, cqe_bcnt, metasize); @@ -1720,11 +1720,11 @@ mlx5e_skb_from_cqe_nonlinear(struct mlx5e_rq *rq, struct mlx5e_wqe_frag_info *wi struct mlx5_cqe64 *cqe, u32 cqe_bcnt) { struct mlx5e_rq_frag_info *frag_info = &rq->wqe.info.arr[0]; + struct mlx5e_xdp_buff *mxbuf = &rq->mxbuf; struct mlx5e_wqe_frag_info *head_wi = wi; u16 rx_headroom = rq->buff.headroom; struct mlx5e_frag_page *frag_page; struct skb_shared_info *sinfo; - struct mlx5e_xdp_buff mxbuf; u32 frag_consumed_bytes; struct bpf_prog *prog; struct sk_buff *skb; @@ -1744,8 +1744,8 @@ mlx5e_skb_from_cqe_nonlinear(struct mlx5e_rq *rq, struct mlx5e_wqe_frag_info *wi net_prefetch(va + rx_headroom);
mlx5e_fill_mxbuf(rq, cqe, va, rx_headroom, rq->buff.frame0_sz, - frag_consumed_bytes, &mxbuf); - sinfo = xdp_get_shared_info_from_buff(&mxbuf.xdp); + frag_consumed_bytes, mxbuf); + sinfo = xdp_get_shared_info_from_buff(&mxbuf->xdp); truesize = 0;
cqe_bcnt -= frag_consumed_bytes; @@ -1757,8 +1757,9 @@ mlx5e_skb_from_cqe_nonlinear(struct mlx5e_rq *rq, struct mlx5e_wqe_frag_info *wi
frag_consumed_bytes = min_t(u32, frag_info->frag_size, cqe_bcnt);
- mlx5e_add_skb_shared_info_frag(rq, sinfo, &mxbuf.xdp, frag_page, - wi->offset, frag_consumed_bytes); + mlx5e_add_skb_shared_info_frag(rq, sinfo, &mxbuf->xdp, + frag_page, wi->offset, + frag_consumed_bytes); truesize += frag_info->frag_stride;
cqe_bcnt -= frag_consumed_bytes; @@ -1767,7 +1768,7 @@ mlx5e_skb_from_cqe_nonlinear(struct mlx5e_rq *rq, struct mlx5e_wqe_frag_info *wi }
prog = rcu_dereference(rq->xdp_prog); - if (prog && mlx5e_xdp_handle(rq, prog, &mxbuf)) { + if (prog && mlx5e_xdp_handle(rq, prog, mxbuf)) { if (__test_and_clear_bit(MLX5E_RQ_FLAG_XDP_XMIT, rq->flags)) { struct mlx5e_wqe_frag_info *pwi;
@@ -1777,21 +1778,23 @@ mlx5e_skb_from_cqe_nonlinear(struct mlx5e_rq *rq, struct mlx5e_wqe_frag_info *wi return NULL; /* page/packet was consumed by XDP */ }
- skb = mlx5e_build_linear_skb(rq, mxbuf.xdp.data_hard_start, rq->buff.frame0_sz, - mxbuf.xdp.data - mxbuf.xdp.data_hard_start, - mxbuf.xdp.data_end - mxbuf.xdp.data, - mxbuf.xdp.data - mxbuf.xdp.data_meta); + skb = mlx5e_build_linear_skb( + rq, mxbuf->xdp.data_hard_start, rq->buff.frame0_sz, + mxbuf->xdp.data - mxbuf->xdp.data_hard_start, + mxbuf->xdp.data_end - mxbuf->xdp.data, + mxbuf->xdp.data - mxbuf->xdp.data_meta); if (unlikely(!skb)) return NULL;
skb_mark_for_recycle(skb); head_wi->frag_page->frags++;
- if (xdp_buff_has_frags(&mxbuf.xdp)) { + if (xdp_buff_has_frags(&mxbuf->xdp)) { /* sinfo->nr_frags is reset by build_skb, calculate again. */ xdp_update_skb_shared_info(skb, wi - head_wi - 1, sinfo->xdp_frags_size, truesize, - xdp_buff_is_frag_pfmemalloc(&mxbuf.xdp)); + xdp_buff_is_frag_pfmemalloc( + &mxbuf->xdp));
for (struct mlx5e_wqe_frag_info *pwi = head_wi + 1; pwi < wi; pwi++) pwi->frag_page->frags++; @@ -1991,10 +1994,10 @@ mlx5e_skb_from_cqe_mpwrq_nonlinear(struct mlx5e_rq *rq, struct mlx5e_mpw_info *w struct mlx5e_frag_page *frag_page = &wi->alloc_units.frag_pages[page_idx]; u16 headlen = min_t(u16, MLX5E_RX_MAX_HEAD, cqe_bcnt); struct mlx5e_frag_page *head_page = frag_page; + struct mlx5e_xdp_buff *mxbuf = &rq->mxbuf; u32 frag_offset = head_offset; u32 byte_cnt = cqe_bcnt; struct skb_shared_info *sinfo; - struct mlx5e_xdp_buff mxbuf; unsigned int truesize = 0; struct bpf_prog *prog; struct sk_buff *skb; @@ -2040,9 +2043,10 @@ mlx5e_skb_from_cqe_mpwrq_nonlinear(struct mlx5e_rq *rq, struct mlx5e_mpw_info *w } }
- mlx5e_fill_mxbuf(rq, cqe, va, linear_hr, linear_frame_sz, linear_data_len, &mxbuf); + mlx5e_fill_mxbuf(rq, cqe, va, linear_hr, linear_frame_sz, + linear_data_len, mxbuf);
- sinfo = xdp_get_shared_info_from_buff(&mxbuf.xdp); + sinfo = xdp_get_shared_info_from_buff(&mxbuf->xdp);
while (byte_cnt) { /* Non-linear mode, hence non-XSK, which always uses PAGE_SIZE. */ @@ -2053,7 +2057,8 @@ mlx5e_skb_from_cqe_mpwrq_nonlinear(struct mlx5e_rq *rq, struct mlx5e_mpw_info *w else truesize += ALIGN(pg_consumed_bytes, BIT(rq->mpwqe.log_stride_sz));
- mlx5e_add_skb_shared_info_frag(rq, sinfo, &mxbuf.xdp, frag_page, frag_offset, + mlx5e_add_skb_shared_info_frag(rq, sinfo, &mxbuf->xdp, + frag_page, frag_offset, pg_consumed_bytes); byte_cnt -= pg_consumed_bytes; frag_offset = 0; @@ -2061,7 +2066,7 @@ mlx5e_skb_from_cqe_mpwrq_nonlinear(struct mlx5e_rq *rq, struct mlx5e_mpw_info *w }
if (prog) { - if (mlx5e_xdp_handle(rq, prog, &mxbuf)) { + if (mlx5e_xdp_handle(rq, prog, mxbuf)) { if (__test_and_clear_bit(MLX5E_RQ_FLAG_XDP_XMIT, rq->flags)) { struct mlx5e_frag_page *pfp;
@@ -2074,10 +2079,10 @@ mlx5e_skb_from_cqe_mpwrq_nonlinear(struct mlx5e_rq *rq, struct mlx5e_mpw_info *w return NULL; /* page/packet was consumed by XDP */ }
- skb = mlx5e_build_linear_skb(rq, mxbuf.xdp.data_hard_start, - linear_frame_sz, - mxbuf.xdp.data - mxbuf.xdp.data_hard_start, 0, - mxbuf.xdp.data - mxbuf.xdp.data_meta); + skb = mlx5e_build_linear_skb( + rq, mxbuf->xdp.data_hard_start, linear_frame_sz, + mxbuf->xdp.data - mxbuf->xdp.data_hard_start, 0, + mxbuf->xdp.data - mxbuf->xdp.data_meta); if (unlikely(!skb)) { mlx5e_page_release_fragmented(rq, &wi->linear_page); return NULL; @@ -2087,13 +2092,14 @@ mlx5e_skb_from_cqe_mpwrq_nonlinear(struct mlx5e_rq *rq, struct mlx5e_mpw_info *w wi->linear_page.frags++; mlx5e_page_release_fragmented(rq, &wi->linear_page);
- if (xdp_buff_has_frags(&mxbuf.xdp)) { + if (xdp_buff_has_frags(&mxbuf->xdp)) { struct mlx5e_frag_page *pagep;
/* sinfo->nr_frags is reset by build_skb, calculate again. */ xdp_update_skb_shared_info(skb, frag_page - head_page, sinfo->xdp_frags_size, truesize, - xdp_buff_is_frag_pfmemalloc(&mxbuf.xdp)); + xdp_buff_is_frag_pfmemalloc( + &mxbuf->xdp));
pagep = head_page; do @@ -2104,12 +2110,13 @@ mlx5e_skb_from_cqe_mpwrq_nonlinear(struct mlx5e_rq *rq, struct mlx5e_mpw_info *w } else { dma_addr_t addr;
- if (xdp_buff_has_frags(&mxbuf.xdp)) { + if (xdp_buff_has_frags(&mxbuf->xdp)) { struct mlx5e_frag_page *pagep;
xdp_update_skb_shared_info(skb, sinfo->nr_frags, sinfo->xdp_frags_size, truesize, - xdp_buff_is_frag_pfmemalloc(&mxbuf.xdp)); + xdp_buff_is_frag_pfmemalloc( + &mxbuf->xdp));
pagep = frag_page - sinfo->nr_frags; do @@ -2159,20 +2166,20 @@ mlx5e_skb_from_cqe_mpwrq_linear(struct mlx5e_rq *rq, struct mlx5e_mpw_info *wi,
prog = rcu_dereference(rq->xdp_prog); if (prog) { - struct mlx5e_xdp_buff mxbuf; + struct mlx5e_xdp_buff *mxbuf = &rq->mxbuf;
net_prefetchw(va); /* xdp_frame data area */ mlx5e_fill_mxbuf(rq, cqe, va, rx_headroom, rq->buff.frame0_sz, - cqe_bcnt, &mxbuf); - if (mlx5e_xdp_handle(rq, prog, &mxbuf)) { + cqe_bcnt, mxbuf); + if (mlx5e_xdp_handle(rq, prog, mxbuf)) { if (__test_and_clear_bit(MLX5E_RQ_FLAG_XDP_XMIT, rq->flags)) frag_page->frags++; return NULL; /* page/packet was consumed by XDP */ }
- rx_headroom = mxbuf.xdp.data - mxbuf.xdp.data_hard_start; - metasize = mxbuf.xdp.data - mxbuf.xdp.data_meta; - cqe_bcnt = mxbuf.xdp.data_end - mxbuf.xdp.data; + rx_headroom = mxbuf->xdp.data - mxbuf->xdp.data_hard_start; + metasize = mxbuf->xdp.data - mxbuf->xdp.data_meta; + cqe_bcnt = mxbuf->xdp.data_end - mxbuf->xdp.data; } frag_size = MLX5_SKB_FRAG_SZ(rx_headroom + cqe_bcnt); skb = mlx5e_build_linear_skb(rq, va, frag_size, rx_headroom, cqe_bcnt, metasize);