6.5-stable review patch. If anyone has any objections, please let me know.
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From: Dragos Tatulea dtatulea@nvidia.com
[ Upstream commit ef9369e9c30846f5e052a11ccc70e1f6b8dc557a ]
When a page allocation fails during refill in mlx5e_refill_rx_wqes, the page will be released again on the next refill call. This triggers the page_pool negative page fragment count warning below:
[ 338.326070] WARNING: CPU: 4 PID: 0 at include/net/page_pool/helpers.h:130 mlx5e_page_release_fragmented.isra.0+0x42/0x50 [mlx5_core] ... [ 338.328993] RIP: 0010:mlx5e_page_release_fragmented.isra.0+0x42/0x50 [mlx5_core] [ 338.329094] Call Trace: [ 338.329097] <IRQ> [ 338.329100] ? __warn+0x7d/0x120 [ 338.329105] ? mlx5e_page_release_fragmented.isra.0+0x42/0x50 [mlx5_core] [ 338.329173] ? report_bug+0x155/0x180 [ 338.329179] ? handle_bug+0x3c/0x60 [ 338.329183] ? exc_invalid_op+0x13/0x60 [ 338.329187] ? asm_exc_invalid_op+0x16/0x20 [ 338.329192] ? mlx5e_page_release_fragmented.isra.0+0x42/0x50 [mlx5_core] [ 338.329259] mlx5e_post_rx_wqes+0x210/0x5a0 [mlx5_core] [ 338.329327] ? mlx5e_poll_rx_cq+0x88/0x6f0 [mlx5_core] [ 338.329394] mlx5e_napi_poll+0x127/0x6b0 [mlx5_core] [ 338.329461] __napi_poll+0x25/0x1a0 [ 338.329465] net_rx_action+0x28a/0x300 [ 338.329468] __do_softirq+0xcd/0x279 [ 338.329473] irq_exit_rcu+0x6a/0x90 [ 338.329477] common_interrupt+0x82/0xa0 [ 338.329482] </IRQ>
This patch fixes the legacy rq case by releasing all allocated fragments and then setting the skip flag on all released fragments. It is important to note that the number of released fragments will be higher than the number of allocated fragments when an allocation error occurs.
Fixes: 3f93f82988bc ("net/mlx5e: RX, Defer page release in legacy rq for better recycling") Tested-by: Chris Mason clm@fb.com Reported-by: Chris Mason clm@fb.com Closes: https://lore.kernel.org/netdev/117FF31A-7BE0-4050-B2BB-E41F224FF72F@meta.com Signed-off-by: Dragos Tatulea dtatulea@nvidia.com Reviewed-by: Tariq Toukan tariqt@nvidia.com Signed-off-by: Saeed Mahameed saeedm@nvidia.com Signed-off-by: Sasha Levin sashal@kernel.org --- .../net/ethernet/mellanox/mlx5/core/en_rx.c | 33 ++++++++++++++----- 1 file changed, 24 insertions(+), 9 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c index 0b558db1a9455..5df970e6e29d5 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c @@ -457,26 +457,41 @@ static int mlx5e_alloc_rx_wqes(struct mlx5e_rq *rq, u16 ix, int wqe_bulk) static int mlx5e_refill_rx_wqes(struct mlx5e_rq *rq, u16 ix, int wqe_bulk) { int remaining = wqe_bulk; - int i = 0; + int total_alloc = 0; + int refill_alloc; + int refill;
/* The WQE bulk is split into smaller bulks that are sized * according to the page pool cache refill size to avoid overflowing * the page pool cache due to too many page releases at once. */ do { - int refill = min_t(u16, rq->wqe.info.refill_unit, remaining); - int alloc_count; + refill = min_t(u16, rq->wqe.info.refill_unit, remaining);
- mlx5e_free_rx_wqes(rq, ix + i, refill); - alloc_count = mlx5e_alloc_rx_wqes(rq, ix + i, refill); - i += alloc_count; - if (unlikely(alloc_count != refill)) - break; + mlx5e_free_rx_wqes(rq, ix + total_alloc, refill); + refill_alloc = mlx5e_alloc_rx_wqes(rq, ix + total_alloc, refill); + if (unlikely(refill_alloc != refill)) + goto err_free;
+ total_alloc += refill_alloc; remaining -= refill; } while (remaining);
- return i; + return total_alloc; + +err_free: + mlx5e_free_rx_wqes(rq, ix, total_alloc + refill_alloc); + + for (int i = 0; i < total_alloc + refill; i++) { + int j = mlx5_wq_cyc_ctr2ix(&rq->wqe.wq, ix + i); + struct mlx5e_wqe_frag_info *frag; + + frag = get_frag(rq, j); + for (int k = 0; k < rq->wqe.info.num_frags; k++, frag++) + frag->flags |= BIT(MLX5E_WQE_FRAG_SKIP_RELEASE); + } + + return 0; }
static void