6.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Joshua Hay joshua.a.hay@intel.com
[ Upstream commit f2d18e16479cac7a708d77cbfb4220a9114a71fc ]
Track the gap between next_to_use and the last RE index. Set RE again if the gap is large enough to ensure RE bit is set frequently. This is critical before removing the stashing mechanisms because the opportunistic descriptor ring cleaning from the out-of-order completions will go away. Previously the descriptors would be "cleaned" by both the descriptor (RE) completion and the out-of-order completions. Without the latter, we must ensure the RE bit is set more frequently. Otherwise, it's theoretically possible for the descriptor ring next_to_clean to never advance. The previous implementation was dependent on the start of a packet falling on a 64th index in the descriptor ring, which is not guaranteed with large packets.
Signed-off-by: Luigi Rizzo lrizzo@google.com Signed-off-by: Brian Vazquez brianvv@google.com Signed-off-by: Joshua Hay joshua.a.hay@intel.com Reviewed-by: Madhu Chittim madhu.chittim@intel.com Tested-by: Samuel Salin Samuel.salin@intel.com Signed-off-by: Tony Nguyen anthony.l.nguyen@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/ethernet/intel/idpf/idpf_txrx.c | 20 +++++++++++++++++++- drivers/net/ethernet/intel/idpf/idpf_txrx.h | 6 ++++-- 2 files changed, 23 insertions(+), 3 deletions(-)
--- a/drivers/net/ethernet/intel/idpf/idpf_txrx.c +++ b/drivers/net/ethernet/intel/idpf/idpf_txrx.c @@ -313,6 +313,8 @@ static int idpf_tx_desc_alloc(const stru */ idpf_queue_change(GEN_CHK, refillq);
+ tx_q->last_re = tx_q->desc_count - IDPF_TX_SPLITQ_RE_MIN_GAP; + return 0;
err_alloc: @@ -2709,6 +2711,21 @@ netdev_tx_t idpf_tx_drop_skb(struct idpf }
/** + * idpf_tx_splitq_need_re - check whether RE bit needs to be set + * @tx_q: pointer to Tx queue + * + * Return: true if RE bit needs to be set, false otherwise + */ +static bool idpf_tx_splitq_need_re(struct idpf_tx_queue *tx_q) +{ + int gap = tx_q->next_to_use - tx_q->last_re; + + gap += (gap < 0) ? tx_q->desc_count : 0; + + return gap >= IDPF_TX_SPLITQ_RE_MIN_GAP; +} + +/** * idpf_tx_splitq_frame - Sends buffer on Tx ring using flex descriptors * @skb: send buffer * @tx_q: queue to send buffer on @@ -2788,9 +2805,10 @@ static netdev_tx_t idpf_tx_splitq_frame( * MIN_RING size to ensure it will be set at least once each * time around the ring. */ - if (!(tx_q->next_to_use % IDPF_TX_SPLITQ_RE_MIN_GAP)) { + if (idpf_tx_splitq_need_re(tx_q)) { tx_params.eop_cmd |= IDPF_TXD_FLEX_FLOW_CMD_RE; tx_q->txq_grp->num_completions_pending++; + tx_q->last_re = tx_q->next_to_use; }
if (skb->ip_summed == CHECKSUM_PARTIAL) --- a/drivers/net/ethernet/intel/idpf/idpf_txrx.h +++ b/drivers/net/ethernet/intel/idpf/idpf_txrx.h @@ -623,6 +623,8 @@ libeth_cacheline_set_assert(struct idpf_ * @netdev: &net_device corresponding to this queue * @next_to_use: Next descriptor to use * @next_to_clean: Next descriptor to clean + * @last_re: last descriptor index that RE bit was set + * @tx_max_bufs: Max buffers that can be transmitted with scatter-gather * @cleaned_bytes: Splitq only, TXQ only: When a TX completion is received on * the TX completion queue, it can be for any TXQ associated * with that completion queue. This means we can clean up to @@ -633,7 +635,6 @@ libeth_cacheline_set_assert(struct idpf_ * only once at the end of the cleaning routine. * @clean_budget: singleq only, queue cleaning budget * @cleaned_pkts: Number of packets cleaned for the above said case - * @tx_max_bufs: Max buffers that can be transmitted with scatter-gather * @stash: Tx buffer stash for Flow-based scheduling mode * @refillq: Pointer to refill queue * @compl_tag_bufid_m: Completion tag buffer id mask @@ -674,6 +675,8 @@ struct idpf_tx_queue { __cacheline_group_begin_aligned(read_write); u16 next_to_use; u16 next_to_clean; + u16 last_re; + u16 tx_max_bufs;
union { u32 cleaned_bytes; @@ -681,7 +684,6 @@ struct idpf_tx_queue { }; u16 cleaned_pkts;
- u16 tx_max_bufs; struct idpf_txq_stash *stash; struct idpf_sw_queue *refillq;