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Date: Wed, 5 Oct 2022 10:50:32 -0700 From: Joe Damato <jdamato@...tly.com> To: Maciej Fijalkowski <maciej.fijalkowski@...el.com> Cc: intel-wired-lan@...ts.osuosl.org, netdev@...r.kernel.org, kuba@...nel.org, davem@...emloft.net, anthony.l.nguyen@...el.com, jesse.brandeburg@...el.com Subject: Re: [next-queue 2/3] i40e: i40e_clean_tx_irq returns work done On Wed, Oct 05, 2022 at 12:46:31PM +0200, Maciej Fijalkowski wrote: > On Wed, Oct 05, 2022 at 01:31:42AM -0700, Joe Damato wrote: > > Adjust i40e_clean_tx_irq to return the actual number of packets cleaned > > and adjust the logic in i40e_napi_poll to check this value. > > > > Signed-off-by: Joe Damato <jdamato@...tly.com> > > --- > > drivers/net/ethernet/intel/i40e/i40e_txrx.c | 24 +++++++++++++----------- > > drivers/net/ethernet/intel/i40e/i40e_xsk.c | 12 ++++++------ > > drivers/net/ethernet/intel/i40e/i40e_xsk.h | 2 +- > > 3 files changed, 20 insertions(+), 18 deletions(-) > > > > diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c > > index b97c95f..ed88309 100644 > > --- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c > > +++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c > > @@ -924,10 +924,10 @@ void i40e_detect_recover_hung(struct i40e_vsi *vsi) > > * @tx_ring: Tx ring to clean > > * @napi_budget: Used to determine if we are in netpoll > > * > > - * Returns true if there's any budget left (e.g. the clean is finished) > > + * Returns the number of packets cleaned > > **/ > > -static bool i40e_clean_tx_irq(struct i40e_vsi *vsi, > > - struct i40e_ring *tx_ring, int napi_budget) > > +static int i40e_clean_tx_irq(struct i40e_vsi *vsi, > > + struct i40e_ring *tx_ring, int napi_budget) > > { > > int i = tx_ring->next_to_clean; > > struct i40e_tx_buffer *tx_buf; > > @@ -1026,7 +1026,7 @@ static bool i40e_clean_tx_irq(struct i40e_vsi *vsi, > > i40e_arm_wb(tx_ring, vsi, budget); > > > > if (ring_is_xdp(tx_ring)) > > - return !!budget; > > + return total_packets; > > > > /* notify netdev of completed buffers */ > > netdev_tx_completed_queue(txring_txq(tx_ring), > > @@ -1048,7 +1048,7 @@ static bool i40e_clean_tx_irq(struct i40e_vsi *vsi, > > } > > } > > > > - return !!budget; > > + return total_packets; > > } > > > > /** > > @@ -2689,10 +2689,12 @@ int i40e_napi_poll(struct napi_struct *napi, int budget) > > container_of(napi, struct i40e_q_vector, napi); > > struct i40e_vsi *vsi = q_vector->vsi; > > struct i40e_ring *ring; > > + bool tx_clean_complete = true; > > bool clean_complete = true; > > bool arm_wb = false; > > int budget_per_ring; > > int work_done = 0; > > + int tx_wd = 0; > > > > if (test_bit(__I40E_VSI_DOWN, vsi->state)) { > > napi_complete(napi); > > @@ -2703,12 +2705,12 @@ int i40e_napi_poll(struct napi_struct *napi, int budget) > > * budget and be more aggressive about cleaning up the Tx descriptors. > > */ > > i40e_for_each_ring(ring, q_vector->tx) { > > - bool wd = ring->xsk_pool ? > > - i40e_clean_xdp_tx_irq(vsi, ring) : > > - i40e_clean_tx_irq(vsi, ring, budget); > > + tx_wd = ring->xsk_pool ? > > + i40e_clean_xdp_tx_irq(vsi, ring) : > > + i40e_clean_tx_irq(vsi, ring, budget); > > > > - if (!wd) { > > - clean_complete = false; > > + if (tx_wd >= budget) { > > + tx_clean_complete = false; > > This will break for AF_XDP Tx ZC. AF_XDP Tx ZC in intel drivers ignores > budget given by NAPI. If you look at i40e_xmit_zc(): > > func def: > static bool i40e_xmit_zc(struct i40e_ring *xdp_ring, unsigned int budget) > > callsite: > return i40e_xmit_zc(tx_ring, I40E_DESC_UNUSED(tx_ring)); > > we give free ring space as a budget and with your change we would be > returning the amount of processed tx descriptors which you will be > comparing against NAPI budget (64, unless you have busy poll enabled with > a different batch size). Say you start with empty ring and your HW rings > are sized to 1k but there was only 512 AF_XDP descriptors ready for Tx. > You produced all of them successfully to ring and you return 512 up to > i40e_napi_poll. Good point, my bad. I've reworked this for the v2 and have given i40e_clean_tx_irq, and i40e_clean_xdp_tx_irq an out parameter which will record the number TXes cleaned. I tweaked i40e_xmit_zc to return the number of packets (nb_pkts) and moved the boolean to check if that's under the "budget" (I40E_DESC_UNUSED(tx_ring)) into i40e_clean_xdp_tx_irq. I think that might solve the issues you've described. > > continue; > > } > > arm_wb |= ring->arm_wb; > > @@ -2742,7 +2744,7 @@ int i40e_napi_poll(struct napi_struct *napi, int budget) > > } > > > > /* If work not completed, return budget and polling will return */ > > - if (!clean_complete) { > > + if (!clean_complete || !tx_clean_complete) { > > int cpu_id = smp_processor_id(); > > > > /* It is possible that the interrupt affinity has changed but, > > diff --git a/drivers/net/ethernet/intel/i40e/i40e_xsk.c b/drivers/net/ethernet/intel/i40e/i40e_xsk.c > > index 790aaeff..925682c 100644 > > --- a/drivers/net/ethernet/intel/i40e/i40e_xsk.c > > +++ b/drivers/net/ethernet/intel/i40e/i40e_xsk.c > > @@ -531,9 +531,9 @@ static void i40e_set_rs_bit(struct i40e_ring *xdp_ring) > > * @xdp_ring: XDP Tx ring > > * @budget: NAPI budget > > * > > - * Returns true if the work is finished. > > + * Returns number of packets cleaned > > **/ > > -static bool i40e_xmit_zc(struct i40e_ring *xdp_ring, unsigned int budget) > > +static int i40e_xmit_zc(struct i40e_ring *xdp_ring, unsigned int budget) > > { > > struct xdp_desc *descs = xdp_ring->xsk_pool->tx_descs; > > u32 nb_pkts, nb_processed = 0; > > @@ -541,7 +541,7 @@ static bool i40e_xmit_zc(struct i40e_ring *xdp_ring, unsigned int budget) > > > > nb_pkts = xsk_tx_peek_release_desc_batch(xdp_ring->xsk_pool, budget); > > if (!nb_pkts) > > - return true; > > + return 0; > > > > if (xdp_ring->next_to_use + nb_pkts >= xdp_ring->count) { > > nb_processed = xdp_ring->count - xdp_ring->next_to_use; > > @@ -558,7 +558,7 @@ static bool i40e_xmit_zc(struct i40e_ring *xdp_ring, unsigned int budget) > > > > i40e_update_tx_stats(xdp_ring, nb_pkts, total_bytes); > > > > - return nb_pkts < budget; > > + return nb_pkts; > > } > > > > /** > > @@ -582,9 +582,9 @@ static void i40e_clean_xdp_tx_buffer(struct i40e_ring *tx_ring, > > * @vsi: Current VSI > > * @tx_ring: XDP Tx ring > > * > > - * Returns true if cleanup/tranmission is done. > > + * Returns number of packets cleaned > > **/ > > -bool i40e_clean_xdp_tx_irq(struct i40e_vsi *vsi, struct i40e_ring *tx_ring) > > +int i40e_clean_xdp_tx_irq(struct i40e_vsi *vsi, struct i40e_ring *tx_ring) > > { > > struct xsk_buff_pool *bp = tx_ring->xsk_pool; > > u32 i, completed_frames, xsk_frames = 0; > > diff --git a/drivers/net/ethernet/intel/i40e/i40e_xsk.h b/drivers/net/ethernet/intel/i40e/i40e_xsk.h > > index 821df24..4e810c2 100644 > > --- a/drivers/net/ethernet/intel/i40e/i40e_xsk.h > > +++ b/drivers/net/ethernet/intel/i40e/i40e_xsk.h > > @@ -30,7 +30,7 @@ int i40e_xsk_pool_setup(struct i40e_vsi *vsi, struct xsk_buff_pool *pool, > > bool i40e_alloc_rx_buffers_zc(struct i40e_ring *rx_ring, u16 cleaned_count); > > int i40e_clean_rx_irq_zc(struct i40e_ring *rx_ring, int budget); > > > > -bool i40e_clean_xdp_tx_irq(struct i40e_vsi *vsi, struct i40e_ring *tx_ring); > > +int i40e_clean_xdp_tx_irq(struct i40e_vsi *vsi, struct i40e_ring *tx_ring); > > int i40e_xsk_wakeup(struct net_device *dev, u32 queue_id, u32 flags); > > int i40e_realloc_rx_bi_zc(struct i40e_vsi *vsi, bool zc); > > void i40e_clear_rx_bi_zc(struct i40e_ring *rx_ring); > > -- > > 2.7.4 > >
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