| Message ID | 20241022215246.307821-3-jdamato@fastly.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | igc: Link IRQs and queues to NAPIs | expand |
On 10/23/2024 12:52 AM, Joe Damato wrote: > Link queues to NAPI instances via netdev-genl API so that users can > query this information with netlink. Handle a few cases in the driver: > 1. Link/unlink the NAPIs when XDP is enabled/disabled > 2. Handle IGC_FLAG_QUEUE_PAIRS enabled and disabled > > Example output when IGC_FLAG_QUEUE_PAIRS is enabled: > > $ ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/netdev.yaml \ > --dump queue-get --json='{"ifindex": 2}' > > [{'id': 0, 'ifindex': 2, 'napi-id': 8193, 'type': 'rx'}, > {'id': 1, 'ifindex': 2, 'napi-id': 8194, 'type': 'rx'}, > {'id': 2, 'ifindex': 2, 'napi-id': 8195, 'type': 'rx'}, > {'id': 3, 'ifindex': 2, 'napi-id': 8196, 'type': 'rx'}, > {'id': 0, 'ifindex': 2, 'napi-id': 8193, 'type': 'tx'}, > {'id': 1, 'ifindex': 2, 'napi-id': 8194, 'type': 'tx'}, > {'id': 2, 'ifindex': 2, 'napi-id': 8195, 'type': 'tx'}, > {'id': 3, 'ifindex': 2, 'napi-id': 8196, 'type': 'tx'}] > > Since IGC_FLAG_QUEUE_PAIRS is enabled, you'll note that the same NAPI ID > is present for both rx and tx queues at the same index, for example > index 0: > > {'id': 0, 'ifindex': 2, 'napi-id': 8193, 'type': 'rx'}, > {'id': 0, 'ifindex': 2, 'napi-id': 8193, 'type': 'tx'}, > > To test IGC_FLAG_QUEUE_PAIRS disabled, a test system was booted using > the grub command line option "maxcpus=2" to force > igc_set_interrupt_capability to disable IGC_FLAG_QUEUE_PAIRS. > > Example output when IGC_FLAG_QUEUE_PAIRS is disabled: > > $ lscpu | grep "On-line CPU" > On-line CPU(s) list: 0,2 > > $ ethtool -l enp86s0 | tail -5 > Current hardware settings: > RX: n/a > TX: n/a > Other: 1 > Combined: 2 > > $ cat /proc/interrupts | grep enp > 144: [...] enp86s0 > 145: [...] enp86s0-rx-0 > 146: [...] enp86s0-rx-1 > 147: [...] enp86s0-tx-0 > 148: [...] enp86s0-tx-1 > > 1 "other" IRQ, and 2 IRQs for each of RX and Tx, so we expect netlink to > report 4 IRQs with unique NAPI IDs: > > $ ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/netdev.yaml \ > --dump napi-get --json='{"ifindex": 2}' > [{'id': 8196, 'ifindex': 2, 'irq': 148}, > {'id': 8195, 'ifindex': 2, 'irq': 147}, > {'id': 8194, 'ifindex': 2, 'irq': 146}, > {'id': 8193, 'ifindex': 2, 'irq': 145}] > > Now we examine which queues these NAPIs are associated with, expecting > that since IGC_FLAG_QUEUE_PAIRS is disabled each RX and TX queue will > have its own NAPI instance: > > $ ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/netdev.yaml \ > --dump queue-get --json='{"ifindex": 2}' > [{'id': 0, 'ifindex': 2, 'napi-id': 8193, 'type': 'rx'}, > {'id': 1, 'ifindex': 2, 'napi-id': 8194, 'type': 'rx'}, > {'id': 0, 'ifindex': 2, 'napi-id': 8195, 'type': 'tx'}, > {'id': 1, 'ifindex': 2, 'napi-id': 8196, 'type': 'tx'}] > > Signed-off-by: Joe Damato <jdamato@fastly.com> > Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com> > --- > v4: > - Add rtnl_lock/rtnl_unlock in two paths: igc_resume and > igc_io_error_detected. The code added to the latter is inspired by > a similar implementation in ixgbe's ixgbe_io_error_detected. > > v3: > - Replace igc_unset_queue_napi with igc_set_queue_napi(adapater, i, > NULL), as suggested by Vinicius Costa Gomes > - Simplify implemention of igc_set_queue_napi as suggested by Kurt > Kanzenbach, with a tweak to use ring->queue_index > > v2: > - Update commit message to include tests for IGC_FLAG_QUEUE_PAIRS > disabled > - Refactored code to move napi queue mapping and unmapping to helper > functions igc_set_queue_napi and igc_unset_queue_napi > - Adjust the code to handle IGC_FLAG_QUEUE_PAIRS disabled > - Call helpers to map/unmap queues to NAPIs in igc_up, __igc_open, > igc_xdp_enable_pool, and igc_xdp_disable_pool > > drivers/net/ethernet/intel/igc/igc.h | 2 ++ > drivers/net/ethernet/intel/igc/igc_main.c | 41 ++++++++++++++++++++--- > drivers/net/ethernet/intel/igc/igc_xdp.c | 2 ++ > 3 files changed, 40 insertions(+), 5 deletions(-) > > diff --git a/drivers/net/ethernet/intel/igc/igc.h b/drivers/net/ethernet/intel/igc/igc.h > index eac0f966e0e4..b8111ad9a9a8 100644 > --- a/drivers/net/ethernet/intel/igc/igc.h > +++ b/drivers/net/ethernet/intel/igc/igc.h > @@ -337,6 +337,8 @@ struct igc_adapter { > struct igc_led_classdev *leds; > }; > > +void igc_set_queue_napi(struct igc_adapter *adapter, int q_idx, > + struct napi_struct *napi); > void igc_up(struct igc_adapter *adapter); > void igc_down(struct igc_adapter *adapter); > int igc_open(struct net_device *netdev); > diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c > index 7964bbedb16c..04aa216ef612 100644 > --- a/drivers/net/ethernet/intel/igc/igc_main.c > +++ b/drivers/net/ethernet/intel/igc/igc_main.c > @@ -4948,6 +4948,22 @@ static int igc_sw_init(struct igc_adapter *adapter) > return 0; > } > > +void igc_set_queue_napi(struct igc_adapter *adapter, int vector, > + struct napi_struct *napi) > +{ > + struct igc_q_vector *q_vector = adapter->q_vector[vector]; > + > + if (q_vector->rx.ring) > + netif_queue_set_napi(adapter->netdev, > + q_vector->rx.ring->queue_index, > + NETDEV_QUEUE_TYPE_RX, napi); > + > + if (q_vector->tx.ring) > + netif_queue_set_napi(adapter->netdev, > + q_vector->tx.ring->queue_index, > + NETDEV_QUEUE_TYPE_TX, napi); > +} > + > /** > * igc_up - Open the interface and prepare it to handle traffic > * @adapter: board private structure > @@ -4955,6 +4971,7 @@ static int igc_sw_init(struct igc_adapter *adapter) > void igc_up(struct igc_adapter *adapter) > { > struct igc_hw *hw = &adapter->hw; > + struct napi_struct *napi; > int i = 0; > > /* hardware has been reset, we need to reload some things */ > @@ -4962,8 +4979,11 @@ void igc_up(struct igc_adapter *adapter) > > clear_bit(__IGC_DOWN, &adapter->state); > > - for (i = 0; i < adapter->num_q_vectors; i++) > - napi_enable(&adapter->q_vector[i]->napi); > + for (i = 0; i < adapter->num_q_vectors; i++) { > + napi = &adapter->q_vector[i]->napi; > + napi_enable(napi); > + igc_set_queue_napi(adapter, i, napi); > + } > > if (adapter->msix_entries) > igc_configure_msix(adapter); > @@ -5192,6 +5212,7 @@ void igc_down(struct igc_adapter *adapter) > for (i = 0; i < adapter->num_q_vectors; i++) { > if (adapter->q_vector[i]) { > napi_synchronize(&adapter->q_vector[i]->napi); > + igc_set_queue_napi(adapter, i, NULL); > napi_disable(&adapter->q_vector[i]->napi); > } > } > @@ -6021,6 +6042,7 @@ static int __igc_open(struct net_device *netdev, bool resuming) > struct igc_adapter *adapter = netdev_priv(netdev); > struct pci_dev *pdev = adapter->pdev; > struct igc_hw *hw = &adapter->hw; > + struct napi_struct *napi; > int err = 0; > int i = 0; > > @@ -6056,8 +6078,11 @@ static int __igc_open(struct net_device *netdev, bool resuming) > > clear_bit(__IGC_DOWN, &adapter->state); > > - for (i = 0; i < adapter->num_q_vectors; i++) > - napi_enable(&adapter->q_vector[i]->napi); > + for (i = 0; i < adapter->num_q_vectors; i++) { > + napi = &adapter->q_vector[i]->napi; > + napi_enable(napi); > + igc_set_queue_napi(adapter, i, napi); > + } > > /* Clear any pending interrupts. */ > rd32(IGC_ICR); > @@ -7385,7 +7410,9 @@ static int igc_resume(struct device *dev) > wr32(IGC_WUS, ~0); > > if (netif_running(netdev)) { > + rtnl_lock(); This change will bring back the deadlock issue that was fixed in commit: 6f31d6b: "igc: Refactor runtime power management flow". > err = __igc_open(netdev, true); > + rtnl_unlock(); > if (!err) > netif_device_attach(netdev); > } > @@ -7440,14 +7467,18 @@ static pci_ers_result_t igc_io_error_detected(struct pci_dev *pdev, > struct net_device *netdev = pci_get_drvdata(pdev); > struct igc_adapter *adapter = netdev_priv(netdev); > > + rtnl_lock(); > netif_device_detach(netdev); > > - if (state == pci_channel_io_perm_failure) > + if (state == pci_channel_io_perm_failure) { > + rtnl_unlock(); > return PCI_ERS_RESULT_DISCONNECT; > + } > > if (netif_running(netdev)) > igc_down(adapter); > pci_disable_device(pdev); > + rtnl_unlock(); > > /* Request a slot reset. */ > return PCI_ERS_RESULT_NEED_RESET; > diff --git a/drivers/net/ethernet/intel/igc/igc_xdp.c b/drivers/net/ethernet/intel/igc/igc_xdp.c > index e27af72aada8..4da633430b80 100644 > --- a/drivers/net/ethernet/intel/igc/igc_xdp.c > +++ b/drivers/net/ethernet/intel/igc/igc_xdp.c > @@ -84,6 +84,7 @@ static int igc_xdp_enable_pool(struct igc_adapter *adapter, > napi_disable(napi); > } > > + igc_set_queue_napi(adapter, queue_id, NULL); > set_bit(IGC_RING_FLAG_AF_XDP_ZC, &rx_ring->flags); > set_bit(IGC_RING_FLAG_AF_XDP_ZC, &tx_ring->flags); > > @@ -133,6 +134,7 @@ static int igc_xdp_disable_pool(struct igc_adapter *adapter, u16 queue_id) > xsk_pool_dma_unmap(pool, IGC_RX_DMA_ATTR); > clear_bit(IGC_RING_FLAG_AF_XDP_ZC, &rx_ring->flags); > clear_bit(IGC_RING_FLAG_AF_XDP_ZC, &tx_ring->flags); > + igc_set_queue_napi(adapter, queue_id, napi); > > if (needs_reset) { > napi_enable(napi); > Hi Joe, The current version will cause a regression, a possible deadlock, due to the addition of the rtnl_lock in igc_resume that was fixed previously. You can refer to the following link: https://github.com/torvalds/linux/commit/6f31d6b643a32cc126cf86093fca1ea575948bf0#diff-d5b32b873e9902b496280a5f42c246043c8f0691d8b3a6bbd56df99ce8ceb394L7190
On Sun, Oct 27, 2024 at 11:49:33AM +0200, Lifshits, Vitaly wrote: > > On 10/23/2024 12:52 AM, Joe Damato wrote: > > Link queues to NAPI instances via netdev-genl API so that users can > > query this information with netlink. Handle a few cases in the driver: > > 1. Link/unlink the NAPIs when XDP is enabled/disabled > > 2. Handle IGC_FLAG_QUEUE_PAIRS enabled and disabled > > > > Example output when IGC_FLAG_QUEUE_PAIRS is enabled: > > > > $ ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/netdev.yaml \ > > --dump queue-get --json='{"ifindex": 2}' > > > > [{'id': 0, 'ifindex': 2, 'napi-id': 8193, 'type': 'rx'}, > > {'id': 1, 'ifindex': 2, 'napi-id': 8194, 'type': 'rx'}, > > {'id': 2, 'ifindex': 2, 'napi-id': 8195, 'type': 'rx'}, > > {'id': 3, 'ifindex': 2, 'napi-id': 8196, 'type': 'rx'}, > > {'id': 0, 'ifindex': 2, 'napi-id': 8193, 'type': 'tx'}, > > {'id': 1, 'ifindex': 2, 'napi-id': 8194, 'type': 'tx'}, > > {'id': 2, 'ifindex': 2, 'napi-id': 8195, 'type': 'tx'}, > > {'id': 3, 'ifindex': 2, 'napi-id': 8196, 'type': 'tx'}] > > > > Since IGC_FLAG_QUEUE_PAIRS is enabled, you'll note that the same NAPI ID > > is present for both rx and tx queues at the same index, for example > > index 0: > > > > {'id': 0, 'ifindex': 2, 'napi-id': 8193, 'type': 'rx'}, > > {'id': 0, 'ifindex': 2, 'napi-id': 8193, 'type': 'tx'}, > > > > To test IGC_FLAG_QUEUE_PAIRS disabled, a test system was booted using > > the grub command line option "maxcpus=2" to force > > igc_set_interrupt_capability to disable IGC_FLAG_QUEUE_PAIRS. > > > > Example output when IGC_FLAG_QUEUE_PAIRS is disabled: > > > > $ lscpu | grep "On-line CPU" > > On-line CPU(s) list: 0,2 > > > > $ ethtool -l enp86s0 | tail -5 > > Current hardware settings: > > RX: n/a > > TX: n/a > > Other: 1 > > Combined: 2 > > > > $ cat /proc/interrupts | grep enp > > 144: [...] enp86s0 > > 145: [...] enp86s0-rx-0 > > 146: [...] enp86s0-rx-1 > > 147: [...] enp86s0-tx-0 > > 148: [...] enp86s0-tx-1 > > > > 1 "other" IRQ, and 2 IRQs for each of RX and Tx, so we expect netlink to > > report 4 IRQs with unique NAPI IDs: > > > > $ ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/netdev.yaml \ > > --dump napi-get --json='{"ifindex": 2}' > > [{'id': 8196, 'ifindex': 2, 'irq': 148}, > > {'id': 8195, 'ifindex': 2, 'irq': 147}, > > {'id': 8194, 'ifindex': 2, 'irq': 146}, > > {'id': 8193, 'ifindex': 2, 'irq': 145}] > > > > Now we examine which queues these NAPIs are associated with, expecting > > that since IGC_FLAG_QUEUE_PAIRS is disabled each RX and TX queue will > > have its own NAPI instance: > > > > $ ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/netdev.yaml \ > > --dump queue-get --json='{"ifindex": 2}' > > [{'id': 0, 'ifindex': 2, 'napi-id': 8193, 'type': 'rx'}, > > {'id': 1, 'ifindex': 2, 'napi-id': 8194, 'type': 'rx'}, > > {'id': 0, 'ifindex': 2, 'napi-id': 8195, 'type': 'tx'}, > > {'id': 1, 'ifindex': 2, 'napi-id': 8196, 'type': 'tx'}] > > > > Signed-off-by: Joe Damato <jdamato@fastly.com> > > Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com> > > --- > > v4: > > - Add rtnl_lock/rtnl_unlock in two paths: igc_resume and > > igc_io_error_detected. The code added to the latter is inspired by > > a similar implementation in ixgbe's ixgbe_io_error_detected. > > > > v3: > > - Replace igc_unset_queue_napi with igc_set_queue_napi(adapater, i, > > NULL), as suggested by Vinicius Costa Gomes > > - Simplify implemention of igc_set_queue_napi as suggested by Kurt > > Kanzenbach, with a tweak to use ring->queue_index > > > > v2: > > - Update commit message to include tests for IGC_FLAG_QUEUE_PAIRS > > disabled > > - Refactored code to move napi queue mapping and unmapping to helper > > functions igc_set_queue_napi and igc_unset_queue_napi > > - Adjust the code to handle IGC_FLAG_QUEUE_PAIRS disabled > > - Call helpers to map/unmap queues to NAPIs in igc_up, __igc_open, > > igc_xdp_enable_pool, and igc_xdp_disable_pool > > > > drivers/net/ethernet/intel/igc/igc.h | 2 ++ > > drivers/net/ethernet/intel/igc/igc_main.c | 41 ++++++++++++++++++++--- > > drivers/net/ethernet/intel/igc/igc_xdp.c | 2 ++ > > 3 files changed, 40 insertions(+), 5 deletions(-) > > > > diff --git a/drivers/net/ethernet/intel/igc/igc.h b/drivers/net/ethernet/intel/igc/igc.h > > index eac0f966e0e4..b8111ad9a9a8 100644 > > --- a/drivers/net/ethernet/intel/igc/igc.h > > +++ b/drivers/net/ethernet/intel/igc/igc.h > > @@ -337,6 +337,8 @@ struct igc_adapter { > > struct igc_led_classdev *leds; > > }; > > +void igc_set_queue_napi(struct igc_adapter *adapter, int q_idx, > > + struct napi_struct *napi); > > void igc_up(struct igc_adapter *adapter); > > void igc_down(struct igc_adapter *adapter); > > int igc_open(struct net_device *netdev); > > diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c > > index 7964bbedb16c..04aa216ef612 100644 > > --- a/drivers/net/ethernet/intel/igc/igc_main.c > > +++ b/drivers/net/ethernet/intel/igc/igc_main.c > > @@ -4948,6 +4948,22 @@ static int igc_sw_init(struct igc_adapter *adapter) > > return 0; > > } > > +void igc_set_queue_napi(struct igc_adapter *adapter, int vector, > > + struct napi_struct *napi) > > +{ > > + struct igc_q_vector *q_vector = adapter->q_vector[vector]; > > + > > + if (q_vector->rx.ring) > > + netif_queue_set_napi(adapter->netdev, > > + q_vector->rx.ring->queue_index, > > + NETDEV_QUEUE_TYPE_RX, napi); > > + > > + if (q_vector->tx.ring) > > + netif_queue_set_napi(adapter->netdev, > > + q_vector->tx.ring->queue_index, > > + NETDEV_QUEUE_TYPE_TX, napi); > > +} > > + > > /** > > * igc_up - Open the interface and prepare it to handle traffic > > * @adapter: board private structure > > @@ -4955,6 +4971,7 @@ static int igc_sw_init(struct igc_adapter *adapter) > > void igc_up(struct igc_adapter *adapter) > > { > > struct igc_hw *hw = &adapter->hw; > > + struct napi_struct *napi; > > int i = 0; > > /* hardware has been reset, we need to reload some things */ > > @@ -4962,8 +4979,11 @@ void igc_up(struct igc_adapter *adapter) > > clear_bit(__IGC_DOWN, &adapter->state); > > - for (i = 0; i < adapter->num_q_vectors; i++) > > - napi_enable(&adapter->q_vector[i]->napi); > > + for (i = 0; i < adapter->num_q_vectors; i++) { > > + napi = &adapter->q_vector[i]->napi; > > + napi_enable(napi); > > + igc_set_queue_napi(adapter, i, napi); > > + } > > if (adapter->msix_entries) > > igc_configure_msix(adapter); > > @@ -5192,6 +5212,7 @@ void igc_down(struct igc_adapter *adapter) > > for (i = 0; i < adapter->num_q_vectors; i++) { > > if (adapter->q_vector[i]) { > > napi_synchronize(&adapter->q_vector[i]->napi); > > + igc_set_queue_napi(adapter, i, NULL); > > napi_disable(&adapter->q_vector[i]->napi); > > } > > } > > @@ -6021,6 +6042,7 @@ static int __igc_open(struct net_device *netdev, bool resuming) > > struct igc_adapter *adapter = netdev_priv(netdev); > > struct pci_dev *pdev = adapter->pdev; > > struct igc_hw *hw = &adapter->hw; > > + struct napi_struct *napi; > > int err = 0; > > int i = 0; > > @@ -6056,8 +6078,11 @@ static int __igc_open(struct net_device *netdev, bool resuming) > > clear_bit(__IGC_DOWN, &adapter->state); > > - for (i = 0; i < adapter->num_q_vectors; i++) > > - napi_enable(&adapter->q_vector[i]->napi); > > + for (i = 0; i < adapter->num_q_vectors; i++) { > > + napi = &adapter->q_vector[i]->napi; > > + napi_enable(napi); > > + igc_set_queue_napi(adapter, i, napi); > > + } > > /* Clear any pending interrupts. */ > > rd32(IGC_ICR); > > @@ -7385,7 +7410,9 @@ static int igc_resume(struct device *dev) > > wr32(IGC_WUS, ~0); > > if (netif_running(netdev)) { > > + rtnl_lock(); > > This change will bring back the deadlock issue that was fixed in commit: > 6f31d6b: "igc: Refactor runtime power management flow". OK, thanks for letting me know. I think I better understand what the issue is. It seems that: - igc_resume can be called with rtnl held via ethtool (which I didn't know), which calls __igc_open - __igc_open re-enables NAPIs and re-links queues to NAPI IDs (which requires rtnl) so, it seems like the rtnl_lock() I've added to igc_resume is unnecessary. I suppose I don't know all of the paths where the pm functions can be called -- are there others where RTNL is _not_ already held? I looked at e1000e and it seems that driver does not re-enable NAPIs in its resume path and thus does not suffer from the same issue as igc. So my questions are: 1. Are there are other contexts where igc_resume is called where RTNL is not held? 2. If the answer is that RTNL is always held when igc_resume is called, then I can send a v5 that removes the rtnl_lock/rtnl_unlock. What do you think? [...] > > Hi Joe, > > > The current version will cause a regression, a possible deadlock, due to the > addition of the rtnl_lock in igc_resume that was fixed previously. > > You can refer to the following link: > > https://github.com/torvalds/linux/commit/6f31d6b643a32cc126cf86093fca1ea575948bf0#diff-d5b32b873e9902b496280a5f42c246043c8f0691d8b3a6bbd56df99ce8ceb394L7190 Thanks for the link.
On Mon, Oct 28, 2024 at 08:50:38AM -0700, Joe Damato wrote: > On Sun, Oct 27, 2024 at 11:49:33AM +0200, Lifshits, Vitaly wrote: > > > > On 10/23/2024 12:52 AM, Joe Damato wrote: > > > Link queues to NAPI instances via netdev-genl API so that users can > > > query this information with netlink. Handle a few cases in the driver: > > > 1. Link/unlink the NAPIs when XDP is enabled/disabled > > > 2. Handle IGC_FLAG_QUEUE_PAIRS enabled and disabled > > > > > > Example output when IGC_FLAG_QUEUE_PAIRS is enabled: > > > > > > $ ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/netdev.yaml \ > > > --dump queue-get --json='{"ifindex": 2}' > > > > > > [{'id': 0, 'ifindex': 2, 'napi-id': 8193, 'type': 'rx'}, > > > {'id': 1, 'ifindex': 2, 'napi-id': 8194, 'type': 'rx'}, > > > {'id': 2, 'ifindex': 2, 'napi-id': 8195, 'type': 'rx'}, > > > {'id': 3, 'ifindex': 2, 'napi-id': 8196, 'type': 'rx'}, > > > {'id': 0, 'ifindex': 2, 'napi-id': 8193, 'type': 'tx'}, > > > {'id': 1, 'ifindex': 2, 'napi-id': 8194, 'type': 'tx'}, > > > {'id': 2, 'ifindex': 2, 'napi-id': 8195, 'type': 'tx'}, > > > {'id': 3, 'ifindex': 2, 'napi-id': 8196, 'type': 'tx'}] > > > > > > Since IGC_FLAG_QUEUE_PAIRS is enabled, you'll note that the same NAPI ID > > > is present for both rx and tx queues at the same index, for example > > > index 0: > > > > > > {'id': 0, 'ifindex': 2, 'napi-id': 8193, 'type': 'rx'}, > > > {'id': 0, 'ifindex': 2, 'napi-id': 8193, 'type': 'tx'}, > > > > > > To test IGC_FLAG_QUEUE_PAIRS disabled, a test system was booted using > > > the grub command line option "maxcpus=2" to force > > > igc_set_interrupt_capability to disable IGC_FLAG_QUEUE_PAIRS. > > > > > > Example output when IGC_FLAG_QUEUE_PAIRS is disabled: > > > > > > $ lscpu | grep "On-line CPU" > > > On-line CPU(s) list: 0,2 > > > > > > $ ethtool -l enp86s0 | tail -5 > > > Current hardware settings: > > > RX: n/a > > > TX: n/a > > > Other: 1 > > > Combined: 2 > > > > > > $ cat /proc/interrupts | grep enp > > > 144: [...] enp86s0 > > > 145: [...] enp86s0-rx-0 > > > 146: [...] enp86s0-rx-1 > > > 147: [...] enp86s0-tx-0 > > > 148: [...] enp86s0-tx-1 > > > > > > 1 "other" IRQ, and 2 IRQs for each of RX and Tx, so we expect netlink to > > > report 4 IRQs with unique NAPI IDs: > > > > > > $ ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/netdev.yaml \ > > > --dump napi-get --json='{"ifindex": 2}' > > > [{'id': 8196, 'ifindex': 2, 'irq': 148}, > > > {'id': 8195, 'ifindex': 2, 'irq': 147}, > > > {'id': 8194, 'ifindex': 2, 'irq': 146}, > > > {'id': 8193, 'ifindex': 2, 'irq': 145}] > > > > > > Now we examine which queues these NAPIs are associated with, expecting > > > that since IGC_FLAG_QUEUE_PAIRS is disabled each RX and TX queue will > > > have its own NAPI instance: > > > > > > $ ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/netdev.yaml \ > > > --dump queue-get --json='{"ifindex": 2}' > > > [{'id': 0, 'ifindex': 2, 'napi-id': 8193, 'type': 'rx'}, > > > {'id': 1, 'ifindex': 2, 'napi-id': 8194, 'type': 'rx'}, > > > {'id': 0, 'ifindex': 2, 'napi-id': 8195, 'type': 'tx'}, > > > {'id': 1, 'ifindex': 2, 'napi-id': 8196, 'type': 'tx'}] > > > > > > Signed-off-by: Joe Damato <jdamato@fastly.com> > > > Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com> > > > --- > > > v4: > > > - Add rtnl_lock/rtnl_unlock in two paths: igc_resume and > > > igc_io_error_detected. The code added to the latter is inspired by > > > a similar implementation in ixgbe's ixgbe_io_error_detected. > > > > > > v3: > > > - Replace igc_unset_queue_napi with igc_set_queue_napi(adapater, i, > > > NULL), as suggested by Vinicius Costa Gomes > > > - Simplify implemention of igc_set_queue_napi as suggested by Kurt > > > Kanzenbach, with a tweak to use ring->queue_index > > > > > > v2: > > > - Update commit message to include tests for IGC_FLAG_QUEUE_PAIRS > > > disabled > > > - Refactored code to move napi queue mapping and unmapping to helper > > > functions igc_set_queue_napi and igc_unset_queue_napi > > > - Adjust the code to handle IGC_FLAG_QUEUE_PAIRS disabled > > > - Call helpers to map/unmap queues to NAPIs in igc_up, __igc_open, > > > igc_xdp_enable_pool, and igc_xdp_disable_pool > > > > > > drivers/net/ethernet/intel/igc/igc.h | 2 ++ > > > drivers/net/ethernet/intel/igc/igc_main.c | 41 ++++++++++++++++++++--- > > > drivers/net/ethernet/intel/igc/igc_xdp.c | 2 ++ > > > 3 files changed, 40 insertions(+), 5 deletions(-) > > > > > > diff --git a/drivers/net/ethernet/intel/igc/igc.h b/drivers/net/ethernet/intel/igc/igc.h > > > index eac0f966e0e4..b8111ad9a9a8 100644 > > > --- a/drivers/net/ethernet/intel/igc/igc.h > > > +++ b/drivers/net/ethernet/intel/igc/igc.h > > > @@ -337,6 +337,8 @@ struct igc_adapter { > > > struct igc_led_classdev *leds; > > > }; > > > +void igc_set_queue_napi(struct igc_adapter *adapter, int q_idx, > > > + struct napi_struct *napi); > > > void igc_up(struct igc_adapter *adapter); > > > void igc_down(struct igc_adapter *adapter); > > > int igc_open(struct net_device *netdev); > > > diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c > > > index 7964bbedb16c..04aa216ef612 100644 > > > --- a/drivers/net/ethernet/intel/igc/igc_main.c > > > +++ b/drivers/net/ethernet/intel/igc/igc_main.c > > > @@ -4948,6 +4948,22 @@ static int igc_sw_init(struct igc_adapter *adapter) > > > return 0; > > > } > > > +void igc_set_queue_napi(struct igc_adapter *adapter, int vector, > > > + struct napi_struct *napi) > > > +{ > > > + struct igc_q_vector *q_vector = adapter->q_vector[vector]; > > > + > > > + if (q_vector->rx.ring) > > > + netif_queue_set_napi(adapter->netdev, > > > + q_vector->rx.ring->queue_index, > > > + NETDEV_QUEUE_TYPE_RX, napi); > > > + > > > + if (q_vector->tx.ring) > > > + netif_queue_set_napi(adapter->netdev, > > > + q_vector->tx.ring->queue_index, > > > + NETDEV_QUEUE_TYPE_TX, napi); > > > +} > > > + > > > /** > > > * igc_up - Open the interface and prepare it to handle traffic > > > * @adapter: board private structure > > > @@ -4955,6 +4971,7 @@ static int igc_sw_init(struct igc_adapter *adapter) > > > void igc_up(struct igc_adapter *adapter) > > > { > > > struct igc_hw *hw = &adapter->hw; > > > + struct napi_struct *napi; > > > int i = 0; > > > /* hardware has been reset, we need to reload some things */ > > > @@ -4962,8 +4979,11 @@ void igc_up(struct igc_adapter *adapter) > > > clear_bit(__IGC_DOWN, &adapter->state); > > > - for (i = 0; i < adapter->num_q_vectors; i++) > > > - napi_enable(&adapter->q_vector[i]->napi); > > > + for (i = 0; i < adapter->num_q_vectors; i++) { > > > + napi = &adapter->q_vector[i]->napi; > > > + napi_enable(napi); > > > + igc_set_queue_napi(adapter, i, napi); > > > + } > > > if (adapter->msix_entries) > > > igc_configure_msix(adapter); > > > @@ -5192,6 +5212,7 @@ void igc_down(struct igc_adapter *adapter) > > > for (i = 0; i < adapter->num_q_vectors; i++) { > > > if (adapter->q_vector[i]) { > > > napi_synchronize(&adapter->q_vector[i]->napi); > > > + igc_set_queue_napi(adapter, i, NULL); > > > napi_disable(&adapter->q_vector[i]->napi); > > > } > > > } > > > @@ -6021,6 +6042,7 @@ static int __igc_open(struct net_device *netdev, bool resuming) > > > struct igc_adapter *adapter = netdev_priv(netdev); > > > struct pci_dev *pdev = adapter->pdev; > > > struct igc_hw *hw = &adapter->hw; > > > + struct napi_struct *napi; > > > int err = 0; > > > int i = 0; > > > @@ -6056,8 +6078,11 @@ static int __igc_open(struct net_device *netdev, bool resuming) > > > clear_bit(__IGC_DOWN, &adapter->state); > > > - for (i = 0; i < adapter->num_q_vectors; i++) > > > - napi_enable(&adapter->q_vector[i]->napi); > > > + for (i = 0; i < adapter->num_q_vectors; i++) { > > > + napi = &adapter->q_vector[i]->napi; > > > + napi_enable(napi); > > > + igc_set_queue_napi(adapter, i, napi); > > > + } > > > /* Clear any pending interrupts. */ > > > rd32(IGC_ICR); > > > @@ -7385,7 +7410,9 @@ static int igc_resume(struct device *dev) > > > wr32(IGC_WUS, ~0); > > > if (netif_running(netdev)) { > > > + rtnl_lock(); > > > > This change will bring back the deadlock issue that was fixed in commit: > > 6f31d6b: "igc: Refactor runtime power management flow". > > OK, thanks for letting me know. > > I think I better understand what the issue is. It seems that: > > - igc_resume can be called with rtnl held via ethtool (which I > didn't know), which calls __igc_open > - __igc_open re-enables NAPIs and re-links queues to NAPI IDs (which > requires rtnl) > > so, it seems like the rtnl_lock() I've added to igc_resume is > unnecessary. > > I suppose I don't know all of the paths where the pm functions can > be called -- are there others where RTNL is _not_ already held? > > I looked at e1000e and it seems that driver does not re-enable NAPIs > in its resume path and thus does not suffer from the same issue as > igc. > > So my questions are: > > 1. Are there are other contexts where igc_resume is called where > RTNL is not held? > > 2. If the answer is that RTNL is always held when igc_resume is > called, then I can send a v5 that removes the > rtnl_lock/rtnl_unlock. What do you think? I see, so it looks like there is: - resume - runtime_resume The bug I am reintroducing is runtime_resume already holding RTNL before my added call to rtnl_lock. OK. Does resume also hold rtnl before the driver's igc_resume is called? I am asking because I don't know much about how PM works. If resume does not hold RTNL (but runtime resume does, as the bug you pointed out shows), it seems like a wrapper can be added to tell the code whether rtnl should be held or not based on which resume is happening. Does anyone know if: resume (not runtime_resume) already holds RTNL? I'll try to take a look and see, but I am not very familiar with PM.
On Mon, Oct 28, 2024 at 09:00:06AM -0700, Joe Damato wrote: > On Mon, Oct 28, 2024 at 08:50:38AM -0700, Joe Damato wrote: > > On Sun, Oct 27, 2024 at 11:49:33AM +0200, Lifshits, Vitaly wrote: > > > > > > On 10/23/2024 12:52 AM, Joe Damato wrote: > > > > Link queues to NAPI instances via netdev-genl API so that users can > > > > query this information with netlink. Handle a few cases in the driver: > > > > 1. Link/unlink the NAPIs when XDP is enabled/disabled > > > > 2. Handle IGC_FLAG_QUEUE_PAIRS enabled and disabled > > > > > > > > Example output when IGC_FLAG_QUEUE_PAIRS is enabled: > > > > > > > > $ ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/netdev.yaml \ > > > > --dump queue-get --json='{"ifindex": 2}' > > > > > > > > [{'id': 0, 'ifindex': 2, 'napi-id': 8193, 'type': 'rx'}, > > > > {'id': 1, 'ifindex': 2, 'napi-id': 8194, 'type': 'rx'}, > > > > {'id': 2, 'ifindex': 2, 'napi-id': 8195, 'type': 'rx'}, > > > > {'id': 3, 'ifindex': 2, 'napi-id': 8196, 'type': 'rx'}, > > > > {'id': 0, 'ifindex': 2, 'napi-id': 8193, 'type': 'tx'}, > > > > {'id': 1, 'ifindex': 2, 'napi-id': 8194, 'type': 'tx'}, > > > > {'id': 2, 'ifindex': 2, 'napi-id': 8195, 'type': 'tx'}, > > > > {'id': 3, 'ifindex': 2, 'napi-id': 8196, 'type': 'tx'}] > > > > > > > > Since IGC_FLAG_QUEUE_PAIRS is enabled, you'll note that the same NAPI ID > > > > is present for both rx and tx queues at the same index, for example > > > > index 0: > > > > > > > > {'id': 0, 'ifindex': 2, 'napi-id': 8193, 'type': 'rx'}, > > > > {'id': 0, 'ifindex': 2, 'napi-id': 8193, 'type': 'tx'}, > > > > > > > > To test IGC_FLAG_QUEUE_PAIRS disabled, a test system was booted using > > > > the grub command line option "maxcpus=2" to force > > > > igc_set_interrupt_capability to disable IGC_FLAG_QUEUE_PAIRS. > > > > > > > > Example output when IGC_FLAG_QUEUE_PAIRS is disabled: > > > > > > > > $ lscpu | grep "On-line CPU" > > > > On-line CPU(s) list: 0,2 > > > > > > > > $ ethtool -l enp86s0 | tail -5 > > > > Current hardware settings: > > > > RX: n/a > > > > TX: n/a > > > > Other: 1 > > > > Combined: 2 > > > > > > > > $ cat /proc/interrupts | grep enp > > > > 144: [...] enp86s0 > > > > 145: [...] enp86s0-rx-0 > > > > 146: [...] enp86s0-rx-1 > > > > 147: [...] enp86s0-tx-0 > > > > 148: [...] enp86s0-tx-1 > > > > > > > > 1 "other" IRQ, and 2 IRQs for each of RX and Tx, so we expect netlink to > > > > report 4 IRQs with unique NAPI IDs: > > > > > > > > $ ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/netdev.yaml \ > > > > --dump napi-get --json='{"ifindex": 2}' > > > > [{'id': 8196, 'ifindex': 2, 'irq': 148}, > > > > {'id': 8195, 'ifindex': 2, 'irq': 147}, > > > > {'id': 8194, 'ifindex': 2, 'irq': 146}, > > > > {'id': 8193, 'ifindex': 2, 'irq': 145}] > > > > > > > > Now we examine which queues these NAPIs are associated with, expecting > > > > that since IGC_FLAG_QUEUE_PAIRS is disabled each RX and TX queue will > > > > have its own NAPI instance: > > > > > > > > $ ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/netdev.yaml \ > > > > --dump queue-get --json='{"ifindex": 2}' > > > > [{'id': 0, 'ifindex': 2, 'napi-id': 8193, 'type': 'rx'}, > > > > {'id': 1, 'ifindex': 2, 'napi-id': 8194, 'type': 'rx'}, > > > > {'id': 0, 'ifindex': 2, 'napi-id': 8195, 'type': 'tx'}, > > > > {'id': 1, 'ifindex': 2, 'napi-id': 8196, 'type': 'tx'}] > > > > > > > > Signed-off-by: Joe Damato <jdamato@fastly.com> > > > > Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com> > > > > --- > > > > v4: > > > > - Add rtnl_lock/rtnl_unlock in two paths: igc_resume and > > > > igc_io_error_detected. The code added to the latter is inspired by > > > > a similar implementation in ixgbe's ixgbe_io_error_detected. > > > > > > > > v3: > > > > - Replace igc_unset_queue_napi with igc_set_queue_napi(adapater, i, > > > > NULL), as suggested by Vinicius Costa Gomes > > > > - Simplify implemention of igc_set_queue_napi as suggested by Kurt > > > > Kanzenbach, with a tweak to use ring->queue_index > > > > > > > > v2: > > > > - Update commit message to include tests for IGC_FLAG_QUEUE_PAIRS > > > > disabled > > > > - Refactored code to move napi queue mapping and unmapping to helper > > > > functions igc_set_queue_napi and igc_unset_queue_napi > > > > - Adjust the code to handle IGC_FLAG_QUEUE_PAIRS disabled > > > > - Call helpers to map/unmap queues to NAPIs in igc_up, __igc_open, > > > > igc_xdp_enable_pool, and igc_xdp_disable_pool > > > > > > > > drivers/net/ethernet/intel/igc/igc.h | 2 ++ > > > > drivers/net/ethernet/intel/igc/igc_main.c | 41 ++++++++++++++++++++--- > > > > drivers/net/ethernet/intel/igc/igc_xdp.c | 2 ++ > > > > 3 files changed, 40 insertions(+), 5 deletions(-) > > > > > > > > diff --git a/drivers/net/ethernet/intel/igc/igc.h b/drivers/net/ethernet/intel/igc/igc.h > > > > index eac0f966e0e4..b8111ad9a9a8 100644 > > > > --- a/drivers/net/ethernet/intel/igc/igc.h > > > > +++ b/drivers/net/ethernet/intel/igc/igc.h > > > > @@ -337,6 +337,8 @@ struct igc_adapter { > > > > struct igc_led_classdev *leds; > > > > }; > > > > +void igc_set_queue_napi(struct igc_adapter *adapter, int q_idx, > > > > + struct napi_struct *napi); > > > > void igc_up(struct igc_adapter *adapter); > > > > void igc_down(struct igc_adapter *adapter); > > > > int igc_open(struct net_device *netdev); > > > > diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c > > > > index 7964bbedb16c..04aa216ef612 100644 > > > > --- a/drivers/net/ethernet/intel/igc/igc_main.c > > > > +++ b/drivers/net/ethernet/intel/igc/igc_main.c > > > > @@ -4948,6 +4948,22 @@ static int igc_sw_init(struct igc_adapter *adapter) > > > > return 0; > > > > } > > > > +void igc_set_queue_napi(struct igc_adapter *adapter, int vector, > > > > + struct napi_struct *napi) > > > > +{ > > > > + struct igc_q_vector *q_vector = adapter->q_vector[vector]; > > > > + > > > > + if (q_vector->rx.ring) > > > > + netif_queue_set_napi(adapter->netdev, > > > > + q_vector->rx.ring->queue_index, > > > > + NETDEV_QUEUE_TYPE_RX, napi); > > > > + > > > > + if (q_vector->tx.ring) > > > > + netif_queue_set_napi(adapter->netdev, > > > > + q_vector->tx.ring->queue_index, > > > > + NETDEV_QUEUE_TYPE_TX, napi); > > > > +} > > > > + > > > > /** > > > > * igc_up - Open the interface and prepare it to handle traffic > > > > * @adapter: board private structure > > > > @@ -4955,6 +4971,7 @@ static int igc_sw_init(struct igc_adapter *adapter) > > > > void igc_up(struct igc_adapter *adapter) > > > > { > > > > struct igc_hw *hw = &adapter->hw; > > > > + struct napi_struct *napi; > > > > int i = 0; > > > > /* hardware has been reset, we need to reload some things */ > > > > @@ -4962,8 +4979,11 @@ void igc_up(struct igc_adapter *adapter) > > > > clear_bit(__IGC_DOWN, &adapter->state); > > > > - for (i = 0; i < adapter->num_q_vectors; i++) > > > > - napi_enable(&adapter->q_vector[i]->napi); > > > > + for (i = 0; i < adapter->num_q_vectors; i++) { > > > > + napi = &adapter->q_vector[i]->napi; > > > > + napi_enable(napi); > > > > + igc_set_queue_napi(adapter, i, napi); > > > > + } > > > > if (adapter->msix_entries) > > > > igc_configure_msix(adapter); > > > > @@ -5192,6 +5212,7 @@ void igc_down(struct igc_adapter *adapter) > > > > for (i = 0; i < adapter->num_q_vectors; i++) { > > > > if (adapter->q_vector[i]) { > > > > napi_synchronize(&adapter->q_vector[i]->napi); > > > > + igc_set_queue_napi(adapter, i, NULL); > > > > napi_disable(&adapter->q_vector[i]->napi); > > > > } > > > > } > > > > @@ -6021,6 +6042,7 @@ static int __igc_open(struct net_device *netdev, bool resuming) > > > > struct igc_adapter *adapter = netdev_priv(netdev); > > > > struct pci_dev *pdev = adapter->pdev; > > > > struct igc_hw *hw = &adapter->hw; > > > > + struct napi_struct *napi; > > > > int err = 0; > > > > int i = 0; > > > > @@ -6056,8 +6078,11 @@ static int __igc_open(struct net_device *netdev, bool resuming) > > > > clear_bit(__IGC_DOWN, &adapter->state); > > > > - for (i = 0; i < adapter->num_q_vectors; i++) > > > > - napi_enable(&adapter->q_vector[i]->napi); > > > > + for (i = 0; i < adapter->num_q_vectors; i++) { > > > > + napi = &adapter->q_vector[i]->napi; > > > > + napi_enable(napi); > > > > + igc_set_queue_napi(adapter, i, napi); > > > > + } > > > > /* Clear any pending interrupts. */ > > > > rd32(IGC_ICR); > > > > @@ -7385,7 +7410,9 @@ static int igc_resume(struct device *dev) > > > > wr32(IGC_WUS, ~0); > > > > if (netif_running(netdev)) { > > > > + rtnl_lock(); > > > > > > This change will bring back the deadlock issue that was fixed in commit: > > > 6f31d6b: "igc: Refactor runtime power management flow". > > > > OK, thanks for letting me know. > > > > I think I better understand what the issue is. It seems that: > > > > - igc_resume can be called with rtnl held via ethtool (which I > > didn't know), which calls __igc_open > > - __igc_open re-enables NAPIs and re-links queues to NAPI IDs (which > > requires rtnl) > > > > so, it seems like the rtnl_lock() I've added to igc_resume is > > unnecessary. > > > > I suppose I don't know all of the paths where the pm functions can > > be called -- are there others where RTNL is _not_ already held? > > > > I looked at e1000e and it seems that driver does not re-enable NAPIs > > in its resume path and thus does not suffer from the same issue as > > igc. > > > > So my questions are: > > > > 1. Are there are other contexts where igc_resume is called where > > RTNL is not held? > > > > 2. If the answer is that RTNL is always held when igc_resume is > > called, then I can send a v5 that removes the > > rtnl_lock/rtnl_unlock. What do you think? > > I see, so it looks like there is: > - resume > - runtime_resume > > The bug I am reintroducing is runtime_resume already holding RTNL > before my added call to rtnl_lock. > > OK. > > Does resume also hold rtnl before the driver's igc_resume is called? > I am asking because I don't know much about how PM works. > > If resume does not hold RTNL (but runtime resume does, as the bug > you pointed out shows), it seems like a wrapper can be added to tell > the code whether rtnl should be held or not based on which resume is > happening. > > Does anyone know if: resume (not runtime_resume) already holds RTNL? > I'll try to take a look and see, but I am not very familiar with PM. Well, I took a look and I'm probably wrong, but here's my assessment: - runtime_suspend can happen via ethtool or netlink when rtnl is held, so rtnl_lock will deadlock as pointed out above - suspend happens via device_suspend in kernel/power/main.c, so I think taking rtnl is safe for "regular" suspend. Other drivers (like bnxt) seem to take rtnl in their "regular" suspend callbacks. If the above assessment is correct, I think this change should fix the issue Vitaly mentioned and I'll submit this as part of v5. It adds a wrapper to tell igc_resume to either hold rtnl or not depending on whether it's called from runtime_suspend or suspend. I'll submit this as v5 shortly, and my apologies on my lack of knowledge of PM; I am happy to perform any sort of testing on my igc device you folks think would help verify that this is working properly. diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c index 04aa216ef612..051a0cdb1143 100644 --- a/drivers/net/ethernet/intel/igc/igc_main.c +++ b/drivers/net/ethernet/intel/igc/igc_main.c @@ -7367,7 +7367,7 @@ static void igc_deliver_wake_packet(struct net_device *netdev) netif_rx(skb); } -static int igc_resume(struct device *dev) +static int __igc_do_resume(struct device *dev, bool need_rtnl) { struct pci_dev *pdev = to_pci_dev(dev); struct net_device *netdev = pci_get_drvdata(pdev); @@ -7410,9 +7410,11 @@ static int igc_resume(struct device *dev) wr32(IGC_WUS, ~0); if (netif_running(netdev)) { - rtnl_lock(); + if (need_rtnl) + rtnl_lock(); err = __igc_open(netdev, true); - rtnl_unlock(); + if (need_rtnl) + rtnl_unlock(); if (!err) netif_device_attach(netdev); } @@ -7420,9 +7422,14 @@ static int igc_resume(struct device *dev) return err; } +static int igc_resume(struct device *dev) +{ + return __igc_do_resume(dev, true); +} + static int igc_runtime_resume(struct device *dev) { - return igc_resume(dev); + return __igc_do_resume(dev, false); } static int igc_suspend(struct device *dev)
On 10/28/2024 9:00 AM, Joe Damato wrote: > > I see, so it looks like there is: > - resume > - runtime_resume > > The bug I am reintroducing is runtime_resume already holding RTNL > before my added call to rtnl_lock. > > OK. > > Does resume also hold rtnl before the driver's igc_resume is called? > I am asking because I don't know much about how PM works. > > If resume does not hold RTNL (but runtime resume does, as the bug > you pointed out shows), it seems like a wrapper can be added to tell > the code whether rtnl should be held or not based on which resume is > happening. > > Does anyone know if: resume (not runtime_resume) already holds RTNL? > I'll try to take a look and see, but I am not very familiar with PM. I believe the resume doesn't hold RTNL, as its part of the core device code, which is not networking specific. It shouldn't be acquiring RTNL since that is a network specific lock. I believe the code you posted as v5 should resolve this, and makes sense to me. Thanks for digging into this :) -Jake
On Mon, Oct 28, 2024 at 11:53:55AM -0700, Jacob Keller wrote: > > > On 10/28/2024 9:00 AM, Joe Damato wrote: > > > > I see, so it looks like there is: > > - resume > > - runtime_resume > > > > The bug I am reintroducing is runtime_resume already holding RTNL > > before my added call to rtnl_lock. > > > > OK. > > > > Does resume also hold rtnl before the driver's igc_resume is called? > > I am asking because I don't know much about how PM works. > > > > If resume does not hold RTNL (but runtime resume does, as the bug > > you pointed out shows), it seems like a wrapper can be added to tell > > the code whether rtnl should be held or not based on which resume is > > happening. > > > > Does anyone know if: resume (not runtime_resume) already holds RTNL? > > I'll try to take a look and see, but I am not very familiar with PM. > > I believe the resume doesn't hold RTNL, as its part of the core device > code, which is not networking specific. It shouldn't be acquiring RTNL > since that is a network specific lock. > > I believe the code you posted as v5 should resolve this, and makes sense > to me. > > Thanks for digging into this :) No problem; sorry for all the back and forth on this one and I really appreciate your patience and reviews. Thanks, Joe
diff --git a/drivers/net/ethernet/intel/igc/igc.h b/drivers/net/ethernet/intel/igc/igc.h index eac0f966e0e4..b8111ad9a9a8 100644 --- a/drivers/net/ethernet/intel/igc/igc.h +++ b/drivers/net/ethernet/intel/igc/igc.h @@ -337,6 +337,8 @@ struct igc_adapter { struct igc_led_classdev *leds; }; +void igc_set_queue_napi(struct igc_adapter *adapter, int q_idx, + struct napi_struct *napi); void igc_up(struct igc_adapter *adapter); void igc_down(struct igc_adapter *adapter); int igc_open(struct net_device *netdev); diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c index 7964bbedb16c..04aa216ef612 100644 --- a/drivers/net/ethernet/intel/igc/igc_main.c +++ b/drivers/net/ethernet/intel/igc/igc_main.c @@ -4948,6 +4948,22 @@ static int igc_sw_init(struct igc_adapter *adapter) return 0; } +void igc_set_queue_napi(struct igc_adapter *adapter, int vector, + struct napi_struct *napi) +{ + struct igc_q_vector *q_vector = adapter->q_vector[vector]; + + if (q_vector->rx.ring) + netif_queue_set_napi(adapter->netdev, + q_vector->rx.ring->queue_index, + NETDEV_QUEUE_TYPE_RX, napi); + + if (q_vector->tx.ring) + netif_queue_set_napi(adapter->netdev, + q_vector->tx.ring->queue_index, + NETDEV_QUEUE_TYPE_TX, napi); +} + /** * igc_up - Open the interface and prepare it to handle traffic * @adapter: board private structure @@ -4955,6 +4971,7 @@ static int igc_sw_init(struct igc_adapter *adapter) void igc_up(struct igc_adapter *adapter) { struct igc_hw *hw = &adapter->hw; + struct napi_struct *napi; int i = 0; /* hardware has been reset, we need to reload some things */ @@ -4962,8 +4979,11 @@ void igc_up(struct igc_adapter *adapter) clear_bit(__IGC_DOWN, &adapter->state); - for (i = 0; i < adapter->num_q_vectors; i++) - napi_enable(&adapter->q_vector[i]->napi); + for (i = 0; i < adapter->num_q_vectors; i++) { + napi = &adapter->q_vector[i]->napi; + napi_enable(napi); + igc_set_queue_napi(adapter, i, napi); + } if (adapter->msix_entries) igc_configure_msix(adapter); @@ -5192,6 +5212,7 @@ void igc_down(struct igc_adapter *adapter) for (i = 0; i < adapter->num_q_vectors; i++) { if (adapter->q_vector[i]) { napi_synchronize(&adapter->q_vector[i]->napi); + igc_set_queue_napi(adapter, i, NULL); napi_disable(&adapter->q_vector[i]->napi); } } @@ -6021,6 +6042,7 @@ static int __igc_open(struct net_device *netdev, bool resuming) struct igc_adapter *adapter = netdev_priv(netdev); struct pci_dev *pdev = adapter->pdev; struct igc_hw *hw = &adapter->hw; + struct napi_struct *napi; int err = 0; int i = 0; @@ -6056,8 +6078,11 @@ static int __igc_open(struct net_device *netdev, bool resuming) clear_bit(__IGC_DOWN, &adapter->state); - for (i = 0; i < adapter->num_q_vectors; i++) - napi_enable(&adapter->q_vector[i]->napi); + for (i = 0; i < adapter->num_q_vectors; i++) { + napi = &adapter->q_vector[i]->napi; + napi_enable(napi); + igc_set_queue_napi(adapter, i, napi); + } /* Clear any pending interrupts. */ rd32(IGC_ICR); @@ -7385,7 +7410,9 @@ static int igc_resume(struct device *dev) wr32(IGC_WUS, ~0); if (netif_running(netdev)) { + rtnl_lock(); err = __igc_open(netdev, true); + rtnl_unlock(); if (!err) netif_device_attach(netdev); } @@ -7440,14 +7467,18 @@ static pci_ers_result_t igc_io_error_detected(struct pci_dev *pdev, struct net_device *netdev = pci_get_drvdata(pdev); struct igc_adapter *adapter = netdev_priv(netdev); + rtnl_lock(); netif_device_detach(netdev); - if (state == pci_channel_io_perm_failure) + if (state == pci_channel_io_perm_failure) { + rtnl_unlock(); return PCI_ERS_RESULT_DISCONNECT; + } if (netif_running(netdev)) igc_down(adapter); pci_disable_device(pdev); + rtnl_unlock(); /* Request a slot reset. */ return PCI_ERS_RESULT_NEED_RESET; diff --git a/drivers/net/ethernet/intel/igc/igc_xdp.c b/drivers/net/ethernet/intel/igc/igc_xdp.c index e27af72aada8..4da633430b80 100644 --- a/drivers/net/ethernet/intel/igc/igc_xdp.c +++ b/drivers/net/ethernet/intel/igc/igc_xdp.c @@ -84,6 +84,7 @@ static int igc_xdp_enable_pool(struct igc_adapter *adapter, napi_disable(napi); } + igc_set_queue_napi(adapter, queue_id, NULL); set_bit(IGC_RING_FLAG_AF_XDP_ZC, &rx_ring->flags); set_bit(IGC_RING_FLAG_AF_XDP_ZC, &tx_ring->flags); @@ -133,6 +134,7 @@ static int igc_xdp_disable_pool(struct igc_adapter *adapter, u16 queue_id) xsk_pool_dma_unmap(pool, IGC_RX_DMA_ATTR); clear_bit(IGC_RING_FLAG_AF_XDP_ZC, &rx_ring->flags); clear_bit(IGC_RING_FLAG_AF_XDP_ZC, &tx_ring->flags); + igc_set_queue_napi(adapter, queue_id, napi); if (needs_reset) { napi_enable(napi);
Link queues to NAPI instances via netdev-genl API so that users can query this information with netlink. Handle a few cases in the driver: 1. Link/unlink the NAPIs when XDP is enabled/disabled 2. Handle IGC_FLAG_QUEUE_PAIRS enabled and disabled Example output when IGC_FLAG_QUEUE_PAIRS is enabled: $ ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/netdev.yaml \ --dump queue-get --json='{"ifindex": 2}' [{'id': 0, 'ifindex': 2, 'napi-id': 8193, 'type': 'rx'}, {'id': 1, 'ifindex': 2, 'napi-id': 8194, 'type': 'rx'}, {'id': 2, 'ifindex': 2, 'napi-id': 8195, 'type': 'rx'}, {'id': 3, 'ifindex': 2, 'napi-id': 8196, 'type': 'rx'}, {'id': 0, 'ifindex': 2, 'napi-id': 8193, 'type': 'tx'}, {'id': 1, 'ifindex': 2, 'napi-id': 8194, 'type': 'tx'}, {'id': 2, 'ifindex': 2, 'napi-id': 8195, 'type': 'tx'}, {'id': 3, 'ifindex': 2, 'napi-id': 8196, 'type': 'tx'}] Since IGC_FLAG_QUEUE_PAIRS is enabled, you'll note that the same NAPI ID is present for both rx and tx queues at the same index, for example index 0: {'id': 0, 'ifindex': 2, 'napi-id': 8193, 'type': 'rx'}, {'id': 0, 'ifindex': 2, 'napi-id': 8193, 'type': 'tx'}, To test IGC_FLAG_QUEUE_PAIRS disabled, a test system was booted using the grub command line option "maxcpus=2" to force igc_set_interrupt_capability to disable IGC_FLAG_QUEUE_PAIRS. Example output when IGC_FLAG_QUEUE_PAIRS is disabled: $ lscpu | grep "On-line CPU" On-line CPU(s) list: 0,2 $ ethtool -l enp86s0 | tail -5 Current hardware settings: RX: n/a TX: n/a Other: 1 Combined: 2 $ cat /proc/interrupts | grep enp 144: [...] enp86s0 145: [...] enp86s0-rx-0 146: [...] enp86s0-rx-1 147: [...] enp86s0-tx-0 148: [...] enp86s0-tx-1 1 "other" IRQ, and 2 IRQs for each of RX and Tx, so we expect netlink to report 4 IRQs with unique NAPI IDs: $ ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/netdev.yaml \ --dump napi-get --json='{"ifindex": 2}' [{'id': 8196, 'ifindex': 2, 'irq': 148}, {'id': 8195, 'ifindex': 2, 'irq': 147}, {'id': 8194, 'ifindex': 2, 'irq': 146}, {'id': 8193, 'ifindex': 2, 'irq': 145}] Now we examine which queues these NAPIs are associated with, expecting that since IGC_FLAG_QUEUE_PAIRS is disabled each RX and TX queue will have its own NAPI instance: $ ./tools/net/ynl/cli.py --spec Documentation/netlink/specs/netdev.yaml \ --dump queue-get --json='{"ifindex": 2}' [{'id': 0, 'ifindex': 2, 'napi-id': 8193, 'type': 'rx'}, {'id': 1, 'ifindex': 2, 'napi-id': 8194, 'type': 'rx'}, {'id': 0, 'ifindex': 2, 'napi-id': 8195, 'type': 'tx'}, {'id': 1, 'ifindex': 2, 'napi-id': 8196, 'type': 'tx'}] Signed-off-by: Joe Damato <jdamato@fastly.com> Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com> --- v4: - Add rtnl_lock/rtnl_unlock in two paths: igc_resume and igc_io_error_detected. The code added to the latter is inspired by a similar implementation in ixgbe's ixgbe_io_error_detected. v3: - Replace igc_unset_queue_napi with igc_set_queue_napi(adapater, i, NULL), as suggested by Vinicius Costa Gomes - Simplify implemention of igc_set_queue_napi as suggested by Kurt Kanzenbach, with a tweak to use ring->queue_index v2: - Update commit message to include tests for IGC_FLAG_QUEUE_PAIRS disabled - Refactored code to move napi queue mapping and unmapping to helper functions igc_set_queue_napi and igc_unset_queue_napi - Adjust the code to handle IGC_FLAG_QUEUE_PAIRS disabled - Call helpers to map/unmap queues to NAPIs in igc_up, __igc_open, igc_xdp_enable_pool, and igc_xdp_disable_pool drivers/net/ethernet/intel/igc/igc.h | 2 ++ drivers/net/ethernet/intel/igc/igc_main.c | 41 ++++++++++++++++++++--- drivers/net/ethernet/intel/igc/igc_xdp.c | 2 ++ 3 files changed, 40 insertions(+), 5 deletions(-)