When running the igc with XDP/ZC in busy polling mode with deferral of hard
interrupts, interrupts still happen from time to time. That is caused by
the igb task watchdog which triggers Rx interrupts periodically.
That mechanism has been introduced to overcome skb/memory allocation
failures [1]. So the Rx clean functions stop processing the Rx ring in case
of such failure. The task watchdog triggers Rx interrupts periodically in
the hope that memory became available in the mean time.
The current behavior is undesirable for real time applications, because the
driver induced Rx interrupts trigger also the softirq processing. However,
all real time packets should be processed by the application which uses the
busy polling method.
Therefore, only trigger the Rx interrupts in case of real allocation
failures. Introduce a new flag for signaling that condition.
Follow the same logic as in commit 8dcf2c2120 ("igc: Get rid of spurious
interrupts").
[1] - https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/?id=3be507547e6177e5c808544bd6a2efa2c7f1d436
Reviewed-by: Joe Damato <jdamato@fastly.com>
Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@intel.com>
Tested-by: Sweta Kumari <sweta.kumari@intel.com>
Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Add support for AF_XDP zero-copy transmit path.
A new TX buffer type IGB_TYPE_XSK is introduced to indicate that the Tx
frame was allocated from the xsk buff pool, so igb_clean_tx_ring() and
igb_clean_tx_irq() can clean the buffers correctly based on type.
igb_xmit_zc() performs the actual packet transmit when AF_XDP zero-copy is
enabled. We share the TX ring between slow path, XDP and AF_XDP
zero-copy, so we use the netdev queue lock to ensure mutual exclusion.
Signed-off-by: Sriram Yagnaraman <sriram.yagnaraman@est.tech>
[Kurt: Set olinfo_status in igb_xmit_zc() so that frames are transmitted,
Use READ_ONCE() for xsk_pool and check Tx disabled and carrier in
igb_xmit_zc(), Add FIXME for RS bit]
Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Tested-by: George Kuruvinakunnel <george.kuruvinakunnel@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Link: https://patch.msgid.link/20250106221929.956999-7-anthony.l.nguyen@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Add the following ring flag:
- IGB_RING_FLAG_TX_DISABLED (when xsk pool is being setup)
Add a xdp_buff array for use with XSK receive batch API, and a pointer
to xsk_pool in igb_adapter.
Add enable/disable functions for TX and RX rings.
Add enable/disable functions for XSK pool.
Add xsk wakeup function.
None of the above functionality will be active until
NETDEV_XDP_ACT_XSK_ZEROCOPY is advertised in netdev->xdp_features.
Signed-off-by: Sriram Yagnaraman <sriram.yagnaraman@est.tech>
[Kurt: Add READ/WRITE_ONCE(), synchronize_net(),
remove IGB_RING_FLAG_AF_XDP_ZC]
Signed-off-by: Kurt Kanzenbach <kurt@linutronix.de>
Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Tested-by: George Kuruvinakunnel <george.kuruvinakunnel@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Link: https://patch.msgid.link/20250106221929.956999-4-anthony.l.nguyen@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
