From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Kirsher Subject: [net-next 12/15] i40evf: Drop i40evf_fire_sw_int as it is prone to races Date: Wed, 3 Jan 2018 13:22:19 -0800 Message-ID: <20180103212222.17378-13-jeffrey.t.kirsher@intel.com> References: <20180103212222.17378-1-jeffrey.t.kirsher@intel.com> Cc: Alexander Duyck , netdev@vger.kernel.org, nhorman@redhat.com, sassmann@redhat.com, jogreene@redhat.com, Jeff Kirsher To: davem@davemloft.net Return-path: Received: from mga07.intel.com ([134.134.136.100]:22572 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751274AbeACVW6 (ORCPT ); Wed, 3 Jan 2018 16:22:58 -0500 In-Reply-To: <20180103212222.17378-1-jeffrey.t.kirsher@intel.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Alexander Duyck Having the interrupts firing while we are polling causes extra overhead and isn't needed for most systems out there. If an interrupt is lost us experiencing a 2s latency spike before recovering is still not acceptable and masks the issue. We are better off just identifying systems that lose interrupts and instead enable workarounds for those systems. To that end I am dropping the code that was strobing the interrupts as there is a narrow window where having them enabled can actually cause race issues anyway where a few stray packets might get misses if the interrupt is re-enabled and fires before we call napi_complete. Also replace one line where we were using bit 31 instead of the define for the bit to represent masking the interrupt enable bit. Signed-off-by: Alexander Duyck Tested-by: Andrew Bowers Signed-off-by: Jeff Kirsher --- drivers/net/ethernet/intel/i40evf/i40evf_main.c | 34 ------------------------- 1 file changed, 34 deletions(-) diff --git a/drivers/net/ethernet/intel/i40evf/i40evf_main.c b/drivers/net/ethernet/intel/i40evf/i40evf_main.c index 5fff62a45323..f92587aba3c7 100644 --- a/drivers/net/ethernet/intel/i40evf/i40evf_main.c +++ b/drivers/net/ethernet/intel/i40evf/i40evf_main.c @@ -281,33 +281,6 @@ void i40evf_irq_enable_queues(struct i40evf_adapter *adapter, u32 mask) } } -/** - * i40evf_fire_sw_int - Generate SW interrupt for specified vectors - * @adapter: board private structure - * @mask: bitmap of vectors to trigger - **/ -static void i40evf_fire_sw_int(struct i40evf_adapter *adapter, u32 mask) -{ - struct i40e_hw *hw = &adapter->hw; - int i; - u32 dyn_ctl; - - if (mask & 1) { - dyn_ctl = rd32(hw, I40E_VFINT_DYN_CTL01); - dyn_ctl |= I40E_VFINT_DYN_CTLN1_SWINT_TRIG_MASK | - I40E_VFINT_DYN_CTLN1_ITR_INDX_MASK; - wr32(hw, I40E_VFINT_DYN_CTL01, dyn_ctl); - } - for (i = 1; i < adapter->num_msix_vectors; i++) { - if (mask & BIT(i)) { - dyn_ctl = rd32(hw, I40E_VFINT_DYN_CTLN1(i - 1)); - dyn_ctl |= I40E_VFINT_DYN_CTLN1_SWINT_TRIG_MASK | - I40E_VFINT_DYN_CTLN1_ITR_INDX_MASK; - wr32(hw, I40E_VFINT_DYN_CTLN1(i - 1), dyn_ctl); - } - } -} - /** * i40evf_irq_enable - Enable default interrupt generation settings * @adapter: board private structure @@ -1743,13 +1716,6 @@ static void i40evf_watchdog_task(struct work_struct *work) if (adapter->state == __I40EVF_RUNNING) i40evf_request_stats(adapter); watchdog_done: - if (adapter->state == __I40EVF_RUNNING) { - i40evf_irq_enable_queues(adapter, ~0); - i40evf_fire_sw_int(adapter, 0xFF); - } else { - i40evf_fire_sw_int(adapter, 0x1); - } - clear_bit(__I40EVF_IN_CRITICAL_TASK, &adapter->crit_section); restart_watchdog: if (adapter->state == __I40EVF_REMOVE) -- 2.15.1