> >My system did lockup after short time of usage. I was only able to capture
> this screenshot:
> >
> >Any ideas?
>
> the problem seems to be that they use sleeping locks in the primary irq
> handler.
>
> iwl_pcie_rx_replenish() takes the same lock (->irq_lock) and additionaly
> ->lock so I think tunrning everything into raw locks isn't very wise for
> the latency.
>
> The threaded handler takes for a very short time irq_lock lock. It also takes
> the ->lock via (iwl_pcie_rxq_inc_wr_ptr()) with irqs off (that one looks short,
> too) and others for instance via iwl_pcie_rx_handle().
> Ideally the driver should hold one spinlock to synchronize the primary and
> threaded irq handler while disabling the interrupt in the iwl hardware.
> Everything else would then hold one or two mutex(es) and could even
> allocate memory with GFP_KERNEL.
We have a patch internally that goes into that direction, but one thing though. If you still have a spinlock in the primary handler, wouldn't that sleep in a non-sleepable context? Forgive my -rt ignorance, but I understood that in -rt, all the spinlock go to sleep which basically mean that we can't take any spinlock in the primary irq handler so I am a bit confused here.
>
> For now I think the simply thing would be just to let both handlers run in the
> thread. Does this patch solve your problem?
>
> diff --git a/drivers/net/wireless/iwlwifi/pcie/trans.c
> b/drivers/net/wireless/iwlwifi/pcie/trans.c
> index aeb70e1..42567fc 100644
> --- a/drivers/net/wireless/iwlwifi/pcie/trans.c
> +++ b/drivers/net/wireless/iwlwifi/pcie/trans.c
> @@ -1456,6 +1456,20 @@ static const struct iwl_trans_ops trans_ops_pcie =
> {
> .set_bits_mask = iwl_trans_pcie_set_bits_mask, };
>
> +#ifdef CONFIG_PREEMPT_RT_BASE
> +static irqreturn_t iwl_rt_irq_handler(int irq, void *dev_id) {
> + irqreturn_t ret;
> +
> + local_bh_disable();
> + ret = iwl_pcie_isr_ict(irq, dev_id);
> + local_bh_enable();
> + if (ret == IRQ_WAKE_THREAD)
> + ret = iwl_pcie_irq_handler(irq, dev_id);
> + return ret;
> +}
> +#endif
> +
> struct iwl_trans *iwl_trans_pcie_alloc(struct pci_dev *pdev,
> const struct pci_device_id *ent,
> const struct iwl_cfg *cfg)
> @@ -1566,9 +1580,14 @@ struct iwl_trans *iwl_trans_pcie_alloc(struct
> pci_dev *pdev,
> if (iwl_pcie_alloc_ict(trans))
> goto out_free_cmd_pool;
>
> +#ifdef CONFIG_PREEMPT_RT_BASE
> + if (request_threaded_irq(pdev->irq, NULL, iwl_rt_irq_handler,
> + IRQF_SHARED | IRQF_ONESHOT,
> DRV_NAME, trans)) { #else
> if (request_threaded_irq(pdev->irq, iwl_pcie_isr_ict,
> iwl_pcie_irq_handler,
> IRQF_SHARED, DRV_NAME, trans)) {
> +#endif
> IWL_ERR(trans, "Error allocating IRQ %d\n", pdev->irq);
> goto out_free_ict;
> }
> --
> 1.8.4.rc3
>
>
> >With kind regards
> >Thomas
>
> Sebastian
>
> _______________________________________________
> ilw mailing list
> ilw@xxxxxxxxxxxxxxx
> http://linux.intel.com/mailman/listinfo/ilw
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