Messages in this thread | | | Date | Fri, 4 Aug 2023 11:26:50 +0800 | Subject | Re: [PATCH v2 08/12] iommu: Prepare for separating SVA and IOPF | From | Baolu Lu <> |
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On 2023/8/3 16:16, Tian, Kevin wrote: >> From: Lu Baolu <baolu.lu@linux.intel.com> >> Sent: Thursday, July 27, 2023 1:49 PM >> >> @@ -82,7 +82,7 @@ static void iopf_handler(struct work_struct *work) >> if (!domain || !domain->iopf_handler) >> status = IOMMU_PAGE_RESP_INVALID; >> >> - list_for_each_entry_safe(iopf, next, &group->faults, list) { >> + list_for_each_entry(iopf, &group->faults, list) { >> /* >> * For the moment, errors are sticky: don't handle >> subsequent >> * faults in the group if there is an error. >> @@ -90,14 +90,20 @@ static void iopf_handler(struct work_struct *work) >> if (status == IOMMU_PAGE_RESP_SUCCESS) >> status = domain->iopf_handler(&iopf->fault, >> domain->fault_data); >> - >> - if (!(iopf->fault.prm.flags & >> - IOMMU_FAULT_PAGE_REQUEST_LAST_PAGE)) >> - kfree(iopf); >> } >> >> iopf_complete_group(group->dev, &group->last_fault, status); >> - kfree(group); >> + iopf_free_group(group); >> +} > > this is perf-critical path. It's not good to traverse the list twice.
Freeing the fault group is not critical anymore, right?
> >> + >> +static int iopf_queue_work(struct iopf_group *group, work_func_t func) >> +{ >> + struct iopf_device_param *iopf_param = group->dev->iommu- >>> iopf_param; >> + >> + INIT_WORK(&group->work, func); >> + queue_work(iopf_param->queue->wq, &group->work); >> + >> + return 0; >> } > > Is there plan to introduce further error in the future? otherwise this should > be void.
queue_work() return true or false. I should check and return the value.
> > btw the work queue is only for sva. If there is no other caller this can be > just kept in iommu-sva.c. No need to create a helper.
The definition of struct iopf_device_param is in this file. So I added a helper to avoid making iopf_device_param visible globally.
> >> @@ -199,8 +204,11 @@ int iommu_queue_iopf(struct iommu_fault *fault, >> struct device *dev) >> list_move(&iopf->list, &group->faults); >> } >> >> - queue_work(iopf_param->queue->wq, &group->work); >> - return 0; >> + ret = iopf_queue_work(group, iopf_handler); >> + if (ret) >> + iopf_free_group(group); >> + >> + return ret; >> > > Here we can document that the iopf handler (in patch10) should free the > group, allowing the optimization inside the handler.
Yeah!
Best regards, baolu
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