On Tue, Apr 19, 2016 at 10:09 PM, David Woodhouse <[email protected]> wrote:
>> --- a/drivers/iommu/intel-iommu.c
>> +++ b/drivers/iommu/intel-iommu.c
>> @@ -392,6 +392,7 @@ struct dmar_domain {
>> * to VT-d spec, section 9.3 */
>>
>> struct list_head devices; /* all devices' list */
>> + bool has_iotlb_device;
>
> If you put that *before* the 'devices' field then the array will pack
> better.
Will do.
>> @@ -1523,6 +1553,9 @@ static void iommu_flush_dev_iotlb(struct dmar_domain
>> *domain,
>> unsigned long flags;
>> struct device_domain_info *info;
>>
>> + if (!domain->has_iotlb_device)
>> + return;
>> +
>> spin_lock_irqsave(&device_domain_lock, flags);
>> list_for_each_entry(info, &domain->devices, link) {
>> if (!info->ats_enabled)
>>
>
> Hm, I wonder if it would be nicer to check this in the caller (both of
> them). As things stand, in flush_unmaps() we'll now be calculating
> ilog2(nrpages) for (possibly) no reason before calling this function.
I tend to leave it as is, since I'm not seeing this ilog2() in the profiles.
> Other than that, this all looks excellent; thanks. I'll apply it when I
> get home from LSF/MM later this week or next.
>
> Only a few cosmetic things to change — please use 'iommu/vt-d:' as the
> prefix on each commit, and spell 'MiB' and 'KiB' correctly in the final
> patch in the series. (And I'm not sure I quite understand 'a CPU can
> cache at most 32 MiB and the global cache is bounded by 4 MiB.' either
> way...)
Great, thanks! I'll report a v4 addressing these issues (and clarify
the explanation about the caches).
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