[PATCH] iommu/amd: flush IOTLB for specific domains only (v2)

[Michel Dänzer]

On 22/05/17 10:08 AM, Michel Dänzer wrote:
> On 19/05/17 07:02 PM, arindam.nath at amd.com wrote:
>> From: Arindam Nath <arindam.nath at amd.com>
>>
>> Change History
>> --------------
>>
>> v2: changes suggested by Joerg
>> - add flush flag to improve efficiency of flush operation
>>
>> v1:
>> - The idea behind flush queues is to defer the IOTLB flushing
>>   for domains for which the mappings are no longer valid. We
>>   add such domains in queue_add(), and when the queue size
>>   reaches FLUSH_QUEUE_SIZE, we perform __queue_flush().
>>
>>   Since we have already taken lock before __queue_flush()
>>   is called, we need to make sure the IOTLB flushing is
>>   performed as quickly as possible.
>>
>>   In the current implementation, we perform IOTLB flushing
>>   for all domains irrespective of which ones were actually
>>   added in the flush queue initially. This can be quite
>>   expensive especially for domains for which unmapping is
>>   not required at this point of time.
>>
>>   This patch makes use of domain information in
>>   'struct flush_queue_entry' to make sure we only flush
>>   IOTLBs for domains who need it, skipping others.
>>
>> Suggested-by: Joerg Roedel <joro at 8bytes.org>
>> Signed-off-by: Arindam Nath <arindam.nath at amd.com>
> 
> Please add these tags:
> 
> Fixes: b1516a14657a ("iommu/amd: Implement flush queue")
> Cc: stable at vger.kernel.org

Also

Bugzilla: https://bugs.freedesktop.org/101029


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer