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 for domains for which the mappings are no longer valid.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
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Earthling Michel Dänzer | http://www.amd.com
Libre software enthusiast | Mesa and X developer
