On 30/01/17 07:20, Yoshihiro Shimoda wrote:
> Hi Robin, Magnus,
> 
>> -----Original Message-----
>> From: Robin Murphy
>> Sent: Saturday, January 28, 2017 2:38 AM
>>
>> Hi Magnus,
>>
>> On 27/01/17 06:24, Magnus Damm wrote:
>>> From: Magnus Damm <[email protected]>
>>>
>>> Introduce the flag "no_size_align" to allow disabling size-alignment
>>> on a per-domain basis. This follows the suggestion by the comment
>>> in the code, however a per-device control may be preferred?
>>>
>>> Needed to make virtual space contiguous for certain devices.
>>
>> That sounds very suspicious - a single allocation is contiguous with
>> itself by definition, and anyone relying on multiple allocations being
>> contiguous with one another is doing it wrong, because there's no way we
>> could ever guarantee that (with this allocator, at any rate). I'd be
>> very reticent to touch this without a specific example of what problem
>> it solves.
> 
> Thank you for the comment! This patch was from my request.
> But, I completely misunderstood this "size-alignment" behavior.
> And, my concern was already resolved by the following patch at last April:
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/drivers/iommu?id=809eac54cdd62c67afea1e17080e681dfa33dc09
> 
> So, no one needs this patch anymore.

Cool, thanks for the clarification :)

Robin.

> 
> Best regards,
> Yoshihiro Shimoda
> 

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