'InKi Dae'; linux-media@vger.kernel.org;
linux-arm-ker...@lists.infradead.org;
> 'linux-fbdev'; kyungmin.p...@samsung.com
> Subject: Re: Memory sharing issue by application on V4L2 based device
driver
> with system mmu.
>
>
> .. snip..
> > But 64KB or 1MB ph
.. snip..
> But 64KB or 1MB physically contiguous memory is better than 4KB page in the
> point of performance.
Could you explain that in more details please? I presume you are
talking about a CPU that has a MMU unit, right?
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Michel Dänzer 쓴 글:
On Fre, 2011-01-07 at 11:17 +0900, InKi Dae wrote:
thank you for your comments.
your second comment has no any problem as I said before, user virtual
addess could be translated in page unit. but the problem, as you said,
is that when cpu access to the memory in user mode, the
On Fre, 2011-01-07 at 11:17 +0900, InKi Dae wrote:
> thank you for your comments.
>
> your second comment has no any problem as I said before, user virtual
> addess could be translated in page unit. but the problem, as you said,
> is that when cpu access to the memory in user mode, the memory
> a
; linux-arm-ker...@lists.infradead.org;
> linux-fbdev;
>> kyungmin.p...@samsung.com
>> Subject: Re: Memory sharing issue by application on V4L2 based device
> driver
>> with system mmu.
>>
>> thank you for your comments.
>>
>> your second comment ha
.com
> Subject: Re: Memory sharing issue by application on V4L2 based device
driver
> with system mmu.
>
> thank you for your comments.
>
> your second comment has no any problem as I said before, user virtual
addess
> could be translated in page unit. but the problem, as you s
thank you for your comments.
your second comment has no any problem as I said before, user virtual
addess could be translated in page unit. but the problem, as you said,
is that when cpu access to the memory in user mode, the memory
allocated by malloc, page fault occurs so we can't find pfn to us
Hello,
There are two reasons why malloc isn't suitable for it.
The first is that malloc doesn't allocate memory when malloc is called.
So driver or vb2 cannot find PFN for it in the VIDIOC_QBUF.
The second is that malloc uses 4KB page allocation.
SYS.MMU(IO-MMU) can handle scattered memory. But
