Re: Question about dataspace
Adam Lackorzynski <[email protected]>
| Newsgroups | gmane.comp.micro-kernel.l4.devel |
|---|---|
| Message-ID | <[email protected]> |
Hi, On Sat May 10, 2014 at 11:23:47 +0800, Yuxin Ren wrote: > I cannot understand dataspace very well. I have some questions about it. > Each time I want to alloc a piece of memory, I must create a dataspace > first? I think you mean that you need to allocate a capability before calling mem_alloc()->alloc()? Yes, you need to do that for each new memory to be allocated. > I look at the example code of memory allocation. > I found after create adataspace, we call > L4Re::Env::env<http://l4re.org/doc/classL4Re_1_1Env.html#aa1181d6256037deda5b5f83c2006ba60>()->mem_alloc()->alloc() > to alloca memory via dataspace. > Can I call this function multiple times on the same dataspace instance > without free? If so, what is its effect? No, don't do that. free the dataspace at mem_alloc() before allocating new memory on the same dataspace (capability). > In addtion we use attach to map the dataspace. Can I attach the same > dataspace multiple times without free? Yes, you can do that. > In this case, does it mean that the same physical memory is mapped into > different virtual address? Yes, exactly. Adam -- Adam [email protected] Lackorzynski http://os.inf.tu-dresden.de/~adam/