align physical memory

[phungha2511]

Hi every one,

I would like to get physical address of share memory. My code likes this:

1. Create a share memory using shm_open();
2. Using shm_ctl() to set attribute of that share memory
3. Map memory object by mmap();
4. Get physical address of this memory by mem_offset();

My problem is that, the physical address is not align to the size of memory. How can I align this physical address?

For example:

• memsize = 4KBytes, the physical address must be multiples of 0x1000
• memsize = 8MBytes, the physical address must be multiples of 0x800000

Thanks.

Zodiac

[mario]

You cannot. mmap/allocated bigger then you need and compensate yourself by setting the pointer to a multiple of what you need. That will waste memory but I don’t know of any other way.

[phungha2511]

Thanks Mario