On Thu, 26 Aug 2010 11:50:17 +0900
KAMEZAWA Hiroyuki [off-list ref] wrote:
 

128MB...too big ? But it's depend on config.

IBM's ppc guys used 16MB section, and recently, a new interface to shrink
the number of /sys files are added, maybe usable.

Something good with this approach will be you can create "cma" memory
before installing driver.

But yes, complicated and need some works.

Ah, I need to clarify what I want to say.

With compaction, it's helpful, but you can't get contiguous memory larger
than MAX_ORDER, I think. To get memory larger than MAX_ORDER on demand,
memory hot-plug code has almost all necessary things.

you may able to add
# echo 0xa0000000-0xa80000000 > /sys/devices/system/memory/cma

to get contiguous isolated memory.

BTW, just curious...the memory for cma need not to be saved at
hibernation ? Or drivers has to write its own hibernation ops by driver suspend
udev or some ?



Thanks,
-Kame