Re: [PATCH v3] MM: CMA: add a simple kernel module as the helperto test CMA

From: Cong Wang
Date: Tue Mar 06 2012 - 23:56:11 EST


On 03/07/2012 12:49 PM, Barry Song wrote:
2012/3/7 Cong Wang<xiyou.wangcong@xxxxxxxxx>:
On 03/07/2012 11:14 AM, Barry Song wrote:

From: Barry Song<Baohua.Song@xxxxxxx>

Any write request to /dev/cma_test will let the module to allocate memory
from
CMA, for example:

1st time
$ echo 1024> /dev/cma_test
will require cma_test to request 1MB(1024KB)
2nd time
$ echo 2048> /dev/cma_test
will require cma_test to request 2MB(2048KB)

Any read request to /dev/cma_test will let the module to free the 1st
valid
memory from CMA, for example:

1st time
$ cat /dev/cma_test
will require cma_test to free the 1MB allocated in the first write request
2nd time
$ cat /dev/cma_test
will require cma_test to free the 2MB allocated in the second write
request


Any reason why using /dev not /proc or /sys?

pls note it is just a test module to verify CMA at runtime. it is not
important either it is /dev, it is /proc or it is /sys.

Why not important? You want it to be merged, don't you?


any way to make things easier, we take that way.


Why /dev interface is easier than /proc and /sys? Confused, actually I think /proc or /sys should be easier...
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