Re: [PATCH 2/4] mm: cma: add functions to get region pages counters

From: Safonov Dmitry
Date: Wed Feb 18 2015 - 08:12:45 EST

On 02/14/2015 10:32 AM, Gioh Kim wrote:
> 2015-02-13 오전 7:15에 Stefan Strogin 이(가) 쓴 글:
>> From: Dmitry Safonov <d.safonov@xxxxxxxxxxxxxxxxxxx>
>> Here are two functions that provide interface to compute/get used size
>> and size of biggest free chunk in cma region.
> I usually just try to allocate memory, not check free size before try,
> becuase free size can be changed after I check it.
> Could you tell me why biggest free chunk size is necessary?
It may have changed after checking - at beginning of allocation
this information is completely useless as you mentioned, but
it may be very helpful after failed allocation to detect fragmentation
problem: i.e, you failed to alloc 20 Mb from 100 Mb CMA region
with 60 Mb free space, so you will know the reason.

Best regards,
Safonov Dmitry.

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at