Re: [PATCH 1/4] (CMA_AGGRESSIVE) Add CMA_AGGRESSIVE to Kconfig

[朱辉]

On 10/22/14 09:27, Pavel Machek wrote:
> Hi!
>
>> Add CMA_AGGRESSIVE config that depend on CMA to Linux kernel config.
>> Add CMA_AGGRESSIVE_PHY_MAX, CMA_AGGRESSIVE_FREE_MIN and CMA_AGGRESSIVE_SHRINK
>> that depend on CMA_AGGRESSIVE.
>>
>> If physical memory size (not include CMA memory) in byte less than or equal to
>> CMA_AGGRESSIVE_PHY_MAX, CMA aggressive switch (sysctl vm.cma-aggressive-switch)
>> will be opened.
>
> Ok...
>
> Do I understand it correctly that there is some problem with
> hibernation not working on machines not working on machines with big
> CMA areas...?

No, these patches want to handle this issue that most of CMA memory is 
not allocated before lowmemorykiller or oom_killer begin to kill tasks.

>
> But adding 4 config options end-user has no chance to set right can
> not be the best solution, can it?
>
>> +config CMA_AGGRESSIVE_PHY_MAX
>> +	hex "Physical memory size in Bytes that auto turn on the CMA aggressive switch"
>> +	depends on CMA_AGGRESSIVE
>> +	default 0x40000000
>> +	help
>> +	  If physical memory size (not include CMA memory) in byte less than or
>> +	  equal to this value, CMA aggressive switch will be opened.
>> +	  After the Linux boot, sysctl "vm.cma-aggressive-switch" can control
>> +	  the CMA AGGRESSIVE switch.
>
> For example... how am I expected to figure right value to place here?

I agree with that.  I will update this config to auto set in next version.

Thanks,
Hui

>
> 									Pavel
>