Re: [PATCH v4] mm: cma: support sysfs

[Dmitry Osipenko]

19.03.2021 16:51, Dmitry Osipenko пишет:
> 19.03.2021 16:47, Greg Kroah-Hartman пишет:
>> On Fri, Mar 19, 2021 at 04:45:21PM +0300, Dmitry Osipenko wrote:
>>> 19.03.2021 16:42, Greg Kroah-Hartman пишет:
>>>> On Fri, Mar 19, 2021 at 04:39:41PM +0300, Dmitry Osipenko wrote:
>>>>> 19.03.2021 15:44, Dmitry Osipenko пишет:
>>>>> ...
>>>>>>>  #include <linux/debugfs.h>
>>>>>>> +#include <linux/kobject.h>
>>>>>>> +
>>>>>>> +struct cma_stat {
>>>>>>> +	spinlock_t lock;
>>>>>>> +	/* the number of CMA page successful allocations */
>>>>>>> +	unsigned long nr_pages_succeeded;
>>>>>>> +	/* the number of CMA page allocation failures */
>>>>>>> +	unsigned long nr_pages_failed;
>>>>>>> +	struct kobject kobj;
>>>>>>> +};
>>>>>>>  
>>>>>>>  struct cma {
>>>>>>>  	unsigned long   base_pfn;
>>>>>>> @@ -16,6 +26,9 @@ struct cma {
>>>>>>>  	struct debugfs_u32_array dfs_bitmap;
>>>>>>>  #endif
>>>>>>>  	char name[CMA_MAX_NAME];
>>>>>>> +#ifdef CONFIG_CMA_SYSFS
>>>>>>> +	struct cma_stat	*stat;
>>>>>>> +#endif
>>>>>
>>>>> What is the point of allocating stat dynamically?
>>>>
>>>> Because static kobjects make me cry.
>>>>
>>>
>>> I meant that it's already a part of struct cma, it looks like the stat
>>> could be embedded into struct cma and then kobj could be initialized
>>> separately.
>>
>> But that structure is statically allocated, so it can not be.  This has
>> been discussed in the past threads for when this was reviewed if you are
>> curious :)
> 
> Indeed, I missed that cma_areas[] is static, thank you.
> 

And in this case should be better to make only the kobj allocated
dynamically instead of the whole cma_stat.