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

[Dmitry Osipenko]

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?

...
>> +void cma_sysfs_alloc_pages_count(struct cma *cma, size_t count)
>> +{
>> +	spin_lock(&cma->stat->lock);
>> +	cma->stat->nr_pages_succeeded += count;
>> +	spin_unlock(&cma->stat->lock);
>> +}
>> +
>> +void cma_sysfs_fail_pages_count(struct cma *cma, size_t count)
>> +{
>> +	spin_lock(&cma->stat->lock);
>> +	cma->stat->nr_pages_failed += count;
>> +	spin_unlock(&cma->stat->lock);
>> +}

You could use atomic increment and then locking isn't needed.