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

Dmitry Osipenko
2021-03-19T13:40:23Z

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.