Re: [PATCH v5] mm: cma: support sysfs

Matthew Wilcox
2021-03-24T03:03:04Z

On Tue, Mar 23, 2021 at 12:50:50PM -0700, Minchan Kim wrote:
> + /* the number of CMA page successful allocations */
> + atomic64_t nr_pages_succeeded;

> +void cma_sysfs_alloc_pages_count(struct cma *cma, size_t count)
> +{
> + atomic64_add(count, &cma->nr_pages_succeeded);
> +}

I don't understand. A size_t is a byte count. But the variable is called
'nr_pages'. So which is it, a byte count or a page count?

> +static ssize_t alloc_pages_success_show(struct kobject *kobj,
> + struct kobj_attribute *attr, char *buf)
> +{
> + struct cma_kobject *cma_kobj = container_of(kobj,
> + struct cma_kobject, kobj);
> + struct cma *cma = cma_kobj->cma;
> +
> + return sysfs_emit(buf, "%llu\n",
> + atomic64_read(&cma->nr_pages_succeeded));

... if it's in bytes, it should probably be reported in kilobytes
and be suffixed with a 'K' like many other stats.