Re: [PATCH 2/3] mm, page_owner: Add page_owner_stacks file to print out only stacks and their counter

[Ammar Faizi]

On 9/1/22 11:42 AM, Oscar Salvador wrote:
> +static unsigned long last_stack = 0;

This @last_stack can just be a static local variable in the new
function you wrote, read_page_owner_stacks(), since no other
functions use it.

> +static ssize_t read_page_owner_stacks(struct file *file, char __user *buf,
> +				      size_t count, loff_t *pos)
> +{
> +	char *kbuf;
> +	int ret = 0;
> +
> +	count = min_t(size_t, count, PAGE_SIZE);
> +	kbuf = kmalloc(count, GFP_KERNEL);
> +	if (!kbuf)
> +		return ENOMEM;

Missing a negative sign, return -ENOMEM;

> +	ret += stack_depot_print_stacks_threshold(kbuf, count, pos, &last_stack);
> +	if (copy_to_user(buf, kbuf, ret))
> +		ret = -EFAULT;
> +
> +	if (!ret)
> +		last_stack = 0;
> +
> +	kfree(kbuf);
> +	return ret;
> +}

--
Ammar Faizi