On Mon, 5 Oct 2020 12:55:14 +0200 SeongJae Park <sjpark@xxxxxxxxxx> wrote:
> From: SeongJae Park <sjpark@xxxxxxxxx>
>
> DAMON is designed to be used by kernel space code such as the memory
> management subsystems, and therefore it provides only kernel space API.
> That said, letting the user space control DAMON could provide some
> benefits to them. For example, it will allow user space to analyze
> their specific workloads and make their own special optimizations.
>
> For such cases, this commit implements a simple DAMON application kernel
> module, namely 'damon-dbgfs', which merely wraps the DAMON api and
> exports those to the user space via the debugfs.
[...]
> +
> +static ssize_t dbgfs_monitor_on_write(struct file *file,
> + const char __user *buf, size_t count, loff_t *ppos)
> +{
> + ssize_t ret = count;
> + char *kbuf;
> + int err;
> +
> + kbuf = user_input_str(buf, count, ppos);
> + if (IS_ERR(kbuf))
> + return PTR_ERR(kbuf);
> +
> + /* Remove white space */
> + if (sscanf(kbuf, "%s", kbuf) != 1)
> + return -EINVAL;
> + if (!strncmp(kbuf, "on", count))
> + err = dbgfs_start_ctxs(dbgfs_ctxs, dbgfs_nr_ctxs);
> + else if (!strncmp(kbuf, "off", count))
> + err = damon_stop(dbgfs_ctxs, dbgfs_nr_ctxs);
> + else
> + return -EINVAL;
> +
> + if (err)
> + ret = err;
> + return ret;
'kbuf' should be freed before returning from this function. I will fix it in
the next version. To find more potential memory leaks, I ran 'kmemleak' after
a set of correctness tests[1], but it didn't find more leaks.
[1] https://github.com/awslabs/damon-tests/tree/master/corr
Thanks,
SeongJae Park
