[RFC] [PATCH] tapset to count number open file handlers and max file handlers for a process

[Stone, Joshua I]

Srinivasa Ds wrote:
[...]
> +// Return the number of open file handlers for the given task
> +function task_open_file_handler:long (task:long) %{
> +    struct task_struct *t = (struct task_struct *)(long)THIS->task;
> +    struct fdtable *fdt = kread(&(t->files->fdt));

This still need to be broken down -- one kread for t->files, and another 
for files->fdt.

> +    unsigned int count=0, fd;
> +    rcu_read_lock();
> +    for (fd = 0; fd < kread(&(fdt->max_fds)); fd++) {

No need to kread every time through the loop.  You can read it once 
right before entering the loop.

[...]
> +// Return the maximum number of file handlers for the given task
> +function task_max_file_handler:long (task:long) %{
> +    struct task_struct *t = (struct task_struct *)(long)THIS->task;
> +    struct files_struct *f = kread (&(t->files));
> +    rcu_read_lock();
> +    THIS->__retvalue = kread(&(f->fdt->max_fds));

Please split this into two kreads, f->fdt and fdt->max_fds.

Otherwise, it looks good.

Josh