Re: [PATCH] distinct tgid/tid I/O statistics

[Andrea Righi]

Balbir Singh wrote:
> > +
> > +    if (!whole) {
> > +#ifdef CONFIG_TASK_XACCT
>
> Can't we abstract this into a function for ease?

Maybe:

#ifdef CONFIG_TASK_XACCT
#define _task_xacct 1
#else
#define _task_xacct 0
#endif

and:

rchar = __task_xacct ? task->rchar : 0;
wchar = __task_xacct ? task->wchar : 0;
syscr = __task_xacct ? task->syscr : 0;
syscw = __task_xacct ? task->syscw : 0;

But it's very ugly anyway. It seems a similar problem has been raised
here:

http://lkml.org/lkml/2008/5/17/154

Apparently with no solution.

> > +        rchar = task->rchar;
> > +        wchar = task->wchar;
> > +        syscr = task->syscr;
> > +        syscw = task->syscw;
> > +#endif
> > +        memcpy(&ioac, &task->ioac, sizeof(ioac));
> > +    } else {
> > +        rchar = wchar = syscr = syscw = 0;
> > +        memset(&ioac, 0, sizeof(ioac));
> > +        rcu_read_lock();
> > +        if (lock_task_sighand(task, &flags)) {
>
> If lock(), what happens otherwise?

mmmh... we must surely move the threads stats accounting code out of
the if statement. OK, I'll post a new patch soon.

Thanks,
-Andrea

> > +        struct signal_struct *sig = task->signal;
> > +        struct task_struct *t = task;
> > +
> > +            do {
> > +#ifdef CONFIG_TASK_XACCT
> > +                rchar += t->rchar;
> > +                wchar += t->wchar;
> > +                syscr += t->syscr;
> > +                syscw += t->syscw;
> > +#endif
> > +                ioac.read_bytes += t->ioac.read_bytes;
> > +                ioac.write_bytes += t->ioac.write_bytes;
> > +                ioac.cancelled_write_bytes +=
> > +                        t->ioac.cancelled_write_bytes;
> > +                t = next_thread(t);
> > +            } while (t != task);
> > +
> > +#ifdef CONFIG_TASK_XACCT
> > +            rchar += sig->rchar;
> > +            wchar += sig->wchar;
> > +            syscr += sig->syscr;
> > +            syscw += sig->syscw;
> > +#endif
> > +            ioac.read_bytes += sig->ioac.read_bytes;
> > +            ioac.write_bytes += sig->ioac.write_bytes;
> > +            ioac.cancelled_write_bytes +=
> > +                    sig->ioac.cancelled_write_bytes;
> > +
> > +            unlock_task_sighand(task, &flags);
> > +        }
> > +        rcu_read_unlock();
> > +    }
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/