code review 7966043: runtime: report at most 10 errors in netpoll

runtime: does not report duplicate errors in netpoll
Prevents storm of error messages if something goes wrong.
In the case of issue 5073 the epoll fd was closed by the test.
Update issue 5073.

[dvyukov, 2013-03-22 08:20:25]

Hello golang-dev@googlegroups.com,

I'd like you to review this change to
https://dvyukov%40google.com@code.google.com/p/go/

[r, 2013-03-22 15:19:26]

What other errors do you see? And does this mean the last one, the one that
caused the program to fail, could be suppressed? If so, maybe the counter could
be reset if the error differs from the last one.

[dvyukov, 2013-03-25 16:51:49]

On Fri, Mar 22, 2013 at 7:19 PM,  <r@golang.org> wrote:
> What other errors do you see? And does this mean the last one, the one
> that caused the program to fail, could be suppressed? If so, maybe the
> counter could be reset if the error differs from the last one.


I do not see other errors, I see EBADF but a looooot of times.
What about remembering the last errno and printing only if differs?

[rsc, 2013-03-25 22:03:08]

sure

[dvyukov, 2013-03-26 07:23:43]

PTAL

Now it does not report subsequent duplicate errors.
In the case of issue 5073 the epoll fd was closed by the test. Netpoller still
enters into dead loop, but there is nothing good we can do in this case.

[r, 2013-03-26 15:17:01]

LGTM

[dvyukov, 2013-03-26 16:26:22]

*** Submitted as https://code.google.com/p/go/source/detail?r=163d528e7436 ***

runtime: does not report duplicate errors in netpoll
Prevents storm of error messages if something goes wrong.
In the case of issue 5073 the epoll fd was closed by the test.
Update issue 5073.

R=golang-dev, r, rsc
CC=golang-dev
https://codereview.appspot.com/7966043