Re: [PATCH] x86_64: fix delayed signals

Török Edwin
2008-07-11T11:14:03Z

On 2008-07-11 08:46, Ingo Molnar wrote:
> * Roland McGrath <roland@redhat.com> wrote:
>
>
>> On three of the several paths in entry_64.S that call
>> do_notify_resume() on the way back to user mode, we fail to properly
>> check again for newly-arrived work that requires another call to
>> do_notify_resume() before going to user mode. These paths set the
>> mask to check only _TIF_NEED_RESCHED, but this is wrong. The other
>> paths that lead to do_notify_resume() do this correctly already, and
>> entry_32.S does it correctly in all cases.
>>
>
> nice find! Roland, is this related to the thread started by Elias
> Oltmanns yesterday:
>
> http://lkml.org/lkml/2008/7/10/57
>

I will try to get a latency trace using the debug features in
linux-next, but first
I have to bisect a boot failure in linux-next.

> which is also related to the thread started by Edwin Török:
>
> http://lkml.org/lkml/2008/6/28/50
>
> ? The weight of complains seems to be on the 64-bit side, in those
> threads 32-bit systems seem to be implicated as well by latencytop.
> Perhaps the 64-bit delays are related to the bug you fix and we could
> chalk up the 32-bit delays to IO delays?
>
> more people Cc:-ed: if your delays happen on 64-bit x86 systems - does
> Roland's patch (also repeated below) fix those delay issues?
>
>

Thanks for CC-ing me.
I will give the patch a try.

Best regards,
--Edwin