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SubjectRe: linux-next: Tree for Jun 28 [ BISECTED: rsyslog/imklog: High CPU usage ]
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On Sun, Jun 30, 2013 at 8:19 PM, Oleg Nesterov <oleg@redhat.com> wrote:
> Andrew, please drop these
>
> wait-introduce-wait_event_commonwq-condition-state-timeout.patch
> wait-introduce-prepare_to_wait_event.patch
>
> patches again. I'll send v3 although it really looks like I should
> never try to touch wait.h.
>
> On 06/29, Sedat Dilek wrote:
>>
>> As this all did not show me what caused the problem I started a
>> git-bisect session.
>>
>> This revealed the following culprit commit:
>>
>> commit bb1f30cb7d3ba21098f0ee7e0382160ba2599a43
>> "wait: introduce wait_event_common(wq, condition, state, timeout)"
>
> Heh. First of all, I am really sorry.
>
> Not only "__wait_no_timeout(tout) ?:" was wrong, I didn't bother
> to recheck this logic even after I got the "warning: the omitted
> middle operand in ?:" reports.
>
> Sedat, thanks you very much! Any chance you can try the patch below?
>

Thanks for the quick fix!

No worries. Good we catched the issue, now.

Yupp, the patch fixes the issue here.

Please, send a patch against reported tree (here: next-20130628) next time.
( Attached is the one which applied here. )

I have zero clue about that "tout-tout" and "?" but you should keep
coding-style within your patch?
...
+ __ret = __wait_no_timeout(tout) ? 0 : \
+ (__tout ?: 1);
\ <--- ((__tout) ?: 1) like below ((tout) ?: 1)
...
+ __ret = __wait_no_timeout(tout) ? 0 : ((tout) ?: 1); \

Feel free to give credits :-).

- Sedat -

> Oleg.
>
>
> --- a/include/linux/wait.h
> +++ b/include/linux/wait.h
> @@ -191,12 +191,8 @@ wait_queue_head_t *bit_waitqueue(void *, int);
> for (;;) { \
> __ret = prepare_to_wait_event(&wq, &__wait, state); \
> if (condition) { \
> - __ret = __wait_no_timeout(tout); \
> - if (!__ret) { \
> - __ret = __tout; \
> - if (!__ret) \
> - __ret = 1; \
> - } \
> + __ret = __wait_no_timeout(tout) ? 0 : \
> + (__tout ?: 1); \
> break; \
> } \
> \
> @@ -217,16 +213,10 @@ wait_queue_head_t *bit_waitqueue(void *, int);
> #define wait_event_common(wq, condition, state, tout) \
> ({ \
> long __ret; \
> - if (condition) { \
> - __ret = __wait_no_timeout(tout); \
> - if (!__ret) { \
> - __ret = tout; \
> - if (!__ret) \
> - __ret = 1; \
> - } \
> - } else { \
> + if (condition) \
> + __ret = __wait_no_timeout(tout) ? 0 : ((tout) ?: 1); \
> + else \
> __ret = __wait_event_common(wq, condition, state, tout);\
> - } \
> __ret; \
> })
>
>
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