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Re: [libvirt] PATCH: 2/4: Interrupt main thread if in poll()



On Mon, May 11, 2009 at 12:17:23PM +0100, Daniel P. Berrange wrote:
> Several methods forgot to call virEventInterruptLocked() in critical
> times, or called it at the wrong point. This fixes that problem.
> 
> It also changes watch and timer numbers to start from 1, instead of 0.
> This is because we've had a number of bugs where code has passed an
> uninitialized timer/watch ID to an update/delete method, and this has
> resulted in deleting a real important timer/watch. Changing to start
> from 1, and logging invalid watches will protect us from uninitialized
> watches/timers.

  Sounds good !


>      virEventLock();
>      for (i = 0 ; i < eventLoop.handlesCount ; i++) {
>          if (eventLoop.handles[i].watch == watch) {
>              eventLoop.handles[i].events =
>                      virEventHandleTypeToPollEvent(events);
> +            virEventInterruptLocked();
>              break;
>          }
>      }
> -    virEventInterruptLocked();
>      virEventUnlock();
>  }

  Okay so basically the core of the patch is to lock as soon as we match
  and not once out of the loop

> @@ -172,11 +185,11 @@ int virEventRemoveHandleImpl(int watch) 
>          if (eventLoop.handles[i].watch == watch) {
>              EVENT_DEBUG("mark delete %d %d", i, eventLoop.handles[i].fd);
>              eventLoop.handles[i].deleted = 1;
> +            virEventInterruptLocked();
>              virEventUnlock();
>              return 0;
>          }
>      }
> -    virEventInterruptLocked();
>      virEventUnlock();
>      return -1;
>  }

  same here

> @@ -244,10 +263,10 @@ void virEventUpdateTimeoutImpl(int timer
>                  frequency >= 0 ? frequency +
>                  (((unsigned long long)tv.tv_sec)*1000) +
>                  (((unsigned long long)tv.tv_usec)/1000) : 0;
> +            virEventInterruptLocked();
>              break;
>          }
>      }
> -    virEventInterruptLocked();
>      virEventUnlock();
>  }

  and here

> @@ -267,11 +292,11 @@ int virEventRemoveTimeoutImpl(int timer)
>  
>          if (eventLoop.timeouts[i].timer == timer) {
>              eventLoop.timeouts[i].deleted = 1;
> +            virEventInterruptLocked();
>              virEventUnlock();
>              return 0;
>          }
>      }
> -    virEventInterruptLocked();
>      virEventUnlock();
>      return -1;
>  }

   and here. I assume the problem were on imbricated loops.

  Patch looks fine, ACK, and an important fix !

Daniel

-- 
Daniel Veillard      | libxml Gnome XML XSLT toolkit  http://xmlsoft.org/
daniel veillard com  | Rpmfind RPM search engine http://rpmfind.net/
http://veillard.com/ | virtualization library  http://libvirt.org/


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