From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: [PATCH][RFC] Use pipe() to simulate signalfd() Date: Tue, 29 Apr 2008 18:15:58 -0500 Message-ID: <4817AC2E.60909@us.ibm.com> References: <1209479294-22325-1-git-send-email-aliguori@us.ibm.com> <20080429223706.GA18006@dmt> <4817A46B.7000302@us.ibm.com> <20080429231313.GA18231@dmt> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel@lists.sourceforge.net, Avi Kivity To: Marcelo Tosatti Return-path: In-Reply-To: <20080429231313.GA18231@dmt> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces@lists.sourceforge.net Errors-To: kvm-devel-bounces@lists.sourceforge.net List-Id: kvm.vger.kernel.org Marcelo Tosatti wrote: > Problem is if the IO thread _receives_ SIGIPI instead of some vcpu > thread. > > So there is potential harm in not blocking it. > Hrm, aren't SIG_IPIs delivered to a particular thread-id though? When would the IO thread receive a SIG_IPI? >>> What is the reason for this loop instead of a straight read? >>> >>> Its alright to be interrupted by a signal. >>> >>> >> Just general habit with QEMU. >> > > Please don't :-) > I don't see the harm. In fact, I think it's more correct. Otherwise, we have to wait for another invocation of the fd callback. >>>> - kvm_eat_signal(&io_signal_table, NULL, 1000); >>>> pthread_mutex_lock(&qemu_mutex); >>>> - cpu_single_env = NULL; >>>> - main_loop_wait(0); >>>> + main_loop_wait(10); >>>> >>>> >>> Increase that 1000 or something. Will make it easier to spot bugs. >>> >>> >> I have actually and it does introduce some bugs. I'm not entirely clear >> what is causing them though. >> > > Should indicate that some event previously delivered through signals and > received by sigtimedwait is not waking up the IO thread. > I'll take a look and see. I'm having time keeping issues in the guest so it's hard to tell what problems are caused by the IO thread verses time. Regards, Anthony Liguori ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Don't miss this year's exciting event. There's still time to save $100. Use priority code J8TL2D2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone