Marcelo Tosatti wrote: > Hi Anthony, > > How is -no-kvm-irqchip working with the patch? >
Seems to work fine. What is your expectation? > On Tue, Apr 29, 2008 at 09:28:14AM -0500, Anthony Liguori wrote: > >> This patch eliminates the use of sigtimedwait() in the IO thread. To avoid >> the >> signal/select race condition, we use a pipe that we write to in the signal >> handlers. This was suggested by Rusty and seems to work well. >> >> +static int kvm_eat_signal(CPUState *env, int timeout) >> { >> struct timespec ts; >> int r, e, ret = 0; >> siginfo_t siginfo; >> + sigset_t waitset; >> >> + sigemptyset(&waitset); >> + sigaddset(&waitset, SIG_IPI); >> ts.tv_sec = timeout / 1000; >> ts.tv_nsec = (timeout % 1000) * 1000000; >> - r = sigtimedwait(&waitset->sigset, &siginfo, &ts); >> + qemu_kvm_unlock(); >> + r = sigtimedwait(&waitset, &siginfo, &ts); >> + qemu_kvm_lock(env); >> + cpu_single_env = env; >> > > This assignment seems redundant now. > Yeah, I have a bigger patch which eliminates all of the explicit assignments to cpu_single_env. >> >> @@ -263,12 +238,8 @@ static void pause_all_threads(void) >> vcpu_info[i].stop = 1; >> pthread_kill(vcpu_info[i].thread, SIG_IPI); >> > > Make sure the IO thread has SIG_IPI blocked (those are for APIC vcpu > initialization only). > Just so I'm clear, there's really no harm in not blocking SIG_IPI because it would just be ignored by the IO thread (since the SIG_IPI handler is a nop). But yeah, we should explicitly block it. >> +static void sig_aio_fd_read(void *opaque) >> +{ >> + int signum; >> + ssize_t len; >> + >> + do { >> + len = read(kvm_sigfd[0], &signum, sizeof(signum)); >> + } while (len == -1 && errno == EINTR); >> > > 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. >> + signal(SIGUSR1, sig_aio_handler); >> + signal(SIGUSR2, sig_aio_handler); >> + signal(SIGALRM, sig_aio_handler); >> + signal(SIGIO, sig_aio_handler); >> + >> + if (pipe(kvm_sigfd) == -1) >> + abort(); >> > > perror() would be nice. > Yeah, everything needs proper error handling. >> - 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. Regards, Anthony Liguori > Similarly in qemu_kvm_aio_wait(). > > ------------------------------------------------------------------------- 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 _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel