On 04/10/2018 07:49 AM, Peter Xu wrote: > cur_mon was only used in main loop so we don't really need that to be > per-thread variable. Now it's possible that we have more than one > thread to operate on it. Let's start to let it be per-thread variable. > > In case we'll create threads within a valid cur_mon setup, we'd better > let the child threads to inherit the cur_mon from parent thread too. Do > that for both posix and win32 threads. > > Signed-off-by: Peter Xu <pet...@redhat.com> > --- > include/monitor/monitor.h | 2 +- > include/qemu/thread-win32.h | 1 + > monitor.c | 2 +- > stubs/monitor.c | 2 +- > tests/test-util-sockets.c | 2 +- > util/qemu-thread-posix.c | 6 ++++++ > util/qemu-thread-win32.c | 6 ++++++ > 7 files changed, 17 insertions(+), 4 deletions(-) >
> @@ -494,6 +496,9 @@ static void *qemu_thread_start(void *args) > void *(*start_routine)(void *) = qemu_thread_args->start_routine; > void *arg = qemu_thread_args->arg; > > + /* Inherit the cur_mon pointer from father thread */ More typical as s/father/parent/ > +++ b/util/qemu-thread-win32.c > @@ -339,6 +341,9 @@ static unsigned __stdcall win32_start_routine(void *arg) > void *(*start_routine)(void *) = data->start_routine; > void *thread_arg = data->arg; > > + /* Inherit the cur_mon pointer from father thread */ > + cur_mon = data->current_monitor; Otherwise makes sense to me. I agree with your analysis that the set of existing OOB commands (just 'x-oob-test') has no direct use of cur_mon. I'm a little fuzzier on whether the OOB changes can cause cur_mon to be modified by two threads in parallel (monitor_qmp_dispatch_one() is futzing around with 'cur_mon' around the call to qmp_dispatch(), and at least qmp_human_monitor_command() is also futzing around with it; is there a case where handling qmp_human_monitor_command() in the dispatch thread in parallel with more input on the main thread could break?) Thus I'm not sure whether this is needed for 2.12 to avoid a regression. -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.org
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