qom/object: update class cache atomically
commitb6b3ccfda015dcd5ab50f70c189ee5cc6c622e91
authorAlex Bennée <alex.bennee@linaro.org>
Fri, 30 Sep 2016 21:30:57 +0000 (30 22:30 +0100)
committerPaolo Bonzini <pbonzini@redhat.com>
Tue, 4 Oct 2016 08:00:26 +0000 (4 10:00 +0200)
treeddd09714020bda3ea47d837ca64fbc0d23f04265
parentf96a8cc3c633b25d9269337408ae2417ebbbad8e
qom/object: update class cache atomically

The idiom CPU_GET_CLASS(cpu) is fairly extensively used in various
threads and trips of ThreadSanitizer due to the fact it updates
obj->class->object_cast_cache behind the scenes. As this is just a
fast-path cache there is no need to lock updates.

However to ensure defined C11 behaviour across threads we need to use
the plain atomic_read/set primitives and keep the sanitizer happy.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20160930213106.20186-7-alex.bennee@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
qom/object.c