On Fri, 8 May 2020 02:26:21 +0000 "Zhang, Chen" wrote: > > -----Original Message----- > > From: Lukas Straub > > Sent: Thursday, May 7, 2020 11:54 PM > > To: Zhang, Chen > > Cc: qemu-devel ; Li Zhijian > > ; Jason Wang ; Marc- > > André Lureau ; Paolo Bonzini > > > > Subject: Re: [PATCH v4 5/6] net/colo-compare.c, softmmu/vl.c: Check that > > colo-compare is active > > > > On Thu, 7 May 2020 11:38:04 +0000 > > "Zhang, Chen" wrote: > > > > > > -----Original Message----- > > > > From: Lukas Straub > > > > Sent: Monday, May 4, 2020 6:28 PM > > > > To: qemu-devel > > > > Cc: Zhang, Chen ; Li Zhijian > > > > ; Jason Wang ; Marc- > > > > André Lureau ; Paolo Bonzini > > > > > > > > Subject: [PATCH v4 5/6] net/colo-compare.c, softmmu/vl.c: Check that > > > > colo- compare is active > > > > > > > > If the colo-compare object is removed before failover and a > > > > checkpoint happens, qemu crashes because it tries to lock the > > > > destroyed event_mtx in colo_notify_compares_event. > > > > > > > > Fix this by checking if everything is initialized by introducing a > > > > new variable colo_compare_active which is protected by a new mutex > > > > colo_compare_mutex. The new mutex also protects against concurrent > > > > access of the net_compares list and makes sure that > > > > colo_notify_compares_event isn't active while we destroy event_mtx > > > > and event_complete_cond. > > > > > > > > With this it also is again possible to use colo without colo-compare > > > > (periodic > > > > mode) and to use multiple colo-compare for multiple network interfaces. > > > > > > > > > > Hi Lukas, > > > > > > For this case I think we don't need to touch vl.c code, we can solve this > > issue from another perspective: > > > How to remove colo-compare? > > > User will use qemu-monitor or QMP command to disable an object, so we > > > just need return operation failed When user try to remove colo-compare > > object while COLO is running. > > > > Yeah, but that still leaves the other problem that colo can't be used without > > colo-compare (qemu crashes then). > > Yes, the COLO-compare is necessary module in COLO original design. > At most cases, user need it do dynamic sync. > For rare cases, maybe we can add a new colo-compare parameter to bypass all the network workload. I think such an parameter would only be a workaround instead of a real solution like this patch. Regards, Lukas Straub > Thanks > Zhang Chen > > > > > Regards, > > Lukas Straub > > > > > Thanks > > > Zhang Chen > > > > > > > Signed-off-by: Lukas Straub > > > > --- > > > > net/colo-compare.c | 35 +++++++++++++++++++++++++++++------ > > > > net/colo-compare.h | 1 + > > > > softmmu/vl.c | 2 ++ > > > > 3 files changed, 32 insertions(+), 6 deletions(-) > > > > > > > > diff --git a/net/colo-compare.c b/net/colo-compare.c index > > > > 56db3d3bfc..c7572d75e9 100644 > > > > --- a/net/colo-compare.c > > > > +++ b/net/colo-compare.c > > > > @@ -54,6 +54,8 @@ static NotifierList colo_compare_notifiers = > > > > #define REGULAR_PACKET_CHECK_MS 3000 #define > > DEFAULT_TIME_OUT_MS > > > > 3000 > > > > > > > > +static QemuMutex colo_compare_mutex; static bool > > > > +colo_compare_active; > > > > static QemuMutex event_mtx; > > > > static QemuCond event_complete_cond; static int > > > > event_unhandled_count; @@ -906,6 +908,12 @@ static void > > > > check_old_packet_regular(void *opaque) void > > > > colo_notify_compares_event(void *opaque, int event, Error **errp) { > > > > CompareState *s; > > > > + qemu_mutex_lock(&colo_compare_mutex); > > > > + > > > > + if (!colo_compare_active) { > > > > + qemu_mutex_unlock(&colo_compare_mutex); > > > > + return; > > > > + } > > > > > > > > qemu_mutex_lock(&event_mtx); > > > > QTAILQ_FOREACH(s, &net_compares, next) { @@ -919,6 +927,7 @@ > > > > void colo_notify_compares_event(void *opaque, int event, Error **errp) > > > > } > > > > > > > > qemu_mutex_unlock(&event_mtx); > > > > + qemu_mutex_unlock(&colo_compare_mutex); > > > > } > > > > > > > > static void colo_compare_timer_init(CompareState *s) @@ -1274,7 > > > > +1283,14 @@ static void colo_compare_complete(UserCreatable *uc, > > Error **errp) > > > > s->vnet_hdr); > > > > } > > > > > > > > + qemu_mutex_lock(&colo_compare_mutex); > > > > + if (!colo_compare_active) { > > > > + qemu_mutex_init(&event_mtx); > > > > + qemu_cond_init(&event_complete_cond); > > > > + colo_compare_active = true; > > > > + } > > > > QTAILQ_INSERT_TAIL(&net_compares, s, next); > > > > + qemu_mutex_unlock(&colo_compare_mutex); > > > > > > > > s->out_sendco.s = s; > > > > s->out_sendco.chr = &s->chr_out; @@ -1290,9 +1306,6 @@ static > > > > void colo_compare_complete(UserCreatable > > > > *uc, Error **errp) > > > > > > > > g_queue_init(&s->conn_list); > > > > > > > > - qemu_mutex_init(&event_mtx); > > > > - qemu_cond_init(&event_complete_cond); > > > > - > > > > s->connection_track_table = > > > > g_hash_table_new_full(connection_key_hash, > > > > connection_key_equal, > > > > g_free, @@ > > > > -1384,12 +1397,19 @@ static void colo_compare_finalize(Object *obj) > > > > > > > > qemu_bh_delete(s->event_bh); > > > > > > > > + qemu_mutex_lock(&colo_compare_mutex); > > > > QTAILQ_FOREACH(tmp, &net_compares, next) { > > > > if (tmp == s) { > > > > QTAILQ_REMOVE(&net_compares, s, next); > > > > break; > > > > } > > > > } > > > > + if (QTAILQ_EMPTY(&net_compares)) { > > > > + colo_compare_active = false; > > > > + qemu_mutex_destroy(&event_mtx); > > > > + qemu_cond_destroy(&event_complete_cond); > > > > + } > > > > + qemu_mutex_unlock(&colo_compare_mutex); > > > > > > > > AioContext *ctx = iothread_get_aio_context(s->iothread); > > > > aio_context_acquire(ctx); > > > > @@ -1413,15 +1433,18 @@ static void colo_compare_finalize(Object *obj) > > > > object_unref(OBJECT(s->iothread)); > > > > } > > > > > > > > - qemu_mutex_destroy(&event_mtx); > > > > - qemu_cond_destroy(&event_complete_cond); > > > > - > > > > g_free(s->pri_indev); > > > > g_free(s->sec_indev); > > > > g_free(s->outdev); > > > > g_free(s->notify_dev); > > > > } > > > > > > > > +void colo_compare_init_globals(void) { > > > > + colo_compare_active = false; > > > > + qemu_mutex_init(&colo_compare_mutex); > > > > +} > > > > + > > > > static const TypeInfo colo_compare_info = { > > > > .name = TYPE_COLO_COMPARE, > > > > .parent = TYPE_OBJECT, > > > > diff --git a/net/colo-compare.h b/net/colo-compare.h index > > > > 22ddd512e2..eb483ac586 100644 > > > > --- a/net/colo-compare.h > > > > +++ b/net/colo-compare.h > > > > @@ -17,6 +17,7 @@ > > > > #ifndef QEMU_COLO_COMPARE_H > > > > #define QEMU_COLO_COMPARE_H > > > > > > > > +void colo_compare_init_globals(void); > > > > void colo_notify_compares_event(void *opaque, int event, Error > > > > **errp); void colo_compare_register_notifier(Notifier *notify); > > > > void colo_compare_unregister_notifier(Notifier *notify); diff --git > > > > a/softmmu/vl.c b/softmmu/vl.c index 32c0047889..a913ed5469 100644 > > > > --- a/softmmu/vl.c > > > > +++ b/softmmu/vl.c > > > > @@ -112,6 +112,7 @@ > > > > #include "qapi/qmp/qerror.h" > > > > #include "sysemu/iothread.h" > > > > #include "qemu/guest-random.h" > > > > +#include "net/colo-compare.h" > > > > > > > > #define MAX_VIRTIO_CONSOLES 1 > > > > > > > > @@ -2906,6 +2907,7 @@ void qemu_init(int argc, char **argv, char > > **envp) > > > > precopy_infrastructure_init(); > > > > postcopy_infrastructure_init(); > > > > monitor_init_globals(); > > > > + colo_compare_init_globals(); > > > > > > > > if (qcrypto_init(&err) < 0) { > > > > error_reportf_err(err, "cannot initialize crypto: "); > > > > -- > > > > 2.20.1 > > > >