memory: switch memory listeners to a QTAILQ
This allows reverse iteration, which in turns allows consistent ordering
among multiple listeners:
l1->add
l2->add
l2->del
l1->del
Signed-off-by: Avi Kivity <avi@redhat.com>
Reviewed-by: Richard Henderson <rth@twiddle.net>
diff --git a/hw/vhost.c b/hw/vhost.c
index 5ece659..4737145 100644
--- a/hw/vhost.c
+++ b/hw/vhost.c
@@ -751,6 +751,7 @@
.log_sync = vhost_log_sync,
.log_global_start = vhost_log_global_start,
.log_global_stop = vhost_log_global_stop,
+ .priority = 10
};
hdev->mem = g_malloc0(offsetof(struct vhost_memory, regions));
hdev->n_mem_sections = 0;
diff --git a/kvm-all.c b/kvm-all.c
index 0b87658..6835fd4 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -726,6 +726,7 @@
.log_sync = kvm_log_sync,
.log_global_start = kvm_log_global_start,
.log_global_stop = kvm_log_global_stop,
+ .priority = 10,
};
static void kvm_handle_interrupt(CPUState *env, int mask)
diff --git a/memory.c b/memory.c
index 570125c..a8fb39e 100644
--- a/memory.c
+++ b/memory.c
@@ -27,8 +27,8 @@
static bool memory_region_update_pending = false;
static bool global_dirty_log = false;
-static QLIST_HEAD(, MemoryListener) memory_listeners
- = QLIST_HEAD_INITIALIZER(memory_listeners);
+static QTAILQ_HEAD(memory_listeners, MemoryListener) memory_listeners
+ = QTAILQ_HEAD_INITIALIZER(memory_listeners);
typedef struct AddrRange AddrRange;
@@ -678,17 +678,31 @@
as->ioeventfd_nb = ioeventfd_nb;
}
-#define MEMORY_LISTENER_CALL(_callback, _args...) \
- do { \
- MemoryListener *_listener; \
- \
- QLIST_FOREACH(_listener, &memory_listeners, link) { \
- _listener->_callback(_listener, ##_args); \
- } \
+enum ListenerDirection { Forward, Reverse };
+
+#define MEMORY_LISTENER_CALL(_callback, _direction, _args...) \
+ do { \
+ MemoryListener *_listener; \
+ \
+ switch (_direction) { \
+ case Forward: \
+ QTAILQ_FOREACH(_listener, &memory_listeners, link) { \
+ _listener->_callback(_listener, ##_args); \
+ } \
+ break; \
+ case Reverse: \
+ QTAILQ_FOREACH_REVERSE(_listener, &memory_listeners, \
+ memory_listeners, link) { \
+ _listener->_callback(_listener, ##_args); \
+ } \
+ break; \
+ default: \
+ abort(); \
+ } \
} while (0)
-#define MEMORY_LISTENER_UPDATE_REGION(fr, as, callback) \
- MEMORY_LISTENER_CALL(callback, &(MemoryRegionSection) { \
+#define MEMORY_LISTENER_UPDATE_REGION(fr, as, dir, callback) \
+ MEMORY_LISTENER_CALL(callback, dir, &(MemoryRegionSection) { \
.mr = (fr)->mr, \
.address_space = (as)->root, \
.offset_within_region = (fr)->offset_in_region, \
@@ -728,7 +742,7 @@
/* In old, but (not in new, or in new but attributes changed). */
if (!adding) {
- MEMORY_LISTENER_UPDATE_REGION(frold, as, region_del);
+ MEMORY_LISTENER_UPDATE_REGION(frold, as, Reverse, region_del);
as->ops->range_del(as, frold);
}
@@ -738,11 +752,11 @@
if (adding) {
if (frold->dirty_log_mask && !frnew->dirty_log_mask) {
- MEMORY_LISTENER_UPDATE_REGION(frnew, as, log_stop);
+ MEMORY_LISTENER_UPDATE_REGION(frnew, as, Reverse, log_stop);
as->ops->log_stop(as, frnew);
} else if (frnew->dirty_log_mask && !frold->dirty_log_mask) {
as->ops->log_start(as, frnew);
- MEMORY_LISTENER_UPDATE_REGION(frnew, as, log_start);
+ MEMORY_LISTENER_UPDATE_REGION(frnew, as, Forward, log_start);
}
}
@@ -753,7 +767,7 @@
if (adding) {
as->ops->range_add(as, frnew);
- MEMORY_LISTENER_UPDATE_REGION(frnew, as, region_add);
+ MEMORY_LISTENER_UPDATE_REGION(frnew, as, Forward, region_add);
}
++inew;
@@ -1142,7 +1156,8 @@
FOR_EACH_FLAT_RANGE(fr, &address_space_memory.current_map) {
if (fr->mr == mr) {
- MEMORY_LISTENER_UPDATE_REGION(fr, &address_space_memory, log_sync);
+ MEMORY_LISTENER_UPDATE_REGION(fr, &address_space_memory,
+ Forward, log_sync);
}
}
}
@@ -1469,7 +1484,7 @@
FlatRange *fr;
FOR_EACH_FLAT_RANGE(fr, &as->current_map) {
- MEMORY_LISTENER_UPDATE_REGION(fr, as, log_sync);
+ MEMORY_LISTENER_UPDATE_REGION(fr, as, Forward, log_sync);
}
}
@@ -1477,13 +1492,13 @@
{
cpu_physical_memory_set_dirty_tracking(1);
global_dirty_log = true;
- MEMORY_LISTENER_CALL(log_global_start);
+ MEMORY_LISTENER_CALL(log_global_start, Forward);
}
void memory_global_dirty_log_stop(void)
{
global_dirty_log = false;
- MEMORY_LISTENER_CALL(log_global_stop);
+ MEMORY_LISTENER_CALL(log_global_stop, Reverse);
cpu_physical_memory_set_dirty_tracking(0);
}
@@ -1509,14 +1524,27 @@
void memory_listener_register(MemoryListener *listener)
{
- QLIST_INSERT_HEAD(&memory_listeners, listener, link);
+ MemoryListener *other = NULL;
+
+ if (QTAILQ_EMPTY(&memory_listeners)
+ || listener->priority >= QTAILQ_LAST(&memory_listeners,
+ memory_listeners)->priority) {
+ QTAILQ_INSERT_TAIL(&memory_listeners, listener, link);
+ } else {
+ QTAILQ_FOREACH(other, &memory_listeners, link) {
+ if (listener->priority < other->priority) {
+ break;
+ }
+ }
+ QTAILQ_INSERT_BEFORE(other, listener, link);
+ }
listener_add_address_space(listener, &address_space_memory);
listener_add_address_space(listener, &address_space_io);
}
void memory_listener_unregister(MemoryListener *listener)
{
- QLIST_REMOVE(listener, link);
+ QTAILQ_REMOVE(&memory_listeners, listener, link);
}
void set_system_memory_map(MemoryRegion *mr)
diff --git a/memory.h b/memory.h
index 4763286..954dc86 100644
--- a/memory.h
+++ b/memory.h
@@ -185,7 +185,9 @@
void (*log_sync)(MemoryListener *listener, MemoryRegionSection *section);
void (*log_global_start)(MemoryListener *listener);
void (*log_global_stop)(MemoryListener *listener);
- QLIST_ENTRY(MemoryListener) link;
+ /* Lower = earlier (during add), later (during del) */
+ unsigned priority;
+ QTAILQ_ENTRY(MemoryListener) link;
};
/**
diff --git a/xen-all.c b/xen-all.c
index fd39168..8cb84ef 100644
--- a/xen-all.c
+++ b/xen-all.c
@@ -495,6 +495,7 @@
.log_sync = xen_log_sync,
.log_global_start = xen_log_global_start,
.log_global_stop = xen_log_global_stop,
+ .priority = 10,
};
/* VCPU Operations, MMIO, IO ring ... */
