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authorJuan Quintela <quintela@redhat.com>2012-09-21 11:18:18 +0200
committerJuan Quintela <quintela@redhat.com>2012-12-20 23:09:25 +0100
commite4ed1541ac9413eac494a03532e34beaf8a7d1c5 (patch)
tree38a01a9697455a8e8f376372cbf9557513f118f5 /savevm.c
parentf50b4986b261fc10065289d2a03deba24d824988 (diff)
downloadqemu-arm-e4ed1541ac9413eac494a03532e34beaf8a7d1c5.tar.gz
savevm: New save live migration method: pending
Code just now does (simplified for clarity) if (qemu_savevm_state_iterate(s->file) == 1) { vm_stop_force_state(RUN_STATE_FINISH_MIGRATE); qemu_savevm_state_complete(s->file); } Problem here is that qemu_savevm_state_iterate() returns 1 when it knows that remaining memory to sent takes less than max downtime. But this means that we could end spending 2x max_downtime, one downtime in qemu_savevm_iterate, and the other in qemu_savevm_state_complete. Changed code to: pending_size = qemu_savevm_state_pending(s->file, max_size); DPRINTF("pending size %lu max %lu\n", pending_size, max_size); if (pending_size >= max_size) { ret = qemu_savevm_state_iterate(s->file); } else { vm_stop_force_state(RUN_STATE_FINISH_MIGRATE); qemu_savevm_state_complete(s->file); } So what we do is: at current network speed, we calculate the maximum number of bytes we can sent: max_size. Then we ask every save_live section how much they have pending. If they are less than max_size, we move to complete phase, otherwise we do an iterate one. This makes things much simpler, because now individual sections don't have to caluclate the bandwidth (it was implossible to do right from there). Signed-off-by: Juan Quintela <quintela@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'savevm.c')
-rw-r--r--savevm.c19
1 files changed, 19 insertions, 0 deletions
diff --git a/savevm.c b/savevm.c
index c93d0b4fde..bcdb92ee81 100644
--- a/savevm.c
+++ b/savevm.c
@@ -1753,6 +1753,25 @@ int qemu_savevm_state_complete(QEMUFile *f)
return qemu_file_get_error(f);
}
+uint64_t qemu_savevm_state_pending(QEMUFile *f, uint64_t max_size)
+{
+ SaveStateEntry *se;
+ uint64_t ret = 0;
+
+ QTAILQ_FOREACH(se, &savevm_handlers, entry) {
+ if (!se->ops || !se->ops->save_live_pending) {
+ continue;
+ }
+ if (se->ops && se->ops->is_active) {
+ if (!se->ops->is_active(se->opaque)) {
+ continue;
+ }
+ }
+ ret += se->ops->save_live_pending(f, se->opaque, max_size);
+ }
+ return ret;
+}
+
void qemu_savevm_state_cancel(QEMUFile *f)
{
SaveStateEntry *se;