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fix dirty-bitmap state migration freeze 

The idea in general is to migrate all the state, which is small for
us, in a single step once. But, QEMU only calls save state if we
return active true.

Hardcoding is-active to return true, like done initially, makes the
migration freeze, as QEMU thinks this is never done, and only stops
calling us and finishes after a few seconds.

So, add a state with an "active" boolean, set to true when
initializing a migration, and set it to false when the state was
saved.

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
master
Thomas Lamprecht 2020-11-05 18:43:01 +01:00
parent 2130e925a8
commit 66eae0ae75
1 changed files with 17 additions and 12 deletions
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29
debian/patches/pve/0055-PVE-Migrate-dirty-bitmap-state-via-savevm.patch vendored
View File

@ -15,11 +15,11 @@ Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>
---
include/migration/misc.h | 3 ++
migration/Makefile.objs | 1 +
migration/pbs-state.c | 92 ++++++++++++++++++++++++++++++++++++++++
migration/pbs-state.c | 97 ++++++++++++++++++++++++++++++++++++++++
pve-backup.c | 1 +
qapi/block-core.json | 9 +++-
softmmu/vl.c | 1 +
6 files changed, 106 insertions(+), 1 deletion(-)
6 files changed, 111 insertions(+), 1 deletion(-)
create mode 100644 migration/pbs-state.c
diff --git a/include/migration/misc.h b/include/migration/misc.h
@ -48,10 +48,10 @@ index 0fc619e380..20b3792599 100644
common-obj-$(CONFIG_RDMA) += rdma.o
diff --git a/migration/pbs-state.c b/migration/pbs-state.c
new file mode 100644
index 0000000000..165895b488
index 0000000000..c711498c3e
--- /dev/null
+++ b/migration/pbs-state.c
@@ -0,0 +1,92 @@
@@ -0,0 +1,97 @@
+/*
+ * PBS (dirty-bitmap) state migration
+ */
@ -63,6 +63,12 @@ index 0000000000..165895b488
+#include "migration/register.h"
+#include "proxmox-backup-qemu.h"
+
+typedef struct PBSState {
+ bool active;
+} PBSState;
+
+static PBSState pbs_state;
+
+static void pbs_state_save_pending(QEMUFile *f, void *opaque,
+ uint64_t max_size,
+ uint64_t *res_precopy_only,
@ -70,9 +76,6 @@ index 0000000000..165895b488
+ uint64_t *res_postcopy_only)
+{
+ /* we send everything in save_setup, so nothing is ever pending */
+ *res_precopy_only = 0;
+ *res_compatible = 0;
+ *res_postcopy_only = 0;
+}
+
+/* receive PBS state via f and deserialize, called on target */
@ -106,20 +109,21 @@ index 0000000000..165895b488
+ qemu_put_buffer(f, buf, buf_size);
+
+ proxmox_free_state_buf(buf);
+ pbs_state.active = false;
+ return 0;
+}
+
+static bool pbs_state_is_active(void *opaque)
+{
+ /* always active, i.e. we do our job for every migration, since there's no
+ * harm done if we just copy an empty buffer */
+ return true;
+ // we need to be return active once, else .save_setup is never called, but,
+ // if we'd just would return true, we'd freeze the migration for ~ 5 - 10s
+ return pbs_state.active;
+}
+
+static bool pbs_state_is_active_iterate(void *opaque)
+{
+ /* we don't iterate, everything is sent in save_setup */
+ return false;
+ return pbs_state_is_active(opaque);
+}
+
+static bool pbs_state_has_postcopy(void *opaque)
@ -140,9 +144,10 @@ index 0000000000..165895b488
+
+void pbs_state_mig_init(void)
+{
+ pbs_state.active = true;
+ register_savevm_live("pbs-state", 0, 1,
+ &savevm_pbs_state_handlers,
+ NULL);
+ &pbs_state);
+}
diff --git a/pve-backup.c b/pve-backup.c
index 1a2647e7a5..c12ff8bb61 100644