[Qemu-devel] [PULL 02/13] migration: Trace improvements

[Amit Shah <amit.shah@redhat.com>]

From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>

A couple of improvements to tracing that have come out of helping
people with migration problems:
  * vmstate_n_elems trace the count/name - for when you have problems
    getting array counts right
  * vmstate_subsection_load_bad - add the idstr, for when you receive a
    subsection you weren't expecting.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <1465896986-16132-1-git-send-email-dgilbert@redhat.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
---
 migration/vmstate.c | 13 +++++++------
 trace-events        |  3 ++-
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/migration/vmstate.c b/migration/vmstate.c
index 46dc55e..fc29acf 100644
--- a/migration/vmstate.c
+++ b/migration/vmstate.c
@@ -32,6 +32,7 @@ static int vmstate_n_elems(void *opaque, VMStateField *field)
         n_elems *= field->num;
     }
 
+    trace_vmstate_n_elems(field->name, n_elems);
     return n_elems;
 }
 
@@ -381,25 +382,25 @@ static int vmstate_subsection_load(QEMUFile *f, const VMStateDescription *vmsd,
         len = qemu_peek_byte(f, 1);
         if (len < strlen(vmsd->name) + 1) {
             /* subsection name has be be "section_name/a" */
-            trace_vmstate_subsection_load_bad(vmsd->name, "(short)");
+            trace_vmstate_subsection_load_bad(vmsd->name, "(short)", "");
             return 0;
         }
         size = qemu_peek_buffer(f, (uint8_t **)&idstr_ret, len, 2);
         if (size != len) {
-            trace_vmstate_subsection_load_bad(vmsd->name, "(peek fail)");
+            trace_vmstate_subsection_load_bad(vmsd->name, "(peek fail)", "");
             return 0;
         }
         memcpy(idstr, idstr_ret, size);
         idstr[size] = 0;
 
         if (strncmp(vmsd->name, idstr, strlen(vmsd->name)) != 0) {
-            trace_vmstate_subsection_load_bad(vmsd->name, idstr);
-            /* it don't have a valid subsection name */
+            trace_vmstate_subsection_load_bad(vmsd->name, idstr, "(prefix)");
+            /* it doesn't have a valid subsection name */
             return 0;
         }
         sub_vmsd = vmstate_get_subsection(vmsd->subsections, idstr);
         if (sub_vmsd == NULL) {
-            trace_vmstate_subsection_load_bad(vmsd->name, "(lookup)");
+            trace_vmstate_subsection_load_bad(vmsd->name, idstr, "(lookup)");
             return -ENOENT;
         }
         qemu_file_skip(f, 1); /* subsection */
@@ -409,7 +410,7 @@ static int vmstate_subsection_load(QEMUFile *f, const VMStateDescription *vmsd,
 
         ret = vmstate_load_state(f, sub_vmsd, opaque, version_id);
         if (ret) {
-            trace_vmstate_subsection_load_bad(vmsd->name, "(child)");
+            trace_vmstate_subsection_load_bad(vmsd->name, idstr, "(child)");
             return ret;
         }
     }
diff --git a/trace-events b/trace-events
index 104b64f..17e901b 100644
--- a/trace-events
+++ b/trace-events
@@ -1271,8 +1271,9 @@ vmstate_load_field_error(const char *field, int ret) "field \"%s\" load failed,
 vmstate_load_state(const char *name, int version_id) "%s v%d"
 vmstate_load_state_end(const char *name, const char *reason, int val) "%s %s/%d"
 vmstate_load_state_field(const char *name, const char *field) "%s:%s"
+vmstate_n_elems(const char *name, int n_elems) "%s: %d"
 vmstate_subsection_load(const char *parent) "%s"
-vmstate_subsection_load_bad(const char *parent,  const char *sub) "%s: %s"
+vmstate_subsection_load_bad(const char *parent,  const char *sub, const char *sub2) "%s: %s/%s"
 vmstate_subsection_load_good(const char *parent) "%s"
 
 # qemu-file.c
-- 
2.7.4