[PATCH v2] migration: I messed state_pending_exact/estimate

[PATCH v2] migration: I messed state_pending_exact/estimate

[Juan Quintela]

I called the helper function from the wrong top level function.

This code was introduced in:

commit c8df4a7aeffcb46020f610526eea621fa5b0cd47
Author: Juan Quintela <quintela@redhat.com>
Date:   Mon Oct 3 02:00:03 2022 +0200

    migration: Split save_live_pending() into state_pending_*

    We split the function into to:

    - state_pending_estimate: We estimate the remaining state size without
      stopping the machine.

    - state pending_exact: We calculate the exact amount of remaining
      state.

Thanks to Avihai Horon <avihaih@nvidia.com> for finding it.

Signed-off-by: Juan Quintela <quintela@redhat.com>
---
 migration/savevm.c | 50 +++++++++++++++++++++++-----------------------
 1 file changed, 25 insertions(+), 25 deletions(-)

diff --git a/migration/savevm.c b/migration/savevm.c
index e9cf4999ad..ce181e21e1 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -1551,31 +1551,6 @@ void qemu_savevm_state_pending_estimate(uint64_t *res_precopy_only,
     *res_compatible = 0;
     *res_postcopy_only = 0;
 
-    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
-        if (!se->ops || !se->ops->state_pending_exact) {
-            continue;
-        }
-        if (se->ops->is_active) {
-            if (!se->ops->is_active(se->opaque)) {
-                continue;
-            }
-        }
-        se->ops->state_pending_exact(se->opaque,
-                                     res_precopy_only, res_compatible,
-                                     res_postcopy_only);
-    }
-}
-
-void qemu_savevm_state_pending_exact(uint64_t *res_precopy_only,
-                                     uint64_t *res_compatible,
-                                     uint64_t *res_postcopy_only)
-{
-    SaveStateEntry *se;
-
-    *res_precopy_only = 0;
-    *res_compatible = 0;
-    *res_postcopy_only = 0;
-
     QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
         if (!se->ops || !se->ops->state_pending_estimate) {
             continue;
@@ -1591,6 +1566,31 @@ void qemu_savevm_state_pending_exact(uint64_t *res_precopy_only,
     }
 }
 
+void qemu_savevm_state_pending_exact(uint64_t *res_precopy_only,
+                                     uint64_t *res_compatible,
+                                     uint64_t *res_postcopy_only)
+{
+    SaveStateEntry *se;
+
+    *res_precopy_only = 0;
+    *res_compatible = 0;
+    *res_postcopy_only = 0;
+
+    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
+        if (!se->ops || !se->ops->state_pending_exact) {
+            continue;
+        }
+        if (se->ops->is_active) {
+            if (!se->ops->is_active(se->opaque)) {
+                continue;
+            }
+        }
+        se->ops->state_pending_exact(se->opaque,
+                                     res_precopy_only, res_compatible,
+                                     res_postcopy_only);
+    }
+}
+
 void qemu_savevm_state_cleanup(void)
 {
     SaveStateEntry *se;
-- 
2.39.1

Re: [PATCH v2] migration: I messed state_pending_exact/estimate

[Peter Maydell]

On Thu, 9 Feb 2023 at 15:23, Juan Quintela <quintela@redhat.com> wrote:
>
> I called the helper function from the wrong top level function.
>
> This code was introduced in:
>
> commit c8df4a7aeffcb46020f610526eea621fa5b0cd47
> Author: Juan Quintela <quintela@redhat.com>
> Date:   Mon Oct 3 02:00:03 2022 +0200
>
>     migration: Split save_live_pending() into state_pending_*
>
>     We split the function into to:
>
>     - state_pending_estimate: We estimate the remaining state size without
>       stopping the machine.
>
>     - state pending_exact: We calculate the exact amount of remaining
>       state.

Given that this commit has already gone out in a
release, it would be useful to describe in the commit
message what the consequences of the bug are, if any.

A Fixes: line would also record the commit being fixed
in a more easily processable way.

thanks
-- PMM

Re: [PATCH v2] migration: I messed state_pending_exact/estimate

[Dr. David Alan Gilbert]

* Juan Quintela (quintela@redhat.com) wrote:
> I called the helper function from the wrong top level function.

Oops yes; as Peter says, this needs a Fixes: line, bu tother than that.


Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

> This code was introduced in:
> 
> commit c8df4a7aeffcb46020f610526eea621fa5b0cd47
> Author: Juan Quintela <quintela@redhat.com>
> Date:   Mon Oct 3 02:00:03 2022 +0200
> 
>     migration: Split save_live_pending() into state_pending_*
> 
>     We split the function into to:
> 
>     - state_pending_estimate: We estimate the remaining state size without
>       stopping the machine.
> 
>     - state pending_exact: We calculate the exact amount of remaining
>       state.
> 
> Thanks to Avihai Horon <avihaih@nvidia.com> for finding it.
> 
> Signed-off-by: Juan Quintela <quintela@redhat.com>
> ---
>  migration/savevm.c | 50 +++++++++++++++++++++++-----------------------
>  1 file changed, 25 insertions(+), 25 deletions(-)
> 
> diff --git a/migration/savevm.c b/migration/savevm.c
> index e9cf4999ad..ce181e21e1 100644
> --- a/migration/savevm.c
> +++ b/migration/savevm.c
> @@ -1551,31 +1551,6 @@ void qemu_savevm_state_pending_estimate(uint64_t *res_precopy_only,
>      *res_compatible = 0;
>      *res_postcopy_only = 0;
>  
> -    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
> -        if (!se->ops || !se->ops->state_pending_exact) {
> -            continue;
> -        }
> -        if (se->ops->is_active) {
> -            if (!se->ops->is_active(se->opaque)) {
> -                continue;
> -            }
> -        }
> -        se->ops->state_pending_exact(se->opaque,
> -                                     res_precopy_only, res_compatible,
> -                                     res_postcopy_only);
> -    }
> -}
> -
> -void qemu_savevm_state_pending_exact(uint64_t *res_precopy_only,
> -                                     uint64_t *res_compatible,
> -                                     uint64_t *res_postcopy_only)
> -{
> -    SaveStateEntry *se;
> -
> -    *res_precopy_only = 0;
> -    *res_compatible = 0;
> -    *res_postcopy_only = 0;
> -
>      QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
>          if (!se->ops || !se->ops->state_pending_estimate) {
>              continue;
> @@ -1591,6 +1566,31 @@ void qemu_savevm_state_pending_exact(uint64_t *res_precopy_only,
>      }
>  }
>  
> +void qemu_savevm_state_pending_exact(uint64_t *res_precopy_only,
> +                                     uint64_t *res_compatible,
> +                                     uint64_t *res_postcopy_only)
> +{
> +    SaveStateEntry *se;
> +
> +    *res_precopy_only = 0;
> +    *res_compatible = 0;
> +    *res_postcopy_only = 0;
> +
> +    QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
> +        if (!se->ops || !se->ops->state_pending_exact) {
> +            continue;
> +        }
> +        if (se->ops->is_active) {
> +            if (!se->ops->is_active(se->opaque)) {
> +                continue;
> +            }
> +        }
> +        se->ops->state_pending_exact(se->opaque,
> +                                     res_precopy_only, res_compatible,
> +                                     res_postcopy_only);
> +    }
> +}
> +
>  void qemu_savevm_state_cleanup(void)
>  {
>      SaveStateEntry *se;
> -- 
> 2.39.1
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK