[RFC,13/17] COLO ctl: implement colo save

Commit Message

Yang Hongyang July 23, 2014, 2:25 p.m. UTC

implement colo save

Signed-off-by: Yang Hongyang <[e-mail]>
---
 migration-colo.c | 44 ++++++++++++++++++++++++++++++++++++++------
 1 file changed, 38 insertions(+), 6 deletions(-)

Comments

Dr. David Alan Gilbert Aug. 1, 2014, 3:07 p.m. UTC | #1

* Yang Hongyang ([e-mail]) wrote:
> implement colo save

My postcopy 'QEMU_VM_CMD_PACKAGED' does something similar to
parts of this with the QEMUSizedBuffer, we might be able to share some more:
https://lists.nongnu.org/archive/html/qemu-devel/2014-07/msg00886.html

> +    /* we send the total size of the vmstate first */
> +    ret = colo_ctl_put(s->file, colo_buffer.used);
> +    if (ret) {
> +        goto out;
> +    }
> +
> +    qemu_put_buffer_async(s->file, colo_buffer.data, colo_buffer.used);
> +    ret = qemu_file_get_error(s->file);
> +    if (ret < 0) {
> +        goto out;
> +    }
> +    qemu_fflush(s->file);

Is there a reason to use _async here?  I thought the only gain is
if you were going to do other writes in the shadow of the async, with the fflush
immediately after I'm not sure it helps.

Dave

>  
>      ret = colo_ctl_get(control, COLO_CHECKPOINT_RECEIVED);
>      if (ret) {
>          goto out;
>      }
>  
> -    /* TODO: Flush network etc. */
> +    /* Flush network etc. */
> +    colo_compare_flush();
>  
>      ret = colo_ctl_get(control, COLO_CHECKPOINT_LOADED);
>      if (ret) {
>          goto out;
>      }
>  
> -    /* TODO: resume master */
> +    colo_compare_resume();
> +    ret = 0;
>  
>  out:
> +    /* resume master */
> +    qemu_mutex_lock_iothread();
> +    vm_start();
> +    qemu_mutex_unlock_iothread();
> +
>      return ret;
>  }
>  
> -- 
> 1.9.1
> 
--
Dr. David Alan Gilbert / [e-mail] / Manchester, UK
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Patch

diff --git a/migration-colo.c b/migration-colo.c
index a708872..03ac157 100644
--- a/migration-colo.c
+++ b/migration-colo.c
@@ -14,6 +14,7 @@ 
 #include "qemu/error-report.h"
 #include "hw/qdev-core.h"
 #include "qemu/timer.h"
+#include "sysemu/sysemu.h"
 #include "migration/migration-colo.h"
 #include <sys/ioctl.h>
 
@@ -106,12 +107,12 @@  static int colo_compare(void)
     return ioctl(comp_fd, COMP_IOCTWAIT, 250);
 }
 
-static __attribute__((unused)) int colo_compare_flush(void)
+static int colo_compare_flush(void)
 {
     return ioctl(comp_fd, COMP_IOCTFLUSH, 1);
 }
 
-static __attribute__((unused)) int colo_compare_resume(void)
+static int colo_compare_resume(void)
 {
     return ioctl(comp_fd, COMP_IOCTRESUME, 1);
 }
@@ -315,30 +316,61 @@  static int do_colo_transaction(MigrationState *s, QEMUFile *control,
         goto out;
     }
 
-    /* TODO: suspend and save vm state to colo buffer */
+    /* suspend and save vm state to colo buffer */
+
+    qemu_mutex_lock_iothread();
+    vm_stop_force_state(RUN_STATE_COLO);
+    qemu_mutex_unlock_iothread();
+    /* Disable block migration */
+    s->params.blk = 0;
+    s->params.shared = 0;
+    qemu_savevm_state_begin(trans, &s->params);
+    qemu_savevm_state_complete(trans);
+
+    qemu_fflush(trans);
 
     ret = colo_ctl_put(s->file, COLO_CHECKPOINT_SEND);
     if (ret) {
         goto out;
     }
 
-    /* TODO: send vmstate to slave */
+    /* send vmstate to slave */
+
+    /* we send the total size of the vmstate first */
+    ret = colo_ctl_put(s->file, colo_buffer.used);
+    if (ret) {
+        goto out;
+    }
+
+    qemu_put_buffer_async(s->file, colo_buffer.data, colo_buffer.used);
+    ret = qemu_file_get_error(s->file);
+    if (ret < 0) {
+        goto out;
+    }
+    qemu_fflush(s->file);
 
     ret = colo_ctl_get(control, COLO_CHECKPOINT_RECEIVED);
     if (ret) {
         goto out;
     }
 
-    /* TODO: Flush network etc. */
+    /* Flush network etc. */
+    colo_compare_flush();
 
     ret = colo_ctl_get(control, COLO_CHECKPOINT_LOADED);
     if (ret) {
         goto out;
     }
 
-    /* TODO: resume master */
+    colo_compare_resume();
+    ret = 0;
 
 out:
+    /* resume master */
+    qemu_mutex_lock_iothread();
+    vm_start();
+    qemu_mutex_unlock_iothread();
+
     return ret;
 }