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From: "Dr. David Alan Gilbert (git)" <dgilbert@redhat.com>
To: qemu-devel@nongnu.org, andrey.gruzdev@virtuozzo.com,
	huangy81@chinatelecom.cn
Subject: [PULL 2/6] migration: Fix missing qemu_fflush() on buffer file in bg_migration_thread
Date: Wed,  7 Apr 2021 11:20:17 +0100	[thread overview]
Message-ID: <20210407102021.95225-3-dgilbert@redhat.com> (raw)
In-Reply-To: <20210407102021.95225-1-dgilbert@redhat.com>

From: Andrey Gruzdev <andrey.gruzdev@virtuozzo.com>

Added missing qemu_fflush() on buffer file holding precopy device state.
Increased initial QIOChannelBuffer allocation to 512KB to avoid reallocs.
Typical configurations often require >200KB for device state and VMDESC.

Fixes: 8518278a6af589ccc401f06e35f171b1e6fae800 (migration: implementation
  of background snapshot thread)
Signed-off-by: Andrey Gruzdev <andrey.gruzdev@virtuozzo.com>
Message-Id: <20210401092226.102804-2-andrey.gruzdev@virtuozzo.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
---
 migration/migration.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/migration/migration.c b/migration/migration.c
index ca8b97baa5..00e13f9d58 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -3812,7 +3812,7 @@ static void *bg_migration_thread(void *opaque)
      * with vCPUs running and, finally, write stashed non-RAM part of
      * the vmstate from the buffer to the migration stream.
      */
-    s->bioc = qio_channel_buffer_new(128 * 1024);
+    s->bioc = qio_channel_buffer_new(512 * 1024);
     qio_channel_set_name(QIO_CHANNEL(s->bioc), "vmstate-buffer");
     fb = qemu_fopen_channel_output(QIO_CHANNEL(s->bioc));
     object_unref(OBJECT(s->bioc));
@@ -3866,6 +3866,12 @@ static void *bg_migration_thread(void *opaque)
     if (qemu_savevm_state_complete_precopy_non_iterable(fb, false, false)) {
         goto fail;
     }
+    /*
+     * Since we are going to get non-iterable state data directly
+     * from s->bioc->data, explicit flush is needed here.
+     */
+    qemu_fflush(fb);
+
     /* Now initialize UFFD context and start tracking RAM writes */
     if (ram_write_tracking_start()) {
         goto fail;
-- 
2.31.1



  parent reply	other threads:[~2021-04-07 10:27 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-07 10:20 [PULL 0/6] migration + virtiofsd queue Dr. David Alan Gilbert (git)
2021-04-07 10:20 ` [PULL 1/6] virtiofsd: Fix security.capability comparison Dr. David Alan Gilbert (git)
2021-04-07 10:20 ` Dr. David Alan Gilbert (git) [this message]
2021-04-07 10:20 ` [PULL 3/6] migration: Inhibit virtio-balloon for the duration of background snapshot Dr. David Alan Gilbert (git)
2021-04-07 10:20 ` [PULL 4/6] migration: Pre-fault memory before starting background snasphot Dr. David Alan Gilbert (git)
2021-04-07 10:20 ` [PULL 5/6] migration: Rename 'bs' to 'block' in background snapshot code Dr. David Alan Gilbert (git)
2021-04-07 10:20 ` [PULL 6/6] tests/migration: fix parameter of auto-converge migration Dr. David Alan Gilbert (git)
2021-04-07 13:25 ` [PULL 0/6] migration + virtiofsd queue Peter Maydell
2021-04-07 16:50   ` Dr. David Alan Gilbert
2021-04-08  9:16     ` Andrey Gruzdev
2021-04-08 10:50       ` Dr. David Alan Gilbert
2021-04-08 12:27         ` Andrey Gruzdev
2021-04-07 17:54 [PULL 0/6] V2 " Dr. David Alan Gilbert (git)
2021-04-07 17:54 ` [PULL 2/6] migration: Fix missing qemu_fflush() on buffer file in bg_migration_thread Dr. David Alan Gilbert (git)

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