From ecb23efea0899be6723f4ea9636de5cf7de90cfe Mon Sep 17 00:00:00 2001 From: Andrey Gruzdev Date: Thu, 1 Apr 2021 12:22:23 +0300 Subject: [PATCH] migration: Fix missing qemu_fflush() on buffer file in bg_migration_thread 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 Message-Id: <20210401092226.102804-2-andrey.gruzdev@virtuozzo.com> Reviewed-by: Dr. David Alan Gilbert Signed-off-by: Dr. David Alan Gilbert --- 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;