On Wed, May 03, 2017 at 11:42:57AM +0100, Dr. David Alan Gilbert (git) wrote:
A small comment inline, in the 'ifndef' section.
> From: "Dr. David Alan Gilbert" <dgilb...@redhat.com>
>
> Many users now prefer to use drive_mirror over NBD as an
> alternative to the older migrate -b option; drive_mirror is
> more complex to setup but gives you more options (e.g. only
> migrating some of the disks if some of them are shared).
>
> Allow the large chunk of block migration code to be compiled
> out for those who don't use it.
>
> Based on a downstream-patch we've had for a while by Jeff Cody.
>
> Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
> ---
> configure | 11 +++++++++++
> migration/Makefile.objs | 2 +-
> migration/migration.c | 12 ++++++++++++
> vl.c | 2 ++
> 4 files changed, 26 insertions(+), 1 deletion(-)
>
> diff --git a/configure b/configure
> index 48a9370cc6..69eed5fb8d 100755
> --- a/configure
> +++ b/configure
> @@ -316,6 +316,7 @@ vte=""
> virglrenderer=""
> tpm="yes"
> libssh2=""
> +live_block_migration="yes"
> numa=""
> tcmalloc="no"
> jemalloc="no"
> @@ -1168,6 +1169,10 @@ for opt do
> ;;
> --enable-libssh2) libssh2="yes"
> ;;
> + --disable-live-block-migration) live_block_migration="no"
> + ;;
> + --enable-live-block-migration) live_block_migration="yes"
> + ;;
> --disable-numa) numa="no"
> ;;
> --enable-numa) numa="yes"
> @@ -1400,6 +1405,7 @@ disabled with --disable-FEATURE, default is enabled if
> available:
> libnfs nfs support
> smartcard smartcard support (libcacard)
> libusb libusb (for usb passthrough)
> + live-block-migration Block migration in the main migration stream
> usb-redir usb network redirection support
> lzo support of lzo compression library
> snappy support of snappy compression library
> @@ -5210,6 +5216,7 @@ echo "TPM support $tpm"
> echo "libssh2 support $libssh2"
> echo "TPM passthrough $tpm_passthrough"
> echo "QOM debugging $qom_cast_debug"
> +echo "Live block migration $live_block_migration"
> echo "lzo support $lzo"
> echo "snappy support $snappy"
> echo "bzip2 support $bzip2"
> @@ -5776,6 +5783,10 @@ if test "$libssh2" = "yes" ; then
> echo "LIBSSH2_LIBS=$libssh2_libs" >> $config_host_mak
> fi
>
> +if test "$live_block_migration" = "yes" ; then
> + echo "CONFIG_LIVE_BLOCK_MIGRATION=y" >> $config_host_mak
> +fi
> +
> # USB host support
> if test "$libusb" = "yes"; then
> echo "HOST_USB=libusb legacy" >> $config_host_mak
> diff --git a/migration/Makefile.objs b/migration/Makefile.objs
> index 480dd493a9..200b5e0c67 100644
> --- a/migration/Makefile.objs
> +++ b/migration/Makefile.objs
> @@ -9,5 +9,5 @@ common-obj-y += qjson.o
>
> common-obj-$(CONFIG_RDMA) += rdma.o
>
> -common-obj-y += block.o
> +common-obj-$(CONFIG_LIVE_BLOCK_MIGRATION) += block.o
>
> diff --git a/migration/migration.c b/migration/migration.c
> index 353f2728cf..ffce72aabc 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -692,6 +692,7 @@ MigrationInfo *qmp_query_migrate(Error **errp)
>
> populate_ram_info(info, s);
>
> +#ifdef CONFIG_LIVE_BLOCK_MIGRATION
> if (blk_mig_active()) {
> info->has_disk = true;
> info->disk = g_malloc0(sizeof(*info->disk));
> @@ -699,6 +700,7 @@ MigrationInfo *qmp_query_migrate(Error **errp)
> info->disk->remaining = blk_mig_bytes_remaining();
> info->disk->total = blk_mig_bytes_total();
> }
> +#endif
>
> if (cpu_throttle_active()) {
> info->has_cpu_throttle_percentage = true;
> @@ -720,6 +722,7 @@ MigrationInfo *qmp_query_migrate(Error **errp)
>
> populate_ram_info(info, s);
>
> +#ifdef CONFIG_LIVE_BLOCK_MIGRATION
> if (blk_mig_active()) {
> info->has_disk = true;
> info->disk = g_malloc0(sizeof(*info->disk));
> @@ -727,6 +730,7 @@ MigrationInfo *qmp_query_migrate(Error **errp)
> info->disk->remaining = blk_mig_bytes_remaining();
> info->disk->total = blk_mig_bytes_total();
> }
> +#endif
>
> get_xbzrle_cache_stats(info);
> break;
> @@ -1222,6 +1226,14 @@ void qmp_migrate(const char *uri, bool has_blk, bool
> blk,
> params.blk = has_blk && blk;
> params.shared = has_inc && inc;
>
> +#ifndef CONFIG_LIVE_BLOCK_MIGRATION
> + if (params.blk || params.shared) {
> + error_setg(errp, "QEMU compiled without old-style block migration. "
> + "Use drive_mirror+NBD.");
Is it worth spelling out briefly what the "old-style block migration"
is? Something like:
"QEMU compiled without old-style (i.e. QMP `migrate` with
"inc":true) block migration. Use `drive-mirror`+NBD")
But I also wonder if it's needlessly wordy, so your call to incorporate
it or not.
I spelled out the QMP equivalent (as opposed to HMP: 'migrate -b')
because, that's what users of higher layers (libvirt, OpenStack etc) see
in their QMP interactions with QEMU, when the old-style approach is
used:
{"execute":"migrate","arguments":{{"detach":true,"blk":false,"inc":true,"uri":"fd:migrate"}
[...]
--
/kashyap
