[libvirt] [PATCH] qemu: fix hang in p2p + xbzrle compression + parallel migration
When we do parallel migration, The multifd-channels migration parameter needs to be set on the destination side as well before incoming migration URI, unless we accept the default number of connections(2). Usually, This can be correctly handled by libvirtd. But in this case if we use p2p + xbzrle compression without parameter '--comp-xbzrle-cache', qemuMigrationParamsDump returns too early, The corresponding migration parameter will not be set on the destination side, It results QEMU hangs. Reproducer: virsh migrate --live --p2p --comp-methods xbzrle \ --parallel --parallel-connections 3 GUEST qemu+ssh://dsthost/system or virsh migrate --live --p2p --compressed \ --parallel --parallel-connections 3 GUEST qemu+ssh://dsthost/system Signed-off-by: Lin Ma <lma@suse.com> --- src/qemu/qemu_migration_params.c | 1 - 1 file changed, 1 deletion(-) diff --git a/src/qemu/qemu_migration_params.c b/src/qemu/qemu_migration_params.c index dd5e2ce1b6..810199370f 100644 --- a/src/qemu/qemu_migration_params.c +++ b/src/qemu/qemu_migration_params.c @@ -630,7 +630,6 @@ qemuMigrationParamsDump(qemuMigrationParamsPtr migParams, if (migParams->compMethods == 1ULL << QEMU_MIGRATION_COMPRESS_XBZRLE && !migParams->params[QEMU_MIGRATION_PARAM_XBZRLE_CACHE_SIZE].set) { *flags |= VIR_MIGRATE_COMPRESSED; - return 0; } for (i = 0; i < QEMU_MIGRATION_COMPRESS_LAST; ++i) { -- 2.23.0
On Thu, Apr 16, 2020 at 12:44:51 +0800, Lin Ma wrote:
When we do parallel migration, The multifd-channels migration parameter needs to be set on the destination side as well before incoming migration URI, unless we accept the default number of connections(2).
Usually, This can be correctly handled by libvirtd. But in this case if we use p2p + xbzrle compression without parameter '--comp-xbzrle-cache', qemuMigrationParamsDump returns too early, The corresponding migration parameter will not be set on the destination side, It results QEMU hangs.
Reproducer: virsh migrate --live --p2p --comp-methods xbzrle \ --parallel --parallel-connections 3 GUEST qemu+ssh://dsthost/system
or
virsh migrate --live --p2p --compressed \ --parallel --parallel-connections 3 GUEST qemu+ssh://dsthost/system
Signed-off-by: Lin Ma <lma@suse.com> --- src/qemu/qemu_migration_params.c | 1 - 1 file changed, 1 deletion(-)
diff --git a/src/qemu/qemu_migration_params.c b/src/qemu/qemu_migration_params.c index dd5e2ce1b6..810199370f 100644 --- a/src/qemu/qemu_migration_params.c +++ b/src/qemu/qemu_migration_params.c @@ -630,7 +630,6 @@ qemuMigrationParamsDump(qemuMigrationParamsPtr migParams, if (migParams->compMethods == 1ULL << QEMU_MIGRATION_COMPRESS_XBZRLE && !migParams->params[QEMU_MIGRATION_PARAM_XBZRLE_CACHE_SIZE].set) { *flags |= VIR_MIGRATE_COMPRESSED; - return 0; }
for (i = 0; i < QEMU_MIGRATION_COMPRESS_LAST; ++i) {
Oops, looks like a leftover from the past when xbzrle-cache-size was the only parameter. Reviewed-by: Jiri Denemark <jdenemar@redhat.com>
participants (2)
-
Jiri Denemark -
Lin Ma