* zhanghailiang (zhang.zhanghaili...@huawei.com) wrote: > We need communications protocol of user-defined to control the checkpoint > process. > > The new checkpoint request is started by Primary VM, and the interactive > process > like below: > Checkpoint synchronizing points, > > Primary Secondary > initial work > 'checkpoint-ready' <------------------------------ @ > > 'checkpoint-request' @ -----------------------------> > Suspend (Only in > hybrid mode) > 'checkpoint-reply' <------------------------------ @ > Suspend&Save state > 'vmstate-send' @ -----------------------------> > Send state Receive state > 'vmstate-received' <------------------------------ @ > Release packets Load state > 'vmstate-load' <------------------------------ @ > Resume Resume (Only in hybrid > mode) > > Start Comparing (Only in hybrid mode) > NOTE: > 1) '@' who sends the message > 2) Every sync-point is synchronized by two sides with only > one handshake(single direction) for low-latency. > If more strict synchronization is required, a opposite direction > sync-point should be added. > 3) Since sync-points are single direction, the remote side may > go forward a lot when this side just receives the sync-point. > 4) For now, we only support 'periodic' checkpoint, for which > the Secondary VM is not running, later we will support 'hybrid' mode. > > Signed-off-by: zhanghailiang <zhang.zhanghaili...@huawei.com> > Signed-off-by: Li Zhijian <lizhij...@cn.fujitsu.com> > Signed-off-by: Gonglei <arei.gong...@huawei.com> > Cc: Eric Blake <ebl...@redhat.com> > --- > v11: > - Add missing 'checkpoint-ready' communication in comment. > - Use parameter to return 'value' for colo_ctl_get() (Dave's suggestion) > - Fix trace for colo_ctl_get() to trace command and value both > v10: > - Rename enum COLOCmd to COLOCommand (Eric's suggestion). > - Remove unused 'ram-steal' > --- > migration/colo.c | 198 > ++++++++++++++++++++++++++++++++++++++++++++++++++++++- > qapi-schema.json | 27 ++++++++ > trace-events | 2 + > 3 files changed, 225 insertions(+), 2 deletions(-) > > diff --git a/migration/colo.c b/migration/colo.c > index 0ab9618..c045d61 100644 > --- a/migration/colo.c > +++ b/migration/colo.c > @@ -10,10 +10,12 @@ > * later. See the COPYING file in the top-level directory. > */ > > +#include <unistd.h> > #include "sysemu/sysemu.h" > #include "migration/colo.h" > #include "trace.h" > #include "qemu/error-report.h" > +#include "qemu/sockets.h" > > bool colo_supported(void) > { > @@ -34,9 +36,107 @@ bool migration_incoming_in_colo_state(void) > return mis && (mis->state == MIGRATION_STATUS_COLO); > } > > +/* colo checkpoint control helper */ > +static int colo_ctl_put(QEMUFile *f, uint32_t cmd, uint64_t value) > +{ > + int ret = 0; > + > + qemu_put_be32(f, cmd); > + qemu_put_be64(f, value); > + qemu_fflush(f); > + > + ret = qemu_file_get_error(f); > + trace_colo_ctl_put(COLOCommand_lookup[cmd], value); > + > + return ret; > +} > + > +static int colo_ctl_get_cmd(QEMUFile *f, uint32_t *cmd) > +{ > + int ret = 0; > + > + *cmd = qemu_get_be32(f); > + ret = qemu_file_get_error(f); > + if (ret < 0) { > + return ret; > + } > + if (*cmd >= COLO_COMMAND_MAX) { > + error_report("Invalid colo command, got cmd:%d", *cmd); > + return -EINVAL; > + } > + > + return 0; > +} > + > +static int colo_ctl_get(QEMUFile *f, uint32_t require, uint64_t *value) > +{ > + int ret; > + uint32_t cmd; > + > + ret = colo_ctl_get_cmd(f, &cmd); > + if (ret < 0) { > + return ret; > + } > + if (cmd != require) { > + error_report("Unexpect colo command, expect:%d, but got cmd:%d", > + require, cmd);
I think you need to use PRIu32 rather than %d since they are uint32_t (I doubt it will break on anything, but it's correct). > + return -EINVAL; > + } > + > + *value = qemu_get_be64(f); > + trace_colo_ctl_get(COLOCommand_lookup[cmd], *value); > + ret = qemu_file_get_error(f); > + > + return ret; > +} > + > +static int colo_do_checkpoint_transaction(MigrationState *s) > +{ > + int ret; > + uint64_t value; > + > + ret = colo_ctl_put(s->to_dst_file, COLO_COMMAND_CHECKPOINT_REQUEST, 0); > + if (ret < 0) { > + goto out; > + } > + > + ret = colo_ctl_get(s->rp_state.from_dst_file, > + COLO_COMMAND_CHECKPOINT_REPLY, &value); > + if (ret < 0) { > + goto out; > + } > + > + /* TODO: suspend and save vm state to colo buffer */ > + > + ret = colo_ctl_put(s->to_dst_file, COLO_COMMAND_VMSTATE_SEND, 0); > + if (ret < 0) { > + goto out; > + } > + > + /* TODO: send vmstate to Secondary */ > + > + ret = colo_ctl_get(s->rp_state.from_dst_file, > + COLO_COMMAND_VMSTATE_RECEIVED, &value); > + if (ret < 0) { > + goto out; > + } > + > + ret = colo_ctl_get(s->rp_state.from_dst_file, > + COLO_COMMAND_VMSTATE_LOADED, &value); > + if (ret < 0) { > + goto out; > + } > + > + /* TODO: resume Primary */ > + > +out: > + return ret; > +} > + > static void colo_process_checkpoint(MigrationState *s) > { > int ret = 0; > + uint64_t value; > > s->rp_state.from_dst_file = qemu_file_get_return_path(s->to_dst_file); > if (!s->rp_state.from_dst_file) { > @@ -45,12 +145,28 @@ static void colo_process_checkpoint(MigrationState *s) > goto out; > } > > + /* > + * Wait for Secondary finish loading vm states and enter COLO > + * restore. > + */ > + ret = colo_ctl_get(s->rp_state.from_dst_file, > + COLO_COMMAND_CHECKPOINT_READY, &value); > + if (ret < 0) { > + goto out; > + } > + > qemu_mutex_lock_iothread(); > vm_start(); > qemu_mutex_unlock_iothread(); > trace_colo_vm_state_change("stop", "run"); > > - /*TODO: COLO checkpoint savevm loop*/ > + while (s->state == MIGRATION_STATUS_COLO) { > + /* start a colo checkpoint */ > + ret = colo_do_checkpoint_transaction(s); > + if (ret < 0) { > + goto out; > + } > + } > > out: > if (ret < 0) { > @@ -73,10 +189,46 @@ void migrate_start_colo_process(MigrationState *s) > qemu_mutex_lock_iothread(); > } > > +/* > + * return: > + * 0: start a checkpoint > + * -1: some error happened, exit colo restore > + */ > +static int colo_wait_handle_cmd(QEMUFile *f, int *checkpoint_request) > +{ > + int ret; > + uint32_t cmd; > + uint64_t value; > + > + ret = colo_ctl_get_cmd(f, &cmd); > + if (ret < 0) { > + /* do failover ? */ > + return ret; > + } > + /* Fix me: this value should be 0, which is not so good, > + * should be used for checking ? > + */ You could use something simple like an incrementing value, if you just wanted to make it a little more robust against problems. > + value = qemu_get_be64(f); > + if (value != 0) { > + error_report("Got unexpected value %" PRIu64 " for '%s' command", > + value, COLOCommand_lookup[cmd]); > + return -EINVAL; > + } > + > + switch (cmd) { > + case COLO_COMMAND_CHECKPOINT_REQUEST: > + *checkpoint_request = 1; > + return 0; > + default: > + return -EINVAL; > + } > +} > + > void *colo_process_incoming_thread(void *opaque) > { > MigrationIncomingState *mis = opaque; > int ret = 0; > + uint64_t value; > > migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE, > MIGRATION_STATUS_COLO); > @@ -93,7 +245,49 @@ void *colo_process_incoming_thread(void *opaque) > */ > qemu_set_block(qemu_get_fd(mis->from_src_file)); > > - /* TODO: COLO checkpoint restore loop */ > + > + ret = colo_ctl_put(mis->to_src_file, COLO_COMMAND_CHECKPOINT_READY, 0); > + if (ret < 0) { > + goto out; > + } > + > + while (mis->state == MIGRATION_STATUS_COLO) { > + int request = 0; > + int ret = colo_wait_handle_cmd(mis->from_src_file, &request); > + > + if (ret < 0) { > + break; > + } else { > + if (!request) { > + continue; > + } > + } > + /* FIXME: This is unnecessary for periodic checkpoint mode */ > + ret = colo_ctl_put(mis->to_src_file, COLO_COMMAND_CHECKPOINT_REPLY, > 0); > + if (ret < 0) { > + goto out; > + } > + > + ret = colo_ctl_get(mis->from_src_file, COLO_COMMAND_VMSTATE_SEND, > + &value); > + if (ret < 0) { > + goto out; > + } > + > + /* TODO: read migration data into colo buffer */ > + > + ret = colo_ctl_put(mis->to_src_file, COLO_COMMAND_VMSTATE_RECEIVED, > 0); > + if (ret < 0) { > + goto out; > + } > + > + /* TODO: load vm state */ > + > + ret = colo_ctl_put(mis->to_src_file, COLO_COMMAND_VMSTATE_LOADED, 0); > + if (ret < 0) { > + goto out; > + } > + } > > out: > if (ret < 0) { > diff --git a/qapi-schema.json b/qapi-schema.json > index c2f3b63..48a87af 100644 > --- a/qapi-schema.json > +++ b/qapi-schema.json > @@ -722,6 +722,33 @@ > { 'command': 'migrate-start-postcopy' } > > ## > +# @COLOCommand > +# > +# The commands for COLO fault tolerance > +# > +# @invalid: unknown command > +# > +# @checkpoint-ready: SVM is ready for checkpointing > +# > +# @checkpoint-request: PVM tells SVM to prepare for new checkpointing > +# > +# @checkpoint-reply: SVM gets PVM's checkpoint request > +# > +# @vmstate-send: VM's state will be sent by PVM. > +# > +# @vmstate-size: The total size of VMstate. > +# > +# @vmstate-received: VM's state has been received by SVM > +# > +# @vmstate-loaded: VM's state has been loaded by SVM > +# > +# Since: 2.6 > +## > +{ 'enum': 'COLOCommand', > + 'data': [ 'invalid', 'checkpoint-ready', 'checkpoint-request', > + 'checkpoint-reply', 'vmstate-send', 'vmstate-size', > + 'vmstate-received', 'vmstate-loaded' ] } > + > # @MouseInfo: > # > # Information about a mouse device. > diff --git a/trace-events b/trace-events > index c98d473..f8a0959 100644 > --- a/trace-events > +++ b/trace-events > @@ -1579,6 +1579,8 @@ postcopy_ram_incoming_cleanup_join(void) "" > > # migration/colo.c > colo_vm_state_change(const char *old, const char *new) "Change '%s' => '%s'" > +colo_ctl_put(const char *msg, uint64_t value) "Send '%s' cmd, value: %" > PRIu64"" > +colo_ctl_get(const char *msg, uint64_t value) "Receive '%s' cmd, value: %" > PRIu64"" I don't think you need the "" at the end of the line Dave > > # kvm-all.c > kvm_ioctl(int type, void *arg) "type 0x%x, arg %p" > -- > 1.8.3.1 > > -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK