| Message ID | 1451372975-5048-11-git-send-email-zhang.zhanghailiang@huawei.com |
|---|---|
| State | New |
| Headers | show |
* zhanghailiang (zhang.zhanghailiang@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.zhanghailiang@huawei.com> > Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com> > Signed-off-by: Gonglei <arei.gonglei@huawei.com> > Cc: Eric Blake <eblake@redhat.com> > Cc: Markus Armbruster <armbru@redhat.com> > Cc: Dr. David Alan Gilbert <dgilbert@redhat.com> > --- > v13: > - Refactor colo command related helper functions, use 'Error **errp' parameter > instead of return value to indicate success or failure. > - Fix some other comments from Markus. > > v12: > - Rename colo_ctl_put() to colo_put_cmd() > - Rename colo_ctl_get() to colo_get_check_cmd() and drop > the third parameter > - Rename colo_ctl_get_cmd() to colo_get_cmd() > - Remove useless 'invalid' member for COLOcommand enum. > 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 | 201 ++++++++++++++++++++++++++++++++++++++++++++++++++++++- > qapi-schema.json | 25 +++++++ > trace-events | 2 + > 3 files changed, 226 insertions(+), 2 deletions(-) > > diff --git a/migration/colo.c b/migration/colo.c > index 65ac0c9..c76e1fa 100644 > --- a/migration/colo.c > +++ b/migration/colo.c > @@ -10,6 +10,7 @@ > * later. See the COPYING file in the top-level directory. > */ > > +#include <unistd.h> > #include "sysemu/sysemu.h" > #include "migration/colo.h" > #include "trace.h" > @@ -34,22 +35,147 @@ bool migration_incoming_in_colo_state(void) > return mis && (mis->state == MIGRATION_STATUS_COLO); > } > > +static void colo_put_cmd(QEMUFile *f, COLOCommand cmd, > + Error **errp) > +{ > + int ret; > + > + if (cmd >= COLO_COMMAND__MAX) { > + error_setg(errp, "%s: Invalid cmd", __func__); > + return; > + } > + qemu_put_be32(f, cmd); > + qemu_fflush(f); > + > + ret = qemu_file_get_error(f); > + if (ret < 0) { > + error_setg_errno(errp, -ret, "Can't put COLO command"); > + } > + trace_colo_put_cmd(COLOCommand_lookup[cmd]); > +} > + > +static COLOCommand colo_get_cmd(QEMUFile *f, Error **errp) > +{ > + COLOCommand cmd; > + int ret; > + > + cmd = qemu_get_be32(f); > + ret = qemu_file_get_error(f); > + if (ret < 0) { > + error_setg_errno(errp, -ret, "Can't get COLO command"); > + return cmd; > + } > + if (cmd >= COLO_COMMAND__MAX) { I'm not sure this is guaranteed to do the right thing if the value read was negative and converted to the enum; it seems to depend a bit on the compiler as to whether an enum is signed or not; but it seems the normal behaviour is for the enum to be unsigned as long as there are no negative values when it's declared; so it looks safe in practice. Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> > + error_setg(errp, "%s: Invalid cmd", __func__); > + return cmd; > + } > + trace_colo_get_cmd(COLOCommand_lookup[cmd]); > + return cmd; > +} > + > +static void colo_get_check_cmd(QEMUFile *f, COLOCommand expect_cmd, > + Error **errp) > +{ > + COLOCommand cmd; > + Error *local_err = NULL; > + > + cmd = colo_get_cmd(f, &local_err); > + if (local_err) { > + error_propagate(errp, local_err); > + return; > + } > + if (cmd != expect_cmd) { > + error_setg(errp, "Unexpected COLO command %d, expected %d", > + expect_cmd, cmd); > + } > +} > + > +static int colo_do_checkpoint_transaction(MigrationState *s) > +{ > + Error *local_err = NULL; > + > + colo_put_cmd(s->to_dst_file, COLO_COMMAND_CHECKPOINT_REQUEST, > + &local_err); > + if (local_err) { > + goto out; > + } > + > + colo_get_check_cmd(s->rp_state.from_dst_file, > + COLO_COMMAND_CHECKPOINT_REPLY, &local_err); > + if (local_err) { > + goto out; > + } > + > + /* TODO: suspend and save vm state to colo buffer */ > + > + colo_put_cmd(s->to_dst_file, COLO_COMMAND_VMSTATE_SEND, &local_err); > + if (local_err) { > + goto out; > + } > + > + /* TODO: send vmstate to Secondary */ > + > + colo_get_check_cmd(s->rp_state.from_dst_file, > + COLO_COMMAND_VMSTATE_RECEIVED, &local_err); > + if (local_err) { > + goto out; > + } > + > + colo_get_check_cmd(s->rp_state.from_dst_file, > + COLO_COMMAND_VMSTATE_LOADED, &local_err); > + if (local_err) { > + goto out; > + } > + > + /* TODO: resume Primary */ > + > + return 0; > +out: > + if (local_err) { > + error_report_err(local_err); > + } > + return -EINVAL; > +} > + > static void colo_process_checkpoint(MigrationState *s) > { > + Error *local_err = NULL; > + int ret; > + > s->rp_state.from_dst_file = qemu_file_get_return_path(s->to_dst_file); > if (!s->rp_state.from_dst_file) { > error_report("Open QEMUFile from_dst_file failed"); > goto out; > } > > + /* > + * Wait for Secondary finish loading vm states and enter COLO > + * restore. > + */ > + colo_get_check_cmd(s->rp_state.from_dst_file, > + COLO_COMMAND_CHECKPOINT_READY, &local_err); > + if (local_err) { > + 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: > + /* Throw the unreported error message after exited from loop */ > + if (local_err) { > + error_report_err(local_err); > + } > migrate_set_state(&s->state, MIGRATION_STATUS_COLO, > MIGRATION_STATUS_COMPLETED); > > @@ -67,9 +193,33 @@ void migrate_start_colo_process(MigrationState *s) > qemu_mutex_lock_iothread(); > } > > +static void colo_wait_handle_cmd(QEMUFile *f, int *checkpoint_request, > + Error **errp) > +{ > + COLOCommand cmd; > + Error *local_err = NULL; > + > + cmd = colo_get_cmd(f, &local_err); > + if (local_err) { > + error_propagate(errp, local_err); > + return; > + } > + > + switch (cmd) { > + case COLO_COMMAND_CHECKPOINT_REQUEST: > + *checkpoint_request = 1; > + break; > + default: > + *checkpoint_request = 0; > + error_setg(errp, "Got unknown COLO command: %d", cmd); > + break; > + } > +} > + > void *colo_process_incoming_thread(void *opaque) > { > MigrationIncomingState *mis = opaque; > + Error *local_err = NULL; > > migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE, > MIGRATION_STATUS_COLO); > @@ -85,9 +235,56 @@ void *colo_process_incoming_thread(void *opaque) > */ > qemu_file_set_blocking(mis->from_src_file, true); > > - /* TODO: COLO checkpoint restore loop */ > + colo_put_cmd(mis->to_src_file, COLO_COMMAND_CHECKPOINT_READY, > + &local_err); > + if (local_err) { > + goto out; > + } > + > + while (mis->state == MIGRATION_STATUS_COLO) { > + int request; > + > + colo_wait_handle_cmd(mis->from_src_file, &request, &local_err); > + if (local_err) { > + goto out; > + } > + assert(request); > + /* FIXME: This is unnecessary for periodic checkpoint mode */ > + colo_put_cmd(mis->to_src_file, COLO_COMMAND_CHECKPOINT_REPLY, > + &local_err); > + if (local_err) { > + goto out; > + } > + > + colo_get_check_cmd(mis->from_src_file, > + COLO_COMMAND_VMSTATE_SEND, &local_err); > + if (local_err) { > + goto out; > + } > + > + /* TODO: read migration data into colo buffer */ > + > + colo_put_cmd(mis->to_src_file, COLO_COMMAND_VMSTATE_RECEIVED, > + &local_err); > + if (local_err) { > + goto out; > + } > + > + /* TODO: load vm state */ > + > + colo_put_cmd(mis->to_src_file, COLO_COMMAND_VMSTATE_LOADED, > + &local_err); > + if (local_err) { > + goto out; > + } > + } > > out: > + /* Throw the unreported error message after exited from loop */ > + if (local_err) { > + error_report_err(local_err); > + } > + > if (mis->to_src_file) { > qemu_fclose(mis->to_src_file); > } > diff --git a/qapi-schema.json b/qapi-schema.json > index 6eefad2..4ea4108 100644 > --- a/qapi-schema.json > +++ b/qapi-schema.json > @@ -718,6 +718,31 @@ > { 'command': 'migrate-start-postcopy' } > > ## > +# @COLOCommand > +# > +# The commands for COLO fault tolerance > +# > +# @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': [ '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 57ddc8f..51b2305 100644 > --- a/trace-events > +++ b/trace-events > @@ -1581,6 +1581,8 @@ postcopy_ram_incoming_cleanup_join(void) "" > > # migration/colo.c > colo_vm_state_change(const char *old, const char *new) "Change '%s' => '%s'" > +colo_put_cmd(const char *msg) "Send '%s' cmd" > +colo_get_cmd(const char *msg) "Receive '%s' cmd" > > # kvm-all.c > kvm_ioctl(int type, void *arg) "type 0x%x, arg %p" > -- > 1.8.3.1 > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
On 2016/1/29 21:08, Dr. David Alan Gilbert wrote: > * zhanghailiang (zhang.zhanghailiang@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.zhanghailiang@huawei.com> >> Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com> >> Signed-off-by: Gonglei <arei.gonglei@huawei.com> >> Cc: Eric Blake <eblake@redhat.com> >> Cc: Markus Armbruster <armbru@redhat.com> >> Cc: Dr. David Alan Gilbert <dgilbert@redhat.com> >> --- >> v13: >> - Refactor colo command related helper functions, use 'Error **errp' parameter >> instead of return value to indicate success or failure. >> - Fix some other comments from Markus. >> >> v12: >> - Rename colo_ctl_put() to colo_put_cmd() >> - Rename colo_ctl_get() to colo_get_check_cmd() and drop >> the third parameter >> - Rename colo_ctl_get_cmd() to colo_get_cmd() >> - Remove useless 'invalid' member for COLOcommand enum. >> 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 | 201 ++++++++++++++++++++++++++++++++++++++++++++++++++++++- >> qapi-schema.json | 25 +++++++ >> trace-events | 2 + >> 3 files changed, 226 insertions(+), 2 deletions(-) >> >> diff --git a/migration/colo.c b/migration/colo.c >> index 65ac0c9..c76e1fa 100644 >> --- a/migration/colo.c >> +++ b/migration/colo.c >> @@ -10,6 +10,7 @@ >> * later. See the COPYING file in the top-level directory. >> */ >> >> +#include <unistd.h> >> #include "sysemu/sysemu.h" >> #include "migration/colo.h" >> #include "trace.h" >> @@ -34,22 +35,147 @@ bool migration_incoming_in_colo_state(void) >> return mis && (mis->state == MIGRATION_STATUS_COLO); >> } >> >> +static void colo_put_cmd(QEMUFile *f, COLOCommand cmd, >> + Error **errp) >> +{ >> + int ret; >> + >> + if (cmd >= COLO_COMMAND__MAX) { >> + error_setg(errp, "%s: Invalid cmd", __func__); >> + return; >> + } >> + qemu_put_be32(f, cmd); >> + qemu_fflush(f); >> + >> + ret = qemu_file_get_error(f); >> + if (ret < 0) { >> + error_setg_errno(errp, -ret, "Can't put COLO command"); >> + } >> + trace_colo_put_cmd(COLOCommand_lookup[cmd]); >> +} >> + >> +static COLOCommand colo_get_cmd(QEMUFile *f, Error **errp) >> +{ >> + COLOCommand cmd; >> + int ret; >> + >> + cmd = qemu_get_be32(f); >> + ret = qemu_file_get_error(f); >> + if (ret < 0) { >> + error_setg_errno(errp, -ret, "Can't get COLO command"); >> + return cmd; >> + } >> + if (cmd >= COLO_COMMAND__MAX) { > > I'm not sure this is guaranteed to do the right thing if the value > read was negative and converted to the enum; it seems to depend > a bit on the compiler as to whether an enum is signed or not; > but it seems the normal behaviour is for the enum to be unsigned Interesting question, we can define a negative enumeration-constant, enum test { TEST_A = -2, TEST_B = 0, } value; So i suppose an enum is signed, and ISO C standard (c99 6.4.4.3) states that the enumeration constants are of type int. But it seems that gcc does not follow this standard strictly, i got the exact answer from its specification: https://gcc.gnu.org/onlinedocs/gcc/Structures-unions-enumerations-and-bit-fields-implementation.html#Structures-unions-enumerations-and-bit-fields-implementation "Normally, the type is unsigned int if there are no negative values in the enumeration, otherwise int." > as long as there are no negative values when it's declared; so it looks > safe in practice. > > Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> > Thanks, Hailiang >> + error_setg(errp, "%s: Invalid cmd", __func__); >> + return cmd; >> + } >> + trace_colo_get_cmd(COLOCommand_lookup[cmd]); >> + return cmd; >> +} >> + >> +static void colo_get_check_cmd(QEMUFile *f, COLOCommand expect_cmd, >> + Error **errp) >> +{ >> + COLOCommand cmd; >> + Error *local_err = NULL; >> + >> + cmd = colo_get_cmd(f, &local_err); >> + if (local_err) { >> + error_propagate(errp, local_err); >> + return; >> + } >> + if (cmd != expect_cmd) { >> + error_setg(errp, "Unexpected COLO command %d, expected %d", >> + expect_cmd, cmd); >> + } >> +} >> + >> +static int colo_do_checkpoint_transaction(MigrationState *s) >> +{ >> + Error *local_err = NULL; >> + >> + colo_put_cmd(s->to_dst_file, COLO_COMMAND_CHECKPOINT_REQUEST, >> + &local_err); >> + if (local_err) { >> + goto out; >> + } >> + >> + colo_get_check_cmd(s->rp_state.from_dst_file, >> + COLO_COMMAND_CHECKPOINT_REPLY, &local_err); >> + if (local_err) { >> + goto out; >> + } >> + >> + /* TODO: suspend and save vm state to colo buffer */ >> + >> + colo_put_cmd(s->to_dst_file, COLO_COMMAND_VMSTATE_SEND, &local_err); >> + if (local_err) { >> + goto out; >> + } >> + >> + /* TODO: send vmstate to Secondary */ >> + >> + colo_get_check_cmd(s->rp_state.from_dst_file, >> + COLO_COMMAND_VMSTATE_RECEIVED, &local_err); >> + if (local_err) { >> + goto out; >> + } >> + >> + colo_get_check_cmd(s->rp_state.from_dst_file, >> + COLO_COMMAND_VMSTATE_LOADED, &local_err); >> + if (local_err) { >> + goto out; >> + } >> + >> + /* TODO: resume Primary */ >> + >> + return 0; >> +out: >> + if (local_err) { >> + error_report_err(local_err); >> + } >> + return -EINVAL; >> +} >> + >> static void colo_process_checkpoint(MigrationState *s) >> { >> + Error *local_err = NULL; >> + int ret; >> + >> s->rp_state.from_dst_file = qemu_file_get_return_path(s->to_dst_file); >> if (!s->rp_state.from_dst_file) { >> error_report("Open QEMUFile from_dst_file failed"); >> goto out; >> } >> >> + /* >> + * Wait for Secondary finish loading vm states and enter COLO >> + * restore. >> + */ >> + colo_get_check_cmd(s->rp_state.from_dst_file, >> + COLO_COMMAND_CHECKPOINT_READY, &local_err); >> + if (local_err) { >> + 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: >> + /* Throw the unreported error message after exited from loop */ >> + if (local_err) { >> + error_report_err(local_err); >> + } >> migrate_set_state(&s->state, MIGRATION_STATUS_COLO, >> MIGRATION_STATUS_COMPLETED); >> >> @@ -67,9 +193,33 @@ void migrate_start_colo_process(MigrationState *s) >> qemu_mutex_lock_iothread(); >> } >> >> +static void colo_wait_handle_cmd(QEMUFile *f, int *checkpoint_request, >> + Error **errp) >> +{ >> + COLOCommand cmd; >> + Error *local_err = NULL; >> + >> + cmd = colo_get_cmd(f, &local_err); >> + if (local_err) { >> + error_propagate(errp, local_err); >> + return; >> + } >> + >> + switch (cmd) { >> + case COLO_COMMAND_CHECKPOINT_REQUEST: >> + *checkpoint_request = 1; >> + break; >> + default: >> + *checkpoint_request = 0; >> + error_setg(errp, "Got unknown COLO command: %d", cmd); >> + break; >> + } >> +} >> + >> void *colo_process_incoming_thread(void *opaque) >> { >> MigrationIncomingState *mis = opaque; >> + Error *local_err = NULL; >> >> migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE, >> MIGRATION_STATUS_COLO); >> @@ -85,9 +235,56 @@ void *colo_process_incoming_thread(void *opaque) >> */ >> qemu_file_set_blocking(mis->from_src_file, true); >> >> - /* TODO: COLO checkpoint restore loop */ >> + colo_put_cmd(mis->to_src_file, COLO_COMMAND_CHECKPOINT_READY, >> + &local_err); >> + if (local_err) { >> + goto out; >> + } >> + >> + while (mis->state == MIGRATION_STATUS_COLO) { >> + int request; >> + >> + colo_wait_handle_cmd(mis->from_src_file, &request, &local_err); >> + if (local_err) { >> + goto out; >> + } >> + assert(request); >> + /* FIXME: This is unnecessary for periodic checkpoint mode */ >> + colo_put_cmd(mis->to_src_file, COLO_COMMAND_CHECKPOINT_REPLY, >> + &local_err); >> + if (local_err) { >> + goto out; >> + } >> + >> + colo_get_check_cmd(mis->from_src_file, >> + COLO_COMMAND_VMSTATE_SEND, &local_err); >> + if (local_err) { >> + goto out; >> + } >> + >> + /* TODO: read migration data into colo buffer */ >> + >> + colo_put_cmd(mis->to_src_file, COLO_COMMAND_VMSTATE_RECEIVED, >> + &local_err); >> + if (local_err) { >> + goto out; >> + } >> + >> + /* TODO: load vm state */ >> + >> + colo_put_cmd(mis->to_src_file, COLO_COMMAND_VMSTATE_LOADED, >> + &local_err); >> + if (local_err) { >> + goto out; >> + } >> + } >> >> out: >> + /* Throw the unreported error message after exited from loop */ >> + if (local_err) { >> + error_report_err(local_err); >> + } >> + >> if (mis->to_src_file) { >> qemu_fclose(mis->to_src_file); >> } >> diff --git a/qapi-schema.json b/qapi-schema.json >> index 6eefad2..4ea4108 100644 >> --- a/qapi-schema.json >> +++ b/qapi-schema.json >> @@ -718,6 +718,31 @@ >> { 'command': 'migrate-start-postcopy' } >> >> ## >> +# @COLOCommand >> +# >> +# The commands for COLO fault tolerance >> +# >> +# @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': [ '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 57ddc8f..51b2305 100644 >> --- a/trace-events >> +++ b/trace-events >> @@ -1581,6 +1581,8 @@ postcopy_ram_incoming_cleanup_join(void) "" >> >> # migration/colo.c >> colo_vm_state_change(const char *old, const char *new) "Change '%s' => '%s'" >> +colo_put_cmd(const char *msg) "Send '%s' cmd" >> +colo_get_cmd(const char *msg) "Receive '%s' cmd" >> >> # kvm-all.c >> kvm_ioctl(int type, void *arg) "type 0x%x, arg %p" >> -- >> 1.8.3.1 >> >> > -- > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK > > . >
diff --git a/migration/colo.c b/migration/colo.c index 65ac0c9..c76e1fa 100644 --- a/migration/colo.c +++ b/migration/colo.c @@ -10,6 +10,7 @@ * later. See the COPYING file in the top-level directory. */ +#include <unistd.h> #include "sysemu/sysemu.h" #include "migration/colo.h" #include "trace.h" @@ -34,22 +35,147 @@ bool migration_incoming_in_colo_state(void) return mis && (mis->state == MIGRATION_STATUS_COLO); } +static void colo_put_cmd(QEMUFile *f, COLOCommand cmd, + Error **errp) +{ + int ret; + + if (cmd >= COLO_COMMAND__MAX) { + error_setg(errp, "%s: Invalid cmd", __func__); + return; + } + qemu_put_be32(f, cmd); + qemu_fflush(f); + + ret = qemu_file_get_error(f); + if (ret < 0) { + error_setg_errno(errp, -ret, "Can't put COLO command"); + } + trace_colo_put_cmd(COLOCommand_lookup[cmd]); +} + +static COLOCommand colo_get_cmd(QEMUFile *f, Error **errp) +{ + COLOCommand cmd; + int ret; + + cmd = qemu_get_be32(f); + ret = qemu_file_get_error(f); + if (ret < 0) { + error_setg_errno(errp, -ret, "Can't get COLO command"); + return cmd; + } + if (cmd >= COLO_COMMAND__MAX) { + error_setg(errp, "%s: Invalid cmd", __func__); + return cmd; + } + trace_colo_get_cmd(COLOCommand_lookup[cmd]); + return cmd; +} + +static void colo_get_check_cmd(QEMUFile *f, COLOCommand expect_cmd, + Error **errp) +{ + COLOCommand cmd; + Error *local_err = NULL; + + cmd = colo_get_cmd(f, &local_err); + if (local_err) { + error_propagate(errp, local_err); + return; + } + if (cmd != expect_cmd) { + error_setg(errp, "Unexpected COLO command %d, expected %d", + expect_cmd, cmd); + } +} + +static int colo_do_checkpoint_transaction(MigrationState *s) +{ + Error *local_err = NULL; + + colo_put_cmd(s->to_dst_file, COLO_COMMAND_CHECKPOINT_REQUEST, + &local_err); + if (local_err) { + goto out; + } + + colo_get_check_cmd(s->rp_state.from_dst_file, + COLO_COMMAND_CHECKPOINT_REPLY, &local_err); + if (local_err) { + goto out; + } + + /* TODO: suspend and save vm state to colo buffer */ + + colo_put_cmd(s->to_dst_file, COLO_COMMAND_VMSTATE_SEND, &local_err); + if (local_err) { + goto out; + } + + /* TODO: send vmstate to Secondary */ + + colo_get_check_cmd(s->rp_state.from_dst_file, + COLO_COMMAND_VMSTATE_RECEIVED, &local_err); + if (local_err) { + goto out; + } + + colo_get_check_cmd(s->rp_state.from_dst_file, + COLO_COMMAND_VMSTATE_LOADED, &local_err); + if (local_err) { + goto out; + } + + /* TODO: resume Primary */ + + return 0; +out: + if (local_err) { + error_report_err(local_err); + } + return -EINVAL; +} + static void colo_process_checkpoint(MigrationState *s) { + Error *local_err = NULL; + int ret; + s->rp_state.from_dst_file = qemu_file_get_return_path(s->to_dst_file); if (!s->rp_state.from_dst_file) { error_report("Open QEMUFile from_dst_file failed"); goto out; } + /* + * Wait for Secondary finish loading vm states and enter COLO + * restore. + */ + colo_get_check_cmd(s->rp_state.from_dst_file, + COLO_COMMAND_CHECKPOINT_READY, &local_err); + if (local_err) { + 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: + /* Throw the unreported error message after exited from loop */ + if (local_err) { + error_report_err(local_err); + } migrate_set_state(&s->state, MIGRATION_STATUS_COLO, MIGRATION_STATUS_COMPLETED); @@ -67,9 +193,33 @@ void migrate_start_colo_process(MigrationState *s) qemu_mutex_lock_iothread(); } +static void colo_wait_handle_cmd(QEMUFile *f, int *checkpoint_request, + Error **errp) +{ + COLOCommand cmd; + Error *local_err = NULL; + + cmd = colo_get_cmd(f, &local_err); + if (local_err) { + error_propagate(errp, local_err); + return; + } + + switch (cmd) { + case COLO_COMMAND_CHECKPOINT_REQUEST: + *checkpoint_request = 1; + break; + default: + *checkpoint_request = 0; + error_setg(errp, "Got unknown COLO command: %d", cmd); + break; + } +} + void *colo_process_incoming_thread(void *opaque) { MigrationIncomingState *mis = opaque; + Error *local_err = NULL; migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE, MIGRATION_STATUS_COLO); @@ -85,9 +235,56 @@ void *colo_process_incoming_thread(void *opaque) */ qemu_file_set_blocking(mis->from_src_file, true); - /* TODO: COLO checkpoint restore loop */ + colo_put_cmd(mis->to_src_file, COLO_COMMAND_CHECKPOINT_READY, + &local_err); + if (local_err) { + goto out; + } + + while (mis->state == MIGRATION_STATUS_COLO) { + int request; + + colo_wait_handle_cmd(mis->from_src_file, &request, &local_err); + if (local_err) { + goto out; + } + assert(request); + /* FIXME: This is unnecessary for periodic checkpoint mode */ + colo_put_cmd(mis->to_src_file, COLO_COMMAND_CHECKPOINT_REPLY, + &local_err); + if (local_err) { + goto out; + } + + colo_get_check_cmd(mis->from_src_file, + COLO_COMMAND_VMSTATE_SEND, &local_err); + if (local_err) { + goto out; + } + + /* TODO: read migration data into colo buffer */ + + colo_put_cmd(mis->to_src_file, COLO_COMMAND_VMSTATE_RECEIVED, + &local_err); + if (local_err) { + goto out; + } + + /* TODO: load vm state */ + + colo_put_cmd(mis->to_src_file, COLO_COMMAND_VMSTATE_LOADED, + &local_err); + if (local_err) { + goto out; + } + } out: + /* Throw the unreported error message after exited from loop */ + if (local_err) { + error_report_err(local_err); + } + if (mis->to_src_file) { qemu_fclose(mis->to_src_file); } diff --git a/qapi-schema.json b/qapi-schema.json index 6eefad2..4ea4108 100644 --- a/qapi-schema.json +++ b/qapi-schema.json @@ -718,6 +718,31 @@ { 'command': 'migrate-start-postcopy' } ## +# @COLOCommand +# +# The commands for COLO fault tolerance +# +# @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': [ '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 57ddc8f..51b2305 100644 --- a/trace-events +++ b/trace-events @@ -1581,6 +1581,8 @@ postcopy_ram_incoming_cleanup_join(void) "" # migration/colo.c colo_vm_state_change(const char *old, const char *new) "Change '%s' => '%s'" +colo_put_cmd(const char *msg) "Send '%s' cmd" +colo_get_cmd(const char *msg) "Receive '%s' cmd" # kvm-all.c kvm_ioctl(int type, void *arg) "type 0x%x, arg %p"
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.zhanghailiang@huawei.com> Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com> Signed-off-by: Gonglei <arei.gonglei@huawei.com> Cc: Eric Blake <eblake@redhat.com> Cc: Markus Armbruster <armbru@redhat.com> Cc: Dr. David Alan Gilbert <dgilbert@redhat.com> --- v13: - Refactor colo command related helper functions, use 'Error **errp' parameter instead of return value to indicate success or failure. - Fix some other comments from Markus. v12: - Rename colo_ctl_put() to colo_put_cmd() - Rename colo_ctl_get() to colo_get_check_cmd() and drop the third parameter - Rename colo_ctl_get_cmd() to colo_get_cmd() - Remove useless 'invalid' member for COLOcommand enum. 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 | 201 ++++++++++++++++++++++++++++++++++++++++++++++++++++++- qapi-schema.json | 25 +++++++ trace-events | 2 + 3 files changed, 226 insertions(+), 2 deletions(-)