| Message ID | 1450167779-9960-11-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> > --- > 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' > > Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com> > --- > migration/colo.c | 183 ++++++++++++++++++++++++++++++++++++++++++++++++++++++- > qapi-schema.json | 25 ++++++++ > trace-events | 2 + > 3 files changed, 208 insertions(+), 2 deletions(-) > > diff --git a/migration/colo.c b/migration/colo.c > index 0ab9618..0ce2a6e 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) > { > @@ -34,6 +36,100 @@ bool migration_incoming_in_colo_state(void) > return mis && (mis->state == MIGRATION_STATUS_COLO); > } > > +static int colo_put_cmd(QEMUFile *f, uint32_t cmd) > +{ > + int ret; > + > + if (cmd >= COLO_COMMAND_MAX) { > + error_report("%s: Invalid cmd", __func__); > + return -EINVAL; > + } > + qemu_put_be32(f, cmd); > + qemu_fflush(f); > + > + ret = qemu_file_get_error(f); > + trace_colo_put_cmd(COLOCommand_lookup[cmd]); > + > + return ret; > +} > + > +static int colo_get_cmd(QEMUFile *f, uint32_t *cmd) > +{ > + int ret; > + > + *cmd = qemu_get_be32(f); > + ret = qemu_file_get_error(f); > + if (ret < 0) { > + return ret; > + } > + if (*cmd >= COLO_COMMAND_MAX) { > + error_report("%s: Invalid cmd", __func__); > + return -EINVAL; > + } > + trace_colo_get_cmd(COLOCommand_lookup[*cmd]); > + return 0; > +} > + > +static int colo_get_check_cmd(QEMUFile *f, uint32_t expect_cmd) > +{ > + int ret; > + uint32_t cmd; > + > + ret = colo_get_cmd(f, &cmd); > + if (ret < 0) { > + return ret; > + } > + if (cmd != expect_cmd) { > + error_report("Unexpect colo command, expect:%d, but got cmd:%d", > + expect_cmd, cmd); Those still need to be PRIu32 But other than that, Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> > + return -EINVAL; > + } > + > + return 0; > +} > + > +static int colo_do_checkpoint_transaction(MigrationState *s) > +{ > + int ret; > + > + ret = colo_put_cmd(s->to_dst_file, COLO_COMMAND_CHECKPOINT_REQUEST); > + if (ret < 0) { > + goto out; > + } > + > + ret = colo_get_check_cmd(s->rp_state.from_dst_file, > + COLO_COMMAND_CHECKPOINT_REPLY); > + if (ret < 0) { > + goto out; > + } > + > + /* TODO: suspend and save vm state to colo buffer */ > + > + ret = colo_put_cmd(s->to_dst_file, COLO_COMMAND_VMSTATE_SEND); > + if (ret < 0) { > + goto out; > + } > + > + /* TODO: send vmstate to Secondary */ > + > + ret = colo_get_check_cmd(s->rp_state.from_dst_file, > + COLO_COMMAND_VMSTATE_RECEIVED); > + if (ret < 0) { > + goto out; > + } > + > + ret = colo_get_check_cmd(s->rp_state.from_dst_file, > + COLO_COMMAND_VMSTATE_LOADED); > + if (ret < 0) { > + goto out; > + } > + > + /* TODO: resume Primary */ > + > +out: > + return ret; > +} > + > static void colo_process_checkpoint(MigrationState *s) > { > int ret = 0; > @@ -45,12 +141,28 @@ static void colo_process_checkpoint(MigrationState *s) > goto out; > } > > + /* > + * Wait for Secondary finish loading vm states and enter COLO > + * restore. > + */ > + ret = colo_get_check_cmd(s->rp_state.from_dst_file, > + COLO_COMMAND_CHECKPOINT_READY); > + 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) { > @@ -73,6 +185,31 @@ 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; > + > + ret = colo_get_cmd(f, &cmd); > + if (ret < 0) { > + /* do failover ? */ > + return ret; > + } > + > + 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; > @@ -93,7 +230,49 @@ void *colo_process_incoming_thread(void *opaque) > */ > qemu_set_block(qemu_get_fd(mis->from_src_file)); > > - /* TODO: COLO checkpoint restore loop */ > + > + ret = colo_put_cmd(mis->to_src_file, COLO_COMMAND_CHECKPOINT_READY); > + 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_put_cmd(mis->to_src_file, COLO_COMMAND_CHECKPOINT_REPLY); > + if (ret < 0) { > + goto out; > + } > + > + ret = colo_get_check_cmd(mis->from_src_file, > + COLO_COMMAND_VMSTATE_SEND); > + if (ret < 0) { > + goto out; > + } > + > + /* TODO: read migration data into colo buffer */ > + > + ret = colo_put_cmd(mis->to_src_file, COLO_COMMAND_VMSTATE_RECEIVED); > + if (ret < 0) { > + goto out; > + } > + > + /* TODO: load vm state */ > + > + ret = colo_put_cmd(mis->to_src_file, COLO_COMMAND_VMSTATE_LOADED); > + if (ret < 0) { > + goto out; > + } > + } > > out: > if (ret < 0) { > diff --git a/qapi-schema.json b/qapi-schema.json > index c9ff34e..85f7800 100644 > --- a/qapi-schema.json > +++ b/qapi-schema.json > @@ -720,6 +720,31 @@ > { '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 5565e79..39fdd8d 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_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
Jumping in at v12 for a bit of QAPI review (and whatever else catched my eye nearby), please pardon my ignorance of COLO in general, and previous review of this series in particular. zhanghailiang <zhang.zhanghailiang@huawei.com> writes: > 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) Long lines. Easy to fix: shorten your arrows. > 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. Useful commit message, but shouldn't this explanation (also) be in the source? > 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> > --- > 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' > > Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com> > --- > migration/colo.c | 183 ++++++++++++++++++++++++++++++++++++++++++++++++++++++- > qapi-schema.json | 25 ++++++++ > trace-events | 2 + > 3 files changed, 208 insertions(+), 2 deletions(-) > > diff --git a/migration/colo.c b/migration/colo.c > index 0ab9618..0ce2a6e 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) > { > @@ -34,6 +36,100 @@ bool migration_incoming_in_colo_state(void) > return mis && (mis->state == MIGRATION_STATUS_COLO); > } > > +static int colo_put_cmd(QEMUFile *f, uint32_t cmd) > +{ > + int ret; > + > + if (cmd >= COLO_COMMAND_MAX) { Needs a trivial rebase due to commit 7fb1cf1. > + error_report("%s: Invalid cmd", __func__); > + return -EINVAL; Can this run in a context with different error handling needs? Or asked differently: who may ultimately handle this error? Whoever that may be, how does it need to report errors? Peeking ahead: the immediate callers don't handle this error, they just pass it on their callers. I'm asking because I'm trying to understand whether error_report() is appropriate here, or whether you need to use error_setg(), and leave the actual reporting to the spot that ultimately handles this error. > + } > + qemu_put_be32(f, cmd); > + qemu_fflush(f); > + > + ret = qemu_file_get_error(f); > + trace_colo_put_cmd(COLOCommand_lookup[cmd]); > + > + return ret; > +} Looks like @cmd is a COLOCommand. Why is the parameter type uint32_t? > + > +static int colo_get_cmd(QEMUFile *f, uint32_t *cmd) > +{ > + int ret; > + > + *cmd = qemu_get_be32(f); > + ret = qemu_file_get_error(f); > + if (ret < 0) { > + return ret; > + } > + if (*cmd >= COLO_COMMAND_MAX) { > + error_report("%s: Invalid cmd", __func__); > + return -EINVAL; > + } > + trace_colo_get_cmd(COLOCommand_lookup[*cmd]); > + return 0; > +} Same question. The "get" in the name suggests the function returns the value gotten, like similarly named function elsewhere in migration/ do. > + > +static int colo_get_check_cmd(QEMUFile *f, uint32_t expect_cmd) > +{ > + int ret; > + uint32_t cmd; > + > + ret = colo_get_cmd(f, &cmd); > + if (ret < 0) { > + return ret; > + } > + if (cmd != expect_cmd) { > + error_report("Unexpect colo command, expect:%d, but got cmd:%d", Grammar nit: "Unexpected". Suggest: "Unexpected COLO command %d, expected %d". > + expect_cmd, cmd); > + return -EINVAL; > + } > + > + return 0; > +} > + > +static int colo_do_checkpoint_transaction(MigrationState *s) > +{ > + int ret; > + > + ret = colo_put_cmd(s->to_dst_file, COLO_COMMAND_CHECKPOINT_REQUEST); > + if (ret < 0) { > + goto out; > + } > + > + ret = colo_get_check_cmd(s->rp_state.from_dst_file, > + COLO_COMMAND_CHECKPOINT_REPLY); > + if (ret < 0) { > + goto out; > + } > + > + /* TODO: suspend and save vm state to colo buffer */ > + > + ret = colo_put_cmd(s->to_dst_file, COLO_COMMAND_VMSTATE_SEND); > + if (ret < 0) { > + goto out; > + } > + > + /* TODO: send vmstate to Secondary */ > + > + ret = colo_get_check_cmd(s->rp_state.from_dst_file, > + COLO_COMMAND_VMSTATE_RECEIVED); > + if (ret < 0) { > + goto out; > + } > + > + ret = colo_get_check_cmd(s->rp_state.from_dst_file, > + COLO_COMMAND_VMSTATE_LOADED); > + if (ret < 0) { > + goto out; > + } > + > + /* TODO: resume Primary */ > + > +out: > + return ret; > +} > + > static void colo_process_checkpoint(MigrationState *s) > { > int ret = 0; > @@ -45,12 +141,28 @@ static void colo_process_checkpoint(MigrationState *s) > goto out; > } > > + /* > + * Wait for Secondary finish loading vm states and enter COLO > + * restore. > + */ > + ret = colo_get_check_cmd(s->rp_state.from_dst_file, > + COLO_COMMAND_CHECKPOINT_READY); > + 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) { > @@ -73,6 +185,31 @@ void migrate_start_colo_process(MigrationState *s) > qemu_mutex_lock_iothread(); > } > > +/* > + * return: > + * 0: start a checkpoint > + * -1: some error happened, exit colo restore > + */ Suggest to make this a proper function comment, i.e. /* * One line describing purpose * As many additional lines as it takes to further explain what it does, * preconditions, side effects, return values, error conditions. Use * @name to refer to parameters. */ > +static int colo_wait_handle_cmd(QEMUFile *f, int *checkpoint_request) > +{ > + int ret; > + uint32_t cmd; > + > + ret = colo_get_cmd(f, &cmd); > + if (ret < 0) { > + /* do failover ? */ > + return ret; > + } > + > + switch (cmd) { > + case COLO_COMMAND_CHECKPOINT_REQUEST: > + *checkpoint_request = 1; > + return 0; > + default: > + return -EINVAL; > + } switch makes sense only if you're going to add cases. Suggest to set *checkpoint_request = 0 on error, for robustness. > +} > + > void *colo_process_incoming_thread(void *opaque) > { > MigrationIncomingState *mis = opaque; > @@ -93,7 +230,49 @@ void *colo_process_incoming_thread(void *opaque) > */ > qemu_set_block(qemu_get_fd(mis->from_src_file)); > > - /* TODO: COLO checkpoint restore loop */ > + > + ret = colo_put_cmd(mis->to_src_file, COLO_COMMAND_CHECKPOINT_READY); > + if (ret < 0) { > + goto out; > + } > + > + while (mis->state == MIGRATION_STATUS_COLO) { > + int request = 0; Dead initialization. > + int ret = colo_wait_handle_cmd(mis->from_src_file, &request); > + > + if (ret < 0) { > + break; > + } else { > + if (!request) { > + continue; > + } > + } Convoluted nesting. Suggest if (ret < 0) { break; } if (!request) { continue; } Actually, !request can't happen, so I'd make it. if (ret < 0) { break; } assert(request); until it can happen. > + /* FIXME: This is unnecessary for periodic checkpoint mode */ When you add a FIXME, you should probably point to it in your commit message. May not be necessary when the FIXME goes away later in this series. Pretty much the same for TODO. > + ret = colo_put_cmd(mis->to_src_file, COLO_COMMAND_CHECKPOINT_REPLY); > + if (ret < 0) { > + goto out; Above, you used break to "break" the loop on error. Here, you use "goto out". Suggest to pick one and stick to it. > + } > + > + ret = colo_get_check_cmd(mis->from_src_file, > + COLO_COMMAND_VMSTATE_SEND); > + if (ret < 0) { > + goto out; > + } > + > + /* TODO: read migration data into colo buffer */ > + > + ret = colo_put_cmd(mis->to_src_file, COLO_COMMAND_VMSTATE_RECEIVED); > + if (ret < 0) { > + goto out; > + } > + > + /* TODO: load vm state */ > + > + ret = colo_put_cmd(mis->to_src_file, COLO_COMMAND_VMSTATE_LOADED); > + if (ret < 0) { > + goto out; > + } > + } > > out: > if (ret < 0) { > diff --git a/qapi-schema.json b/qapi-schema.json > index c9ff34e..85f7800 100644 > --- a/qapi-schema.json > +++ b/qapi-schema.json > @@ -720,6 +720,31 @@ > { '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' ] } > + Space after 'vmstate-size', please. 'vmstate-size' is not used in this patch. You may want to add it with its first use instead. Should this enum really be named "COLOCommand"? 'checkpoint-ready', 'checkpoint-request', 'vmstate-send' look like commands to me, but the others look like replies. > # @MouseInfo: > # > # Information about a mouse device. > diff --git a/trace-events b/trace-events > index 5565e79..39fdd8d 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_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" I like how this commit creates just the two state machines, and leaves filling in their actions to later commits. Helps ignorant rewiewers like me :)
Hi Markus, On 2015/12/19 16:54, Markus Armbruster wrote: > Jumping in at v12 for a bit of QAPI review (and whatever else catched my > eye nearby), please pardon my ignorance of COLO in general, and previous > review of this series in particular. > Thanks all the same :) > zhanghailiang <zhang.zhanghailiang@huawei.com> writes: > >> 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) > > Long lines. Easy to fix: shorten your arrows. > >> Start Comparing (Only in hybrid mode) OK. >> 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. > > Useful commit message, but shouldn't this explanation (also) be in the > source? > >> 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> >> --- >> 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' >> >> Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com> >> --- >> migration/colo.c | 183 ++++++++++++++++++++++++++++++++++++++++++++++++++++++- >> qapi-schema.json | 25 ++++++++ >> trace-events | 2 + >> 3 files changed, 208 insertions(+), 2 deletions(-) >> >> diff --git a/migration/colo.c b/migration/colo.c >> index 0ab9618..0ce2a6e 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) >> { >> @@ -34,6 +36,100 @@ bool migration_incoming_in_colo_state(void) >> return mis && (mis->state == MIGRATION_STATUS_COLO); >> } >> >> +static int colo_put_cmd(QEMUFile *f, uint32_t cmd) >> +{ >> + int ret; >> + >> + if (cmd >= COLO_COMMAND_MAX) { > > Needs a trivial rebase due to commit 7fb1cf1. > >> + error_report("%s: Invalid cmd", __func__); >> + return -EINVAL; > > Can this run in a context with different error handling needs? > > Or asked differently: who may ultimately handle this error? Whoever > that may be, how does it need to report errors? > > Peeking ahead: the immediate callers don't handle this error, they just > pass it on their callers. > > I'm asking because I'm trying to understand whether error_report() is > appropriate here, or whether you need to use error_setg(), and leave the > actual reporting to the spot that ultimately handles this error. > Hmm, i know what you mean, we handled them all together after exit from the colo process loop, Use error_setg() seems to be a good idea, with this modification, we can also drop the return value. I will fix it in next version. >> + } >> + qemu_put_be32(f, cmd); >> + qemu_fflush(f); >> + >> + ret = qemu_file_get_error(f); >> + trace_colo_put_cmd(COLOCommand_lookup[cmd]); >> + >> + return ret; >> +} > > Looks like @cmd is a COLOCommand. Why is the parameter type uint32_t? > OK, i will change it to use enum COLOCommand. >> + >> +static int colo_get_cmd(QEMUFile *f, uint32_t *cmd) >> +{ >> + int ret; >> + >> + *cmd = qemu_get_be32(f); >> + ret = qemu_file_get_error(f); >> + if (ret < 0) { >> + return ret; >> + } >> + if (*cmd >= COLO_COMMAND_MAX) { >> + error_report("%s: Invalid cmd", __func__); >> + return -EINVAL; >> + } >> + trace_colo_get_cmd(COLOCommand_lookup[*cmd]); >> + return 0; >> +} > > Same question. > > The "get" in the name suggests the function returns the value gotten, > like similarly named function elsewhere in migration/ do. > Do you mean it should return the cmd value directly, not though parameter way ? After we convert it to use error_setg() to indicate success or not, we can do like that. I will fix it. >> + >> +static int colo_get_check_cmd(QEMUFile *f, uint32_t expect_cmd) >> +{ >> + int ret; >> + uint32_t cmd; >> + >> + ret = colo_get_cmd(f, &cmd); >> + if (ret < 0) { >> + return ret; >> + } >> + if (cmd != expect_cmd) { >> + error_report("Unexpect colo command, expect:%d, but got cmd:%d", > > Grammar nit: "Unexpected". Suggest: "Unexpected COLO command %d, > expected %d". > Will fix it. >> + expect_cmd, cmd); >> + return -EINVAL; >> + } >> + >> + return 0; >> +} >> + >> +static int colo_do_checkpoint_transaction(MigrationState *s) >> +{ >> + int ret; >> + >> + ret = colo_put_cmd(s->to_dst_file, COLO_COMMAND_CHECKPOINT_REQUEST); >> + if (ret < 0) { >> + goto out; >> + } >> + >> + ret = colo_get_check_cmd(s->rp_state.from_dst_file, >> + COLO_COMMAND_CHECKPOINT_REPLY); >> + if (ret < 0) { >> + goto out; >> + } >> + >> + /* TODO: suspend and save vm state to colo buffer */ >> + >> + ret = colo_put_cmd(s->to_dst_file, COLO_COMMAND_VMSTATE_SEND); >> + if (ret < 0) { >> + goto out; >> + } >> + >> + /* TODO: send vmstate to Secondary */ >> + >> + ret = colo_get_check_cmd(s->rp_state.from_dst_file, >> + COLO_COMMAND_VMSTATE_RECEIVED); >> + if (ret < 0) { >> + goto out; >> + } >> + >> + ret = colo_get_check_cmd(s->rp_state.from_dst_file, >> + COLO_COMMAND_VMSTATE_LOADED); >> + if (ret < 0) { >> + goto out; >> + } >> + >> + /* TODO: resume Primary */ >> + >> +out: >> + return ret; >> +} >> + >> static void colo_process_checkpoint(MigrationState *s) >> { >> int ret = 0; >> @@ -45,12 +141,28 @@ static void colo_process_checkpoint(MigrationState *s) >> goto out; >> } >> >> + /* >> + * Wait for Secondary finish loading vm states and enter COLO >> + * restore. >> + */ >> + ret = colo_get_check_cmd(s->rp_state.from_dst_file, >> + COLO_COMMAND_CHECKPOINT_READY); >> + 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) { >> @@ -73,6 +185,31 @@ void migrate_start_colo_process(MigrationState *s) >> qemu_mutex_lock_iothread(); >> } >> >> +/* >> + * return: >> + * 0: start a checkpoint >> + * -1: some error happened, exit colo restore >> + */ > > Suggest to make this a proper function comment, i.e. > Good catch, i will fix it as your suggestion. > /* > * One line describing purpose > * As many additional lines as it takes to further explain what it does, > * preconditions, side effects, return values, error conditions. Use > * @name to refer to parameters. > */ > >> +static int colo_wait_handle_cmd(QEMUFile *f, int *checkpoint_request) >> +{ >> + int ret; >> + uint32_t cmd; >> + >> + ret = colo_get_cmd(f, &cmd); >> + if (ret < 0) { >> + /* do failover ? */ >> + return ret; >> + } >> + >> + switch (cmd) { >> + case COLO_COMMAND_CHECKPOINT_REQUEST: >> + *checkpoint_request = 1; >> + return 0; >> + default: >> + return -EINVAL; >> + } > > switch makes sense only if you're going to add cases. > Yes, we will add COLO_COMMAND_GUEST_SHUTDOWN in the later patch, and maybe all more cases in future. > Suggest to set *checkpoint_request = 0 on error, for robustness. > OK. >> +} >> + >> void *colo_process_incoming_thread(void *opaque) >> { >> MigrationIncomingState *mis = opaque; >> @@ -93,7 +230,49 @@ void *colo_process_incoming_thread(void *opaque) >> */ >> qemu_set_block(qemu_get_fd(mis->from_src_file)); >> >> - /* TODO: COLO checkpoint restore loop */ >> + >> + ret = colo_put_cmd(mis->to_src_file, COLO_COMMAND_CHECKPOINT_READY); >> + if (ret < 0) { >> + goto out; >> + } >> + >> + while (mis->state == MIGRATION_STATUS_COLO) { >> + int request = 0; > > Dead initialization. > >> + int ret = colo_wait_handle_cmd(mis->from_src_file, &request); >> + >> + if (ret < 0) { >> + break; >> + } else { >> + if (!request) { >> + continue; >> + } >> + } > > Convoluted nesting. Suggest > > if (ret < 0) { > break; > } > if (!request) { > continue; > } > > Actually, !request can't happen, so I'd make it. > > if (ret < 0) { > break; > } > assert(request); > > until it can happen. > Yes, you are right, it should never happen. >> + /* FIXME: This is unnecessary for periodic checkpoint mode */ > > When you add a FIXME, you should probably point to it in your commit > message. May not be necessary when the FIXME goes away later in this > series. > > Pretty much the same for TODO. > >> + ret = colo_put_cmd(mis->to_src_file, COLO_COMMAND_CHECKPOINT_REPLY); >> + if (ret < 0) { >> + goto out; > > Above, you used break to "break" the loop on error. Here, you use "goto > out". Suggest to pick one and stick to it. > >> + } >> + >> + ret = colo_get_check_cmd(mis->from_src_file, >> + COLO_COMMAND_VMSTATE_SEND); >> + if (ret < 0) { >> + goto out; >> + } >> + >> + /* TODO: read migration data into colo buffer */ >> + >> + ret = colo_put_cmd(mis->to_src_file, COLO_COMMAND_VMSTATE_RECEIVED); >> + if (ret < 0) { >> + goto out; >> + } >> + >> + /* TODO: load vm state */ >> + >> + ret = colo_put_cmd(mis->to_src_file, COLO_COMMAND_VMSTATE_LOADED); >> + if (ret < 0) { >> + goto out; >> + } >> + } >> >> out: >> if (ret < 0) { >> diff --git a/qapi-schema.json b/qapi-schema.json >> index c9ff34e..85f7800 100644 >> --- a/qapi-schema.json >> +++ b/qapi-schema.json >> @@ -720,6 +720,31 @@ >> { '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' ] } >> + > > Space after 'vmstate-size', please. > > 'vmstate-size' is not used in this patch. You may want to add it with > its first use instead. > OK, i will move it to the corresponding patch. > Should this enum really be named "COLOCommand"? 'checkpoint-ready', > 'checkpoint-request', 'vmstate-send' look like commands to me, but the > others look like replies. > Yes, COLOCommand is not so exact. what about name it COLOProtocol? > >> # @MouseInfo: >> # >> # Information about a mouse device. >> diff --git a/trace-events b/trace-events >> index 5565e79..39fdd8d 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_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" > > I like how this commit creates just the two state machines, and leaves > filling in their actions to later commits. Helps ignorant rewiewers > like me :) > > Do you mean i should split this patch ? Leave this patch with the simplest colo process, maybe just 'ready, request, reply', and add the other states in later patch? Thanks, Hailiang > . >
On 2015/12/18 22:52, 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> >> --- >> 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' >> >> Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com> >> --- >> migration/colo.c | 183 ++++++++++++++++++++++++++++++++++++++++++++++++++++++- >> qapi-schema.json | 25 ++++++++ >> trace-events | 2 + >> 3 files changed, 208 insertions(+), 2 deletions(-) >> >> diff --git a/migration/colo.c b/migration/colo.c >> index 0ab9618..0ce2a6e 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) >> { >> @@ -34,6 +36,100 @@ bool migration_incoming_in_colo_state(void) >> return mis && (mis->state == MIGRATION_STATUS_COLO); >> } >> >> +static int colo_put_cmd(QEMUFile *f, uint32_t cmd) >> +{ >> + int ret; >> + >> + if (cmd >= COLO_COMMAND_MAX) { >> + error_report("%s: Invalid cmd", __func__); >> + return -EINVAL; >> + } >> + qemu_put_be32(f, cmd); >> + qemu_fflush(f); >> + >> + ret = qemu_file_get_error(f); >> + trace_colo_put_cmd(COLOCommand_lookup[cmd]); >> + >> + return ret; >> +} >> + >> +static int colo_get_cmd(QEMUFile *f, uint32_t *cmd) >> +{ >> + int ret; >> + >> + *cmd = qemu_get_be32(f); >> + ret = qemu_file_get_error(f); >> + if (ret < 0) { >> + return ret; >> + } >> + if (*cmd >= COLO_COMMAND_MAX) { >> + error_report("%s: Invalid cmd", __func__); >> + return -EINVAL; >> + } >> + trace_colo_get_cmd(COLOCommand_lookup[*cmd]); >> + return 0; >> +} >> + >> +static int colo_get_check_cmd(QEMUFile *f, uint32_t expect_cmd) >> +{ >> + int ret; >> + uint32_t cmd; >> + >> + ret = colo_get_cmd(f, &cmd); >> + if (ret < 0) { >> + return ret; >> + } >> + if (cmd != expect_cmd) { >> + error_report("Unexpect colo command, expect:%d, but got cmd:%d", >> + expect_cmd, cmd); > > Those still need to be PRIu32 > Er, i have change the type to 'COLOCommand' according to Markus's comment. > But other than that, > > Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Thanks. Hailiang > >> + return -EINVAL; >> + } >> + >> + return 0; >> +} >> + >> +static int colo_do_checkpoint_transaction(MigrationState *s) >> +{ >> + int ret; >> + >> + ret = colo_put_cmd(s->to_dst_file, COLO_COMMAND_CHECKPOINT_REQUEST); >> + if (ret < 0) { >> + goto out; >> + } >> + >> + ret = colo_get_check_cmd(s->rp_state.from_dst_file, >> + COLO_COMMAND_CHECKPOINT_REPLY); >> + if (ret < 0) { >> + goto out; >> + } >> + >> + /* TODO: suspend and save vm state to colo buffer */ >> + >> + ret = colo_put_cmd(s->to_dst_file, COLO_COMMAND_VMSTATE_SEND); >> + if (ret < 0) { >> + goto out; >> + } >> + >> + /* TODO: send vmstate to Secondary */ >> + >> + ret = colo_get_check_cmd(s->rp_state.from_dst_file, >> + COLO_COMMAND_VMSTATE_RECEIVED); >> + if (ret < 0) { >> + goto out; >> + } >> + >> + ret = colo_get_check_cmd(s->rp_state.from_dst_file, >> + COLO_COMMAND_VMSTATE_LOADED); >> + if (ret < 0) { >> + goto out; >> + } >> + >> + /* TODO: resume Primary */ >> + >> +out: >> + return ret; >> +} >> + >> static void colo_process_checkpoint(MigrationState *s) >> { >> int ret = 0; >> @@ -45,12 +141,28 @@ static void colo_process_checkpoint(MigrationState *s) >> goto out; >> } >> >> + /* >> + * Wait for Secondary finish loading vm states and enter COLO >> + * restore. >> + */ >> + ret = colo_get_check_cmd(s->rp_state.from_dst_file, >> + COLO_COMMAND_CHECKPOINT_READY); >> + 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) { >> @@ -73,6 +185,31 @@ 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; >> + >> + ret = colo_get_cmd(f, &cmd); >> + if (ret < 0) { >> + /* do failover ? */ >> + return ret; >> + } >> + >> + 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; >> @@ -93,7 +230,49 @@ void *colo_process_incoming_thread(void *opaque) >> */ >> qemu_set_block(qemu_get_fd(mis->from_src_file)); >> >> - /* TODO: COLO checkpoint restore loop */ >> + >> + ret = colo_put_cmd(mis->to_src_file, COLO_COMMAND_CHECKPOINT_READY); >> + 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_put_cmd(mis->to_src_file, COLO_COMMAND_CHECKPOINT_REPLY); >> + if (ret < 0) { >> + goto out; >> + } >> + >> + ret = colo_get_check_cmd(mis->from_src_file, >> + COLO_COMMAND_VMSTATE_SEND); >> + if (ret < 0) { >> + goto out; >> + } >> + >> + /* TODO: read migration data into colo buffer */ >> + >> + ret = colo_put_cmd(mis->to_src_file, COLO_COMMAND_VMSTATE_RECEIVED); >> + if (ret < 0) { >> + goto out; >> + } >> + >> + /* TODO: load vm state */ >> + >> + ret = colo_put_cmd(mis->to_src_file, COLO_COMMAND_VMSTATE_LOADED); >> + if (ret < 0) { >> + goto out; >> + } >> + } >> >> out: >> if (ret < 0) { >> diff --git a/qapi-schema.json b/qapi-schema.json >> index c9ff34e..85f7800 100644 >> --- a/qapi-schema.json >> +++ b/qapi-schema.json >> @@ -720,6 +720,31 @@ >> { '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 5565e79..39fdd8d 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_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 > > . >
Hailiang Zhang <zhang.zhanghailiang@huawei.com> writes: > Hi Markus, > > On 2015/12/19 16:54, Markus Armbruster wrote: >> Jumping in at v12 for a bit of QAPI review (and whatever else catched my >> eye nearby), please pardon my ignorance of COLO in general, and previous >> review of this series in particular. >> > > Thanks all the same :) [...] >>> diff --git a/migration/colo.c b/migration/colo.c >>> index 0ab9618..0ce2a6e 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) >>> { >>> @@ -34,6 +36,100 @@ bool migration_incoming_in_colo_state(void) >>> return mis && (mis->state == MIGRATION_STATUS_COLO); >>> } >>> >>> +static int colo_put_cmd(QEMUFile *f, uint32_t cmd) >>> +{ >>> + int ret; >>> + >>> + if (cmd >= COLO_COMMAND_MAX) { >> >> Needs a trivial rebase due to commit 7fb1cf1. >> > >>> + error_report("%s: Invalid cmd", __func__); >>> + return -EINVAL; >> >> Can this run in a context with different error handling needs? >> >> Or asked differently: who may ultimately handle this error? Whoever >> that may be, how does it need to report errors? >> >> Peeking ahead: the immediate callers don't handle this error, they just >> pass it on their callers. >> >> I'm asking because I'm trying to understand whether error_report() is >> appropriate here, or whether you need to use error_setg(), and leave the >> actual reporting to the spot that ultimately handles this error. >> > > Hmm, i know what you mean, we handled them all together after exit > from the colo process loop, > Use error_setg() seems to be a good idea, with this modification, we > can also drop the return > value. I will fix it in next version. > > >>> + } >>> + qemu_put_be32(f, cmd); >>> + qemu_fflush(f); >>> + >>> + ret = qemu_file_get_error(f); >>> + trace_colo_put_cmd(COLOCommand_lookup[cmd]); >>> + >>> + return ret; >>> +} >> >> Looks like @cmd is a COLOCommand. Why is the parameter type uint32_t? >> > > OK, i will change it to use enum COLOCommand. > >>> + >>> +static int colo_get_cmd(QEMUFile *f, uint32_t *cmd) >>> +{ >>> + int ret; >>> + >>> + *cmd = qemu_get_be32(f); >>> + ret = qemu_file_get_error(f); >>> + if (ret < 0) { >>> + return ret; >>> + } >>> + if (*cmd >= COLO_COMMAND_MAX) { >>> + error_report("%s: Invalid cmd", __func__); >>> + return -EINVAL; >>> + } >>> + trace_colo_get_cmd(COLOCommand_lookup[*cmd]); >>> + return 0; >>> +} >> >> Same question. >> >> The "get" in the name suggests the function returns the value gotten, >> like similarly named function elsewhere in migration/ do. >> > Do you mean it should return the cmd value directly, not though parameter way ? > After we convert it to use error_setg() to indicate success or not, we > can do like that. > I will fix it. Sounds good to me. [...] >>> diff --git a/qapi-schema.json b/qapi-schema.json >>> index c9ff34e..85f7800 100644 >>> --- a/qapi-schema.json >>> +++ b/qapi-schema.json >>> @@ -720,6 +720,31 @@ >>> { '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' ] } >>> + >> >> Space after 'vmstate-size', please. >> > >> 'vmstate-size' is not used in this patch. You may want to add it with >> its first use instead. >> > > OK, i will move it to the corresponding patch. > >> Should this enum really be named "COLOCommand"? 'checkpoint-ready', >> 'checkpoint-request', 'vmstate-send' look like commands to me, but the >> others look like replies. >> > > Yes, COLOCommand is not so exact. what about name it COLOProtocol? A protocol specifies valid sequences of messages, and what they mean. This isn't a protocol, it's a message within a protocol. COLOMessage? >> >>> # @MouseInfo: >>> # >>> # Information about a mouse device. >>> diff --git a/trace-events b/trace-events >>> index 5565e79..39fdd8d 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_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" >> >> I like how this commit creates just the two state machines, and leaves >> filling in their actions to later commits. Helps ignorant rewiewers >> like me :) >> >> > > Do you mean i should split this patch ? Leave this patch with the > simplest colo process, > maybe just 'ready, request, reply', and add the other states in later patch? No, I *like* how you split up the work.
On 2016/1/11 20:47, Markus Armbruster wrote: > Hailiang Zhang <zhang.zhanghailiang@huawei.com> writes: > >> Hi Markus, >> >> On 2015/12/19 16:54, Markus Armbruster wrote: >>> Jumping in at v12 for a bit of QAPI review (and whatever else catched my >>> eye nearby), please pardon my ignorance of COLO in general, and previous >>> review of this series in particular. >>> >> >> Thanks all the same :) > [...] >>>> diff --git a/migration/colo.c b/migration/colo.c >>>> index 0ab9618..0ce2a6e 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) >>>> { >>>> @@ -34,6 +36,100 @@ bool migration_incoming_in_colo_state(void) >>>> return mis && (mis->state == MIGRATION_STATUS_COLO); >>>> } >>>> >>>> +static int colo_put_cmd(QEMUFile *f, uint32_t cmd) >>>> +{ >>>> + int ret; >>>> + >>>> + if (cmd >= COLO_COMMAND_MAX) { >>> >>> Needs a trivial rebase due to commit 7fb1cf1. >>> >> >>>> + error_report("%s: Invalid cmd", __func__); >>>> + return -EINVAL; >>> >>> Can this run in a context with different error handling needs? >>> >>> Or asked differently: who may ultimately handle this error? Whoever >>> that may be, how does it need to report errors? >>> >>> Peeking ahead: the immediate callers don't handle this error, they just >>> pass it on their callers. >>> >>> I'm asking because I'm trying to understand whether error_report() is >>> appropriate here, or whether you need to use error_setg(), and leave the >>> actual reporting to the spot that ultimately handles this error. >>> >> >> Hmm, i know what you mean, we handled them all together after exit >> from the colo process loop, >> Use error_setg() seems to be a good idea, with this modification, we >> can also drop the return >> value. I will fix it in next version. >> >> >>>> + } >>>> + qemu_put_be32(f, cmd); >>>> + qemu_fflush(f); >>>> + >>>> + ret = qemu_file_get_error(f); >>>> + trace_colo_put_cmd(COLOCommand_lookup[cmd]); >>>> + >>>> + return ret; >>>> +} >>> >>> Looks like @cmd is a COLOCommand. Why is the parameter type uint32_t? >>> >> >> OK, i will change it to use enum COLOCommand. >> >>>> + >>>> +static int colo_get_cmd(QEMUFile *f, uint32_t *cmd) >>>> +{ >>>> + int ret; >>>> + >>>> + *cmd = qemu_get_be32(f); >>>> + ret = qemu_file_get_error(f); >>>> + if (ret < 0) { >>>> + return ret; >>>> + } >>>> + if (*cmd >= COLO_COMMAND_MAX) { >>>> + error_report("%s: Invalid cmd", __func__); >>>> + return -EINVAL; >>>> + } >>>> + trace_colo_get_cmd(COLOCommand_lookup[*cmd]); >>>> + return 0; >>>> +} >>> >>> Same question. >>> >>> The "get" in the name suggests the function returns the value gotten, >>> like similarly named function elsewhere in migration/ do. >>> >> Do you mean it should return the cmd value directly, not though parameter way ? >> After we convert it to use error_setg() to indicate success or not, we >> can do like that. >> I will fix it. > > Sounds good to me. > I have fixed them in v13 version :) > [...] >>>> diff --git a/qapi-schema.json b/qapi-schema.json >>>> index c9ff34e..85f7800 100644 >>>> --- a/qapi-schema.json >>>> +++ b/qapi-schema.json >>>> @@ -720,6 +720,31 @@ >>>> { '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' ] } >>>> + >>> >>> Space after 'vmstate-size', please. >>> >> >>> 'vmstate-size' is not used in this patch. You may want to add it with >>> its first use instead. >>> >> >> OK, i will move it to the corresponding patch. >> >>> Should this enum really be named "COLOCommand"? 'checkpoint-ready', >>> 'checkpoint-request', 'vmstate-send' look like commands to me, but the >>> others look like replies. >>> >> >> Yes, COLOCommand is not so exact. what about name it COLOProtocol? > > A protocol specifies valid sequences of messages, and what they mean. > This isn't a protocol, it's a message within a protocol. COLOMessage? > Yes, COLOMessage is more precise, i will fix it in next version. >>> >>>> # @MouseInfo: >>>> # >>>> # Information about a mouse device. >>>> diff --git a/trace-events b/trace-events >>>> index 5565e79..39fdd8d 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_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" >>> >>> I like how this commit creates just the two state machines, and leaves >>> filling in their actions to later commits. Helps ignorant rewiewers >>> like me :) >>> >>> >> >> Do you mean i should split this patch ? Leave this patch with the >> simplest colo process, >> maybe just 'ready, request, reply', and add the other states in later patch? > > No, I *like* how you split up the work. > OK. Thanks. Hailiang > . >
diff --git a/migration/colo.c b/migration/colo.c index 0ab9618..0ce2a6e 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) { @@ -34,6 +36,100 @@ bool migration_incoming_in_colo_state(void) return mis && (mis->state == MIGRATION_STATUS_COLO); } +static int colo_put_cmd(QEMUFile *f, uint32_t cmd) +{ + int ret; + + if (cmd >= COLO_COMMAND_MAX) { + error_report("%s: Invalid cmd", __func__); + return -EINVAL; + } + qemu_put_be32(f, cmd); + qemu_fflush(f); + + ret = qemu_file_get_error(f); + trace_colo_put_cmd(COLOCommand_lookup[cmd]); + + return ret; +} + +static int colo_get_cmd(QEMUFile *f, uint32_t *cmd) +{ + int ret; + + *cmd = qemu_get_be32(f); + ret = qemu_file_get_error(f); + if (ret < 0) { + return ret; + } + if (*cmd >= COLO_COMMAND_MAX) { + error_report("%s: Invalid cmd", __func__); + return -EINVAL; + } + trace_colo_get_cmd(COLOCommand_lookup[*cmd]); + return 0; +} + +static int colo_get_check_cmd(QEMUFile *f, uint32_t expect_cmd) +{ + int ret; + uint32_t cmd; + + ret = colo_get_cmd(f, &cmd); + if (ret < 0) { + return ret; + } + if (cmd != expect_cmd) { + error_report("Unexpect colo command, expect:%d, but got cmd:%d", + expect_cmd, cmd); + return -EINVAL; + } + + return 0; +} + +static int colo_do_checkpoint_transaction(MigrationState *s) +{ + int ret; + + ret = colo_put_cmd(s->to_dst_file, COLO_COMMAND_CHECKPOINT_REQUEST); + if (ret < 0) { + goto out; + } + + ret = colo_get_check_cmd(s->rp_state.from_dst_file, + COLO_COMMAND_CHECKPOINT_REPLY); + if (ret < 0) { + goto out; + } + + /* TODO: suspend and save vm state to colo buffer */ + + ret = colo_put_cmd(s->to_dst_file, COLO_COMMAND_VMSTATE_SEND); + if (ret < 0) { + goto out; + } + + /* TODO: send vmstate to Secondary */ + + ret = colo_get_check_cmd(s->rp_state.from_dst_file, + COLO_COMMAND_VMSTATE_RECEIVED); + if (ret < 0) { + goto out; + } + + ret = colo_get_check_cmd(s->rp_state.from_dst_file, + COLO_COMMAND_VMSTATE_LOADED); + if (ret < 0) { + goto out; + } + + /* TODO: resume Primary */ + +out: + return ret; +} + static void colo_process_checkpoint(MigrationState *s) { int ret = 0; @@ -45,12 +141,28 @@ static void colo_process_checkpoint(MigrationState *s) goto out; } + /* + * Wait for Secondary finish loading vm states and enter COLO + * restore. + */ + ret = colo_get_check_cmd(s->rp_state.from_dst_file, + COLO_COMMAND_CHECKPOINT_READY); + 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) { @@ -73,6 +185,31 @@ 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; + + ret = colo_get_cmd(f, &cmd); + if (ret < 0) { + /* do failover ? */ + return ret; + } + + 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; @@ -93,7 +230,49 @@ void *colo_process_incoming_thread(void *opaque) */ qemu_set_block(qemu_get_fd(mis->from_src_file)); - /* TODO: COLO checkpoint restore loop */ + + ret = colo_put_cmd(mis->to_src_file, COLO_COMMAND_CHECKPOINT_READY); + 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_put_cmd(mis->to_src_file, COLO_COMMAND_CHECKPOINT_REPLY); + if (ret < 0) { + goto out; + } + + ret = colo_get_check_cmd(mis->from_src_file, + COLO_COMMAND_VMSTATE_SEND); + if (ret < 0) { + goto out; + } + + /* TODO: read migration data into colo buffer */ + + ret = colo_put_cmd(mis->to_src_file, COLO_COMMAND_VMSTATE_RECEIVED); + if (ret < 0) { + goto out; + } + + /* TODO: load vm state */ + + ret = colo_put_cmd(mis->to_src_file, COLO_COMMAND_VMSTATE_LOADED); + if (ret < 0) { + goto out; + } + } out: if (ret < 0) { diff --git a/qapi-schema.json b/qapi-schema.json index c9ff34e..85f7800 100644 --- a/qapi-schema.json +++ b/qapi-schema.json @@ -720,6 +720,31 @@ { '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 5565e79..39fdd8d 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_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> --- 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' Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com> --- migration/colo.c | 183 ++++++++++++++++++++++++++++++++++++++++++++++++++++++- qapi-schema.json | 25 ++++++++ trace-events | 2 + 3 files changed, 208 insertions(+), 2 deletions(-)