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Re: [Qemu-devel] [RFC v2 21/33] migration: new cmd MIG_CMD_POSTCOPY_RESU
From: |
Peter Xu |
Subject: |
Re: [Qemu-devel] [RFC v2 21/33] migration: new cmd MIG_CMD_POSTCOPY_RESUME |
Date: |
Wed, 27 Sep 2017 18:11:41 +0800 |
User-agent: |
Mutt/1.5.24 (2015-08-30) |
On Fri, Sep 22, 2017 at 12:08:06PM +0100, Dr. David Alan Gilbert wrote:
> * Peter Xu (address@hidden) wrote:
> > Introducing this new command to be sent when the source VM is ready to
> > resume the paused migration. What the destination does here is
> > basically release the fault thread to continue service page faults.
> >
> > Signed-off-by: Peter Xu <address@hidden>
> > ---
> > migration/savevm.c | 33 +++++++++++++++++++++++++++++++++
> > migration/savevm.h | 1 +
> > migration/trace-events | 1 +
> > 3 files changed, 35 insertions(+)
> >
> > diff --git a/migration/savevm.c b/migration/savevm.c
> > index 7f77a31..e914346 100644
> > --- a/migration/savevm.c
> > +++ b/migration/savevm.c
> > @@ -77,6 +77,7 @@ enum qemu_vm_cmd {
> > MIG_CMD_POSTCOPY_RAM_DISCARD, /* A list of pages to discard that
> > were previously sent during
> > precopy but are dirty. */
> > + MIG_CMD_POSTCOPY_RESUME, /* resume postcopy on dest */
> > MIG_CMD_PACKAGED, /* Send a wrapped stream within this stream
> > */
> > MIG_CMD_RECV_BITMAP, /* Request for recved bitmap on dst */
> > MIG_CMD_MAX
> > @@ -95,6 +96,7 @@ static struct mig_cmd_args {
> > [MIG_CMD_POSTCOPY_RUN] = { .len = 0, .name = "POSTCOPY_RUN" },
> > [MIG_CMD_POSTCOPY_RAM_DISCARD] = {
> > .len = -1, .name =
> > "POSTCOPY_RAM_DISCARD" },
> > + [MIG_CMD_POSTCOPY_RESUME] = { .len = 0, .name = "POSTCOPY_RESUME" },
> > [MIG_CMD_PACKAGED] = { .len = 4, .name = "PACKAGED" },
> > [MIG_CMD_RECV_BITMAP] = { .len = -1, .name = "RECV_BITMAP" },
> > [MIG_CMD_MAX] = { .len = -1, .name = "MAX" },
> > @@ -931,6 +933,12 @@ void qemu_savevm_send_postcopy_run(QEMUFile *f)
> > qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_RUN, 0, NULL);
> > }
> >
> > +void qemu_savevm_send_postcopy_resume(QEMUFile *f)
> > +{
> > + trace_savevm_send_postcopy_resume();
> > + qemu_savevm_command_send(f, MIG_CMD_POSTCOPY_RESUME, 0, NULL);
> > +}
> > +
> > void qemu_savevm_send_recv_bitmap(QEMUFile *f, char *block_name)
> > {
> > size_t len;
> > @@ -1682,6 +1690,28 @@ static int
> > loadvm_postcopy_handle_run(MigrationIncomingState *mis)
> > return LOADVM_QUIT;
> > }
> >
> > +static int loadvm_postcopy_handle_resume(MigrationIncomingState *mis)
> > +{
> > + if (mis->state != MIGRATION_STATUS_POSTCOPY_RECOVER) {
> > + error_report("%s: illegal resume received", __func__);
> > + /* Don't fail the load, only for this. */
> > + return 0;
> > + }
> > +
> > + /*
> > + * This means source VM is ready to resume the postcopy migration.
> > + * It's time to switch state and release the fault thread to
> > + * continue service page faults.
> > + */
> > + migrate_set_state(&mis->state, MIGRATION_STATUS_POSTCOPY_RECOVER,
> > + MIGRATION_STATUS_POSTCOPY_ACTIVE);
> > + qemu_sem_post(&mis->postcopy_pause_sem_fault);
> > +
> > + /* TODO: Tell source that "we are ready" */
> > +
>
> You might want to add a trace in here; however,
Added.
>
>
> Reviewed-by: Dr. David Alan Gilbert <address@hidden>
Thanks!
--
Peter Xu