On Fri, Feb 14, 2020 at 01:02:46PM +0100, David Hildenbrand wrote:
> From c0049ac2e95d6756037db918852c507fb88297d9 Mon Sep 17 00:00:00 2001
> From: David Hildenbrand <da...@redhat.com>
> Date: Fri, 14 Feb 2020 13:01:03 +0100
> Subject: [PATCH v1] tmp
>
> Signed-off-by: David Hildenbrand <da...@redhat.com>
> ---
> migration/migration.c | 9 +++++++--
> migration/migration.h | 1 +
> migration/ram.c | 42 ++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 50 insertions(+), 2 deletions(-)
>
> diff --git a/migration/migration.c b/migration/migration.c
> index 3a21a4686c..0e7efe2920 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -175,13 +175,18 @@ void migration_object_init(void)
> }
> }
>
> +void migration_cancel(void)
> +{
> + migrate_fd_cancel(current_migration);
> +}
> +
> void migration_shutdown(void)
> {
> /*
> * Cancel the current migration - that will (eventually)
> * stop the migration using this structure
> */
> - migrate_fd_cancel(current_migration);
> + migration_cancel();
> object_unref(OBJECT(current_migration));
> }
>
> @@ -2019,7 +2024,7 @@ void qmp_migrate(const char *uri, bool has_blk, bool
> blk,
>
> void qmp_migrate_cancel(Error **errp)
> {
> - migrate_fd_cancel(migrate_get_current());
> + migration_cancel();
> }
>
> void qmp_migrate_continue(MigrationStatus state, Error **errp)
> diff --git a/migration/migration.h b/migration/migration.h
> index 8473ddfc88..79fd74afa5 100644
> --- a/migration/migration.h
> +++ b/migration/migration.h
> @@ -343,5 +343,6 @@ int foreach_not_ignored_block(RAMBlockIterFunc func, void
> *opaque);
> void migration_make_urgent_request(void);
> void migration_consume_urgent_request(void);
> bool migration_rate_limit(void);
> +void migration_cancel(void);
>
> #endif
> diff --git a/migration/ram.c b/migration/ram.c
> index ed23ed1c7c..f86f32b453 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -52,6 +52,7 @@
> #include "migration/colo.h"
> #include "block.h"
> #include "sysemu/sysemu.h"
> +#include "sysemu/runstate.h"
> #include "savevm.h"
> #include "qemu/iov.h"
> #include "multifd.h"
> @@ -3710,8 +3711,49 @@ static SaveVMHandlers savevm_ram_handlers = {
> .resume_prepare = ram_resume_prepare,
> };
>
> +static void ram_mig_ram_block_resized(RAMBlockNotifier *n, void *host,
> + size_t old_size, size_t new_size)
> +{
> + /*
> + * We don't care about resizes triggered on incoming migration (when
> + * syncing ram blocks), or of course, when no migration is going on.
> + */
> + if (migration_is_idle() || !runstate_is_running()) {
> + return;
> + }
I feel like migration_is_idle() check is enough. Firstly, I feel like
we allow migration even with VM stopped. At the meantime, if VM is
not running, I see no reason that this resizing will happen after all? :)
> +
> + if (!postcopy_is_running()) {
> + Error *err = NULL;
> +
> + /*
> + * Precopy code cannot deal with the size of ram blocks changing at
> + * random points in time. We're still running on the source, abort
> + * the migration and continue running here. Make sure to wait until
> + * migration was canceled.
> + */
> + error_setg(&err, "RAM resized during precopy.");
> + migrate_set_error(migrate_get_current(), err);
> + error_free(err);
> + migration_cancel();
> + } else {
> + /*
> + * Postcopy code cannot deal with the size of ram blocks changing at
> + * random points in time. We're running on the target. Fail hard.
> + *
> + * TODO: How to handle this in a better way?
> + */
> + error_report("RAM resized during postcopy.");
> + exit(-1);
Now I'm rethinking the postcopy case....
ram_dirty_bitmap_reload() should only happen during the postcopy
recovery, and when that happens the VM should be stopped on both
sides. Which means, ram resizing should not trigger there...
Thanks,
> + }
> +}
> +
> +static RAMBlockNotifier ram_mig_ram_notifier = {
> + .ram_block_resized = ram_mig_ram_block_resized,
> +};
> +
> void ram_mig_init(void)
> {
> qemu_mutex_init(&XBZRLE.lock);
> register_savevm_live("ram", 0, 4, &savevm_ram_handlers, &ram_state);
> + ram_block_notifier_add(&ram_mig_ram_notifier);
> }
> --
> 2.24.1
>
>
> Thoughts?
>
> --
> Thanks,
>
> David / dhildenb
>
>
--
Peter Xu
