Liang Li <liang.z...@intel.com> wrote:
> At the end of live migration and before vm_start() on the destination
> side, we should make sure all the decompression tasks are finished, if
> this can not be guaranteed, the VM may get the incorrect memory data,
> or the updated memory may be overwritten by the decompression thread.
> Add the code to fix this potential issue.
>
> Suggested-by: David Alan Gilbert <dgilb...@redhat.com>
> Signed-off-by: Liang Li <liang.z...@intel.com>
> ---
> include/migration/migration.h | 1 +
> migration/migration.c | 2 +-
> migration/ram.c | 20 ++++++++++++++++++++
> 3 files changed, 22 insertions(+), 1 deletion(-)
>
> diff --git a/include/migration/migration.h b/include/migration/migration.h
> index ac2c12c..1c9051e 100644
> --- a/include/migration/migration.h
> +++ b/include/migration/migration.h
> @@ -223,6 +223,7 @@ void migrate_compress_threads_create(void);
> void migrate_compress_threads_join(void);
> void migrate_decompress_threads_create(void);
> void migrate_decompress_threads_join(void);
> +void wait_for_decompress_done(void);
> uint64_t ram_bytes_remaining(void);
> uint64_t ram_bytes_transferred(void);
> uint64_t ram_bytes_total(void);
> diff --git a/migration/migration.c b/migration/migration.c
> index 991313a..5228c28 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -347,7 +347,7 @@ static void process_incoming_migration_bh(void *opaque)
> /* If global state section was not received or we are in running
> state, we need to obey autostart. Any other state is set with
> runstate_set. */
> -
> + wait_for_decompress_done();
> if (!global_state_received() ||
> global_state_get_runstate() == RUN_STATE_RUNNING) {
> if (autostart) {
> diff --git a/migration/ram.c b/migration/ram.c
> index 7ab6ab5..4459b38 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -2220,6 +2220,26 @@ static void *do_data_decompress(void *opaque)
> return NULL;
> }
>
why?
> +void wait_for_decompress_done(void)
> +{
> + int idx, thread_count;
> +
> + if (!migrate_use_compression()) {
> + return;
> + }
> + thread_count = migrate_decompress_threads();
> + for (idx = 0; idx < thread_count; idx++) {
> + if (!decomp_param[idx].done) {
> + qemu_mutex_lock(&decomp_done_lock);
> + while (!decomp_param[idx].done) {
> + qemu_cond_wait(&decomp_done_cond, &decomp_done_lock);
> + }
> + qemu_mutex_unlock(&decomp_done_lock);
> + }
> + }
> +
> +}
> +
thread_count = migrate_decompress_threads();
qemu_mutex_lock(&decomp_done_lock);
for (idx = 0; idx < thread_count; idx++) {
while (!decomp_param[idx].done) {
qemu_cond_wait(&decomp_done_cond, &decomp_done_lock);
}
}
qemu_mutex_unlock(&decomp_done_lock);
Simpler and correct, no?
Later, Juan.
