On Wed, Mar 06, 2024 at 02:34:29PM +0100, Cédric Le Goater wrote:
> Now that the log_global*() handlers take an Error** parameter and
> return a bool, do the same for memory_global_dirty_log_start() and
> memory_global_dirty_log_stop(). The error is reported in the callers
> for now and it will be propagated in the call stack in the next
> changes.
>
> To be noted a functional change in ram_init_bitmaps(), if the dirty
> pages logger fails to start, there is no need to synchronize the dirty
> pages bitmaps. colo_incoming_start_dirty_log() could be modified in a
> similar way.
>
> Cc: Stefano Stabellini <sstabell...@kernel.org>
> Cc: Anthony Perard <anthony.per...@citrix.com>
> Cc: Paul Durrant <p...@xen.org>
> Cc: "Michael S. Tsirkin" <m...@redhat.com>
> Cc: Paolo Bonzini <pbonz...@redhat.com>
> Cc: David Hildenbrand <da...@redhat.com>
> Cc: Hyman Huang <yong.hu...@smartx.com>
> Reviewed-by: Hyman Huang <yong.hu...@smartx.com>
> Signed-off-by: Cédric Le Goater <c...@redhat.com>
> ---
>
> Changes in v4:
>
> - Dropped log_global_stop() and log_global_sync() changes
>
> include/exec/memory.h | 5 ++++-
> hw/i386/xen/xen-hvm.c | 2 +-
> migration/dirtyrate.c | 13 +++++++++++--
> migration/ram.c | 22 ++++++++++++++++++++--
> system/memory.c | 11 +++++------
> 5 files changed, 41 insertions(+), 12 deletions(-)
>
> diff --git a/include/exec/memory.h b/include/exec/memory.h
> index
> 5555567bc4c9fdb53e8f63487f1400980275687d..c129ee6db7162504bd72d4cfc69b5affb2cd87e8
> 100644
> --- a/include/exec/memory.h
> +++ b/include/exec/memory.h
> @@ -2570,8 +2570,11 @@ void memory_listener_unregister(MemoryListener
> *listener);
> * memory_global_dirty_log_start: begin dirty logging for all regions
> *
> * @flags: purpose of starting dirty log, migration or dirty rate
> + * @errp: pointer to Error*, to store an error if it happens.
> + *
> + * Return: true on success, else false setting @errp with error.
> */
> -void memory_global_dirty_log_start(unsigned int flags);
> +bool memory_global_dirty_log_start(unsigned int flags, Error **errp);
>
> /**
> * memory_global_dirty_log_stop: end dirty logging for all regions
> diff --git a/hw/i386/xen/xen-hvm.c b/hw/i386/xen/xen-hvm.c
> index
> 0608ca99f5166fd6379ee674442484e805eff9c0..57cb7df50788a6c31eff68c95e8eaa856fdebede
> 100644
> --- a/hw/i386/xen/xen-hvm.c
> +++ b/hw/i386/xen/xen-hvm.c
> @@ -654,7 +654,7 @@ void xen_hvm_modified_memory(ram_addr_t start, ram_addr_t
> length)
> void qmp_xen_set_global_dirty_log(bool enable, Error **errp)
> {
> if (enable) {
> - memory_global_dirty_log_start(GLOBAL_DIRTY_MIGRATION);
> + memory_global_dirty_log_start(GLOBAL_DIRTY_MIGRATION, errp);
> } else {
> memory_global_dirty_log_stop(GLOBAL_DIRTY_MIGRATION);
> }
> diff --git a/migration/dirtyrate.c b/migration/dirtyrate.c
> index
> 1d2e85746fb7b10eb7f149976970f9a92125af8a..d02d70b7b4b86a29d4d5540ded416543536d8f98
> 100644
> --- a/migration/dirtyrate.c
> +++ b/migration/dirtyrate.c
> @@ -90,9 +90,15 @@ static int64_t do_calculate_dirtyrate(DirtyPageRecord
> dirty_pages,
>
> void global_dirty_log_change(unsigned int flag, bool start)
> {
> + Error *local_err = NULL;
> + bool ret;
> +
> bql_lock();
> if (start) {
> - memory_global_dirty_log_start(flag);
> + ret = memory_global_dirty_log_start(flag, &local_err);
> + if (!ret) {
> + error_report_err(local_err);
> + }
> } else {
> memory_global_dirty_log_stop(flag);
> }
> @@ -608,9 +614,12 @@ static void calculate_dirtyrate_dirty_bitmap(struct
> DirtyRateConfig config)
> {
> int64_t start_time;
> DirtyPageRecord dirty_pages;
> + Error *local_err = NULL;
>
> bql_lock();
> - memory_global_dirty_log_start(GLOBAL_DIRTY_DIRTY_RATE);
> + if (!memory_global_dirty_log_start(GLOBAL_DIRTY_DIRTY_RATE, &local_err))
> {
> + error_report_err(local_err);
> + }
>
> /*
> * 1'round of log sync may return all 1 bits with
> diff --git a/migration/ram.c b/migration/ram.c
> index
> c5149b7d717aefad7f590422af0ea4a40e7507be..397b4c0f218a66d194e44f9c5f9fe8e9885c48b6
> 100644
> --- a/migration/ram.c
> +++ b/migration/ram.c
> @@ -2836,18 +2836,31 @@ static void
> migration_bitmap_clear_discarded_pages(RAMState *rs)
>
> static void ram_init_bitmaps(RAMState *rs)
> {
> + Error *local_err = NULL;
> + bool ret = true;
> +
> qemu_mutex_lock_ramlist();
>
> WITH_RCU_READ_LOCK_GUARD() {
> ram_list_init_bitmaps();
> /* We don't use dirty log with background snapshots */
> if (!migrate_background_snapshot()) {
> - memory_global_dirty_log_start(GLOBAL_DIRTY_MIGRATION);
> + ret = memory_global_dirty_log_start(GLOBAL_DIRTY_MIGRATION,
> + &local_err);
> + if (!ret) {
> + error_report_err(local_err);
> + goto out_unlock;
Here we may need to free the bitmaps created in ram_list_init_bitmaps().
We can have a helper ram_bitmaps_destroy() for that.
One thing be careful is the new file_bmap can be created but missing in the
ram_save_cleanup(), it's because it's freed earlier. IMHO if we will have
a new ram_bitmaps_destroy() we can unconditionally free file_bmap there
too, as if it's freed early g_free() is noop.
> + }
> migration_bitmap_sync_precopy(rs, false);
> }
> }
> +out_unlock:
> qemu_mutex_unlock_ramlist();
>
> + if (!ret) {
> + return;
> + }
> +
> /*
> * After an eventual first bitmap sync, fixup the initial bitmap
> * containing all 1s to exclude any discarded pages from migration.
> @@ -3631,6 +3644,8 @@ int colo_init_ram_cache(void)
> void colo_incoming_start_dirty_log(void)
> {
> RAMBlock *block = NULL;
> + Error *local_err = NULL;
> +
> /* For memory_global_dirty_log_start below. */
> bql_lock();
> qemu_mutex_lock_ramlist();
> @@ -3642,7 +3657,10 @@ void colo_incoming_start_dirty_log(void)
> /* Discard this dirty bitmap record */
> bitmap_zero(block->bmap, block->max_length >> TARGET_PAGE_BITS);
> }
> - memory_global_dirty_log_start(GLOBAL_DIRTY_MIGRATION);
> + if (!memory_global_dirty_log_start(GLOBAL_DIRTY_MIGRATION,
> + &local_err)) {
> + error_report_err(local_err);
> + }
> }
> ram_state->migration_dirty_pages = 0;
> qemu_mutex_unlock_ramlist();
> diff --git a/system/memory.c b/system/memory.c
> index
> 3600e716149407c10a1f6bf8f0a81c2611cf15ba..cbc098216b789f50460f1d1bc7ec122030693d9e
> 100644
> --- a/system/memory.c
> +++ b/system/memory.c
> @@ -2931,10 +2931,9 @@ static void
> memory_global_dirty_log_rollback(MemoryListener *listener,
> }
> }
>
> -void memory_global_dirty_log_start(unsigned int flags)
> +bool memory_global_dirty_log_start(unsigned int flags, Error **errp)
> {
> unsigned int old_flags;
> - Error *local_err = NULL;
>
> assert(flags && !(flags & (~GLOBAL_DIRTY_MASK)));
>
> @@ -2946,7 +2945,7 @@ void memory_global_dirty_log_start(unsigned int flags)
>
> flags &= ~global_dirty_tracking;
> if (!flags) {
> - return;
> + return true;
> }
>
> old_flags = global_dirty_tracking;
> @@ -2959,7 +2958,7 @@ void memory_global_dirty_log_start(unsigned int flags)
>
> QTAILQ_FOREACH(listener, &memory_listeners, link) {
> if (listener->log_global_start) {
> - ret = listener->log_global_start(listener, &local_err);
> + ret = listener->log_global_start(listener, errp);
> if (!ret) {
> break;
> }
> @@ -2969,14 +2968,14 @@ void memory_global_dirty_log_start(unsigned int flags)
> if (!ret) {
> memory_global_dirty_log_rollback(QTAILQ_PREV(listener, link),
> flags);
> - error_report_err(local_err);
> - return;
> + return false;
> }
>
> memory_region_transaction_begin();
> memory_region_update_pending = true;
> memory_region_transaction_commit();
> }
> + return true;
> }
>
> static void memory_global_dirty_log_do_stop(unsigned int flags)
> --
> 2.44.0
>
--
Peter Xu
