* Peter Xu (pet...@redhat.com) wrote:
> Some of the memory listener may want to do log synchronization without
> being able to specify a range of memory to sync but always globally.
> Such a memory listener should provide this new method instead of the
> log_sync() method.
>
> Obviously we can also achieve similar thing when we put the global
> sync logic into a log_sync() handler. However that's not efficient
> enough because otherwise memory_global_dirty_log_sync() may do the
> global sync N times, where N is the number of flat views.
>
> Make this new method be exclusive to log_sync().
>
> Signed-off-by: Peter Xu
OK, so I guess the idea here is that when you have a ring with dirty
pages on it, you just need to clear all outstanding things on the ring
whereever they came from.
Reviewed-by: Dr. David Alan Gilbert
> ---
> include/exec/memory.h | 12
> memory.c | 33 +++--
> 2 files changed, 35 insertions(+), 10 deletions(-)
>
> diff --git a/include/exec/memory.h b/include/exec/memory.h
> index e85b7de99a..c4427094bb 100644
> --- a/include/exec/memory.h
> +++ b/include/exec/memory.h
> @@ -533,6 +533,18 @@ struct MemoryListener {
> */
> void (*log_sync)(MemoryListener *listener, MemoryRegionSection *section);
>
> +/**
> + * @log_sync_global:
> + *
> + * This is the global version of @log_sync when the listener does
> + * not have a way to synchronize the log with finer granularity.
> + * When the listener registers with @log_sync_global defined, then
> + * its @log_sync must be NULL. Vice versa.
> + *
> + * @listener: The #MemoryListener.
> + */
> +void (*log_sync_global)(MemoryListener *listener);
> +
> /**
> * @log_clear:
> *
> diff --git a/memory.c b/memory.c
> index aeaa8dcc9e..53828ba00c 100644
> --- a/memory.c
> +++ b/memory.c
> @@ -2016,6 +2016,10 @@ void memory_region_set_dirty(MemoryRegion *mr, hwaddr
> addr,
>
> memory_region_get_dirty_log_mask(mr));
> }
>
> +/*
> + * If memory region `mr' is NULL, do global sync. Otherwise, sync
> + * dirty bitmap for the specified memory region.
> + */
> static void memory_region_sync_dirty_bitmap(MemoryRegion *mr)
> {
> MemoryListener *listener;
> @@ -2029,18 +2033,24 @@ static void
> memory_region_sync_dirty_bitmap(MemoryRegion *mr)
> * address space once.
> */
> QTAILQ_FOREACH(listener, _listeners, link) {
> -if (!listener->log_sync) {
> -continue;
> -}
> -as = listener->address_space;
> -view = address_space_get_flatview(as);
> -FOR_EACH_FLAT_RANGE(fr, view) {
> -if (fr->dirty_log_mask && (!mr || fr->mr == mr)) {
> -MemoryRegionSection mrs = section_from_flat_range(fr, view);
> -listener->log_sync(listener, );
> +if (listener->log_sync) {
> +as = listener->address_space;
> +view = address_space_get_flatview(as);
> +FOR_EACH_FLAT_RANGE(fr, view) {
> +if (fr->dirty_log_mask && (!mr || fr->mr == mr)) {
> +MemoryRegionSection mrs = section_from_flat_range(fr,
> view);
> +listener->log_sync(listener, );
> +}
> }
> +flatview_unref(view);
> +} else if (listener->log_sync_global) {
> +/*
> + * No matter whether MR is specified, what we can do here
> + * is to do a global sync, because we are not capable to
> + * sync in a finer granularity.
> + */
> +listener->log_sync_global(listener);
> }
> -flatview_unref(view);
> }
> }
>
> @@ -2727,6 +2737,9 @@ void memory_listener_register(MemoryListener *listener,
> AddressSpace *as)
> {
> MemoryListener *other = NULL;
>
> +/* Only one of them can be defined for a listener */
> +assert(!(listener->log_sync && listener->log_sync_global));
> +
> listener->address_space = as;
> if (QTAILQ_EMPTY(_listeners)
> || listener->priority >= QTAILQ_LAST(_listeners)->priority) {
> --
> 2.24.1
>
>
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
