@@ -14,11 +14,13 @@
#ifndef MIGRATION_MISC_H
#define MIGRATION_MISC_H
+#include "exec/cpu-common.h"
#include "qemu/notify.h"
/* migration/ram.c */
void ram_mig_init(void);
+void qemu_guest_free_page_hint(void *addr, size_t len);
/* migration/block.c */
@@ -647,7 +647,7 @@ MigrationParameters *qmp_query_migrate_parameters(Error **errp)
* Return true if we're already in the middle of a migration
* (i.e. any of the active or setup states)
*/
-static bool migration_is_setup_or_active(int state)
+bool migration_is_setup_or_active(int state)
{
switch (state) {
case MIGRATION_STATUS_ACTIVE:
@@ -230,6 +230,7 @@ void migrate_fd_error(MigrationState *s, const Error *error);
void migrate_fd_connect(MigrationState *s, Error *error_in);
void migrate_init(MigrationState *s);
+bool migration_is_setup_or_active(int state);
bool migration_is_blocked(Error **errp);
/* True if outgoing migration has entered postcopy phase */
bool migration_in_postcopy(void);
@@ -2530,6 +2530,54 @@ static void ram_state_resume_prepare(RAMState *rs, QEMUFile *out)
}
/*
+ * This function clears bits of the free pages reported by the caller from the
+ * migration dirty bitmap. @addr is the host address corresponding to the
+ * start of the continuous guest free pages, and @len is the total bytes of
+ * those pages.
+ */
+void qemu_guest_free_page_hint(void *addr, size_t len)
+{
+ RAMBlock *block;
+ ram_addr_t offset;
+ size_t used_len, start, npages;
+ MigrationState *s = migrate_get_current();
+
+ /* This function is currently expected to be used during live migration */
+ if (!migration_is_setup_or_active(s->state)) {
+ return;
+ }
+
+ for (; len > 0; len -= used_len) {
+ block = qemu_ram_block_from_host(addr, false, &offset);
+ assert(block);
+
+ /*
+ * This handles the case that the RAMBlock is resized after the free
+ * page hint is reported.
+ */
+ if (unlikely(offset > block->used_length)) {
+ return;
+ }
+
+ if (len <= block->used_length - offset) {
+ used_len = len;
+ } else {
+ used_len = block->used_length - offset;
+ addr += used_len;
+ }
+
+ start = offset >> TARGET_PAGE_BITS;
+ npages = used_len >> TARGET_PAGE_BITS;
+
+ qemu_mutex_lock(&ram_state->bitmap_mutex);
+ ram_state->migration_dirty_pages -=
+ bitmap_count_one_with_offset(block->bmap, start, npages);
+ bitmap_clear(block->bmap, start, npages);
+ qemu_mutex_unlock(&ram_state->bitmap_mutex);
+ }
+}
+
+/*
* Each of ram_save_setup, ram_save_iterate and ram_save_complete has
* long-running RCU critical section. When rcu-reclaims in the code
* start to become numerous it will be necessary to reduce the
This patch adds an API to clear bits corresponding to guest free pages from the dirty bitmap. Spilt the free page block if it crosses the QEMU RAMBlock boundary. Signed-off-by: Wei Wang <wei.w.wang@intel.com> CC: Dr. David Alan Gilbert <dgilbert@redhat.com> CC: Juan Quintela <quintela@redhat.com> CC: Michael S. Tsirkin <mst@redhat.com> CC: Peter Xu <peterx@redhat.com> --- include/migration/misc.h | 2 ++ migration/migration.c | 2 +- migration/migration.h | 1 + migration/ram.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 52 insertions(+), 1 deletion(-)