From: Hyman Huang(黄勇) <yong.huang@xxxxxxxxxx>
Implement dirty-limit convergence algo for live migration,
which is kind of like auto-converge algo but using dirty-limit
instead of cpu throttle to make migration convergent.
Enable dirty page limit if dirty_rate_high_cnt greater than 2
when dirty-limit capability enabled, Disable dirty-limit if
migration be canceled.
Note that "set_vcpu_dirty_limit", "cancel_vcpu_dirty_limit"
commands are not allowed during dirty-limit live migration.
Signed-off-by: Hyman Huang(黄勇) <yong.huang@xxxxxxxxxx>
Reviewed-by: Markus Armbruster <armbru@xxxxxxxxxx>
Message-ID: <168733225273.5845.15871826788879741674-7@xxxxxxxxx>
Reviewed-by: Juan Quintela <quintela@xxxxxxxxxx>
Signed-off-by: Juan Quintela <quintela@xxxxxxxxxx>
---
migration/migration.c | 3 +++
migration/ram.c | 36 ++++++++++++++++++++++++++++++++++++
softmmu/dirtylimit.c | 29 +++++++++++++++++++++++++++++
migration/trace-events | 1 +
4 files changed, 69 insertions(+)
diff --git a/migration/migration.c b/migration/migration.c
index ae49d42eab..49332251e8 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -166,6 +166,9 @@ void migration_cancel(const Error *error)
if (error) {
migrate_set_error(current_migration, error);
}
+ if (migrate_dirty_limit()) {
+ qmp_cancel_vcpu_dirty_limit(false, -1, NULL);
+ }
migrate_fd_cancel(current_migration);
}
diff --git a/migration/ram.c b/migration/ram.c
index 1d9300f4c5..9040d66e61 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -46,6 +46,7 @@
#include "qapi/error.h"
#include "qapi/qapi-types-migration.h"
#include "qapi/qapi-events-migration.h"
+#include "qapi/qapi-commands-migration.h"
#include "qapi/qmp/qerror.h"
#include "trace.h"
#include "exec/ram_addr.h"
@@ -59,6 +60,8 @@
#include "multifd.h"
#include "sysemu/runstate.h"
#include "options.h"
+#include "sysemu/dirtylimit.h"
+#include "sysemu/kvm.h"
#include "hw/boards.h" /* for machine_dump_guest_core() */
@@ -984,6 +987,37 @@ static void migration_update_rates(RAMState *rs, int64_t end_time)
}
}
+/*
+ * Enable dirty-limit to throttle down the guest
+ */
+static void migration_dirty_limit_guest(void)
+{
+ /*
+ * dirty page rate quota for all vCPUs fetched from
+ * migration parameter 'vcpu_dirty_limit'
+ */
+ static int64_t quota_dirtyrate;
+ MigrationState *s = migrate_get_current();
+
+ /*
+ * If dirty limit already enabled and migration parameter
+ * vcpu-dirty-limit untouched.
+ */
+ if (dirtylimit_in_service() &&
+ quota_dirtyrate == s->parameters.vcpu_dirty_limit) {
+ return;
+ }
+
+ quota_dirtyrate = s->parameters.vcpu_dirty_limit;
+
+ /*
+ * Set all vCPU a quota dirtyrate, note that the second
+ * parameter will be ignored if setting all vCPU for the vm
+ */
+ qmp_set_vcpu_dirty_limit(false, -1, quota_dirtyrate, NULL);
+ trace_migration_dirty_limit_guest(quota_dirtyrate);
+}
+
static void migration_trigger_throttle(RAMState *rs)
{
uint64_t threshold = migrate_throttle_trigger_threshold();
@@ -1013,6 +1047,8 @@ static void migration_trigger_throttle(RAMState *rs)
trace_migration_throttle();
mig_throttle_guest_down(bytes_dirty_period,
bytes_dirty_threshold);
+ } else if (migrate_dirty_limit()) {
+ migration_dirty_limit_guest();
}
}
}
diff --git a/softmmu/dirtylimit.c b/softmmu/dirtylimit.c
index 942d876523..a6d854d161 100644
--- a/softmmu/dirtylimit.c
+++ b/softmmu/dirtylimit.c
@@ -436,6 +436,23 @@ static void dirtylimit_cleanup(void)
dirtylimit_state_finalize();
}
+/*
+ * dirty page rate limit is not allowed to set if migration
+ * is running with dirty-limit capability enabled.
+ */
+static bool dirtylimit_is_allowed(void)
+{
+ MigrationState *ms = migrate_get_current();
+
+ if (migration_is_running(ms->state) &&
+ (!qemu_thread_is_self(&ms->thread)) &&
+ migrate_dirty_limit() &&
+ dirtylimit_in_service()) {
+ return false;
+ }
+ return true;
+}
+
void qmp_cancel_vcpu_dirty_limit(bool has_cpu_index,
int64_t cpu_index,
Error **errp)
@@ -449,6 +466,12 @@ void qmp_cancel_vcpu_dirty_limit(bool has_cpu_index,
return;
}
+ if (!dirtylimit_is_allowed()) {
+ error_setg(errp, "can't cancel dirty page rate limit while"
+ " migration is running");
+ return;
+ }
+
if (!dirtylimit_in_service()) {
return;
}
@@ -499,6 +522,12 @@ void qmp_set_vcpu_dirty_limit(bool has_cpu_index,
return;
}
+ if (!dirtylimit_is_allowed()) {
+ error_setg(errp, "can't set dirty page rate limit while"
+ " migration is running");
+ return;
+ }
+
if (!dirty_rate) {
qmp_cancel_vcpu_dirty_limit(has_cpu_index, cpu_index, errp);
return;
diff --git a/migration/trace-events b/migration/trace-events
index 4e43fe20fc..4666f19325 100644
--- a/migration/trace-events
+++ b/migration/trace-events
@@ -93,6 +93,7 @@ migration_bitmap_sync_start(void) ""
migration_bitmap_sync_end(uint64_t dirty_pages) "dirty_pages %" PRIu64
migration_bitmap_clear_dirty(char *str, uint64_t start, uint64_t size, unsigned long page) "rb %s start 0x%"PRIx64" size 0x%"PRIx64" page 0x%lx"
migration_throttle(void) ""
+migration_dirty_limit_guest(int64_t dirtyrate) "guest dirty page rate limit %" PRIi64 " MB/s"
ram_discard_range(const char *rbname, uint64_t start, size_t len) "%s: start: %" PRIx64 " %zx"
ram_load_loop(const char *rbname, uint64_t addr, int flags, void *host) "%s: addr: 0x%" PRIx64 " flags: 0x%x host: %p"
ram_load_postcopy_loop(int channel, uint64_t addr, int flags) "chan=%d addr=0x%" PRIx64 " flags=0x%x"
--
2.40.1
