From: Hyman Huang(黄勇)
Introduce migration dirty-limit capability, which can
be turned on before live migration and limit dirty
page rate durty live migration.
Introduce migrate_dirty_limit function to help check
if dirty-limit capability enabled during live migration.
Meanwhile, refactor vcpu_dirty_rate_stat_collect
so that period can be configured instead of hardcoded.
dirty-limit capability is kind of like auto-converge
but using dirty limit instead of traditional cpu-throttle
to throttle guest down. To enable this feature, turn on
the dirty-limit capability before live migration using
migratioin-set-capabilities, and set the parameters
"x-vcpu-dirty-limit-period", "vcpu-dirty-limit" suitably
to speed up convergence.
Signed-off-by: Hyman Huang(黄勇)
---
migration/migration.c | 25 +
migration/migration.h | 1 +
qapi/migration.json | 4 +++-
softmmu/dirtylimit.c | 11 ++-
4 files changed, 39 insertions(+), 2 deletions(-)
diff --git a/migration/migration.c b/migration/migration.c
index e2aada2..86950a1 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -61,6 +61,7 @@
#include "sysemu/cpus.h"
#include "yank_functions.h"
#include "sysemu/qtest.h"
+#include "sysemu/kvm.h"
#define MAX_THROTTLE (128 << 20) /* Migration transfer speed throttling
*/
@@ -1348,6 +1349,20 @@ static bool migrate_caps_check(bool *cap_list,
}
}
+if (cap_list[MIGRATION_CAPABILITY_DIRTY_LIMIT]) {
+if (cap_list[MIGRATION_CAPABILITY_AUTO_CONVERGE]) {
+error_setg(errp, "dirty-limit conflicts with auto-converge"
+ " either of then available currently");
+return false;
+}
+
+if (!kvm_enabled() || !kvm_dirty_ring_enabled()) {
+error_setg(errp, "dirty-limit requires KVM with accelerator"
+ " property 'dirty-ring-size' set");
+return false;
+}
+}
+
return true;
}
@@ -2526,6 +2541,15 @@ bool migrate_auto_converge(void)
return s->enabled_capabilities[MIGRATION_CAPABILITY_AUTO_CONVERGE];
}
+bool migrate_dirty_limit(void)
+{
+MigrationState *s;
+
+s = migrate_get_current();
+
+return s->enabled_capabilities[MIGRATION_CAPABILITY_DIRTY_LIMIT];
+}
+
bool migrate_zero_blocks(void)
{
MigrationState *s;
@@ -4455,6 +4479,7 @@ static Property migration_properties[] = {
DEFINE_PROP_MIG_CAP("x-zero-copy-send",
MIGRATION_CAPABILITY_ZERO_COPY_SEND),
#endif
+DEFINE_PROP_MIG_CAP("x-dirty-limit", MIGRATION_CAPABILITY_DIRTY_LIMIT),
DEFINE_PROP_END_OF_LIST(),
};
diff --git a/migration/migration.h b/migration/migration.h
index cdad8ac..7fbb9f8 100644
--- a/migration/migration.h
+++ b/migration/migration.h
@@ -409,6 +409,7 @@ bool migrate_ignore_shared(void);
bool migrate_validate_uuid(void);
bool migrate_auto_converge(void);
+bool migrate_dirty_limit(void);
bool migrate_use_multifd(void);
bool migrate_pause_before_switchover(void);
int migrate_multifd_channels(void);
diff --git a/qapi/migration.json b/qapi/migration.json
index dd667dd..af6b2da 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -477,6 +477,8 @@
#will be handled faster. This is a performance feature and
#should not affect the correctness of postcopy migration.
#(since 7.1)
+# @dirty-limit: Use dirty-limit to throttle down guest if enabled.
+# (since 7.1)
#
# Features:
# @unstable: Members @x-colo and @x-ignore-shared are experimental.
@@ -492,7 +494,7 @@
'dirty-bitmaps', 'postcopy-blocktime', 'late-block-activate',
{ 'name': 'x-ignore-shared', 'features': [ 'unstable' ] },
'validate-uuid', 'background-snapshot',
- 'zero-copy-send', 'postcopy-preempt'] }
+ 'zero-copy-send', 'postcopy-preempt', 'dirty-limit'] }
##
# @MigrationCapabilityStatus:
diff --git a/softmmu/dirtylimit.c b/softmmu/dirtylimit.c
index c42eddd..4537c51 100644
--- a/softmmu/dirtylimit.c
+++ b/softmmu/dirtylimit.c
@@ -23,6 +23,8 @@
#include "exec/memory.h"
#include "hw/boards.h"
#include "sysemu/kvm.h"
+#include "migration/misc.h"
+#include "migration/migration.h"
#include "trace.h"
/*
@@ -75,11 +77,18 @@ static bool dirtylimit_quit;
static void vcpu_dirty_rate_stat_collect(void)
{
+MigrationState *s = migrate_get_current();
VcpuStat stat;
int i = 0;
+int64_t period = DIRTYLIMIT_CALC_TIME_MS;
+
+if (migrate_dirty_limit() &&
+migration_is_active(s)) {
+period = s->parameters.x_vcpu_dirty_limit_period;
+}
/* calculate vcpu dirtyrate */
-vcpu_calculate_dirtyrate(DIRTYLIMIT_CALC_TIME_MS,
+vcpu_calculate_dirtyrate(period,
,
GLOBAL_DIRTY_LIMIT,
false);
--
1.8.3.1
