[PULL 09/25] migration: Implement dirty-limit convergence algo

From: Hyman Huang(黄勇) <yong.huang(a)smartx.com&gt; 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(a)smartx.com&gt; Reviewed-by: Markus Armbruster <armbru(a)redhat.com&gt; Message-ID: <168733225273.5845.15871826788879741674-7(a)git.sr.ht&gt; Reviewed-by: Juan Quintela <quintela(a)redhat.com&gt; Signed-off-by: Juan Quintela <quintela(a)redhat.com&gt; --- 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