From: Hyman Huang(黄勇) <yong.huang@xxxxxxxxxx> 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 migrate-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) <yong.huang@xxxxxxxxxx> Acked-by: Peter Xu <peterx@xxxxxxxxxx> Reviewed-by: Juan Quintela <quintela@xxxxxxxxxx> Message-Id: <168618975839.6361.17407633874747688653-4@xxxxxxxxx> Signed-off-by: Juan Quintela <quintela@xxxxxxxxxx> --- qapi/migration.json | 13 ++++++++++++- migration/options.h | 1 + migration/options.c | 23 ++++++++++++++++++++++- softmmu/dirtylimit.c | 18 ++++++++++++++---- 4 files changed, 49 insertions(+), 6 deletions(-) diff --git a/qapi/migration.json b/qapi/migration.json index 22104cef08..e094438d74 100644 --- a/qapi/migration.json +++ b/qapi/migration.json @@ -497,6 +497,16 @@ # are present. 'return-path' capability must be enabled to use # it. (since 8.1) # +# @dirty-limit: If enabled, migration will use the dirty-limit algo to +# throttle down guest instead of auto-converge algo. +# Throttle algo only works when vCPU's dirtyrate greater +# than 'vcpu-dirty-limit', read processes in guest os +# aren't penalized any more, so this algo can improve +# performance of vCPU during live migration. This is an +# optional performance feature and should not affect the +# correctness of the existing auto-converge algo. +# (since 8.1) +# # Features: # # @unstable: Members @x-colo and @x-ignore-shared are experimental. @@ -512,7 +522,8 @@ 'dirty-bitmaps', 'postcopy-blocktime', 'late-block-activate', { 'name': 'x-ignore-shared', 'features': [ 'unstable' ] }, 'validate-uuid', 'background-snapshot', - 'zero-copy-send', 'postcopy-preempt', 'switchover-ack'] } + 'zero-copy-send', 'postcopy-preempt', 'switchover-ack', + 'dirty-limit'] } ## # @MigrationCapabilityStatus: diff --git a/migration/options.h b/migration/options.h index 9aaf363322..045e2a41a2 100644 --- a/migration/options.h +++ b/migration/options.h @@ -29,6 +29,7 @@ bool migrate_block(void); bool migrate_colo(void); bool migrate_compress(void); bool migrate_dirty_bitmaps(void); +bool migrate_dirty_limit(void); bool migrate_events(void); bool migrate_ignore_shared(void); bool migrate_late_block_activate(void); diff --git a/migration/options.c b/migration/options.c index 7d2d98830e..7d83f190d6 100644 --- a/migration/options.c +++ b/migration/options.c @@ -27,6 +27,7 @@ #include "qemu-file.h" #include "ram.h" #include "options.h" +#include "sysemu/kvm.h" /* Maximum migrate downtime set to 2000 seconds */ #define MAX_MIGRATE_DOWNTIME_SECONDS 2000 @@ -196,7 +197,7 @@ Property migration_properties[] = { #endif DEFINE_PROP_MIG_CAP("x-switchover-ack", MIGRATION_CAPABILITY_SWITCHOVER_ACK), - + DEFINE_PROP_MIG_CAP("x-dirty-limit", MIGRATION_CAPABILITY_DIRTY_LIMIT), DEFINE_PROP_END_OF_LIST(), }; @@ -242,6 +243,13 @@ bool migrate_dirty_bitmaps(void) return s->capabilities[MIGRATION_CAPABILITY_DIRTY_BITMAPS]; } +bool migrate_dirty_limit(void) +{ + MigrationState *s = migrate_get_current(); + + return s->capabilities[MIGRATION_CAPABILITY_DIRTY_LIMIT]; +} + bool migrate_events(void) { MigrationState *s = migrate_get_current(); @@ -572,6 +580,19 @@ bool migrate_caps_check(bool *old_caps, bool *new_caps, Error **errp) return false; } } + if (new_caps[MIGRATION_CAPABILITY_DIRTY_LIMIT]) { + if (new_caps[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; } diff --git a/softmmu/dirtylimit.c b/softmmu/dirtylimit.c index e80201097a..942d876523 100644 --- a/softmmu/dirtylimit.c +++ b/softmmu/dirtylimit.c @@ -24,6 +24,9 @@ #include "hw/boards.h" #include "sysemu/kvm.h" #include "trace.h" +#include "migration/misc.h" +#include "migration/migration.h" +#include "migration/options.h" /* * Dirtylimit stop working if dirty page rate error @@ -75,14 +78,21 @@ 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, - &stat, - GLOBAL_DIRTY_LIMIT, - false); + vcpu_calculate_dirtyrate(period, + &stat, + GLOBAL_DIRTY_LIMIT, + false); for (i = 0; i < stat.nvcpu; i++) { vcpu_dirty_rate_stat->stat.rates[i].id = i; -- 2.40.1