From c7ae0b39eec728d7f88029f932fdd6d3bfda6e68 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Hyman=20Huang=28=E9=BB=84=E5=8B=87=29?= Date: Wed, 7 Jun 2023 23:30:50 +0800 Subject: [PATCH] migration: Introduce dirty-limit capability MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit There is a conflict when merging patches in qemu-6.2.0, and there is a phenomenon that the corresponding files and functions cannot be found.Merge after modifying the patch by wangguochun@kylinos.cn 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) Acked-by: Peter Xu Reviewed-by: Juan Quintela Message-Id: <168618975839.6361.17407633874747688653-4@git.sr.ht> Signed-off-by: Juan Quintela --- migration/migration.c | 25 +++++++++++++++++++++++++ migration/migration.h | 1 + qapi/migration.json | 13 ++++++++++++- softmmu/dirtylimit.c | 17 +++++++++++++---- 4 files changed, 51 insertions(+), 5 deletions(-) diff --git a/migration/migration.c b/migration/migration.c index 06d9b6a15d..50c33fecf3 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -60,6 +60,7 @@ #include "qemu/yank.h" #include "sysemu/cpus.h" #include "yank_functions.h" +#include "sysemu/kvm.h" #define MAX_THROTTLE (128 << 20) /* Migration transfer speed throttling */ @@ -1265,6 +1266,20 @@ static bool migrate_caps_check(bool *cap_list, error_setg(errp, "multifd is not supported by current protocol"); return false; } + + 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; } @@ -2550,6 +2565,15 @@ bool migrate_dirty_bitmaps(void) return s->enabled_capabilities[MIGRATION_CAPABILITY_DIRTY_BITMAPS]; } +bool migrate_dirty_limit(void) +{ + MigrationState *s; + + s = migrate_get_current(); + + return s->enabled_capabilities[MIGRATION_CAPABILITY_DIRTY_LIMIT]; +} + bool migrate_ignore_shared(void) { MigrationState *s; @@ -4316,6 +4340,7 @@ static Property migration_properties[] = { DEFINE_PROP_UINT64("vcpu-dirty-limit", MigrationState, parameters.vcpu_dirty_limit, DEFAULT_MIGRATE_VCPU_DIRTY_LIMIT), + DEFINE_PROP_MIG_CAP("x-dirty-limit", MIGRATION_CAPABILITY_DIRTY_LIMIT), /* Migration capabilities */ DEFINE_PROP_MIG_CAP("x-xbzrle", MIGRATION_CAPABILITY_XBZRLE), diff --git a/migration/migration.h b/migration/migration.h index 6b546a6ac7..9ce1fc8ea0 100644 --- a/migration/migration.h +++ b/migration/migration.h @@ -329,6 +329,7 @@ bool migrate_release_ram(void); bool migrate_postcopy_ram(void); bool migrate_zero_blocks(void); bool migrate_dirty_bitmaps(void); +bool migrate_dirty_limit(void); bool migrate_ignore_shared(void); bool migrate_validate_uuid(void); diff --git a/qapi/migration.json b/qapi/migration.json index f35f0377dc..4751c5ee53 100644 --- a/qapi/migration.json +++ b/qapi/migration.json @@ -452,6 +452,16 @@ # procedure starts. The VM RAM is saved with running VM. # (since 6.0) # +# @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. # @@ -465,7 +475,8 @@ 'block', 'return-path', 'pause-before-switchover', 'multifd', 'dirty-bitmaps', 'postcopy-blocktime', 'late-block-activate', { 'name': 'x-ignore-shared', 'features': [ 'unstable' ] }, - 'validate-uuid', 'background-snapshot'] } + 'validate-uuid', 'background-snapshot', + 'dirty-limit'] } ## # @MigrationCapabilityStatus: diff --git a/softmmu/dirtylimit.c b/softmmu/dirtylimit.c index 5041c230d0..4d770aaba4 100644 --- a/softmmu/dirtylimit.c +++ b/softmmu/dirtylimit.c @@ -24,6 +24,8 @@ #include "hw/boards.h" #include "sysemu/kvm.h" #include "trace.h" +#include "migration/misc.h" +#include "migration/migration.h" /* * Dirtylimit stop working if dirty page rate error @@ -75,14 +77,21 @@ 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; -- 2.27.0