From nobody Mon Feb 9 19:43:03 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1658563081257237.3820615747503; Sat, 23 Jul 2022 00:58:01 -0700 (PDT) Received: from localhost ([::1]:51148 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oFA1Q-0000eF-2x for importer@patchew.org; Sat, 23 Jul 2022 03:58:00 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:36880) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oF9tT-0001YI-Sp for qemu-devel@nongnu.org; Sat, 23 Jul 2022 03:49:49 -0400 Received: from prt-mail.chinatelecom.cn ([42.123.76.222]:53319 helo=chinatelecom.cn) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oF9tN-0000QA-Ey for qemu-devel@nongnu.org; Sat, 23 Jul 2022 03:49:45 -0400 Received: from clientip-125.69.42.4 (unknown [172.18.0.218]) by chinatelecom.cn (HERMES) with SMTP id CFA682800C0; Sat, 23 Jul 2022 15:49:36 +0800 (CST) Received: from ([172.18.0.218]) by app0025 with ESMTP id 84bcf62c3eb04ff5a2bbdc7a1906b26d for qemu-devel@nongnu.org; Sat, 23 Jul 2022 15:49:38 CST HMM_SOURCE_IP: 172.18.0.218:34686.1353564676 HMM_ATTACHE_NUM: 0000 HMM_SOURCE_TYPE: SMTP X-189-SAVE-TO-SEND: +huangy81@chinatelecom.cn X-Transaction-ID: 84bcf62c3eb04ff5a2bbdc7a1906b26d X-Real-From: huangy81@chinatelecom.cn X-Receive-IP: 172.18.0.218 X-MEDUSA-Status: 0 From: huangy81@chinatelecom.cn To: qemu-devel Cc: Juan Quintela , "Dr. David Alan Gilbert" , Eric Blake , Markus Armbruster , Thomas Huth , Laurent Vivier , Paolo Bonzini , peterx@redhat.com, "Daniel P. Berrange" , =?UTF-8?q?Hyman=20Huang=28=E9=BB=84=E5=8B=87=29?= Subject: [PATCH 4/8] migration: Implement dirty-limit convergence algo Date: Sat, 23 Jul 2022 15:49:16 +0800 Message-Id: X-Mailer: git-send-email 1.8.3.1 In-Reply-To: References: In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=42.123.76.222; envelope-from=huangy81@chinatelecom.cn; helo=chinatelecom.cn X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZM-MESSAGEID: 1658563083009100001 From: Hyman Huang(=E9=BB=84=E5=8B=87) 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. Signed-off-by: Hyman Huang(=E9=BB=84=E5=8B=87) --- migration/ram.c | 53 +++++++++++++++++++++++++++++++++++++---------= ---- migration/trace-events | 1 + 2 files changed, 41 insertions(+), 13 deletions(-) diff --git a/migration/ram.c b/migration/ram.c index b94669b..2a5cd23 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -45,6 +45,7 @@ #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" @@ -57,6 +58,8 @@ #include "qemu/iov.h" #include "multifd.h" #include "sysemu/runstate.h" +#include "sysemu/dirtylimit.h" +#include "sysemu/kvm.h" =20 #include "hw/boards.h" /* for machine_dump_guest_core() */ =20 @@ -1139,6 +1142,21 @@ static void migration_update_rates(RAMState *rs, int= 64_t end_time) } } =20 +/* + * Enable dirty-limit to throttle down the guest + */ +static void migration_dirty_limit_guest(void) +{ + if (!dirtylimit_in_service()) { + MigrationState *s =3D migrate_get_current(); + int64_t quota_dirtyrate =3D s->parameters.vcpu_dirty_limit; + + /* Set quota dirtyrate if dirty limit not in service */ + qmp_set_vcpu_dirty_limit(false, -1, quota_dirtyrate, NULL); + trace_migration_dirty_limit_guest(quota_dirtyrate); + } +} + static void migration_trigger_throttle(RAMState *rs) { MigrationState *s =3D migrate_get_current(); @@ -1148,22 +1166,31 @@ static void migration_trigger_throttle(RAMState *rs) uint64_t bytes_dirty_period =3D rs->num_dirty_pages_period * TARGET_PA= GE_SIZE; uint64_t bytes_dirty_threshold =3D bytes_xfer_period * threshold / 100; =20 - /* During block migration the auto-converge logic incorrectly detects - * that ram migration makes no progress. Avoid this by disabling the - * throttling logic during the bulk phase of block migration. */ - if (migrate_auto_converge() && !blk_mig_bulk_active()) { - /* The following detection logic can be refined later. For now: - Check to see if the ratio between dirtied bytes and the approx. - amount of bytes that just got transferred since the last time - we were in this routine reaches the threshold. If that happens - twice, start or increase throttling. */ - - if ((bytes_dirty_period > bytes_dirty_threshold) && - (++rs->dirty_rate_high_cnt >=3D 2)) { + /* + * The following detection logic can be refined later. For now: + * Check to see if the ratio between dirtied bytes and the approx. + * amount of bytes that just got transferred since the last time + * we were in this routine reaches the threshold. If that happens + * twice, start or increase throttling. + */ + + if ((bytes_dirty_period > bytes_dirty_threshold) && + (++rs->dirty_rate_high_cnt >=3D 2)) { + rs->dirty_rate_high_cnt =3D 0; + /* + * During block migration the auto-converge logic incorrectly dete= cts + * that ram migration makes no progress. Avoid this by disabling t= he + * throttling logic during the bulk phase of block migration + */ + + if (migrate_auto_converge() && !blk_mig_bulk_active()) { trace_migration_throttle(); - rs->dirty_rate_high_cnt =3D 0; mig_throttle_guest_down(bytes_dirty_period, bytes_dirty_threshold); + } else if (migrate_dirty_limit() && + kvm_dirty_ring_enabled() && + migration_is_active(s)) { + migration_dirty_limit_guest(); } } } diff --git a/migration/trace-events b/migration/trace-events index a34afe7..3eb4b0d 100644 --- a/migration/trace-events +++ b/migration/trace-events @@ -89,6 +89,7 @@ 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, uns= igned 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 limi= t %" PRIi64 " MB/s" ram_discard_range(const char *rbname, uint64_t start, size_t len) "%s: sta= rt: %" 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=3D%d a= ddr=3D0x%" PRIx64 " flags=3D0x%x" --=20 1.8.3.1