From 2a5ea92ca0a5dffad54e4d06a683f683996cea9a Mon Sep 17 00:00:00 2001 From: Juan Quintela Date: Tue, 21 Jun 2022 12:13:14 +0200 Subject: [PATCH 05/12] multifd: Create property multifd-flush-after-each-section MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit RH-Author: quintela1 RH-MergeRequest: 186: Multifd flushes its channels 10 times per second RH-Bugzilla: 2196295 RH-Acked-by: Peter Xu RH-Acked-by: Leonardo Brás RH-Commit: [1/3] 5bf5348e8be5b1d1629b859ce1ddb7aa0d72c0d6 (juan.quintela/c9s-qemu-kvm) We used to flush all channels at the end of each RAM section sent. That is not needed, so preparing to only flush after a full iteration through all the RAM. Default value of the property is false. But we return "true" in migrate_multifd_flush_after_each_section() until we implement the code in following patches. Signed-off-by: Juan Quintela Reviewed-by: Dr. David Alan Gilbert Acked-by: Peter Xu --- Rename each-iteration to after-each-section Rename multifd-sync-after-each-section to multifd-flush-after-each-section Move to machine-8.0 (peter) conflit hw_compat_8_0 and hw_compat_rhel_9_2 (cherry picked from commit 77c259a4cb1c9799754b48f570301ebf1de5ded8) --- hw/core/machine.c | 2 ++ migration/migration.h | 12 ++++++++++++ migration/options.c | 13 +++++++++++++ migration/options.h | 1 + 4 files changed, 28 insertions(+) diff --git a/hw/core/machine.c b/hw/core/machine.c index 5abdc8c39b..5ea52317b9 100644 --- a/hw/core/machine.c +++ b/hw/core/machine.c @@ -54,6 +54,8 @@ const char *rhel_old_machine_deprecation = "machine types for previous major releases are deprecated"; GlobalProperty hw_compat_rhel_9_2[] = { + /* hw_compat_rhel_9_2 from hw_compat_8_0 */ + { "migration", "multifd-flush-after-each-section", "on"}, /* hw_compat_rhel_9_2 from hw_compat_7_2 */ { "e1000e", "migrate-timadj", "off" }, /* hw_compat_rhel_9_2 from hw_compat_7_2 */ diff --git a/migration/migration.h b/migration/migration.h index 7ccf460aa2..04c78c1fd6 100644 --- a/migration/migration.h +++ b/migration/migration.h @@ -411,6 +411,18 @@ struct MigrationState { */ bool preempt_pre_7_2; + /* + * flush every channel after each section sent. + * + * This assures that we can't mix pages from one iteration through + * ram pages with pages for the following iteration. We really + * only need to do this flush after we have go through all the + * dirty pages. For historical reasons, we do that after each + * section. This is suboptimal (we flush too many times). + * Default value is false. Setting this property has no effect + * until the patch that removes this comment. (since 8.1) + */ + bool multifd_flush_after_each_section; /* * This decides the size of guest memory chunk that will be used * to track dirty bitmap clearing. The size of memory chunk will diff --git a/migration/options.c b/migration/options.c index ccd7ef3907..5b0d080ecb 100644 --- a/migration/options.c +++ b/migration/options.c @@ -88,6 +88,8 @@ Property migration_properties[] = { send_section_footer, true), DEFINE_PROP_BOOL("decompress-error-check", MigrationState, decompress_error_check, true), + DEFINE_PROP_BOOL("multifd-flush-after-each-section", MigrationState, + multifd_flush_after_each_section, true), DEFINE_PROP_UINT8("x-clear-bitmap-shift", MigrationState, clear_bitmap_shift, CLEAR_BITMAP_SHIFT_DEFAULT), DEFINE_PROP_BOOL("x-preempt-pre-7-2", MigrationState, @@ -344,6 +346,17 @@ bool migrate_zero_copy_send(void) /* pseudo capabilities */ +bool migrate_multifd_flush_after_each_section(void) +{ + MigrationState *s = migrate_get_current(); + + /* + * Until the patch that remove this comment, we always return that + * the property is enabled. + */ + return true || s->multifd_flush_after_each_section; +} + bool migrate_postcopy(void) { return migrate_postcopy_ram() || migrate_dirty_bitmaps(); diff --git a/migration/options.h b/migration/options.h index 0fc7be6869..271f49ae5f 100644 --- a/migration/options.h +++ b/migration/options.h @@ -60,6 +60,7 @@ bool migrate_zero_copy_send(void); * check, but they are not a capability. */ +bool migrate_multifd_flush_after_each_section(void); bool migrate_postcopy(void); bool migrate_tls(void); -- 2.39.3