From 77c259a4cb1c9799754b48f570301ebf1de5ded8 Mon Sep 17 00:00:00 2001 From: Juan Quintela Date: Tue, 21 Jun 2022 12:13:14 +0200 Subject: [PATCH] multifd: Create property multifd-flush-after-each-section 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) --- hw/core/machine.c | 4 +++- migration/migration.h | 12 ++++++++++++ migration/options.c | 13 +++++++++++++ migration/options.h | 1 + 4 files changed, 29 insertions(+), 1 deletion(-) diff --git a/hw/core/machine.c b/hw/core/machine.c index 2ce97a5d3b..47a34841a5 100644 --- a/hw/core/machine.c +++ b/hw/core/machine.c @@ -39,7 +39,9 @@ #include "hw/virtio/virtio.h" #include "hw/virtio/virtio-pci.h" -GlobalProperty hw_compat_8_0[] = {}; +GlobalProperty hw_compat_8_0[] = { + { "migration", "multifd-flush-after-each-section", "on"}, +}; const size_t hw_compat_8_0_len = G_N_ELEMENTS(hw_compat_8_0); GlobalProperty hw_compat_7_2[] = { diff --git a/migration/migration.h b/migration/migration.h index 2b71df8617..e2247d708f 100644 --- a/migration/migration.h +++ b/migration/migration.h @@ -405,6 +405,18 @@ 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 * be GUEST_PAGE_SIZE << N. Say, N=0 means we will clear dirty diff --git a/migration/options.c b/migration/options.c index f2a77cdef1..690c8f718e 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, @@ -335,6 +337,17 @@ 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 00854d60f9..3c322867cd 100644 --- a/migration/options.h +++ b/migration/options.h @@ -59,6 +59,7 @@ 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); -- 2.11.4.GIT