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 <quint...@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
Acked-by: Peter Xu <pet...@redhat.com>
---
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
@@ -404,6 +404,18 @@ 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 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);
--
2.40.0
