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 <quintela@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Acked-by: Peter Xu <peterx@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)
This commit is contained in:
Juan Quintela 2022-06-21 12:13:14 +02:00
parent f9436522c8
commit 77c259a4cb
4 changed files with 29 additions and 1 deletions

View File

@ -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[] = {

View File

@ -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

View File

@ -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();

View File

@ -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);