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[PATCH v3 14/19] migration: Parameter x-postcopy-preempt-break-huge
From: |
Peter Xu |
Subject: |
[PATCH v3 14/19] migration: Parameter x-postcopy-preempt-break-huge |
Date: |
Wed, 30 Mar 2022 17:39:03 -0400 |
Add a parameter that can conditionally disable the "break sending huge
page" behavior in postcopy preemption. By default it's enabled.
It should only be used for debugging purposes, and we should never remove
the "x-" prefix.
Signed-off-by: Peter Xu <peterx@redhat.com>
---
migration/migration.c | 2 ++
migration/migration.h | 7 +++++++
migration/ram.c | 7 +++++++
3 files changed, 16 insertions(+)
diff --git a/migration/migration.c b/migration/migration.c
index 33faa0ff6e..ee3df9e229 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -4330,6 +4330,8 @@ static Property migration_properties[] = {
DEFINE_PROP_SIZE("announce-step", MigrationState,
parameters.announce_step,
DEFAULT_MIGRATE_ANNOUNCE_STEP),
+ DEFINE_PROP_BOOL("x-postcopy-preempt-break-huge", MigrationState,
+ postcopy_preempt_break_huge, true),
/* Migration capabilities */
DEFINE_PROP_MIG_CAP("x-xbzrle", MIGRATION_CAPABILITY_XBZRLE),
diff --git a/migration/migration.h b/migration/migration.h
index f898b8547a..6ee520642f 100644
--- a/migration/migration.h
+++ b/migration/migration.h
@@ -340,6 +340,13 @@ struct MigrationState {
bool send_configuration;
/* Whether we send section footer during migration */
bool send_section_footer;
+ /*
+ * Whether we allow break sending huge pages when postcopy preempt is
+ * enabled. When disabled, we won't interrupt precopy within sending a
+ * host huge page, which is the old behavior of vanilla postcopy.
+ * NOTE: this parameter is ignored if postcopy preempt is not enabled.
+ */
+ bool postcopy_preempt_break_huge;
/* Needed by postcopy-pause state */
QemuSemaphore postcopy_pause_sem;
diff --git a/migration/ram.c b/migration/ram.c
index 518d511874..3400cde6e9 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -2266,11 +2266,18 @@ static int ram_save_target_page(RAMState *rs,
PageSearchStatus *pss)
static bool postcopy_needs_preempt(RAMState *rs, PageSearchStatus *pss)
{
+ MigrationState *ms = migrate_get_current();
+
/* Not enabled eager preempt? Then never do that. */
if (!migrate_postcopy_preempt()) {
return false;
}
+ /* If the user explicitly disabled breaking of huge page, skip */
+ if (!ms->postcopy_preempt_break_huge) {
+ return false;
+ }
+
/* If the ramblock we're sending is a small page? Never bother. */
if (qemu_ram_pagesize(pss->block) == TARGET_PAGE_SIZE) {
return false;
--
2.32.0
- [PATCH v3 09/19] migration: Postcopy preemption preparation on channel creation, (continued)
- [PATCH v3 09/19] migration: Postcopy preemption preparation on channel creation, Peter Xu, 2022/03/30
- [PATCH v3 08/19] migration: Add postcopy-preempt capability, Peter Xu, 2022/03/30
- [PATCH v3 10/19] migration: Postcopy preemption enablement, Peter Xu, 2022/03/30
- [PATCH v3 07/19] migration: Allow migrate-recover to run multiple times, Peter Xu, 2022/03/30
- [PATCH v3 12/19] migration: Create the postcopy preempt channel asynchronously, Peter Xu, 2022/03/30
- [PATCH v3 15/19] migration: Add helpers to detect TLS capability, Peter Xu, 2022/03/30
- [PATCH v3 16/19] migration: Export tls-[creds|hostname|authz] params to cmdline too, Peter Xu, 2022/03/30
- [PATCH v3 13/19] migration: Enable TLS for preempt channel, Peter Xu, 2022/03/30
- [PATCH v3 11/19] migration: Postcopy recover with preempt enabled, Peter Xu, 2022/03/30
- [PATCH v3 18/19] tests: Add postcopy tls recovery migration test, Peter Xu, 2022/03/30
- [PATCH v3 14/19] migration: Parameter x-postcopy-preempt-break-huge,
Peter Xu <=
- [PATCH v3 17/19] tests: Add postcopy tls migration test, Peter Xu, 2022/03/30
- [PATCH v3 19/19] tests: Add postcopy preempt tests, Peter Xu, 2022/03/30