From 7cbfdb081de6e4eb684447ba48869082df798419 Mon Sep 17 00:00:00 2001

Message-Id: <7cbfdb081de6e4eb684447ba48869082df798419@dist-git>

From: Jiri Denemark <jdenemar@redhat.com>

Date: Wed, 22 Jun 2022 16:12:02 +0200

Subject: [PATCH] qemu_migration: Restore original memory locking limit

MIME-Version: 1.0

Content-Type: text/plain; charset=UTF-8

Content-Transfer-Encoding: 8bit

For RDMA migration we update memory locking limit, but never set it back

once migration finishes (on the destination host) or aborts (on the

source host).

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>

Reviewed-by: Ján Tomko <jtomko@redhat.com>

(cherry picked from commit d4d3bb813031275c2c7cf72724b83c97ce82ab7a)

https://bugzilla.redhat.com/show_bug.cgi?id=2117272

Conflicts:

	src/qemu/qemu_migration.c

            - post-copy resovery not backported

The original 8.7.0 backport contained a bug which was later fixed by

"qemu_migration: Fix restoring memlock limit on destination". This

backport includes the follow up fix squashed in.

Signed-off-by: Jiri Denemark <jdenemar@redhat.com>

---

 src/qemu/qemu_domain.c    | 12 ++++++++++++

 src/qemu/qemu_domain.h    |  3 +++

 src/qemu/qemu_migration.c | 11 +++++++++--

 3 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/src/qemu/qemu_domain.c b/src/qemu/qemu_domain.c

index a81789f194..c24d1e4d53 100644

--- a/src/qemu/qemu_domain.c

+++ b/src/qemu/qemu_domain.c

@@ -2389,6 +2389,11 @@ qemuDomainObjPrivateXMLFormat(virBuffer *buf,

                           priv->originalMemlock);

     }

+    if (priv->preMigrationMemlock > 0) {

+        virBufferAsprintf(buf, "<preMigrationMemlock>%llu</preMigrationMemlock>\n",

+                          priv->preMigrationMemlock);

+    }

+

     return 0;

 }

@@ -3117,6 +3122,13 @@ qemuDomainObjPrivateXMLParse(xmlXPathContextPtr ctxt,

         goto error;

     }

+    if (virXPathULongLong("string(./preMigrationMemlock)", ctxt,

+                          &priv->preMigrationMemlock) == -2) {

+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",

+                       _("failed to parse pre-migration memlock limit"));

+        return -1;

+    }

+

     return 0;

  error:

diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h

index 6d1d23439a..d6e8a7a0fb 100644

--- a/src/qemu/qemu_domain.h

+++ b/src/qemu/qemu_domain.h

@@ -146,6 +146,9 @@ struct _qemuDomainObjPrivate {

     int nbdPort; /* Port used for migration with NBD */

     unsigned short migrationPort;

     int preMigrationState;

+    unsigned long long preMigrationMemlock; /* Original RLIMIT_MEMLOCK in case

+                                               it was changed for the current

+                                               migration job. */

     virChrdevs *devs;

diff --git a/src/qemu/qemu_migration.c b/src/qemu/qemu_migration.c

index 10338f8e87..01102c4300 100644

--- a/src/qemu/qemu_migration.c

+++ b/src/qemu/qemu_migration.c

@@ -2974,7 +2974,8 @@ qemuMigrationDstPrepareAny(virQEMUDriver *driver,

     if (STREQ_NULLABLE(protocol, "rdma") &&

         vm->def->mem.hard_limit > 0 &&

-        qemuDomainSetMaxMemLock(vm, vm->def->mem.hard_limit << 10, NULL) < 0) {

+        qemuDomainSetMaxMemLock(vm, vm->def->mem.hard_limit << 10,

+                                &priv->preMigrationMemlock) < 0) {

         goto stopjob;

     }

@@ -3451,6 +3452,7 @@ qemuMigrationSrcConfirmPhase(virQEMUDriver *driver,

                                          VIR_DOMAIN_EVENT_STOPPED_MIGRATED);

         virObjectEventStateQueue(driver->domainEventState, event);

         qemuDomainEventEmitJobCompleted(driver, vm);

+        priv->preMigrationMemlock = 0;

     } else {

         virErrorPtr orig_err;

         int reason;

@@ -3471,6 +3473,7 @@ qemuMigrationSrcConfirmPhase(virQEMUDriver *driver,

         qemuMigrationParamsReset(driver, vm, QEMU_ASYNC_JOB_MIGRATION_OUT,

                                  jobPriv->migParams, priv->job.apiFlags);

+        qemuDomainSetMaxMemLock(vm, 0, &priv->preMigrationMemlock);

         qemuDomainSaveStatus(vm);

     }

@@ -4224,7 +4227,8 @@ qemuMigrationSrcRun(virQEMUDriver *driver,

     case MIGRATION_DEST_HOST:

         if (STREQ(spec->dest.host.protocol, "rdma") &&

             vm->def->mem.hard_limit > 0 &&

-            qemuDomainSetMaxMemLock(vm, vm->def->mem.hard_limit << 10, NULL) < 0) {

+            qemuDomainSetMaxMemLock(vm, vm->def->mem.hard_limit << 10,

+                                    &priv->preMigrationMemlock) < 0) {

             goto exit_monitor;

         }

         rc = qemuMonitorMigrateToHost(priv->mon, migrate_flags,

@@ -5408,6 +5412,7 @@ qemuMigrationSrcPerformPhase(virQEMUDriver *driver,

     if (ret < 0) {

         qemuMigrationParamsReset(driver, vm, QEMU_ASYNC_JOB_MIGRATION_OUT,

                                  jobPriv->migParams, priv->job.apiFlags);

+        qemuDomainSetMaxMemLock(vm, 0, &priv->preMigrationMemlock);

         qemuMigrationJobFinish(driver, vm);

     } else {

         qemuMigrationJobContinue(vm);

@@ -5869,6 +5874,8 @@ qemuMigrationDstFinish(virQEMUDriver *driver,

          */

         if (inPostCopy)

             g_clear_pointer(&priv->job.completed, qemuDomainJobInfoFree);

+

+        qemuDomainSetMaxMemLock(vm, 0, &priv->preMigrationMemlock);

     }

     qemuMigrationParamsReset(driver, vm, QEMU_ASYNC_JOB_MIGRATION_IN,

-- 

2.35.1