Re: [libvirt] [PATCH 2/2] qemu: Migrate memory on numatune change
On 03/11/2015 08:39 AM, Martin Kletzander wrote:
We've never set the cpuset.memory_migrate value to anything,
keeping it
on default. However, we allow changing cpuset.mems on live domain.
That setting, however, don't have any consequence on a domain unless
it's going to allocate new memory.
I managed to make 'virsh numatune' move all the memory to any node I
wanted even without disabling libnuma's numa_set_membind(), so this
should be safe to use with it as well.
Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1198497
Signed-off-by: Martin Kletzander <mkletzan(a)redhat.com>
---
src/qemu/qemu_cgroup.c | 36 +++++++++++++++++++++++++++++++++++-
1 file changed, 35 insertions(+), 1 deletion(-)
diff --git a/src/qemu/qemu_cgroup.c b/src/qemu/qemu_cgroup.c
index 2b5a182..976a8c4 100644
--- a/src/qemu/qemu_cgroup.c
+++ b/src/qemu/qemu_cgroup.c
@@ -1,7 +1,7 @@
/*
* qemu_cgroup.c: QEMU cgroup management
*
- * Copyright (C) 2006-2014 Red Hat, Inc.
+ * Copyright (C) 2006-2015 Red Hat, Inc.
* Copyright (C) 2006 Daniel P. Berrange
*
* This library is free software; you can redistribute it and/or
@@ -652,6 +652,9 @@ qemuSetupCpusetCgroup(virDomainObjPtr vm,
if (!virCgroupHasController(priv->cgroup, VIR_CGROUP_CONTROLLER_CPUSET))
return 0;
+ if (virCgroupSetCpusetMemoryMigrate(priv->cgroup, true) < 0)
+ return -1;
+
Is this OK to set even if NUMA isn't enabled? I didn't follow the
callers all the way back and this isn't something I know a lot about, so
I'm curious. I do see from the man page it's available since Linux
2.6.16, so one would hope/think that we're OK in assuming we can access
it...
Is it possible that someone wouldn't want to migrate the memory? That
is should this be a configurable attribute?
if (vm->def->cpumask ||
(vm->def->placement_mode == VIR_DOMAIN_CPU_PLACEMENT_MODE_AUTO)) {
@@ -792,9 +795,12 @@ static void
qemuRestoreCgroupState(virDomainObjPtr vm)
{
char *mem_mask = NULL;
+ char *nodeset = NULL;
int empty = -1;
qemuDomainObjPrivatePtr priv = vm->privateData;
+ size_t i = 0;
virBitmapPtr all_nodes;
+ virCgroupPtr cgroup_temp = NULL;
if (!(all_nodes = virNumaGetHostNodeset()))
goto error;
@@ -809,9 +815,37 @@ qemuRestoreCgroupState(virDomainObjPtr vm)
So this is the path for currently running guests to be adjusted on
livirtd restart after install, right?
if (virCgroupSetCpusetMems(priv->cgroup, mem_mask) < 0)
goto error;
+ for (i = 0; i < priv->nvcpupids; i++) {
+ if (virCgroupNewVcpu(priv->cgroup, i, false, &cgroup_temp) < 0 ||
+ virCgroupSetCpusetMemoryMigrate(cgroup_temp, true) < 0 ||
+ virCgroupGetCpusetMems(cgroup_temp, &nodeset) < 0 ||
+ virCgroupSetCpusetMems(cgroup_temp, nodeset) < 0)
+ goto cleanup;
+
+ virCgroupFree(&cgroup_temp);
+ }
+
+ for (i = 0; i < priv->niothreadpids; i++) {
+ if (virCgroupNewIOThread(priv->cgroup, i, false, &cgroup_temp) < 0 ||
cgroup iothread id's are 1..n, so I believe this should be 'i + 1'
simple enough to test by adding <iothreads>2</iothreads> to your domain
definition and making sure this works...
Beyond that - seems reasonable to me
John
+ virCgroupSetCpusetMemoryMigrate(cgroup_temp, true) <
0 ||
+ virCgroupGetCpusetMems(cgroup_temp, &nodeset) < 0 ||
+ virCgroupSetCpusetMems(cgroup_temp, nodeset) < 0)
+ goto cleanup;
+
+ virCgroupFree(&cgroup_temp);
+ }
+
+ if (virCgroupNewEmulator(priv->cgroup, false, &cgroup_temp) < 0 ||
+ virCgroupSetCpusetMemoryMigrate(cgroup_temp, true) < 0 ||
+ virCgroupGetCpusetMems(cgroup_temp, &nodeset) < 0 ||
+ virCgroupSetCpusetMems(cgroup_temp, nodeset) < 0)
+ goto cleanup;
+
cleanup:
VIR_FREE(mem_mask);
+ VIR_FREE(nodeset);
virBitmapFree(all_nodes);
+ virCgroupFree(&cgroup_temp);
return;
error: