From 3dfa22b502f065f5171475b6459a4cc18d74c125 Mon Sep 17 00:00:00 2001
Message-Id: <3dfa22b502f065f5171475b6459a4cc18d74c125@dist-git>
From: Wang Rui <moon.wangrui@huawei.com>
Date: Fri, 28 Nov 2014 14:36:26 +0100
Subject: [PATCH] qemu: fix domain startup failing with 'strict' mode in
 numatune

https://bugzilla.redhat.com/show_bug.cgi?id=1168866

If the memory mode is specified as 'strict' and with one node, we
get the following error when starting domain.

error: Unable to write to '$cgroup_path/cpuset.mems': Device or resource busy

XML is configured with numatune as follows:
  <numatune>
    <memory mode='strict' nodeset='0'/>
  </numatune>

It's broken by Commit 411cea638f6ec8503b7142a31e58b1cd85dbeaba
which moved qemuSetupCgroupForEmulator() before setting cpuset.mems
in qemuSetupCgroupPostInit.

Directory '$cgroup_path/emulator/' is created in qemuSetupCgroupForEmulator.
But '$cgroup_path/emulator/cpuset.mems' it not set and has a default value
(all nodes, such as 0-1). Then we setup '$cgroup_path/cpuset.mems' to the
nodemask (in this case it's '0') in qemuSetupCgroupPostInit. It must fail.

This patch makes '$cgroup_path/emulator/cpuset.mems' is set before
'$cgroup_path/cpuset.mems'. The action is similar with that in
qemuDomainSetNumaParamsLive.

Signed-off-by: Wang Rui <moon.wangrui@huawei.com>
(cherry picked from commit c6e90248676126c209b3b6017ad27cf6c6a0ab8f)
Signed-off-by: Martin Kletzander <mkletzan@redhat.com>
Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
---
 src/qemu/qemu_cgroup.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/src/qemu/qemu_cgroup.c b/src/qemu/qemu_cgroup.c
index bd22b7f..7609c0f 100644
--- a/src/qemu/qemu_cgroup.c
+++ b/src/qemu/qemu_cgroup.c
@@ -611,6 +611,7 @@ static int
 qemuSetupCpusetMems(virDomainObjPtr vm,
                     virBitmapPtr nodemask)
 {
+    virCgroupPtr cgroup_temp = NULL;
     qemuDomainObjPrivatePtr priv = vm->privateData;
     char *mem_mask = NULL;
     int ret = -1;
@@ -623,13 +624,16 @@ qemuSetupCpusetMems(virDomainObjPtr vm,
                                             &mem_mask, -1) < 0)
         goto cleanup;
 
-    if (mem_mask &&
-        virCgroupSetCpusetMems(priv->cgroup, mem_mask) < 0)
-        goto cleanup;
+    if (mem_mask)
+        if (virCgroupNewEmulator(priv->cgroup, false, &cgroup_temp) < 0 ||
+            virCgroupSetCpusetMems(cgroup_temp, mem_mask) < 0 ||
+            virCgroupSetCpusetMems(priv->cgroup, mem_mask) < 0)
+            goto cleanup;
 
     ret = 0;
  cleanup:
     VIR_FREE(mem_mask);
+    virCgroupFree(&cgroup_temp);
     return ret;
 }
 
-- 
2.1.3