By default disable the new dynamic halt polling behavior

The default behavior introduced by kernel commit aca6ff29c
(KVM: dynamic halt-polling) causes a spike in cpu usage and
massive performance degradation with virtio network under
network load. This patch changes the newly introduced kvm
module parameters to reflect the old behavior.

diff --git a/Makefile b/Makefile
index 5851d9dcd8bbe63667a3b9608ecc85d148061ea4..7fb83d5215a890f8b0f78dda5bcda3bdefb87001 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -242,6 +242,7 @@ ${KERNEL_SRC}/README ${KERNEL_CFG_ORG}: ${KERNELSRCTAR}
        cd ${KERNEL_SRC}; patch -p1 < ../CVE-2016-4485-net-fix-infoleak-in-llc.patch
        cd ${KERNEL_SRC}; patch -p1 < ../CVE-2016-4486-net-fix-infoleak-in-rtnetlink.patch
        cd ${KERNEL_SRC}; patch -p1 < ../CVE-2016-4558-bpf-fix-refcnt-overflow.patch
+       cd ${KERNEL_SRC}; patch -p1 < ../kvm-dynamic-halt-polling-disable-default.patch
        sed -i ${KERNEL_SRC}/Makefile -e 's/^EXTRAVERSION.*$$/EXTRAVERSION=${EXTRAVERSION}/'
        touch $@
 

diff --git a/changelog.Debian b/changelog.Debian
index faff21bddea4e1c03a854ba1d4a5ab117ba33f4b..2a9eb81019e498619768652219e5427f69402e86 100644 (file)
--- a/changelog.Debian
+++ b/changelog.Debian
@@ -2,6 +2,8 @@ pve-kernel (4.4.8-50) unstable; urgency=medium
 
   * Fix CVE-2016-4485, CVE-2016-4486, CVE-2016-4558
 
+  * By default disable the new dynamic halt polling behavior
+
  -- Proxmox Support Team <support@proxmox.com>  Thu, 12 May 2016 09:20:02 +0200
 
 pve-kernel (4.4.8-49) unstable; urgency=medium

diff --git a/kvm-dynamic-halt-polling-disable-default.patch b/kvm-dynamic-halt-polling-disable-default.patch
new file mode 100644 (file)
index 0000000..dcf1dee
--- /dev/null
+++ b/kvm-dynamic-halt-polling-disable-default.patch
@@ -0,0 +1,12 @@
+diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
+--- a/virt/kvm/kvm_main.c 2016-05-12 10:39:37.540387127 +0200
++++ b/virt/kvm/kvm_main.c 2016-05-04 10:43:38.063996221 +0200
+@@ -71,7 +71,7 @@ static unsigned int halt_poll_ns = KVM_H
+ module_param(halt_poll_ns, uint, S_IRUGO | S_IWUSR);
+
+ /* Default doubles per-vcpu halt_poll_ns. */
+-static unsigned int halt_poll_ns_grow = 2;
++static unsigned int halt_poll_ns_grow = 0;
+ module_param(halt_poll_ns_grow, int, S_IRUGO);
+
+ /* Default resets per-vcpu halt_poll_ns . */