From d3cd3abf1a1c03a641ab1b491d93bd550e5c97a6 Mon Sep 17 00:00:00 2001
From: David Gibson <dgibson@redhat.com>
Date: Thu, 3 Sep 2015 04:09:04 +0200
Subject: [PATCH 2/3] RHEL: Set vcpus hard limit to 240 for Power
Message-id: <1441253344-15819-1-git-send-email-dgibson@redhat.com>
Patchwork-id: 67655
O-Subject: [RHEL7.2 qemu-kvm-rhev PATCH] RHEL: Set vcpus hard limit to 240 for Power
Bugzilla: 1257781
RH-Acked-by: Laurent Vivier <lvivier@redhat.com>
RH-Acked-by: Thomas Huth <thuth@redhat.com>
RH-Acked-by: Laszlo Ersek <lersek@redhat.com>
On POWER, the kernel advertises a soft limit based on the number of CPU
threads on the host. We want to allow exceeding this for testing purposes,
so we don't want to set hard limit to soft limit as on x86.
However the POWER hard limit advertised by the kernel is 2048 (== NR_CPUS)
but we only want to allow up to the number of vCPUs we actually test, so
we force the hard limit to 240.
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1257781
Brew: https://bugzilla.redhat.com/show_bug.cgi?id=1257781
Upstream: Downstream only
Signed-off-by: David Gibson <dgibson@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
kvm-all.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/kvm-all.c b/kvm-all.c
index dc71496..8c74e6d 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -1509,8 +1509,27 @@ static int kvm_init(MachineState *ms)
soft_vcpus_limit = kvm_recommended_vcpus(s);
hard_vcpus_limit = kvm_max_vcpus(s);
+#ifdef HOST_PPC64
+ /*
+ * RHEL hack:
+ *
+ * On POWER, the kernel advertises a soft limit based on the
+ * number of CPU threads on the host. We want to allow exceeding
+ * this for testing purposes, so we don't want to set hard limit
+ * to soft limit as on x86.
+ *
+ * However the POWER hard limit advertised by the kernel is 2048
+ * (== NR_CPUS) but we only want to allow up to the number of
+ * vCPUs we actually test, so we force the hard limit to 240
+ */
+ hard_vcpus_limit = 240;
+ if (soft_vcpus_limit > hard_vcpus_limit) {
+ soft_vcpus_limit = hard_vcpus_limit;
+ }
+#else
/* RHEL doesn't support nr_vcpus > soft_vcpus_limit */
hard_vcpus_limit = soft_vcpus_limit;
+#endif
while (nc->name) {
if (nc->num > soft_vcpus_limit) {
--
1.8.3.1