summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorDavid Hildenbrand <dahi@linux.vnet.ibm.com>2015-09-18 12:34:53 +0200
committerPaolo Bonzini <pbonzini@redhat.com>2015-09-25 10:31:30 +0200
commit920552b213e3dc832a874b4e7ba29ecddbab31bc (patch)
treec07ed91961b7842a5056f98794c4827a0e493cea
parent58c95070da3a504fbeca7939435bbb062cb96ea3 (diff)
downloadop-kernel-dev-920552b213e3dc832a874b4e7ba29ecddbab31bc.zip
op-kernel-dev-920552b213e3dc832a874b4e7ba29ecddbab31bc.tar.gz
KVM: disable halt_poll_ns as default for s390x
We observed some performance degradation on s390x with dynamic halt polling. Until we can provide a proper fix, let's enable halt_poll_ns as default only for supported architectures. Architectures are now free to set their own halt_poll_ns default value. Signed-off-by: David Hildenbrand <dahi@linux.vnet.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
-rw-r--r--arch/arm/include/asm/kvm_host.h1
-rw-r--r--arch/arm64/include/asm/kvm_host.h1
-rw-r--r--arch/mips/include/asm/kvm_host.h1
-rw-r--r--arch/powerpc/include/asm/kvm_host.h1
-rw-r--r--arch/s390/include/asm/kvm_host.h1
-rw-r--r--arch/x86/include/asm/kvm_host.h1
-rw-r--r--virt/kvm/kvm_main.c4
7 files changed, 8 insertions, 2 deletions
diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
index 3df1e97..c4072d9 100644
--- a/arch/arm/include/asm/kvm_host.h
+++ b/arch/arm/include/asm/kvm_host.h
@@ -33,6 +33,7 @@
#define KVM_PRIVATE_MEM_SLOTS 4
#define KVM_COALESCED_MMIO_PAGE_OFFSET 1
#define KVM_HAVE_ONE_REG
+#define KVM_HALT_POLL_NS_DEFAULT 500000
#define KVM_VCPU_MAX_FEATURES 2
diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 4562459..ed03968 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -33,6 +33,7 @@
#define KVM_USER_MEM_SLOTS 32
#define KVM_PRIVATE_MEM_SLOTS 4
#define KVM_COALESCED_MMIO_PAGE_OFFSET 1
+#define KVM_HALT_POLL_NS_DEFAULT 500000
#include <kvm/arm_vgic.h>
#include <kvm/arm_arch_timer.h>
diff --git a/arch/mips/include/asm/kvm_host.h b/arch/mips/include/asm/kvm_host.h
index 3a54dbc..5a1a882 100644
--- a/arch/mips/include/asm/kvm_host.h
+++ b/arch/mips/include/asm/kvm_host.h
@@ -61,6 +61,7 @@
#define KVM_PRIVATE_MEM_SLOTS 0
#define KVM_COALESCED_MMIO_PAGE_OFFSET 1
+#define KVM_HALT_POLL_NS_DEFAULT 500000
diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
index 195886a..827a38d 100644
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -44,6 +44,7 @@
#ifdef CONFIG_KVM_MMIO
#define KVM_COALESCED_MMIO_PAGE_OFFSET 1
#endif
+#define KVM_HALT_POLL_NS_DEFAULT 500000
/* These values are internal and can be increased later */
#define KVM_NR_IRQCHIPS 1
diff --git a/arch/s390/include/asm/kvm_host.h b/arch/s390/include/asm/kvm_host.h
index 6ce4a0b..8ced426 100644
--- a/arch/s390/include/asm/kvm_host.h
+++ b/arch/s390/include/asm/kvm_host.h
@@ -35,6 +35,7 @@
*/
#define KVM_NR_IRQCHIPS 1
#define KVM_IRQCHIP_NUM_PINS 4096
+#define KVM_HALT_POLL_NS_DEFAULT 0
#define SIGP_CTRL_C 0x80
#define SIGP_CTRL_SCN_MASK 0x3f
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 349f80a..2beee03 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -40,6 +40,7 @@
#define KVM_PIO_PAGE_OFFSET 1
#define KVM_COALESCED_MMIO_PAGE_OFFSET 2
+#define KVM_HALT_POLL_NS_DEFAULT 500000
#define KVM_IRQCHIP_NUM_PINS KVM_IOAPIC_NUM_PINS
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 04146a2..8db1d93 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -66,8 +66,8 @@
MODULE_AUTHOR("Qumranet");
MODULE_LICENSE("GPL");
-/* halt polling only reduces halt latency by 5-7 us, 500us is enough */
-static unsigned int halt_poll_ns = 500000;
+/* Architectures should define their poll value according to the halt latency */
+static unsigned int halt_poll_ns = KVM_HALT_POLL_NS_DEFAULT;
module_param(halt_poll_ns, uint, S_IRUGO | S_IWUSR);
/* Default doubles per-vcpu halt_poll_ns. */
OpenPOWER on IntegriCloud