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authorGlauber Costa <glommer@redhat.com>2011-07-11 15:28:14 -0400
committerAvi Kivity <avi@redhat.com>2011-07-14 12:59:14 +0300
commitc9aaa8957f203bd6df83b002fb40b98390bed078 (patch)
tree96930ff2cbf73f6b0a3f4973e3933d036af13544 /kernel/delayacct.c
parent9ddabbe72e41ca6794cb4947c70929c9410e6752 (diff)
downloadlwn-c9aaa8957f203bd6df83b002fb40b98390bed078.tar.gz
lwn-c9aaa8957f203bd6df83b002fb40b98390bed078.zip
KVM: Steal time implementation
To implement steal time, we need the hypervisor to pass the guest information about how much time was spent running other processes outside the VM, while the vcpu had meaningful work to do - halt time does not count. This information is acquired through the run_delay field of delayacct/schedstats infrastructure, that counts time spent in a runqueue but not running. Steal time is a per-cpu information, so the traditional MSR-based infrastructure is used. A new msr, KVM_MSR_STEAL_TIME, holds the memory area address containing information about steal time This patch contains the hypervisor part of the steal time infrasructure, and can be backported independently of the guest portion. [avi, yongjie: export delayacct_on, to avoid build failures in some configs] Signed-off-by: Glauber Costa <glommer@redhat.com> Tested-by: Eric B Munson <emunson@mgebm.net> CC: Rik van Riel <riel@redhat.com> CC: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> CC: Peter Zijlstra <peterz@infradead.org> CC: Anthony Liguori <aliguori@us.ibm.com> Signed-off-by: Yongjie Ren <yongjie.ren@intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'kernel/delayacct.c')
-rw-r--r--kernel/delayacct.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/delayacct.c b/kernel/delayacct.c
index ead9b610aa71..418b3f7053aa 100644
--- a/kernel/delayacct.c
+++ b/kernel/delayacct.c
@@ -19,8 +19,10 @@
#include <linux/time.h>
#include <linux/sysctl.h>
#include <linux/delayacct.h>
+#include <linux/module.h>
int delayacct_on __read_mostly = 1; /* Delay accounting turned on/off */
+EXPORT_SYMBOL_GPL(delayacct_on);
struct kmem_cache *delayacct_cache;
static int __init delayacct_setup_disable(char *str)