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authorEric B Munson <emunson@mgebm.net>2012-03-10 14:37:28 -0500
committerAvi Kivity <avi@redhat.com>2012-04-08 12:49:03 +0300
commit5d1c0f4a80a6df73395fb3fc2c302510f8f09d36 (patch)
tree7819e75a82c6620e6240a78813b4217a1f4a08dc /kernel/watchdog.c
parent1c0b28c2a46d98cd258d96b8c222144b22876c46 (diff)
downloadlinux-linaro-stable-5d1c0f4a80a6df73395fb3fc2c302510f8f09d36.tar.gz
watchdog: add check for suspended vm in softlockup detector
A suspended VM can cause spurious soft lockup warnings. To avoid these, the watchdog now checks if the kernel knows it was stopped by the host and skips the warning if so. When the watchdog is reset successfully, clear the guest paused flag. Signed-off-by: Eric B Munson <emunson@mgebm.net> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'kernel/watchdog.c')
-rw-r--r--kernel/watchdog.c12
1 files changed, 12 insertions, 0 deletions
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index df30ee08bdd4..e5e1d85b8c7c 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -24,6 +24,7 @@
#include <linux/sysctl.h>
#include <asm/irq_regs.h>
+#include <linux/kvm_para.h>
#include <linux/perf_event.h>
int watchdog_enabled = 1;
@@ -280,6 +281,9 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
__this_cpu_write(softlockup_touch_sync, false);
sched_clock_tick();
}
+
+ /* Clear the guest paused flag on watchdog reset */
+ kvm_check_and_clear_guest_paused();
__touch_watchdog();
return HRTIMER_RESTART;
}
@@ -292,6 +296,14 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
*/
duration = is_softlockup(touch_ts);
if (unlikely(duration)) {
+ /*
+ * If a virtual machine is stopped by the host it can look to
+ * the watchdog like a soft lockup, check to see if the host
+ * stopped the vm before we issue the warning
+ */
+ if (kvm_check_and_clear_guest_paused())
+ return HRTIMER_RESTART;
+
/* only warn once */
if (__this_cpu_read(soft_watchdog_warn) == true)
return HRTIMER_RESTART;