Save/restore steal times in syscore suspend/resume during PM
hibernation. Commit '5e25f5db6abb9: ("xen/time: do not
decrease steal time after live migration on xen")' fixes xen
guest steal time handling during migration. A similar issue is seen
during PM hibernation.
Currently, steal time accounting code in scheduler expects steal clock
callback to provide monotonically increasing value. If the accounting
code receives a smaller value than previous one, it uses a negative
value to calculate steal time and results in incorrectly updated idle
and steal time accounting. This breaks userspace tools which read
/proc/stat.
top - 08:05:35 up 2:12, 3 users, load average: 0.00, 0.07, 0.23
Tasks: 80 total, 1 running, 79 sleeping, 0 stopped, 0 zombie
Cpu(s): 0.0%us, 0.0%sy, 0.0%ni,30100.0%id, 0.0%wa, 0.0%hi,
0.0%si,-1253874204672.0%st
This can actually happen when a Xen PVHVM guest gets restored from
hibernation, because such a restored guest is just a fresh domain from
Xen perspective and the time information in runstate info starts over
from scratch.
Changelog:
v1->v2: Removed patches that introduced new function calls for saving/restoring
sched clock offset and using existing ones that are used during LM
Signed-off-by: Anchal Agarwal <ancha...@amazon.com>
---
arch/x86/xen/suspend.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/x86/xen/suspend.c b/arch/x86/xen/suspend.c
index 550aa0fc9465..b12db6966af6 100644
--- a/arch/x86/xen/suspend.c
+++ b/arch/x86/xen/suspend.c
@@ -99,6 +99,7 @@ static int xen_syscore_suspend(void)
gnttab_suspend();
+ xen_manage_runstate_time(-1);
xrfp.domid = DOMID_SELF;
xrfp.gpfn = __pa(HYPERVISOR_shared_info) >> PAGE_SHIFT;
@@ -119,7 +120,7 @@ static void xen_syscore_resume(void)
xen_hvm_map_shared_info();
pvclock_resume();
-
+ xen_manage_runstate_time(0);
gnttab_resume();
}
--
2.16.6
