[PATCH] s390: cputime misaccounting
finish_arch_switch needs to update the user cpu time as well, not just the
system cpu time. Otherwise the partial user cpu time of a process that is
stored in the lowcore will be (mis-)accounted to the next process.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/s390/kernel/vtime.c b/arch/s390/kernel/vtime.c
index 22a895e..dfe6f08 100644
--- a/arch/s390/kernel/vtime.c
+++ b/arch/s390/kernel/vtime.c
@@ -32,7 +32,7 @@
* Update process times based on virtual cpu times stored by entry.S
* to the lowcore fields user_timer, system_timer & steal_clock.
*/
-void account_user_vtime(struct task_struct *tsk)
+void account_tick_vtime(struct task_struct *tsk)
{
cputime_t cputime;
__u64 timer, clock;
@@ -76,6 +76,31 @@
* Update process times based on virtual cpu times stored by entry.S
* to the lowcore fields user_timer, system_timer & steal_clock.
*/
+void account_vtime(struct task_struct *tsk)
+{
+ cputime_t cputime;
+ __u64 timer;
+
+ timer = S390_lowcore.last_update_timer;
+ asm volatile (" STPT %0" /* Store current cpu timer value */
+ : "=m" (S390_lowcore.last_update_timer) );
+ S390_lowcore.system_timer += timer - S390_lowcore.last_update_timer;
+
+ cputime = S390_lowcore.user_timer >> 12;
+ S390_lowcore.user_timer -= cputime << 12;
+ S390_lowcore.steal_clock -= cputime << 12;
+ account_user_time(tsk, cputime);
+
+ cputime = S390_lowcore.system_timer >> 12;
+ S390_lowcore.system_timer -= cputime << 12;
+ S390_lowcore.steal_clock -= cputime << 12;
+ account_system_time(tsk, 0, cputime);
+}
+
+/*
+ * Update process times based on virtual cpu times stored by entry.S
+ * to the lowcore fields user_timer, system_timer & steal_clock.
+ */
void account_system_vtime(struct task_struct *tsk)
{
cputime_t cputime;