From 08e4570a4a393bcc241f78dfc444cb0b07995fc0 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 26 Nov 2007 21:21:49 +0100 Subject: [PATCH] sched: fix prev_stime calculation Srivatsa Vaddagiri noticed occasionally incorrect CPU usage values in top and tracked it down to stime going below 0 in task_stime(). Negative values are possible there due to the sampled nature of stime/utime. Fix suggested by Balbir Singh. Signed-off-by: Ingo Molnar Tested-by: Srivatsa Vaddagiri Reviewed-by: Balbir Singh --- fs/proc/array.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/fs/proc/array.c b/fs/proc/array.c index eba339ec..65c62e1 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -374,7 +374,9 @@ static cputime_t task_stime(struct task_struct *p) stime = nsec_to_clock_t(p->se.sum_exec_runtime) - cputime_to_clock_t(task_utime(p)); - p->prev_stime = max(p->prev_stime, clock_t_to_cputime(stime)); + if (stime >= 0) + p->prev_stime = max(p->prev_stime, clock_t_to_cputime(stime)); + return p->prev_stime; } #endif -- 2.7.4