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| author | Frans Pop <elendil@planet.nl> | 2007-11-14 01:18:19 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2007-11-16 08:12:44 -0800 |
| commit | e823c33c6f670beba3c14f4a451fd2b34c3eb40c (patch) | |
| tree | fae5671652e463b861e3737524caab6d992adcf6 | |
| parent | 436e61d93605a3a36902c9ee510b0ecba0d7d361 (diff) | |
| download | lwn-e823c33c6f670beba3c14f4a451fd2b34c3eb40c.tar.gz lwn-e823c33c6f670beba3c14f4a451fd2b34c3eb40c.zip | |
sched: keep utime/stime monotonic
sched: keep utime/stime monotonic
cpustats use utime/stime as a ratio against sum_exec_runtime, as a
consequence it can happen - when the ratio changes faster than time
accumulates - that either can be appear to go backwards.
Combined backport for 2.6.23 of the following patches from mainline:
commit 73a2bcb0edb9ffb0b007b3546b430e2c6e415eee
Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
sched: keep utime/stime monotonic
commit 9301899be75b464ef097f0b5af7af6d9bd8f68a7
Author: Balbir Singh <balbir@linux.vnet.ibm.com>
sched: fix /proc/<PID>/stat stime/utime monotonicity, part 2
Signed-off-by: Frans Pop <elendil@planet.nl>
CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
CC: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | fs/proc/array.c | 6 | ||||
| -rw-r--r-- | include/linux/sched.h | 1 | ||||
| -rw-r--r-- | kernel/fork.c | 2 |
3 files changed, 7 insertions, 2 deletions
diff --git a/fs/proc/array.c b/fs/proc/array.c index ee4814dd98f9..20d7ae4582e2 100644 --- a/fs/proc/array.c +++ b/fs/proc/array.c @@ -351,7 +351,8 @@ static cputime_t task_utime(struct task_struct *p) } utime = (clock_t)temp; - return clock_t_to_cputime(utime); + p->prev_utime = max(p->prev_utime, clock_t_to_cputime(utime)); + return p->prev_utime; } static cputime_t task_stime(struct task_struct *p) @@ -366,7 +367,8 @@ 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)); - return clock_t_to_cputime(stime); + p->prev_stime = max(p->prev_stime, clock_t_to_cputime(stime)); + return p->prev_stime; } #endif diff --git a/include/linux/sched.h b/include/linux/sched.h index 313c6b6e774f..f509fbd97df9 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1022,6 +1022,7 @@ struct task_struct { unsigned int rt_priority; cputime_t utime, stime; + cputime_t prev_utime, prev_stime; unsigned long nvcsw, nivcsw; /* context switch counts */ struct timespec start_time; /* monotonic time */ struct timespec real_start_time; /* boot based time */ diff --git a/kernel/fork.c b/kernel/fork.c index 33f12f48684a..f299d4522a2d 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1045,6 +1045,8 @@ static struct task_struct *copy_process(unsigned long clone_flags, p->utime = cputime_zero; p->stime = cputime_zero; + p->prev_utime = cputime_zero; + p->prev_stime = cputime_zero; #ifdef CONFIG_TASK_XACCT p->rchar = 0; /* I/O counter: bytes read */ |