linux-kernel - [GIT PULL] cputime tree

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Thu, 24 Sep 2009 13:31:36 +0200
From:	Martin Schwidefsky <schwidefsky@...ibm.com>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Michael Abbott <michael@...neidae.co.uk>,
	Jan Engelhardt <jengelh@...ozas.de>,
	Johan van Baarlen <jf@...baarlen.demon.nl>
Subject: [GIT PULL] cputime tree

Hi Linus,

with git commit 79741dd "idle cputime accounting" the semantic
of the stime field of the idle processes has changed. It used to
contain the amount of time the idle process has been scheduled.
Since git commit 79741dd is contains the cpu time spent in the
system by the idle process.

This change broke the output of second field of /proc/uptime. On
systems without VIRT_CPU_ACCOUNTING the field is always zero.
The legacy output of the field is the amount of time the idle
process has been scheduled on cpu #0. It is good enough to
calculate the load on an uni-processor system, it is useless
on a multi-processor. To restore the legacy behaviour and give
meaning to the multi-processor case the best we could come up
with is to add the idle time over all cpus. That fixes uni-
processors systems and gives a defined semantic on smp.

So please pull from 'cputime' branch of

	git://git390.marist.edu/pub/scm/linux-2.6.git cputime

to receive the following updates:

Michael Abbott (1):
      Fix idle time field in /proc/uptime

 fs/proc/uptime.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/fs/proc/uptime.c b/fs/proc/uptime.c
index 0c10a0b..766b1d4 100644
--- a/fs/proc/uptime.c
+++ b/fs/proc/uptime.c
@@ -4,13 +4,18 @@
 #include <linux/sched.h>
 #include <linux/seq_file.h>
 #include <linux/time.h>
+#include <linux/kernel_stat.h>
 #include <asm/cputime.h>

 static int uptime_proc_show(struct seq_file *m, void *v)
 {
 	struct timespec uptime;
 	struct timespec idle;
-	cputime_t idletime = cputime_add(init_task.utime, init_task.stime);
+	int i;
+	cputime_t idletime = cputime_zero;
+
+	for_each_possible_cpu(i)
+		idletime = cputime64_add(idletime, kstat_cpu(i).cpustat.idle);

 	do_posix_clock_monotonic_gettime(&uptime);
 	monotonic_to_bootbased(&uptime);
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/