aboutsummaryrefslogtreecommitdiffstats
path: root/kernel/posix-cpu-timers.c
diff options
context:
space:
mode:
authorHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>2009-03-31 16:56:03 +0900
committerIngo Molnar <mingo@elte.hu>2009-04-01 16:44:16 +0200
commitc5f8d99585d7b5b7e857fabf8aefd0174903a98c (patch)
tree504127a7d4b6a0e3aee56d0822e5e8b23f8062d7 /kernel/posix-cpu-timers.c
parent13b8bd0a5713bdf05659019badd7c0407984ece1 (diff)
downloadmrst-s0i3-test-c5f8d99585d7b5b7e857fabf8aefd0174903a98c.tar.gz
mrst-s0i3-test-c5f8d99585d7b5b7e857fabf8aefd0174903a98c.tar.xz
mrst-s0i3-test-c5f8d99585d7b5b7e857fabf8aefd0174903a98c.zip
posixtimers, sched: Fix posix clock monotonicity
Impact: Regression fix (against clock_gettime() backwarding bug) This patch re-introduces a couple of functions, task_sched_runtime and thread_group_sched_runtime, which was once removed at the time of 2.6.28-rc1. These functions protect the sampling of thread/process clock with rq lock. This rq lock is required not to update rq->clock during the sampling. i.e. The clock_gettime() may return ((accounted runtime before update) + (delta after update)) that is less than what it should be. v2 -> v3: - Rename static helper function __task_delta_exec() to do_task_delta_exec() since -tip tree already has a __task_delta_exec() of different version. v1 -> v2: - Revises comments of function and patch description. - Add note about accuracy of thread group's runtime. Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: stable@kernel.org [2.6.28.x][2.6.29.x] LKML-Reference: <49D1CC93.4080401@jp.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/posix-cpu-timers.c')
-rw-r--r--kernel/posix-cpu-timers.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index fa07da94d7b..4318c308578 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -224,7 +224,7 @@ static int cpu_clock_sample(const clockid_t which_clock, struct task_struct *p,
cpu->cpu = virt_ticks(p);
break;
case CPUCLOCK_SCHED:
- cpu->sched = p->se.sum_exec_runtime + task_delta_exec(p);
+ cpu->sched = task_sched_runtime(p);
break;
}
return 0;
@@ -240,18 +240,19 @@ static int cpu_clock_sample_group(const clockid_t which_clock,
{
struct task_cputime cputime;
- thread_group_cputime(p, &cputime);
switch (CPUCLOCK_WHICH(which_clock)) {
default:
return -EINVAL;
case CPUCLOCK_PROF:
+ thread_group_cputime(p, &cputime);
cpu->cpu = cputime_add(cputime.utime, cputime.stime);
break;
case CPUCLOCK_VIRT:
+ thread_group_cputime(p, &cputime);
cpu->cpu = cputime.utime;
break;
case CPUCLOCK_SCHED:
- cpu->sched = cputime.sum_exec_runtime + task_delta_exec(p);
+ cpu->sched = thread_group_sched_runtime(p);
break;
}
return 0;