diff options
| author | Li Zefan <lizf@cn.fujitsu.com> | 2009-03-12 09:23:01 +0800 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-03-13 04:54:58 +0100 |
| commit | 7a46c594bf7f1f2eeb1e12d4b857d5f581957a92 (patch) | |
| tree | 35731095fd8f01938a36d2647995ee86747e3bbf | |
| parent | 65a37b29a8d7492f081d4f8da2227467af1c0c1d (diff) | |
cpuacct: reduce one NULL check in fast-path
Impact: micro-optimization
In cpuacct_charge(), task_ca() will never return NULL, so change
for(...) to do { } while(...) to save one NULL check.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Menage <menage@google.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Bharata B Rao <bharata@linux.vnet.ibm.com>
LKML-Reference: <49B863F5.2060400@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | kernel/sched.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 0a76d0b6f21..61e63562f27 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -9599,10 +9599,11 @@ static void cpuacct_charge(struct task_struct *tsk, u64 cputime) cpu = task_cpu(tsk); ca = task_ca(tsk); - for (; ca; ca = ca->parent) { + do { u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu); *cpuusage += cputime; - } + ca = ca->parent; + } while (ca); } struct cgroup_subsys cpuacct_subsys = { |