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authorLi Zefan <lizefan@huawei.com>2013-03-29 14:37:29 +0800
committerIngo Molnar <mingo@kernel.org>2013-04-10 13:54:18 +0200
commit543bc0e76e6bb84300eaf9833edc5a481f788678 (patch)
treeb3584f05bedffee2bd604fa63d0e8b613cda28d4 /kernel/sched/cpuacct.c
parent1966aaf7d54608e8ddb7ac454b461840e763409a (diff)
downloadlinux-543bc0e76e6bb84300eaf9833edc5a481f788678.tar.bz2
sched/cpuacct: Remove redundant NULL checks in cpuacct_charge()
This is a micro optimization for the hot path. - We don't need to check if @ca is NULL in parent_ca(). - We don't need to check if @ca is NULL in the beginning of the for loop. Signed-off-by: Li Zefan <lizefan@huawei.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/515536A9.5000700@huawei.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched/cpuacct.c')
-rw-r--r--kernel/sched/cpuacct.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/kernel/sched/cpuacct.c b/kernel/sched/cpuacct.c
index 72bd971ea377..b2aaaba16d46 100644
--- a/kernel/sched/cpuacct.c
+++ b/kernel/sched/cpuacct.c
@@ -210,9 +210,13 @@ void cpuacct_charge(struct task_struct *tsk, u64 cputime)
ca = task_ca(tsk);
- for (; ca; ca = parent_ca(ca)) {
+ while (true) {
u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
*cpuusage += cputime;
+
+ ca = parent_ca(ca);
+ if (!ca)
+ break;
}
rcu_read_unlock();