From 543bc0e76e6bb84300eaf9833edc5a481f788678 Mon Sep 17 00:00:00 2001 From: Li Zefan Date: Fri, 29 Mar 2013 14:37:29 +0800 Subject: 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 Acked-by: Peter Zijlstra Link: http://lkml.kernel.org/r/515536A9.5000700@huawei.com Signed-off-by: Ingo Molnar --- kernel/sched/cpuacct.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) (limited to 'kernel/sched/cpuacct.c') 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(); -- cgit