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| author |   Li Zefan <lizefan@huawei.com> | 2013-03-29 14:37:29 +0800 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2013-04-10 13:54:18 +0200 |
| commit | 543bc0e76e6bb84300eaf9833edc5a481f788678 (patch) | |
| tree | b3584f05bedffee2bd604fa63d0e8b613cda28d4 /kernel/sched/cpuacct.c | |
| parent | sched/cpuacct: Add cpuacct_acount_field() (diff) | |
| download | linux-dev-543bc0e76e6bb84300eaf9833edc5a481f788678.tar.xz linux-dev-543bc0e76e6bb84300eaf9833edc5a481f788678.zip | |
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.c | 6 |
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(); |