alloc_percpu: Use __get_cpu_ptr / get_cpu_ptr / get_cpu_var in kernel Impact: slight efficiency improvement on some archs. Let's use __get_cpu_ptr and get_cpu_ptr now, rather than per_cpu_ptr(..., smp_processor_id()). Signed-off-by: Rusty Russell Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Dipankar Sarma --- kernel/sched.c | 5 ++--- kernel/srcu.c | 4 ++-- kernel/workqueue.c | 4 ++-- 3 files changed, 6 insertions(+), 7 deletions(-) diff --git a/kernel/sched.c b/kernel/sched.c --- a/kernel/sched.c +++ b/kernel/sched.c @@ -693,12 +693,11 @@ static inline void update_rq_clock(struc */ int runqueue_is_locked(void) { - int cpu = get_cpu(); - struct rq *rq = cpu_rq(cpu); + struct rq *rq = &get_cpu_var(runqueues); int ret; ret = spin_is_locked(&rq->lock); - put_cpu(); + put_cpu_var(runqueues); return ret; } diff --git a/kernel/srcu.c b/kernel/srcu.c --- a/kernel/srcu.c +++ b/kernel/srcu.c @@ -113,7 +113,7 @@ int srcu_read_lock(struct srcu_struct *s preempt_disable(); idx = sp->completed & 0x1; barrier(); /* ensure compiler looks -once- at sp->completed. */ - per_cpu_ptr(sp->per_cpu_ref, smp_processor_id())->c[idx]++; + __get_cpu_ptr(sp->per_cpu_ref)->c[idx]++; srcu_barrier(); /* ensure compiler won't misorder critical section. */ preempt_enable(); return idx; @@ -133,7 +133,7 @@ void srcu_read_unlock(struct srcu_struct { preempt_disable(); srcu_barrier(); /* ensure compiler won't misorder critical section. */ - per_cpu_ptr(sp->per_cpu_ref, smp_processor_id())->c[idx]--; + __get_cpu_ptr(sp->per_cpu_ref)->c[idx]--; preempt_enable(); } diff --git a/kernel/workqueue.c b/kernel/workqueue.c --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -739,12 +739,12 @@ int current_is_keventd(void) int current_is_keventd(void) { struct cpu_workqueue_struct *cwq; - int cpu = raw_smp_processor_id(); /* preempt-safe: keventd is per-cpu */ int ret = 0; BUG_ON(!keventd_wq); - cwq = per_cpu_ptr(keventd_wq->cpu_wq, cpu); + /* preempt-safe: keventd is per-cpu */ + cwq = __raw_get_cpu_ptr(keventd_wq->cpu_wq); if (current == cwq->thread) ret = 1;