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this_cpu: Use this_cpu operations in RCU

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RCU does not do dynamic allocations but it increments per cpu variables
a lot. These instructions results in a move to a register and then back
to memory. This patch will make it use the inc/dec instructions on x86
that do not need a register.

Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Christoph Lameter 2009-10-03 19:48:23 +09:00 committed by Tejun Heo
parent 4dac3e9884
commit e800879d50
1 changed files with 4 additions and 4 deletions
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8
kernel/rcutorture.c
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@ -731,13 +731,13 @@ static void rcu_torture_timer(unsigned long unused)
/* Should not happen, but... */ /* Should not happen, but... */
pipe_count = RCU_TORTURE_PIPE_LEN; pipe_count = RCU_TORTURE_PIPE_LEN;
} }
++__get_cpu_var(rcu_torture_count)[pipe_count]; __this_cpu_inc(per_cpu_var(rcu_torture_count)[pipe_count]);
completed = cur_ops->completed() - completed; completed = cur_ops->completed() - completed;
if (completed > RCU_TORTURE_PIPE_LEN) { if (completed > RCU_TORTURE_PIPE_LEN) {
/* Should not happen, but... */ /* Should not happen, but... */
completed = RCU_TORTURE_PIPE_LEN; completed = RCU_TORTURE_PIPE_LEN;
} }
++__get_cpu_var(rcu_torture_batch)[completed]; __this_cpu_inc(per_cpu_var(rcu_torture_batch)[completed]);
preempt_enable(); preempt_enable();
cur_ops->readunlock(idx); cur_ops->readunlock(idx);
} }
@ -786,13 +786,13 @@ rcu_torture_reader(void *arg)
/* Should not happen, but... */ /* Should not happen, but... */
pipe_count = RCU_TORTURE_PIPE_LEN; pipe_count = RCU_TORTURE_PIPE_LEN;
} }
++__get_cpu_var(rcu_torture_count)[pipe_count]; __this_cpu_inc(per_cpu_var(rcu_torture_count)[pipe_count]);
completed = cur_ops->completed() - completed; completed = cur_ops->completed() - completed;
if (completed > RCU_TORTURE_PIPE_LEN) { if (completed > RCU_TORTURE_PIPE_LEN) {
/* Should not happen, but... */ /* Should not happen, but... */
completed = RCU_TORTURE_PIPE_LEN; completed = RCU_TORTURE_PIPE_LEN;
} }
++__get_cpu_var(rcu_torture_batch)[completed]; __this_cpu_inc(per_cpu_var(rcu_torture_batch)[completed]);
preempt_enable(); preempt_enable();
cur_ops->readunlock(idx); cur_ops->readunlock(idx);
schedule(); schedule();