AcoSail/kernel_optimize_test
8
0
Fork 0
forked from luck/tmp_suning_uos_patched
Code Pull Requests Activity

score: Add missing RCU idle APIs on idle loop

Browse Source 
In the old times, the whole idle task was considered
as an RCU quiescent state. But as RCU became more and
more successful overtime, some RCU read side critical
section have been added even in the code of some
architectures idle tasks, for tracing for example.

So nowadays, rcu_idle_enter() and rcu_idle_exit() must
be called by the architecture to tell RCU about the part
in the idle loop that doesn't make use of rcu read side
critical sections, typically the part that puts the CPU
in low power mode.

This is necessary for RCU to find the quiescent states in
idle in order to complete grace periods.

Add this missing pair of calls in scores's idle loop.

Reported-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Chen Liqin <liqin.chen@sunplusct.com>
Cc: Lennox Wu <lennox.wu@gmail.com>
Cc: <stable@vger.kernel.org> # 3.3+
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
This commit is contained in:
Frederic Weisbecker 2012-08-22 17:27:34 +02:00 committed by Paul E. McKenney
parent fbe752188d
commit 0ee23fda59
1 changed files with 3 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
arch/score/kernel/process.c
View File

@ -27,6 +27,7 @@
#include <linux/reboot.h>
#include <linux/elfcore.h>
#include <linux/pm.h>
#include <linux/rcupdate.h>
void (*pm_power_off)(void);
EXPORT_SYMBOL(pm_power_off);
@ -50,9 +51,10 @@ void __noreturn cpu_idle(void)
{
/* endless idle loop with no priority at all */
while (1) {
rcu_idle_enter();
while (!need_resched())
barrier();
rcu_idle_exit();
schedule_preempt_disabled();
}
}