diff options
| author | Vincent Guittot <vincent.guittot@linaro.org> | 2012-10-23 01:21:49 +0200 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2012-11-15 00:36:09 +0100 |
| commit | dde8437d06560366d8988c92b5774039ec703864 (patch) | |
| tree | 80ee897c0964a325be3c2d8a626ff82dd89013b3 | |
| parent | Linux 3.7-rc5 (diff) | |
| download | linux-dde8437d06560366d8988c92b5774039ec703864.tar.xz linux-dde8437d06560366d8988c92b5774039ec703864.zip | |
PM / OPP: RCU reclaim
synchronize_rcu() blocks the caller of opp_enable/disbale
for a complete grace period. This blocking duration prevents
any intensive use of the functions. Replace synchronize_rcu()
by call_rcu() which will call our function for freeing the old
opp element.
The duration of opp_enable() and opp_disable() will be no more
dependant of the grace period.
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to '')
| -rw-r--r-- | drivers/base/power/opp.c | 19 |
1 files changed, 14 insertions, 5 deletions
diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c index d9468642fc41..1211210b15b0 100644 --- a/drivers/base/power/opp.c +++ b/drivers/base/power/opp.c @@ -65,6 +65,7 @@ struct opp { unsigned long u_volt; struct device_opp *dev_opp; + struct rcu_head head; }; /** @@ -442,6 +443,17 @@ int opp_add(struct device *dev, unsigned long freq, unsigned long u_volt) } /** + * opp_free_rcu() - helper to clear the struct opp when grace period has + * elapsed without blocking the the caller of opp_set_availability + */ +static void opp_free_rcu(struct rcu_head *head) +{ + struct opp *opp = container_of(head, struct opp, head); + + kfree(opp); +} + +/** * opp_set_availability() - helper to set the availability of an opp * @dev: device for which we do this operation * @freq: OPP frequency to modify availability @@ -512,7 +524,7 @@ static int opp_set_availability(struct device *dev, unsigned long freq, list_replace_rcu(&opp->node, &new_opp->node); mutex_unlock(&dev_opp_list_lock); - synchronize_rcu(); + call_rcu(&opp->head, opp_free_rcu); /* Notify the change of the OPP availability */ if (availability_req) @@ -522,13 +534,10 @@ static int opp_set_availability(struct device *dev, unsigned long freq, srcu_notifier_call_chain(&dev_opp->head, OPP_EVENT_DISABLE, new_opp); - /* clean up old opp */ - new_opp = opp; - goto out; + return 0; unlock: mutex_unlock(&dev_opp_list_lock); -out: kfree(new_opp); return r; } |