diff options
| author |   Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2016-10-30 17:32:43 +0100 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-10-31 11:42:51 -0600 |
| commit | baa8809f60971d10220dfe79248f54b2b265f003 (patch) | |
| tree | 51a4d0c63734bdd7923c025e9ed4e0dd537e3c76 /drivers/base/power/runtime.c | |
| parent | PM / runtime: Use device links (diff) | |
| download | linux-dev-baa8809f60971d10220dfe79248f54b2b265f003.tar.xz linux-dev-baa8809f60971d10220dfe79248f54b2b265f003.zip | |
PM / runtime: Optimize the use of device links
If the device has no links to suppliers that should be used for
runtime PM (links with DEVICE_LINK_PM_RUNTIME set), there is no
reason to walk the list of suppliers for that device during
runtime suspend and resume.
Add a simple mechanism to detect that case and possibly avoid the
extra unnecessary overhead.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/base/power/runtime.c')
| -rw-r--r-- | drivers/base/power/runtime.c | 23 |
1 files changed, 20 insertions, 3 deletions
diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c index 462f90e952f8..ba7b4a8c07e5 100644 --- a/drivers/base/power/runtime.c +++ b/drivers/base/power/runtime.c @@ -305,6 +305,7 @@ static int __rpm_callback(int (*cb)(struct device *), struct device *dev) __releases(&dev->power.lock) __acquires(&dev->power.lock) { int retval, idx; + bool use_links = dev->power.links_count > 0; if (dev->power.irq_safe) { spin_unlock(&dev->power.lock); @@ -318,7 +319,7 @@ static int __rpm_callback(int (*cb)(struct device *), struct device *dev) * routine returns, so it is safe to read the status outside of * the lock. */ - if (dev->power.runtime_status == RPM_RESUMING) { + if (use_links && dev->power.runtime_status == RPM_RESUMING) { idx = device_links_read_lock(); retval = rpm_get_suppliers(dev); @@ -341,8 +342,9 @@ static int __rpm_callback(int (*cb)(struct device *), struct device *dev) * * Do that if resume fails too. */ - if ((dev->power.runtime_status == RPM_SUSPENDING && !retval) - || (dev->power.runtime_status == RPM_RESUMING && retval)) { + if (use_links + && ((dev->power.runtime_status == RPM_SUSPENDING && !retval) + || (dev->power.runtime_status == RPM_RESUMING && retval))) { idx = device_links_read_lock(); fail: @@ -1593,6 +1595,21 @@ void pm_runtime_put_suppliers(struct device *dev) device_links_read_unlock(idx); } +void pm_runtime_new_link(struct device *dev) +{ + spin_lock_irq(&dev->power.lock); + dev->power.links_count++; + spin_unlock_irq(&dev->power.lock); +} + +void pm_runtime_drop_link(struct device *dev) +{ + spin_lock_irq(&dev->power.lock); + WARN_ON(dev->power.links_count == 0); + dev->power.links_count--; + spin_unlock_irq(&dev->power.lock); +} + /** * pm_runtime_force_suspend - Force a device into suspend state if needed. * @dev: Device to suspend. |