On Thu, Jan 05, 2017 at 11:29:46PM +0800, Alex Shi wrote: > The cpu-dma PM QoS constraint impacts all the cpus in the system. There > is no way to let the user to choose a PM QoS constraint per cpu. > > The following patch exposes to the userspace a per cpu based sysfs file > in order to let the userspace to change the value of the PM QoS latency > constraint. > > This change is inoperative in its form and the cpuidle governors have to > take into account the per cpu latency constraint in addition to the > global cpu-dma latency constraint in order to operate properly. > > BTW > The pm_qos_resume_latency usage defined in > Documentation/ABI/testing/sysfs-devices-power > The /sys/devices/.../power/pm_qos_resume_latency_us attribute > contains the PM QoS resume latency limit for the given device, > which is the maximum allowed time it can take to resume the > device, after it has been suspended at run time, from a resume > request to the moment the device will be ready to process I/O, > in microseconds. If it is equal to 0, however, this means that > the PM QoS resume latency may be arbitrary. > > Signed-off-by: Alex Shi <alex....@linaro.org> > To: linux-kernel@vger.kernel.org > To: Greg Kroah-Hartman <gre...@linuxfoundation.org> > Cc: linux...@vger.kernel.org > Cc: Ulf Hansson <ulf.hans...@linaro.org> > Cc: Daniel Lezcano <daniel.lezc...@linaro.org> > Cc: "Rafael J. Wysocki" <rafael.j.wyso...@intel.com> > --- > drivers/base/cpu.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c > index 4c28e1a..29cf3459 100644 > --- a/drivers/base/cpu.c > +++ b/drivers/base/cpu.c > @@ -17,6 +17,7 @@ > #include <linux/of.h> > #include <linux/cpufeature.h> > #include <linux/tick.h> > +#include <linux/pm_qos.h> > > #include "base.h" > > @@ -376,6 +377,9 @@ int register_cpu(struct cpu *cpu, int num) > > per_cpu(cpu_sys_devices, num) = &cpu->dev; > register_cpu_under_node(num, cpu_to_node(num)); > +#ifdef CONFIG_CPU_IDLE_GOV_MENU > + dev_pm_qos_expose_latency_limit(&cpu->dev, 0); > +#endif
No way to do this without the #ifdef? That's really not recommended for .c code :( thanks, greg k-h
