On 18/08/2020 08:30, Yue Hu wrote: > From: Yue Hu <[email protected]> > > We observed warning about kzalloc() when register thermal cooling device > in backlight_device_register(). backlight display can be a cooling device > since reducing screen brightness will can help reduce temperature. > > However, ->get_max_state of backlight will assign max brightness of 1024 > to states. The memory size can be getting 1MB+ due to states * states.
What are the benefits of a 1024 states cooling device ? Is the difference noticeable with a such small step ? > That is so large to trigger kmalloc() warning. > > So, let's remove it and try vzalloc() if kzalloc() fails. > > Signed-off-by: Yue Hu <[email protected]> > --- > drivers/thermal/thermal_sysfs.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/drivers/thermal/thermal_sysfs.c b/drivers/thermal/thermal_sysfs.c > index aa99edb..9bae0b6 100644 > --- a/drivers/thermal/thermal_sysfs.c > +++ b/drivers/thermal/thermal_sysfs.c > @@ -16,6 +16,8 @@ > #include <linux/device.h> > #include <linux/err.h> > #include <linux/slab.h> > +#include <linux/vmalloc.h> > +#include <linux/mm.h> > #include <linux/string.h> > #include <linux/jiffies.h> > > @@ -919,7 +921,9 @@ static void cooling_device_stats_setup(struct > thermal_cooling_device *cdev) > var += sizeof(*stats->time_in_state) * states; > var += sizeof(*stats->trans_table) * states * states; > > - stats = kzalloc(var, GFP_KERNEL); > + stats = kzalloc(var, GFP_KERNEL | __GFP_NOWARN); > + if (!stats) > + stats = vzalloc(var); > if (!stats) > return; > > @@ -938,7 +942,7 @@ static void cooling_device_stats_setup(struct > thermal_cooling_device *cdev) > > static void cooling_device_stats_destroy(struct thermal_cooling_device *cdev) > { > - kfree(cdev->stats); > + kvfree(cdev->stats); > cdev->stats = NULL; > } > > -- <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | <http://twitter.com/#!/linaroorg> Twitter | <http://www.linaro.org/linaro-blog/> Blog
