| Message ID | 20200821024406.10404-1-zbestahu@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Zhang Rui |
| Headers | show |
| Series | thermal: sysfs: Fall back to vmalloc() for cooling device's statistics | expand |
On 21-08-20, 10:44, Yue Hu wrote: > From: Yue Hu <huyue2@yulong.com> > > 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. > That is so large to trigger kmalloc() warning. > > So, let's use kvzalloc() to avoid the issue, also change kfree -> kvfree. > > Suggested-by: Amit Kucheria <amitk@kernel.org> > Signed-off-by: Yue Hu <huyue2@yulong.com> > --- > drivers/thermal/thermal_sysfs.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
On Fri, Aug 21, 2020 at 8:14 AM Yue Hu <zbestahu@gmail.com> wrote: > > From: Yue Hu <huyue2@yulong.com> > > 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. > That is so large to trigger kmalloc() warning. > > So, let's use kvzalloc() to avoid the issue, also change kfree -> kvfree. > > Suggested-by: Amit Kucheria <amitk@kernel.org> > Signed-off-by: Yue Hu <huyue2@yulong.com> Reviewed-by: Amit Kucheria <amitk@kernel.org> > --- > drivers/thermal/thermal_sysfs.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/drivers/thermal/thermal_sysfs.c b/drivers/thermal/thermal_sysfs.c > index aa99edb..d1703ee 100644 > --- a/drivers/thermal/thermal_sysfs.c > +++ b/drivers/thermal/thermal_sysfs.c > @@ -16,6 +16,7 @@ > #include <linux/device.h> > #include <linux/err.h> > #include <linux/slab.h> > +#include <linux/mm.h> > #include <linux/string.h> > #include <linux/jiffies.h> > > @@ -919,7 +920,7 @@ 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 = kvzalloc(var, GFP_KERNEL); > if (!stats) > return; > > @@ -938,7 +939,7 @@ 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; > } > > -- > 1.9.1 >
From: Yue Hu > Sent: 21 August 2020 03:44 > > From: Yue Hu <huyue2@yulong.com> > > 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. > That is so large to trigger kmalloc() warning. I can't help feeling that there is an 'adequate' implementation that doesn't require anywhere near 1MB of memory. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
On Fri, 21 Aug 2020 08:39:45 +0000 David Laight <David.Laight@ACULAB.COM> wrote: > From: Yue Hu > > Sent: 21 August 2020 03:44 > > > > From: Yue Hu <huyue2@yulong.com> > > > > 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. > > That is so large to trigger kmalloc() warning. > > I can't help feeling that there is an 'adequate' implementation > that doesn't require anywhere near 1MB of memory. However, it should be a potential issue due to what i described above, rt? Thx. > > David > > - > Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK > Registration No: 1397386 (Wales) >
diff --git a/drivers/thermal/thermal_sysfs.c b/drivers/thermal/thermal_sysfs.c index aa99edb..d1703ee 100644 --- a/drivers/thermal/thermal_sysfs.c +++ b/drivers/thermal/thermal_sysfs.c @@ -16,6 +16,7 @@ #include <linux/device.h> #include <linux/err.h> #include <linux/slab.h> +#include <linux/mm.h> #include <linux/string.h> #include <linux/jiffies.h> @@ -919,7 +920,7 @@ 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 = kvzalloc(var, GFP_KERNEL); if (!stats) return; @@ -938,7 +939,7 @@ 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; }