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| author | Venki Pallipadi <venkatesh.pallipadi@intel.com> | 2007-06-20 14:24:52 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2007-08-15 09:25:10 -0700 |
| commit | 72a63b079035709b481edffa301c4a694e008384 (patch) | |
| tree | 6658b67019adbec1adda112478b4631fb1d327c0 | |
| parent | 42418d94efa05105ba5a467119d3864201425430 (diff) | |
| download | lwn-72a63b079035709b481edffa301c4a694e008384.tar.gz lwn-72a63b079035709b481edffa301c4a694e008384.zip | |
CPUFREQ: ondemand: add a check to avoid negative load calculation
Due to rounding and inexact jiffy accounting, idle_ticks can sometimes
be higher than total_ticks. Make sure those cases are handled as
zero load case.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | drivers/cpufreq/cpufreq_ondemand.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/cpufreq/cpufreq_ondemand.c b/drivers/cpufreq/cpufreq_ondemand.c index b6b3e52c9f28..e794527e4925 100644 --- a/drivers/cpufreq/cpufreq_ondemand.c +++ b/drivers/cpufreq/cpufreq_ondemand.c @@ -335,7 +335,7 @@ static struct attribute_group dbs_attr_group = { static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info) { unsigned int idle_ticks, total_ticks; - unsigned int load; + unsigned int load = 0; cputime64_t cur_jiffies; struct cpufreq_policy *policy; @@ -381,7 +381,8 @@ static void dbs_check_cpu(struct cpu_dbs_info_s *this_dbs_info) if (tmp_idle_ticks < idle_ticks) idle_ticks = tmp_idle_ticks; } - load = (100 * (total_ticks - idle_ticks)) / total_ticks; + if (likely(total_ticks > idle_ticks)) + load = (100 * (total_ticks - idle_ticks)) / total_ticks; /* Check for frequency increase */ if (load > dbs_tuners_ins.up_threshold) { |