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| author | Michael Neuling <mikey@neuling.org> | 2007-11-20 15:18:40 +1100 |
|---|---|---|
| committer | Paul Mackerras <paulus@samba.org> | 2007-11-20 16:10:28 +1100 |
| commit | 2b46b5673ca67d23302c2afac045def988a3cade (patch) | |
| tree | 02b291c7d8fe862e2ac76b22a4fc361e4620f0a3 /arch/powerpc | |
| parent | c443acab2eebf12dce7e78fe29e76786f55ad1be (diff) | |
| download | linux-2b46b5673ca67d23302c2afac045def988a3cade.tar.gz linux-2b46b5673ca67d23302c2afac045def988a3cade.tar.bz2 linux-2b46b5673ca67d23302c2afac045def988a3cade.zip | |
[POWERPC] Fix possible division by zero in scaled time accounting
If we get no user time and no system time allocated since the last
account_system_vtime, the system to user time ratio estimate can end
up dividing by zero.
This was causing a problem noticed by Balbir Singh.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/kernel/time.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c index c0d77723ba11..a925a8eae121 100644 --- a/arch/powerpc/kernel/time.c +++ b/arch/powerpc/kernel/time.c @@ -241,8 +241,9 @@ void account_system_vtime(struct task_struct *tsk) /* deltascaled includes both user and system time. * Hence scale it based on the purr ratio to estimate * the system time */ - deltascaled = deltascaled * get_paca()->system_time / - (get_paca()->system_time + get_paca()->user_time); + if (get_paca()->user_time) + deltascaled = deltascaled * get_paca()->system_time / + (get_paca()->system_time + get_paca()->user_time); delta += get_paca()->system_time; get_paca()->system_time = 0; } |