Re: lockdep: access percpu variable too early

2013-03-06 Thread Ming Lei
On Wed, Mar 6, 2013 at 6:34 PM, Ingo Molnar wrote: > > * Ming Lei wrote: > >> On Wed, Mar 6, 2013 at 6:20 PM, Ingo Molnar wrote: >> > >> > What's the practical effect of it? Do we copy the value from the boot CPU >> > and >> > thus the secondary CPUs start with slightly increased stats? >> >> Y

Re: lockdep: access percpu variable too early

2013-03-06 Thread Ingo Molnar
* Ming Lei wrote: > On Wed, Mar 6, 2013 at 6:20 PM, Ingo Molnar wrote: > > > > What's the practical effect of it? Do we copy the value from the boot CPU > > and > > thus the secondary CPUs start with slightly increased stats? > > Yes, it is the major effect. > > Also the arch dependent __my

Re: lockdep: access percpu variable too early

2013-03-06 Thread Ming Lei
On Wed, Mar 6, 2013 at 6:20 PM, Ingo Molnar wrote: > > What's the practical effect of it? Do we copy the value from the boot CPU and > thus > the secondary CPUs start with slightly increased stats? Yes, it is the major effect. Also the arch dependent __my_cpu_offset might be initialized a bit l

Re: lockdep: access percpu variable too early

2013-03-06 Thread Ingo Molnar
* Ming Lei wrote: > Hi, > > The percpu variables of 'lockdep_stats' and 'cpu_lock_stat' may be accessed > before > percpu area is brought up in case of CONFIG_DEBUG_LOCKDEP/CONFIG_LOCK_STAT, > so > these variables in non-boot CPUs will be initialized incorrectly. What's the practical effec

lockdep: access percpu variable too early

2013-02-28 Thread Ming Lei
Hi, The percpu variables of 'lockdep_stats' and 'cpu_lock_stat' may be accessed before percpu area is brought up in case of CONFIG_DEBUG_LOCKDEP/CONFIG_LOCK_STAT, so these variables in non-boot CPUs will be initialized incorrectly. As far as I think of, there are several solutions for the problem