* [2.6.28-rc5] RCU detected CPU 0 stall (t=4294893165/750 jiffies) @ 2008-11-19 12:37 Folkert van Heusden 2008-11-21 9:30 ` Lai Jiangshan 0 siblings, 1 reply; 7+ messages in thread From: Folkert van Heusden @ 2008-11-19 12:37 UTC (permalink / raw) To: linux-kernel During the boot-process of a 2.6.28-RC5 kernel I got the followin on the console: - [ 3.479998] RCU detected CPU 0 stall (t=4294893165/750 jiffies) ! [ 3.480004] Pid: 1, comm: swapper Not tainted 2.6.28-rc5-custom2 #1 ! [ 3.480004] Call Trace: ! [ 3.480004] [<c0300c33>] ? printk+0xf/0x14 ! [ 3.480004] [<c0166f15>] __rcu_pending+0x53/0x189 ! [ 3.480004] [<c0167067>] rcu_pending+0x1c/0x47 ! [ 3.480004] [<c0132aa4>] update_process_times+0x2b/0x4e ! [ 3.480004] [<c0144c8d>] tick_sched_timer+0x6d/0x9b ! [ 3.480004] [<c0144c20>] ? tick_sched_timer+0x0/0x9b ! [ 3.480004] [<c013e0cc>] __run_hrtimer+0x60/0x97 ! [ 3.480004] [<c013eb35>] hrtimer_interrupt+0xfe/0x166 ! [ 3.480004] [<c0112eea>] smp_apic_timer_interrupt+0x6c/0x7f ! [ 3.480004] [<c0104829>] apic_timer_interrupt+0x2d/0x34 ! [ 3.480004] [<c043c454>] ? inflate_codes+0x272/0x3bc ! [ 3.480004] [<c043cf22>] inflate_dynamic+0x4c0/0x4f0 ! [ 3.480004] [<c043d775>] unpack_to_rootfs+0x524/0x975 ! [ 3.480004] [<c0147eaf>] ? debug_check_no_locks_freed+0x1a/0x123 ! [ 3.480004] [<c043e202>] ? populate_rootfs+0x0/0xcd ! [ 3.480004] [<c043e202>] ? populate_rootfs+0x0/0xcd ! [ 3.480004] [<c043e278>] populate_rootfs+0x76/0xcd ! [ 3.480004] [<c0101130>] _stext+0x48/0x11e ! [ 3.480004] [<c0206830>] ? ida_get_new_above+0x157/0x171 ! [ 3.480004] [<c0218a08>] ? _raw_spin_lock+0x53/0xfa ! [ 3.480004] [<c02189b1>] ? _raw_spin_unlock+0x74/0x78 ! [ 3.480004] [<c0303759>] ? _spin_unlock+0x1d/0x20 ! [ 3.480004] [<c01c1ab1>] ? proc_register+0x146/0x157 ! [ 3.480004] [<c01c1bda>] ? create_proc_entry+0x7b/0x91 ! [ 3.480004] [<c0166600>] ? register_irq_proc+0x7b/0x9b ! [ 3.480004] [<c0166666>] ? init_irq_proc+0x46/0x59 ! [ 3.480004] [<c04392ee>] kernel_init+0x102/0x150 ! [ 3.480004] [<c04391ec>] ? kernel_init+0x0/0x150 ! [ 3.480004] [<c0104987>] kernel_thread_helper+0x7/0x10 + [ 4.773412] Freeing initrd memory: 53252k freed This is a P4 with hyperthreading. 0.5GB ram. IDE disk. Folkert van Heusden -- MultiTail na wan makriki wrokosani fu tan luku den logfile nanga san den commando spiti puru. Piki puru spesrutu sani, wroko nanga difrenti kroru, tya kon makandra, nanga wan lo moro. http://www.vanheusden.com/multitail/ ---------------------------------------------------------------------- Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [2.6.28-rc5] RCU detected CPU 0 stall (t=4294893165/750 jiffies) 2008-11-19 12:37 [2.6.28-rc5] RCU detected CPU 0 stall (t=4294893165/750 jiffies) Folkert van Heusden @ 2008-11-21 9:30 ` Lai Jiangshan 2008-11-21 9:45 ` Folkert van Heusden 0 siblings, 1 reply; 7+ messages in thread From: Lai Jiangshan @ 2008-11-21 9:30 UTC (permalink / raw) To: Folkert van Heusden; +Cc: linux-kernel, Paul E. McKenney Hi, Folkert van Heusden, Can you tell me how can I reproduce this bug. Thanx, Lai Folkert van Heusden wrote: > During the boot-process of a 2.6.28-RC5 kernel I got the followin on > the console: > > - [ 3.479998] RCU detected CPU 0 stall (t=4294893165/750 jiffies) > ! [ 3.480004] Pid: 1, comm: swapper Not tainted 2.6.28-rc5-custom2 #1 > ! [ 3.480004] Call Trace: > ! [ 3.480004] [<c0300c33>] ? printk+0xf/0x14 > ! [ 3.480004] [<c0166f15>] __rcu_pending+0x53/0x189 > ! [ 3.480004] [<c0167067>] rcu_pending+0x1c/0x47 > ! [ 3.480004] [<c0132aa4>] update_process_times+0x2b/0x4e > ! [ 3.480004] [<c0144c8d>] tick_sched_timer+0x6d/0x9b > ! [ 3.480004] [<c0144c20>] ? tick_sched_timer+0x0/0x9b > ! [ 3.480004] [<c013e0cc>] __run_hrtimer+0x60/0x97 > ! [ 3.480004] [<c013eb35>] hrtimer_interrupt+0xfe/0x166 > ! [ 3.480004] [<c0112eea>] smp_apic_timer_interrupt+0x6c/0x7f > ! [ 3.480004] [<c0104829>] apic_timer_interrupt+0x2d/0x34 > ! [ 3.480004] [<c043c454>] ? inflate_codes+0x272/0x3bc > ! [ 3.480004] [<c043cf22>] inflate_dynamic+0x4c0/0x4f0 > ! [ 3.480004] [<c043d775>] unpack_to_rootfs+0x524/0x975 > ! [ 3.480004] [<c0147eaf>] ? debug_check_no_locks_freed+0x1a/0x123 > ! [ 3.480004] [<c043e202>] ? populate_rootfs+0x0/0xcd > ! [ 3.480004] [<c043e202>] ? populate_rootfs+0x0/0xcd > ! [ 3.480004] [<c043e278>] populate_rootfs+0x76/0xcd > ! [ 3.480004] [<c0101130>] _stext+0x48/0x11e > ! [ 3.480004] [<c0206830>] ? ida_get_new_above+0x157/0x171 > ! [ 3.480004] [<c0218a08>] ? _raw_spin_lock+0x53/0xfa > ! [ 3.480004] [<c02189b1>] ? _raw_spin_unlock+0x74/0x78 > ! [ 3.480004] [<c0303759>] ? _spin_unlock+0x1d/0x20 > ! [ 3.480004] [<c01c1ab1>] ? proc_register+0x146/0x157 > ! [ 3.480004] [<c01c1bda>] ? create_proc_entry+0x7b/0x91 > ! [ 3.480004] [<c0166600>] ? register_irq_proc+0x7b/0x9b > ! [ 3.480004] [<c0166666>] ? init_irq_proc+0x46/0x59 > ! [ 3.480004] [<c04392ee>] kernel_init+0x102/0x150 > ! [ 3.480004] [<c04391ec>] ? kernel_init+0x0/0x150 > ! [ 3.480004] [<c0104987>] kernel_thread_helper+0x7/0x10 > + [ 4.773412] Freeing initrd memory: 53252k freed > > This is a P4 with hyperthreading. 0.5GB ram. IDE disk. > > > Folkert van Heusden > ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [2.6.28-rc5] RCU detected CPU 0 stall (t=4294893165/750 jiffies) 2008-11-21 9:30 ` Lai Jiangshan @ 2008-11-21 9:45 ` Folkert van Heusden 2008-11-21 15:12 ` Paul E. McKenney 0 siblings, 1 reply; 7+ messages in thread From: Folkert van Heusden @ 2008-11-21 9:45 UTC (permalink / raw) To: Lai Jiangshan; +Cc: linux-kernel, Paul E. McKenney Hi, I'm afraid there's no script for that: it happens during boot. On Fri, Nov 21, 2008 at 05:30:12PM +0800, Lai Jiangshan wrote: > Hi, Folkert van Heusden, > > Can you tell me how can I reproduce this bug. > > Thanx, Lai > > Folkert van Heusden wrote: > > During the boot-process of a 2.6.28-RC5 kernel I got the followin on > > the console: > > > > - [ 3.479998] RCU detected CPU 0 stall (t=4294893165/750 jiffies) > > ! [ 3.480004] Pid: 1, comm: swapper Not tainted 2.6.28-rc5-custom2 #1 > > ! [ 3.480004] Call Trace: > > ! [ 3.480004] [<c0300c33>] ? printk+0xf/0x14 > > ! [ 3.480004] [<c0166f15>] __rcu_pending+0x53/0x189 > > ! [ 3.480004] [<c0167067>] rcu_pending+0x1c/0x47 > > ! [ 3.480004] [<c0132aa4>] update_process_times+0x2b/0x4e > > ! [ 3.480004] [<c0144c8d>] tick_sched_timer+0x6d/0x9b > > ! [ 3.480004] [<c0144c20>] ? tick_sched_timer+0x0/0x9b > > ! [ 3.480004] [<c013e0cc>] __run_hrtimer+0x60/0x97 > > ! [ 3.480004] [<c013eb35>] hrtimer_interrupt+0xfe/0x166 > > ! [ 3.480004] [<c0112eea>] smp_apic_timer_interrupt+0x6c/0x7f > > ! [ 3.480004] [<c0104829>] apic_timer_interrupt+0x2d/0x34 > > ! [ 3.480004] [<c043c454>] ? inflate_codes+0x272/0x3bc > > ! [ 3.480004] [<c043cf22>] inflate_dynamic+0x4c0/0x4f0 > > ! [ 3.480004] [<c043d775>] unpack_to_rootfs+0x524/0x975 > > ! [ 3.480004] [<c0147eaf>] ? debug_check_no_locks_freed+0x1a/0x123 > > ! [ 3.480004] [<c043e202>] ? populate_rootfs+0x0/0xcd > > ! [ 3.480004] [<c043e202>] ? populate_rootfs+0x0/0xcd > > ! [ 3.480004] [<c043e278>] populate_rootfs+0x76/0xcd > > ! [ 3.480004] [<c0101130>] _stext+0x48/0x11e > > ! [ 3.480004] [<c0206830>] ? ida_get_new_above+0x157/0x171 > > ! [ 3.480004] [<c0218a08>] ? _raw_spin_lock+0x53/0xfa > > ! [ 3.480004] [<c02189b1>] ? _raw_spin_unlock+0x74/0x78 > > ! [ 3.480004] [<c0303759>] ? _spin_unlock+0x1d/0x20 > > ! [ 3.480004] [<c01c1ab1>] ? proc_register+0x146/0x157 > > ! [ 3.480004] [<c01c1bda>] ? create_proc_entry+0x7b/0x91 > > ! [ 3.480004] [<c0166600>] ? register_irq_proc+0x7b/0x9b > > ! [ 3.480004] [<c0166666>] ? init_irq_proc+0x46/0x59 > > ! [ 3.480004] [<c04392ee>] kernel_init+0x102/0x150 > > ! [ 3.480004] [<c04391ec>] ? kernel_init+0x0/0x150 > > ! [ 3.480004] [<c0104987>] kernel_thread_helper+0x7/0x10 > > + [ 4.773412] Freeing initrd memory: 53252k freed > > > > This is a P4 with hyperthreading. 0.5GB ram. IDE disk. > > > > > > Folkert van Heusden > > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ Folkert van Heusden -- Looking for a cheap but fast webhoster with an excellent helpdesk? http://keetweej.vanheusden.com/redir.php?id=1001 ---------------------------------------------------------------------- Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [2.6.28-rc5] RCU detected CPU 0 stall (t=4294893165/750 jiffies) 2008-11-21 9:45 ` Folkert van Heusden @ 2008-11-21 15:12 ` Paul E. McKenney 2008-11-21 15:34 ` Folkert van Heusden 0 siblings, 1 reply; 7+ messages in thread From: Paul E. McKenney @ 2008-11-21 15:12 UTC (permalink / raw) To: Folkert van Heusden; +Cc: Lai Jiangshan, linux-kernel On Fri, Nov 21, 2008 at 10:45:53AM +0100, Folkert van Heusden wrote: > Hi, > > I'm afraid there's no script for that: it happens during boot. This is a HZ=250 machine, correct? If so, please try the following patch (already in -tip), which helps suppress boot-time false positives. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> --- diff --git a/include/linux/rcuclassic.h b/include/linux/rcuclassic.h index 5f89b62..301dda8 100644 --- a/include/linux/rcuclassic.h +++ b/include/linux/rcuclassic.h @@ -41,7 +41,7 @@ #include <linux/seqlock.h> #ifdef CONFIG_RCU_CPU_STALL_DETECTOR -#define RCU_SECONDS_TILL_STALL_CHECK ( 3 * HZ) /* for rcp->jiffies_stall */ +#define RCU_SECONDS_TILL_STALL_CHECK (10 * HZ) /* for rcp->jiffies_stall */ #define RCU_SECONDS_TILL_STALL_RECHECK (30 * HZ) /* for rcp->jiffies_stall */ #endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ > On Fri, Nov 21, 2008 at 05:30:12PM +0800, Lai Jiangshan wrote: > > Hi, Folkert van Heusden, > > > > Can you tell me how can I reproduce this bug. > > > > Thanx, Lai > > > > Folkert van Heusden wrote: > > > During the boot-process of a 2.6.28-RC5 kernel I got the followin on > > > the console: > > > > > > - [ 3.479998] RCU detected CPU 0 stall (t=4294893165/750 jiffies) > > > ! [ 3.480004] Pid: 1, comm: swapper Not tainted 2.6.28-rc5-custom2 #1 > > > ! [ 3.480004] Call Trace: > > > ! [ 3.480004] [<c0300c33>] ? printk+0xf/0x14 > > > ! [ 3.480004] [<c0166f15>] __rcu_pending+0x53/0x189 > > > ! [ 3.480004] [<c0167067>] rcu_pending+0x1c/0x47 > > > ! [ 3.480004] [<c0132aa4>] update_process_times+0x2b/0x4e > > > ! [ 3.480004] [<c0144c8d>] tick_sched_timer+0x6d/0x9b > > > ! [ 3.480004] [<c0144c20>] ? tick_sched_timer+0x0/0x9b > > > ! [ 3.480004] [<c013e0cc>] __run_hrtimer+0x60/0x97 > > > ! [ 3.480004] [<c013eb35>] hrtimer_interrupt+0xfe/0x166 > > > ! [ 3.480004] [<c0112eea>] smp_apic_timer_interrupt+0x6c/0x7f > > > ! [ 3.480004] [<c0104829>] apic_timer_interrupt+0x2d/0x34 > > > ! [ 3.480004] [<c043c454>] ? inflate_codes+0x272/0x3bc > > > ! [ 3.480004] [<c043cf22>] inflate_dynamic+0x4c0/0x4f0 > > > ! [ 3.480004] [<c043d775>] unpack_to_rootfs+0x524/0x975 > > > ! [ 3.480004] [<c0147eaf>] ? debug_check_no_locks_freed+0x1a/0x123 > > > ! [ 3.480004] [<c043e202>] ? populate_rootfs+0x0/0xcd > > > ! [ 3.480004] [<c043e202>] ? populate_rootfs+0x0/0xcd > > > ! [ 3.480004] [<c043e278>] populate_rootfs+0x76/0xcd > > > ! [ 3.480004] [<c0101130>] _stext+0x48/0x11e > > > ! [ 3.480004] [<c0206830>] ? ida_get_new_above+0x157/0x171 > > > ! [ 3.480004] [<c0218a08>] ? _raw_spin_lock+0x53/0xfa > > > ! [ 3.480004] [<c02189b1>] ? _raw_spin_unlock+0x74/0x78 > > > ! [ 3.480004] [<c0303759>] ? _spin_unlock+0x1d/0x20 > > > ! [ 3.480004] [<c01c1ab1>] ? proc_register+0x146/0x157 > > > ! [ 3.480004] [<c01c1bda>] ? create_proc_entry+0x7b/0x91 > > > ! [ 3.480004] [<c0166600>] ? register_irq_proc+0x7b/0x9b > > > ! [ 3.480004] [<c0166666>] ? init_irq_proc+0x46/0x59 > > > ! [ 3.480004] [<c04392ee>] kernel_init+0x102/0x150 > > > ! [ 3.480004] [<c04391ec>] ? kernel_init+0x0/0x150 > > > ! [ 3.480004] [<c0104987>] kernel_thread_helper+0x7/0x10 > > > + [ 4.773412] Freeing initrd memory: 53252k freed > > > > > > This is a P4 with hyperthreading. 0.5GB ram. IDE disk. > > > > > > > > > Folkert van Heusden > > > > > > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > Please read the FAQ at http://www.tux.org/lkml/ > > > Folkert van Heusden > > -- > Looking for a cheap but fast webhoster with an excellent helpdesk? > http://keetweej.vanheusden.com/redir.php?id=1001 > ---------------------------------------------------------------------- > Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com ^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [2.6.28-rc5] RCU detected CPU 0 stall (t=4294893165/750 jiffies) 2008-11-21 15:12 ` Paul E. McKenney @ 2008-11-21 15:34 ` Folkert van Heusden 2008-11-21 15:53 ` Paul E. McKenney 0 siblings, 1 reply; 7+ messages in thread From: Folkert van Heusden @ 2008-11-21 15:34 UTC (permalink / raw) To: Paul E. McKenney; +Cc: Lai Jiangshan, linux-kernel > > I'm afraid there's no script for that: it happens during boot. > > This is a HZ=250 machine, correct? If so, please try the following > patch (already in -tip), which helps suppress boot-time false positives. That's correct, 250Hz. > diff --git a/include/linux/rcuclassic.h b/include/linux/rcuclassic.h > index 5f89b62..301dda8 100644 > --- a/include/linux/rcuclassic.h > +++ b/include/linux/rcuclassic.h > @@ -41,7 +41,7 @@ > #include <linux/seqlock.h> > > #ifdef CONFIG_RCU_CPU_STALL_DETECTOR > -#define RCU_SECONDS_TILL_STALL_CHECK ( 3 * HZ) /* for rcp->jiffies_stall */ > +#define RCU_SECONDS_TILL_STALL_CHECK (10 * HZ) /* for rcp->jiffies_stall */ Isn't it better to let the define depend on the value of CONFIG_HZ? E.g. Signed-off-by: Folkert van Heusden <folkert@vanheusden.com> diff --git a/include/linux/rcuclassic.h b/include/linux/rcuclassic.h index 5f89b62..301dda8 100644 --- a/include/linux/rcuclassic.h +++ b/include/linux/rcuclassic.h @@ -41,7 +41,7 @@ #include <linux/seqlock.h> #ifdef CONFIG_RCU_CPU_STALL_DETECTOR -#define RCU_SECONDS_TILL_STALL_CHECK ( 3 * HZ) /* for rcp->jiffies_stall */ +#define RCU_SECONDS_TILL_STALL_CHECK ( (CONFIG_HZ / 100) * 3 * HZ) /* for rcp->jiffies_stall */ #define RCU_SECONDS_TILL_STALL_RECHECK (30 * HZ) /* for rcp->jiffies_stall */ #endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ Folkert van Heusden -- MultiTail na wan makriki wrokosani fu tan luku den logfile nanga san den commando spiti puru. Piki puru spesrutu sani, wroko nanga difrenti kroru, tya kon makandra, nanga wan lo moro. http://www.vanheusden.com/multitail/ ---------------------------------------------------------------------- Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com ^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [2.6.28-rc5] RCU detected CPU 0 stall (t=4294893165/750 jiffies) 2008-11-21 15:34 ` Folkert van Heusden @ 2008-11-21 15:53 ` Paul E. McKenney 2008-11-21 17:38 ` Folkert van Heusden 0 siblings, 1 reply; 7+ messages in thread From: Paul E. McKenney @ 2008-11-21 15:53 UTC (permalink / raw) To: Folkert van Heusden; +Cc: Lai Jiangshan, linux-kernel On Fri, Nov 21, 2008 at 04:34:26PM +0100, Folkert van Heusden wrote: > > > I'm afraid there's no script for that: it happens during boot. > > > > This is a HZ=250 machine, correct? If so, please try the following > > patch (already in -tip), which helps suppress boot-time false positives. > > That's correct, 250Hz. > > > diff --git a/include/linux/rcuclassic.h b/include/linux/rcuclassic.h > > index 5f89b62..301dda8 100644 > > --- a/include/linux/rcuclassic.h > > +++ b/include/linux/rcuclassic.h > > @@ -41,7 +41,7 @@ > > #include <linux/seqlock.h> > > > > #ifdef CONFIG_RCU_CPU_STALL_DETECTOR > > -#define RCU_SECONDS_TILL_STALL_CHECK ( 3 * HZ) /* for rcp->jiffies_stall */ > > +#define RCU_SECONDS_TILL_STALL_CHECK (10 * HZ) /* for rcp->jiffies_stall */ > > Isn't it better to let the define depend on the value of CONFIG_HZ? > E.g. > > Signed-off-by: Folkert van Heusden <folkert@vanheusden.com> > > diff --git a/include/linux/rcuclassic.h b/include/linux/rcuclassic.h > index 5f89b62..301dda8 100644 > --- a/include/linux/rcuclassic.h > +++ b/include/linux/rcuclassic.h > @@ -41,7 +41,7 @@ > #include <linux/seqlock.h> > > #ifdef CONFIG_RCU_CPU_STALL_DETECTOR > -#define RCU_SECONDS_TILL_STALL_CHECK ( 3 * HZ) /* for rcp->jiffies_stall */ > +#define RCU_SECONDS_TILL_STALL_CHECK ( (CONFIG_HZ / 100) * 3 * HZ) /* for rcp->jiffies_stall */ > #define RCU_SECONDS_TILL_STALL_RECHECK (30 * HZ) /* for rcp->jiffies_stall */ > #endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ The stalls occur when CPUs spin in the kernel with preemption (or irqs or whatever) disabled. So while I suppose that there is some possibility that such a spin might be a function of HZ, I have never seen this happen. The reason I asked for your HZ value was to make sure that the stall detection was 3 seconds (750 jiffies). If you had been running a 75HZ system (admittedly unlikely) you would have seen a 10-second stall, and the patch would not help. In that case, the right thing to do would have been to work out why the system was spinning for 10 seconds during boot -- tough to get a 5-second boot when the system spins for 10 seconds coming up, right? ;-) Thanx, Paul > Folkert van Heusden > > -- > MultiTail na wan makriki wrokosani fu tan luku den logfile nanga san > den commando spiti puru. Piki puru spesrutu sani, wroko nanga difrenti > kroru, tya kon makandra, nanga wan lo moro. > http://www.vanheusden.com/multitail/ > ---------------------------------------------------------------------- > Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [2.6.28-rc5] RCU detected CPU 0 stall (t=4294893165/750 jiffies) 2008-11-21 15:53 ` Paul E. McKenney @ 2008-11-21 17:38 ` Folkert van Heusden 0 siblings, 0 replies; 7+ messages in thread From: Folkert van Heusden @ 2008-11-21 17:38 UTC (permalink / raw) To: Paul E. McKenney; +Cc: Lai Jiangshan, linux-kernel > > > > I'm afraid there's no script for that: it happens during boot. > > > This is a HZ=250 machine, correct? If so, please try the following > > > patch (already in -tip), which helps suppress boot-time false positives. > > That's correct, 250Hz. > > > -#define RCU_SECONDS_TILL_STALL_CHECK ( 3 * HZ) /* for rcp->jiffies_stall */ > > > +#define RCU_SECONDS_TILL_STALL_CHECK (10 * HZ) /* for rcp->jiffies_stall */ > > Isn't it better to let the define depend on the value of CONFIG_HZ? > > E.g. > The stalls occur when CPUs spin in the kernel with preemption (or irqs > or whatever) disabled. So while I suppose that there is some > possibility that such a spin might be a function of HZ, I have never > seen this happen. > The reason I asked for your HZ value was to make sure that the stall > detection was 3 seconds (750 jiffies). If you had been running a > 75HZ system (admittedly unlikely) you would have seen a 10-second stall, > and the patch would not help. In that case, the right thing to do would > have been to work out why the system was spinning for 10 seconds during > boot -- tough to get a 5-second boot when the system spins for 10 > seconds coming up, right? ;-) That patch fixes the rcu error. odr:/# grep -i rcu t [ 0.000000] RCU-based detection of stalled CPUs is enabled. Folkert van Heusden -- MultiTail na wan makriki wrokosani fu tan luku den logfile nanga san den commando spiti puru. Piki puru spesrutu sani, wroko nanga difrenti kroru, tya kon makandra, nanga wan lo moro. http://www.vanheusden.com/multitail/ ---------------------------------------------------------------------- Phone: +31-6-41278122, PGP-key: 1F28D8AE, www.vanheusden.com ^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2008-11-21 17:38 UTC | newest] Thread overview: 7+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2008-11-19 12:37 [2.6.28-rc5] RCU detected CPU 0 stall (t=4294893165/750 jiffies) Folkert van Heusden 2008-11-21 9:30 ` Lai Jiangshan 2008-11-21 9:45 ` Folkert van Heusden 2008-11-21 15:12 ` Paul E. McKenney 2008-11-21 15:34 ` Folkert van Heusden 2008-11-21 15:53 ` Paul E. McKenney 2008-11-21 17:38 ` Folkert van Heusden
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