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* Re: [PATCH] sched/fair: fix select_task_rq_fair return -1
@ 2014-12-04  9:05 Hillf Danton
  2014-12-04  9:22 ` Zhang, Jun
  2014-12-04 10:07 ` Vincent Guittot
  0 siblings, 2 replies; 9+ messages in thread
From: Hillf Danton @ 2014-12-04  9:05 UTC (permalink / raw)
  To: jun.zhang
  Cc: Ingo Molnar, Peter Zijlstra, linux-kernel,
	'Chuansheng Liu', 'Changcheng Liu',
	Hillf Danton, Vincent Guittot

> 
> From: zhang jun <jun.zhang@intel.com>
> 
> when cpu == -1 and sd->child == NULL, select_task_rq_fair return -1, system panic.
> 
> [ 0.738326] BUG: unable to handle kernel paging request at ffff8800997ea928
> [ 0.746138] IP: [<ffffffff810b15d3>] wake_up_new_task+0x43/0x1b0
> [ 0.752886] PGD 25df067 PUD 0
> [ 0.756321] Oops: 0000 1 PREEMPT SMP
> [ 0.760743] Modules linked in:
> [ 0.764179] CPU: 0 PID: 6 Comm: kworker/u8:0 Not tainted 3.14.19-quilt-b27ac761 #2
> [ 0.772651] Hardware name: Intel Corporation CHERRYVIEW B1 PLATFORM/Cherry Trail CR, BIOS CHTTRVP1.X64.0003.R08.1411110453
> 11/11/2014
> [ 0.786084] Workqueue: khelper __call_usermodehelper
> [ 0.791649] task: ffff88007955a150 ti: ffff88007955c000 task.ti: ffff88007955c000
> [ 0.800021] RIP: 0010:[<ffffffff810b15d3>] [<ffffffff810b15d3>] wake_up_new_task+0x43/0x1b0
> [ 0.809478] RSP: 0000:ffff88007955dd58 EFLAGS: 00010092
> [ 0.815422] RAX: 00000000ffffffff RBX: 0000000000000001 RCX: 0000000000000020
> [ 0.823404] RDX: 00000000ffffffff RSI: 0000000000000020 RDI: 0000000000000020
> [ 0.831386] RBP: ffff88007955dd80 R08: ffff880079604b58 R09: 00000000ffffffff
> [ 0.839368] R10: 0000000000000004 R11: eae0000000000000 R12: ffff8800797ea650
> [ 0.847350] R13: 0000000000004000 R14: ffff8800797ead52 R15: 0000000000000206
> [ 0.855335] FS: 0000000000000000(0000) GS:ffff88007aa00000(0000) knlGS:0000000000000000
> [ 0.864387] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
> [ 0.870817] CR2: ffff8800997ea928 CR3: 000000000220b000 CR4: 00000000001007f0
> [ 0.878796] Stack:
> [ 0.881046] 0000000000000001 ffff8800797ea650 0000000000004000 0000000000000000
> [ 0.889363] 000000000000003c ffff88007955ddf0 ffffffff8107ddfd ffffffff810b6a95
> [ 0.897680] 0000000000000000 ffff8800796beb00 ffff880000000000 ffffffff81000000
> [ 0.905998] Call Trace:
> [ 0.908752] [<ffffffff8107ddfd>] do_fork+0x12d/0x3b0
> [ 0.914416] [<ffffffff810b6a95>] ? set_next_entity+0x95/0xb0
> [ 0.920856] [<ffffffff8107e0a6>] kernel_thread+0x26/0x30
> [ 0.926903] [<ffffffff8109703e>] __call_usermodehelper+0x2e/0x90
> [ 0.933730] [<ffffffff8109ad31>] process_one_work+0x171/0x490
> [ 0.940264] [<ffffffff8109ba4b>] worker_thread+0x11b/0x3a0
> [ 0.946508] [<ffffffff8109b930>] ? manage_workers.isra.27+0x2b0/0x2b0
> [ 0.953821] [<ffffffff810a1802>] kthread+0xd2/0xf0
> [ 0.959289] [<ffffffff810a1730>] ? kthread_create_on_node+0x170/0x170
> [ 0.966602] [<ffffffff81af81ac>] ret_from_fork+0x7c/0xb0
> [ 0.972652] [<ffffffff810a1730>] ? kthread_create_on_node+0x170/0x170
> [ 0.979956] Code: 49 89 fc 4c 89 f7 53 e8 bc 5c a4 00 49 8b 54 24 08 31 c9 49 89 c7 49 8b 44 24 60 4c 89 e7 8b 72 18 ba 08 00 00 00 ff 50 40 89
> c2 <49> 0f a3 94 24 e0 02 00 00 19 c9 85 c9 0f 84 34 01 00 00 48 8b
> [ 1.001809] RIP [<ffffffff810b15d3>] wake_up_new_task+0x43/0x1b0
> [ 1.008641] RSP <ffff88007955dd58>
> [ 1.012544] CR2: ffff8800997ea928
> [ 1.016279] --[ end trace 9737aaa337a5ca10 ]--
> 
> Signed-off-by: zhang jun <jun.zhang@intel.com>
> Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com>
> Signed-off-by: Changcheng Liu <changcheng.liu@intel.com>
> ---
>  kernel/sched/fair.c |    2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 34baa60..123153f 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -4587,6 +4587,8 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f
>  		if (new_cpu == -1 || new_cpu == cpu) {
>  			/* Now try balancing at a lower domain level of cpu */
>  			sd = sd->child;
> +			if ((!sd) && (new_cpu == -1))
> +				new_cpu = smp_processor_id();
>  			continue;
>  		}
> 
In 3.18-rc7 is -1 still selected?

Hillf


^ permalink raw reply	[flat|nested] 9+ messages in thread
* RE: [PATCH] sched/fair: fix select_task_rq_fair return -1
  2014-12-04  9:05 [PATCH] sched/fair: fix select_task_rq_fair return -1 Hillf Danton
@ 2014-12-04  9:22 ` Zhang, Jun
  2014-12-04  9:32   ` Hillf Danton
  2014-12-04 10:07 ` Vincent Guittot
  1 sibling, 1 reply; 9+ messages in thread
From: Zhang, Jun @ 2014-12-04  9:22 UTC (permalink / raw)
  To: Hillf Danton
  Cc: Ingo Molnar, Peter Zijlstra, linux-kernel, Liu, Chuansheng, Liu,
	Changcheng, Vincent Guittot

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset="utf-8", Size: 4315 bytes --]

Hello, Hillf
This issue happened in 3.14.25. 
Do you know which patch to fix it in 3.18-rc7?
We can try it.

-----Original Message-----
From: Hillf Danton [mailto:hillf.zj@alibaba-inc.com] 
Sent: Thursday, December 04, 2014 5:05 PM
To: Zhang, Jun
Cc: Ingo Molnar; Peter Zijlstra; linux-kernel; Liu, Chuansheng; Liu, Changcheng; Hillf Danton; Vincent Guittot
Subject: Re: [PATCH] sched/fair: fix select_task_rq_fair return -1

> 
> From: zhang jun <jun.zhang@intel.com>
> 
> when cpu == -1 and sd->child == NULL, select_task_rq_fair return -1, system panic.
> 
> [ 0.738326] BUG: unable to handle kernel paging request at 
> ffff8800997ea928 [ 0.746138] IP: [<ffffffff810b15d3>] 
> wake_up_new_task+0x43/0x1b0 [ 0.752886] PGD 25df067 PUD 0 [ 0.756321] 
> Oops: 0000 1 PREEMPT SMP [ 0.760743] Modules linked in:
> [ 0.764179] CPU: 0 PID: 6 Comm: kworker/u8:0 Not tainted 
> 3.14.19-quilt-b27ac761 #2 [ 0.772651] Hardware name: Intel Corporation 
> CHERRYVIEW B1 PLATFORM/Cherry Trail CR, BIOS 
> CHTTRVP1.X64.0003.R08.1411110453
> 11/11/2014
> [ 0.786084] Workqueue: khelper __call_usermodehelper [ 0.791649] task: 
> ffff88007955a150 ti: ffff88007955c000 task.ti: ffff88007955c000 [ 
> 0.800021] RIP: 0010:[<ffffffff810b15d3>] [<ffffffff810b15d3>] 
> wake_up_new_task+0x43/0x1b0 [ 0.809478] RSP: 0000:ffff88007955dd58 
> EFLAGS: 00010092 [ 0.815422] RAX: 00000000ffffffff RBX: 
> 0000000000000001 RCX: 0000000000000020 [ 0.823404] RDX: 
> 00000000ffffffff RSI: 0000000000000020 RDI: 0000000000000020 [ 
> 0.831386] RBP: ffff88007955dd80 R08: ffff880079604b58 R09: 
> 00000000ffffffff [ 0.839368] R10: 0000000000000004 R11: 
> eae0000000000000 R12: ffff8800797ea650 [ 0.847350] R13: 
> 0000000000004000 R14: ffff8800797ead52 R15: 0000000000000206 [ 
> 0.855335] FS: 0000000000000000(0000) GS:ffff88007aa00000(0000) 
> knlGS:0000000000000000 [ 0.864387] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 0.870817] CR2: ffff8800997ea928 CR3: 000000000220b000 CR4: 00000000001007f0 [ 0.878796] Stack:
> [ 0.881046] 0000000000000001 ffff8800797ea650 0000000000004000 
> 0000000000000000 [ 0.889363] 000000000000003c ffff88007955ddf0 
> ffffffff8107ddfd ffffffff810b6a95 [ 0.897680] 0000000000000000 
> ffff8800796beb00 ffff880000000000 ffffffff81000000 [ 0.905998] Call Trace:
> [ 0.908752] [<ffffffff8107ddfd>] do_fork+0x12d/0x3b0 [ 0.914416] 
> [<ffffffff810b6a95>] ? set_next_entity+0x95/0xb0 [ 0.920856] 
> [<ffffffff8107e0a6>] kernel_thread+0x26/0x30 [ 0.926903] 
> [<ffffffff8109703e>] __call_usermodehelper+0x2e/0x90 [ 0.933730] 
> [<ffffffff8109ad31>] process_one_work+0x171/0x490 [ 0.940264] 
> [<ffffffff8109ba4b>] worker_thread+0x11b/0x3a0 [ 0.946508] 
> [<ffffffff8109b930>] ? manage_workers.isra.27+0x2b0/0x2b0
> [ 0.953821] [<ffffffff810a1802>] kthread+0xd2/0xf0 [ 0.959289] 
> [<ffffffff810a1730>] ? kthread_create_on_node+0x170/0x170
> [ 0.966602] [<ffffffff81af81ac>] ret_from_fork+0x7c/0xb0 [ 0.972652] 
> [<ffffffff810a1730>] ? kthread_create_on_node+0x170/0x170
> [ 0.979956] Code: 49 89 fc 4c 89 f7 53 e8 bc 5c a4 00 49 8b 54 24 08 
> 31 c9 49 89 c7 49 8b 44 24 60 4c 89 e7 8b 72 18 ba 08 00 00 00 ff 50 
> 40 89
> c2 <49> 0f a3 94 24 e0 02 00 00 19 c9 85 c9 0f 84 34 01 00 00 48 8b [ 
> 1.001809] RIP [<ffffffff810b15d3>] wake_up_new_task+0x43/0x1b0 [ 
> 1.008641] RSP <ffff88007955dd58> [ 1.012544] CR2: ffff8800997ea928 [ 
> 1.016279] --[ end trace 9737aaa337a5ca10 ]--
> 
> Signed-off-by: zhang jun <jun.zhang@intel.com>
> Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com>
> Signed-off-by: Changcheng Liu <changcheng.liu@intel.com>
> ---
>  kernel/sched/fair.c |    2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 
> 34baa60..123153f 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -4587,6 +4587,8 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f
>  		if (new_cpu == -1 || new_cpu == cpu) {
>  			/* Now try balancing at a lower domain level of cpu */
>  			sd = sd->child;
> +			if ((!sd) && (new_cpu == -1))
> +				new_cpu = smp_processor_id();
>  			continue;
>  		}
> 
In 3.18-rc7 is -1 still selected?

Hillf

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^ permalink raw reply	[flat|nested] 9+ messages in thread
* RE: [PATCH] sched/fair: fix select_task_rq_fair return -1
  2014-12-04  9:22 ` Zhang, Jun
@ 2014-12-04  9:32   ` Hillf Danton
  0 siblings, 0 replies; 9+ messages in thread
From: Hillf Danton @ 2014-12-04  9:32 UTC (permalink / raw)
  To: 'Zhang, Jun'
  Cc: 'Ingo Molnar', 'Peter Zijlstra',
	'linux-kernel', 'Liu, Chuansheng',
	'Liu, Changcheng', 'Vincent Guittot'

> 
> This issue happened in 3.14.25.
> Do you know which patch to fix it in 3.18-rc7?
>
I see no fix needed by 3.18-rc7, but a tiny cleanup of -1

If 3.14 concerned, it is the work, I guess, of those maintainers like Greg KH.

Hillf


^ permalink raw reply	[flat|nested] 9+ messages in thread
* Re: [PATCH] sched/fair: fix select_task_rq_fair return -1
  2014-12-04  9:05 [PATCH] sched/fair: fix select_task_rq_fair return -1 Hillf Danton
  2014-12-04  9:22 ` Zhang, Jun
@ 2014-12-04 10:07 ` Vincent Guittot
  2014-12-04 10:23   ` Liu, Chuansheng
  1 sibling, 1 reply; 9+ messages in thread
From: Vincent Guittot @ 2014-12-04 10:07 UTC (permalink / raw)
  To: Hillf Danton
  Cc: jun.zhang, Ingo Molnar, Peter Zijlstra, linux-kernel,
	Chuansheng Liu, Changcheng Liu

On 4 December 2014 at 10:05, Hillf Danton <hillf.zj@alibaba-inc.com> wrote:
>>
>> From: zhang jun <jun.zhang@intel.com>
>>
>> when cpu == -1 and sd->child == NULL, select_task_rq_fair return -1, system panic.
>>
>> [ 0.738326] BUG: unable to handle kernel paging request at ffff8800997ea928
>> [ 0.746138] IP: [<ffffffff810b15d3>] wake_up_new_task+0x43/0x1b0
>> [ 0.752886] PGD 25df067 PUD 0
>> [ 0.756321] Oops: 0000 1 PREEMPT SMP
>> [ 0.760743] Modules linked in:
>> [ 0.764179] CPU: 0 PID: 6 Comm: kworker/u8:0 Not tainted 3.14.19-quilt-b27ac761 #2
>> [ 0.772651] Hardware name: Intel Corporation CHERRYVIEW B1 PLATFORM/Cherry Trail CR, BIOS CHTTRVP1.X64.0003.R08.1411110453
>> 11/11/2014
>> [ 0.786084] Workqueue: khelper __call_usermodehelper
>> [ 0.791649] task: ffff88007955a150 ti: ffff88007955c000 task.ti: ffff88007955c000
>> [ 0.800021] RIP: 0010:[<ffffffff810b15d3>] [<ffffffff810b15d3>] wake_up_new_task+0x43/0x1b0
>> [ 0.809478] RSP: 0000:ffff88007955dd58 EFLAGS: 00010092
>> [ 0.815422] RAX: 00000000ffffffff RBX: 0000000000000001 RCX: 0000000000000020
>> [ 0.823404] RDX: 00000000ffffffff RSI: 0000000000000020 RDI: 0000000000000020
>> [ 0.831386] RBP: ffff88007955dd80 R08: ffff880079604b58 R09: 00000000ffffffff
>> [ 0.839368] R10: 0000000000000004 R11: eae0000000000000 R12: ffff8800797ea650
>> [ 0.847350] R13: 0000000000004000 R14: ffff8800797ead52 R15: 0000000000000206
>> [ 0.855335] FS: 0000000000000000(0000) GS:ffff88007aa00000(0000) knlGS:0000000000000000
>> [ 0.864387] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
>> [ 0.870817] CR2: ffff8800997ea928 CR3: 000000000220b000 CR4: 00000000001007f0
>> [ 0.878796] Stack:
>> [ 0.881046] 0000000000000001 ffff8800797ea650 0000000000004000 0000000000000000
>> [ 0.889363] 000000000000003c ffff88007955ddf0 ffffffff8107ddfd ffffffff810b6a95
>> [ 0.897680] 0000000000000000 ffff8800796beb00 ffff880000000000 ffffffff81000000
>> [ 0.905998] Call Trace:
>> [ 0.908752] [<ffffffff8107ddfd>] do_fork+0x12d/0x3b0
>> [ 0.914416] [<ffffffff810b6a95>] ? set_next_entity+0x95/0xb0
>> [ 0.920856] [<ffffffff8107e0a6>] kernel_thread+0x26/0x30
>> [ 0.926903] [<ffffffff8109703e>] __call_usermodehelper+0x2e/0x90
>> [ 0.933730] [<ffffffff8109ad31>] process_one_work+0x171/0x490
>> [ 0.940264] [<ffffffff8109ba4b>] worker_thread+0x11b/0x3a0
>> [ 0.946508] [<ffffffff8109b930>] ? manage_workers.isra.27+0x2b0/0x2b0
>> [ 0.953821] [<ffffffff810a1802>] kthread+0xd2/0xf0
>> [ 0.959289] [<ffffffff810a1730>] ? kthread_create_on_node+0x170/0x170
>> [ 0.966602] [<ffffffff81af81ac>] ret_from_fork+0x7c/0xb0
>> [ 0.972652] [<ffffffff810a1730>] ? kthread_create_on_node+0x170/0x170
>> [ 0.979956] Code: 49 89 fc 4c 89 f7 53 e8 bc 5c a4 00 49 8b 54 24 08 31 c9 49 89 c7 49 8b 44 24 60 4c 89 e7 8b 72 18 ba 08 00 00 00 ff 50 40 89
>> c2 <49> 0f a3 94 24 e0 02 00 00 19 c9 85 c9 0f 84 34 01 00 00 48 8b
>> [ 1.001809] RIP [<ffffffff810b15d3>] wake_up_new_task+0x43/0x1b0
>> [ 1.008641] RSP <ffff88007955dd58>
>> [ 1.012544] CR2: ffff8800997ea928
>> [ 1.016279] --[ end trace 9737aaa337a5ca10 ]--
>>
>> Signed-off-by: zhang jun <jun.zhang@intel.com>
>> Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com>
>> Signed-off-by: Changcheng Liu <changcheng.liu@intel.com>
>> ---
>>  kernel/sched/fair.c |    2 ++
>>  1 file changed, 2 insertions(+)
>>
>> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
>> index 34baa60..123153f 100644
>> --- a/kernel/sched/fair.c
>> +++ b/kernel/sched/fair.c
>> @@ -4587,6 +4587,8 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f
>>               if (new_cpu == -1 || new_cpu == cpu) {
>>                       /* Now try balancing at a lower domain level of cpu */
>>                       sd = sd->child;
>> +                     if ((!sd) && (new_cpu == -1))
>> +                             new_cpu = smp_processor_id();
>>                       continue;
>>               }
>>
> In 3.18-rc7 is -1 still selected?

find_idlest_cpu doesn't return -1 anymore but always a valid cpu. The
local cpu will be used if no better cpu has been found

>
> Hillf
>

^ permalink raw reply	[flat|nested] 9+ messages in thread
* RE: [PATCH] sched/fair: fix select_task_rq_fair return -1
  2014-12-04 10:07 ` Vincent Guittot
@ 2014-12-04 10:23   ` Liu, Chuansheng
  2014-12-04 10:43     ` Vincent Guittot
  0 siblings, 1 reply; 9+ messages in thread
From: Liu, Chuansheng @ 2014-12-04 10:23 UTC (permalink / raw)
  To: Vincent Guittot, Hillf Danton
  Cc: Zhang, Jun, Ingo Molnar, Peter Zijlstra, linux-kernel, Liu, Changcheng



> -----Original Message-----
> From: Vincent Guittot [mailto:vincent.guittot@linaro.org]
> Sent: Thursday, December 04, 2014 6:08 PM
> To: Hillf Danton
> Cc: Zhang, Jun; Ingo Molnar; Peter Zijlstra; linux-kernel; Liu, Chuansheng; Liu,
> Changcheng
> Subject: Re: [PATCH] sched/fair: fix select_task_rq_fair return -1
> 
> On 4 December 2014 at 10:05, Hillf Danton <hillf.zj@alibaba-inc.com> wrote:
> >>
> >> From: zhang jun <jun.zhang@intel.com>
> >>
> >> when cpu == -1 and sd->child == NULL, select_task_rq_fair return -1, system
> panic.
> >>
> >> [ 0.738326] BUG: unable to handle kernel paging request at
> ffff8800997ea928
> >> [ 0.746138] IP: [<ffffffff810b15d3>] wake_up_new_task+0x43/0x1b0
> >> [ 0.752886] PGD 25df067 PUD 0
> >> [ 0.756321] Oops: 0000 1 PREEMPT SMP
> >> [ 0.760743] Modules linked in:
> >> [ 0.764179] CPU: 0 PID: 6 Comm: kworker/u8:0 Not tainted
> 3.14.19-quilt-b27ac761 #2
> >> [ 0.772651] Hardware name: Intel Corporation CHERRYVIEW B1
> PLATFORM/Cherry Trail CR, BIOS CHTTRVP1.X64.0003.R08.1411110453
> >> 11/11/2014
> >> [ 0.786084] Workqueue: khelper __call_usermodehelper
> >> [ 0.791649] task: ffff88007955a150 ti: ffff88007955c000 task.ti:
> ffff88007955c000
> >> [ 0.800021] RIP: 0010:[<ffffffff810b15d3>] [<ffffffff810b15d3>]
> wake_up_new_task+0x43/0x1b0
> >> [ 0.809478] RSP: 0000:ffff88007955dd58 EFLAGS: 00010092
> >> [ 0.815422] RAX: 00000000ffffffff RBX: 0000000000000001 RCX:
> 0000000000000020
> >> [ 0.823404] RDX: 00000000ffffffff RSI: 0000000000000020 RDI:
> 0000000000000020
> >> [ 0.831386] RBP: ffff88007955dd80 R08: ffff880079604b58 R09:
> 00000000ffffffff
> >> [ 0.839368] R10: 0000000000000004 R11: eae0000000000000 R12:
> ffff8800797ea650
> >> [ 0.847350] R13: 0000000000004000 R14: ffff8800797ead52 R15:
> 0000000000000206
> >> [ 0.855335] FS: 0000000000000000(0000) GS:ffff88007aa00000(0000)
> knlGS:0000000000000000
> >> [ 0.864387] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
> >> [ 0.870817] CR2: ffff8800997ea928 CR3: 000000000220b000 CR4:
> 00000000001007f0
> >> [ 0.878796] Stack:
> >> [ 0.881046] 0000000000000001 ffff8800797ea650 0000000000004000
> 0000000000000000
> >> [ 0.889363] 000000000000003c ffff88007955ddf0 ffffffff8107ddfd
> ffffffff810b6a95
> >> [ 0.897680] 0000000000000000 ffff8800796beb00 ffff880000000000
> ffffffff81000000
> >> [ 0.905998] Call Trace:
> >> [ 0.908752] [<ffffffff8107ddfd>] do_fork+0x12d/0x3b0
> >> [ 0.914416] [<ffffffff810b6a95>] ? set_next_entity+0x95/0xb0
> >> [ 0.920856] [<ffffffff8107e0a6>] kernel_thread+0x26/0x30
> >> [ 0.926903] [<ffffffff8109703e>] __call_usermodehelper+0x2e/0x90
> >> [ 0.933730] [<ffffffff8109ad31>] process_one_work+0x171/0x490
> >> [ 0.940264] [<ffffffff8109ba4b>] worker_thread+0x11b/0x3a0
> >> [ 0.946508] [<ffffffff8109b930>] ? manage_workers.isra.27+0x2b0/0x2b0
> >> [ 0.953821] [<ffffffff810a1802>] kthread+0xd2/0xf0
> >> [ 0.959289] [<ffffffff810a1730>] ? kthread_create_on_node+0x170/0x170
> >> [ 0.966602] [<ffffffff81af81ac>] ret_from_fork+0x7c/0xb0
> >> [ 0.972652] [<ffffffff810a1730>] ? kthread_create_on_node+0x170/0x170
> >> [ 0.979956] Code: 49 89 fc 4c 89 f7 53 e8 bc 5c a4 00 49 8b 54 24 08 31 c9 49
> 89 c7 49 8b 44 24 60 4c 89 e7 8b 72 18 ba 08 00 00 00 ff 50 40 89
> >> c2 <49> 0f a3 94 24 e0 02 00 00 19 c9 85 c9 0f 84 34 01 00 00 48 8b
> >> [ 1.001809] RIP [<ffffffff810b15d3>] wake_up_new_task+0x43/0x1b0
> >> [ 1.008641] RSP <ffff88007955dd58>
> >> [ 1.012544] CR2: ffff8800997ea928
> >> [ 1.016279] --[ end trace 9737aaa337a5ca10 ]--
> >>
> >> Signed-off-by: zhang jun <jun.zhang@intel.com>
> >> Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com>
> >> Signed-off-by: Changcheng Liu <changcheng.liu@intel.com>
> >> ---
> >>  kernel/sched/fair.c |    2 ++
> >>  1 file changed, 2 insertions(+)
> >>
> >> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> >> index 34baa60..123153f 100644
> >> --- a/kernel/sched/fair.c
> >> +++ b/kernel/sched/fair.c
> >> @@ -4587,6 +4587,8 @@ select_task_rq_fair(struct task_struct *p, int
> prev_cpu, int sd_flag, int wake_f
> >>               if (new_cpu == -1 || new_cpu == cpu) {
> >>                       /* Now try balancing at a lower domain level of
> cpu */
> >>                       sd = sd->child;
> >> +                     if ((!sd) && (new_cpu == -1))
> >> +                             new_cpu = smp_processor_id();
> >>                       continue;
> >>               }
> >>
> > In 3.18-rc7 is -1 still selected?
> 
> find_idlest_cpu doesn't return -1 anymore but always a valid cpu. The
> local cpu will be used if no better cpu has been found

So I guess we can make one similar patch based on 3.14.x branch?
Latest:
find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
return shallowest_idle_cpu != -1 ? shallowest_idle_cpu : least_loaded_cpu;

3.14.X:
find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
return idlest;


^ permalink raw reply	[flat|nested] 9+ messages in thread
* Re: [PATCH] sched/fair: fix select_task_rq_fair return -1
  2014-12-04 10:23   ` Liu, Chuansheng
@ 2014-12-04 10:43     ` Vincent Guittot
  2014-12-04 11:10       ` Hillf Danton
  0 siblings, 1 reply; 9+ messages in thread
From: Vincent Guittot @ 2014-12-04 10:43 UTC (permalink / raw)
  To: Liu, Chuansheng
  Cc: Hillf Danton, Zhang, Jun, Ingo Molnar, Peter Zijlstra,
	linux-kernel, Liu, Changcheng

On 4 December 2014 at 11:23, Liu, Chuansheng <chuansheng.liu@intel.com> wrote:
>
>
>> -----Original Message-----
>> From: Vincent Guittot [mailto:vincent.guittot@linaro.org]
>> Sent: Thursday, December 04, 2014 6:08 PM
>> To: Hillf Danton
>> Cc: Zhang, Jun; Ingo Molnar; Peter Zijlstra; linux-kernel; Liu, Chuansheng; Liu,
>> Changcheng
>> Subject: Re: [PATCH] sched/fair: fix select_task_rq_fair return -1
>>
>> On 4 December 2014 at 10:05, Hillf Danton <hillf.zj@alibaba-inc.com> wrote:
>> >>
>> >> From: zhang jun <jun.zhang@intel.com>
>> >>
>> >> when cpu == -1 and sd->child == NULL, select_task_rq_fair return -1, system
>> panic.
>> >>
>> >> [ 0.738326] BUG: unable to handle kernel paging request at
>> ffff8800997ea928
>> >> [ 0.746138] IP: [<ffffffff810b15d3>] wake_up_new_task+0x43/0x1b0
>> >> [ 0.752886] PGD 25df067 PUD 0
>> >> [ 0.756321] Oops: 0000 1 PREEMPT SMP
>> >> [ 0.760743] Modules linked in:
>> >> [ 0.764179] CPU: 0 PID: 6 Comm: kworker/u8:0 Not tainted
>> 3.14.19-quilt-b27ac761 #2
>> >> [ 0.772651] Hardware name: Intel Corporation CHERRYVIEW B1
>> PLATFORM/Cherry Trail CR, BIOS CHTTRVP1.X64.0003.R08.1411110453
>> >> 11/11/2014
>> >> [ 0.786084] Workqueue: khelper __call_usermodehelper
>> >> [ 0.791649] task: ffff88007955a150 ti: ffff88007955c000 task.ti:
>> ffff88007955c000
>> >> [ 0.800021] RIP: 0010:[<ffffffff810b15d3>] [<ffffffff810b15d3>]
>> wake_up_new_task+0x43/0x1b0
>> >> [ 0.809478] RSP: 0000:ffff88007955dd58 EFLAGS: 00010092
>> >> [ 0.815422] RAX: 00000000ffffffff RBX: 0000000000000001 RCX:
>> 0000000000000020
>> >> [ 0.823404] RDX: 00000000ffffffff RSI: 0000000000000020 RDI:
>> 0000000000000020
>> >> [ 0.831386] RBP: ffff88007955dd80 R08: ffff880079604b58 R09:
>> 00000000ffffffff
>> >> [ 0.839368] R10: 0000000000000004 R11: eae0000000000000 R12:
>> ffff8800797ea650
>> >> [ 0.847350] R13: 0000000000004000 R14: ffff8800797ead52 R15:
>> 0000000000000206
>> >> [ 0.855335] FS: 0000000000000000(0000) GS:ffff88007aa00000(0000)
>> knlGS:0000000000000000
>> >> [ 0.864387] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
>> >> [ 0.870817] CR2: ffff8800997ea928 CR3: 000000000220b000 CR4:
>> 00000000001007f0
>> >> [ 0.878796] Stack:
>> >> [ 0.881046] 0000000000000001 ffff8800797ea650 0000000000004000
>> 0000000000000000
>> >> [ 0.889363] 000000000000003c ffff88007955ddf0 ffffffff8107ddfd
>> ffffffff810b6a95
>> >> [ 0.897680] 0000000000000000 ffff8800796beb00 ffff880000000000
>> ffffffff81000000
>> >> [ 0.905998] Call Trace:
>> >> [ 0.908752] [<ffffffff8107ddfd>] do_fork+0x12d/0x3b0
>> >> [ 0.914416] [<ffffffff810b6a95>] ? set_next_entity+0x95/0xb0
>> >> [ 0.920856] [<ffffffff8107e0a6>] kernel_thread+0x26/0x30
>> >> [ 0.926903] [<ffffffff8109703e>] __call_usermodehelper+0x2e/0x90
>> >> [ 0.933730] [<ffffffff8109ad31>] process_one_work+0x171/0x490
>> >> [ 0.940264] [<ffffffff8109ba4b>] worker_thread+0x11b/0x3a0
>> >> [ 0.946508] [<ffffffff8109b930>] ? manage_workers.isra.27+0x2b0/0x2b0
>> >> [ 0.953821] [<ffffffff810a1802>] kthread+0xd2/0xf0
>> >> [ 0.959289] [<ffffffff810a1730>] ? kthread_create_on_node+0x170/0x170
>> >> [ 0.966602] [<ffffffff81af81ac>] ret_from_fork+0x7c/0xb0
>> >> [ 0.972652] [<ffffffff810a1730>] ? kthread_create_on_node+0x170/0x170
>> >> [ 0.979956] Code: 49 89 fc 4c 89 f7 53 e8 bc 5c a4 00 49 8b 54 24 08 31 c9 49
>> 89 c7 49 8b 44 24 60 4c 89 e7 8b 72 18 ba 08 00 00 00 ff 50 40 89
>> >> c2 <49> 0f a3 94 24 e0 02 00 00 19 c9 85 c9 0f 84 34 01 00 00 48 8b
>> >> [ 1.001809] RIP [<ffffffff810b15d3>] wake_up_new_task+0x43/0x1b0
>> >> [ 1.008641] RSP <ffff88007955dd58>
>> >> [ 1.012544] CR2: ffff8800997ea928
>> >> [ 1.016279] --[ end trace 9737aaa337a5ca10 ]--
>> >>
>> >> Signed-off-by: zhang jun <jun.zhang@intel.com>
>> >> Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com>
>> >> Signed-off-by: Changcheng Liu <changcheng.liu@intel.com>
>> >> ---
>> >>  kernel/sched/fair.c |    2 ++
>> >>  1 file changed, 2 insertions(+)
>> >>
>> >> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
>> >> index 34baa60..123153f 100644
>> >> --- a/kernel/sched/fair.c
>> >> +++ b/kernel/sched/fair.c
>> >> @@ -4587,6 +4587,8 @@ select_task_rq_fair(struct task_struct *p, int
>> prev_cpu, int sd_flag, int wake_f
>> >>               if (new_cpu == -1 || new_cpu == cpu) {
>> >>                       /* Now try balancing at a lower domain level of
>> cpu */
>> >>                       sd = sd->child;
>> >> +                     if ((!sd) && (new_cpu == -1))
>> >> +                             new_cpu = smp_processor_id();
>> >>                       continue;
>> >>               }
>> >>
>> > In 3.18-rc7 is -1 still selected?
>>
>> find_idlest_cpu doesn't return -1 anymore but always a valid cpu. The
>> local cpu will be used if no better cpu has been found
>
> So I guess we can make one similar patch based on 3.14.x branch?
> Latest:
> find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
> return shallowest_idle_cpu != -1 ? shallowest_idle_cpu : least_loaded_cpu;
>
> 3.14.X:
> find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
> return idlest;

The change below  will give a similar behavior than 3.18 for 3.14 and
we still match the condition if (new_cpu == -1 || new_cpu == cpu) in
order to go in the child level

--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4151,7 +4151,7 @@ static int
 find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
 {
        unsigned long load, min_load = ULONG_MAX;
-       int idlest = -1;
+       int idlest = this_cpu;
        int i;

        /* Traverse only the allowed CPUs */

>

^ permalink raw reply	[flat|nested] 9+ messages in thread
* Re: [PATCH] sched/fair: fix select_task_rq_fair return -1
  2014-12-04 10:43     ` Vincent Guittot
@ 2014-12-04 11:10       ` Hillf Danton
  2014-12-04 12:10         ` Vincent Guittot
  0 siblings, 1 reply; 9+ messages in thread
From: Hillf Danton @ 2014-12-04 11:10 UTC (permalink / raw)
  To: 'Vincent Guittot', 'Liu, Chuansheng'
  Cc: 'Zhang, Jun', 'Ingo Molnar',
	'Peter Zijlstra', 'linux-kernel',
	'Liu, Changcheng'

> 
> The change below  will give a similar behavior than 3.18 for 3.14 and
> we still match the condition if (new_cpu == -1 || new_cpu == cpu) in
> 
And -1 is no longer needed.

> order to go in the child level
> 
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -4151,7 +4151,7 @@ static int
>  find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
>  {
>         unsigned long load, min_load = ULONG_MAX;
> -       int idlest = -1;
> +       int idlest = this_cpu;
>         int i;
> 
>         /* Traverse only the allowed CPUs */
> 


^ permalink raw reply	[flat|nested] 9+ messages in thread
* Re: [PATCH] sched/fair: fix select_task_rq_fair return -1
  2014-12-04 11:10       ` Hillf Danton
@ 2014-12-04 12:10         ` Vincent Guittot
  0 siblings, 0 replies; 9+ messages in thread
From: Vincent Guittot @ 2014-12-04 12:10 UTC (permalink / raw)
  To: Hillf Danton
  Cc: Liu, Chuansheng, Zhang, Jun, Ingo Molnar, Peter Zijlstra,
	linux-kernel, Liu, Changcheng

On 4 December 2014 at 12:10, Hillf Danton <hillf.zj@alibaba-inc.com> wrote:
>>
>> The change below  will give a similar behavior than 3.18 for 3.14 and
>> we still match the condition if (new_cpu == -1 || new_cpu == cpu) in
>>
> And -1 is no longer needed.

yes indeed

>
>> order to go in the child level
>>
>> --- a/kernel/sched/fair.c
>> +++ b/kernel/sched/fair.c
>> @@ -4151,7 +4151,7 @@ static int
>>  find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
>>  {
>>         unsigned long load, min_load = ULONG_MAX;
>> -       int idlest = -1;
>> +       int idlest = this_cpu;
>>         int i;
>>
>>         /* Traverse only the allowed CPUs */
>>
>

^ permalink raw reply	[flat|nested] 9+ messages in thread
* [PATCH] sched/fair: fix select_task_rq_fair return -1
@ 2014-12-04  4:27 jun.zhang
  0 siblings, 0 replies; 9+ messages in thread
From: jun.zhang @ 2014-12-04  4:27 UTC (permalink / raw)
  To: mingo, peterz; +Cc: linux-kernel, zhang jun, Chuansheng Liu, Changcheng Liu

From: zhang jun <jun.zhang@intel.com>

when cpu == -1 and sd->child == NULL, select_task_rq_fair return -1, system panic.

[ 0.738326] BUG: unable to handle kernel paging request at ffff8800997ea928
[ 0.746138] IP: [<ffffffff810b15d3>] wake_up_new_task+0x43/0x1b0
[ 0.752886] PGD 25df067 PUD 0
[ 0.756321] Oops: 0000 1 PREEMPT SMP
[ 0.760743] Modules linked in:
[ 0.764179] CPU: 0 PID: 6 Comm: kworker/u8:0 Not tainted 3.14.19-quilt-b27ac761 #2
[ 0.772651] Hardware name: Intel Corporation CHERRYVIEW B1 PLATFORM/Cherry Trail CR, BIOS CHTTRVP1.X64.0003.R08.1411110453 11/11/2014
[ 0.786084] Workqueue: khelper __call_usermodehelper
[ 0.791649] task: ffff88007955a150 ti: ffff88007955c000 task.ti: ffff88007955c000
[ 0.800021] RIP: 0010:[<ffffffff810b15d3>] [<ffffffff810b15d3>] wake_up_new_task+0x43/0x1b0
[ 0.809478] RSP: 0000:ffff88007955dd58 EFLAGS: 00010092
[ 0.815422] RAX: 00000000ffffffff RBX: 0000000000000001 RCX: 0000000000000020
[ 0.823404] RDX: 00000000ffffffff RSI: 0000000000000020 RDI: 0000000000000020
[ 0.831386] RBP: ffff88007955dd80 R08: ffff880079604b58 R09: 00000000ffffffff
[ 0.839368] R10: 0000000000000004 R11: eae0000000000000 R12: ffff8800797ea650
[ 0.847350] R13: 0000000000004000 R14: ffff8800797ead52 R15: 0000000000000206
[ 0.855335] FS: 0000000000000000(0000) GS:ffff88007aa00000(0000) knlGS:0000000000000000
[ 0.864387] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 0.870817] CR2: ffff8800997ea928 CR3: 000000000220b000 CR4: 00000000001007f0
[ 0.878796] Stack:
[ 0.881046] 0000000000000001 ffff8800797ea650 0000000000004000 0000000000000000
[ 0.889363] 000000000000003c ffff88007955ddf0 ffffffff8107ddfd ffffffff810b6a95
[ 0.897680] 0000000000000000 ffff8800796beb00 ffff880000000000 ffffffff81000000
[ 0.905998] Call Trace:
[ 0.908752] [<ffffffff8107ddfd>] do_fork+0x12d/0x3b0
[ 0.914416] [<ffffffff810b6a95>] ? set_next_entity+0x95/0xb0
[ 0.920856] [<ffffffff8107e0a6>] kernel_thread+0x26/0x30
[ 0.926903] [<ffffffff8109703e>] __call_usermodehelper+0x2e/0x90
[ 0.933730] [<ffffffff8109ad31>] process_one_work+0x171/0x490
[ 0.940264] [<ffffffff8109ba4b>] worker_thread+0x11b/0x3a0
[ 0.946508] [<ffffffff8109b930>] ? manage_workers.isra.27+0x2b0/0x2b0
[ 0.953821] [<ffffffff810a1802>] kthread+0xd2/0xf0
[ 0.959289] [<ffffffff810a1730>] ? kthread_create_on_node+0x170/0x170
[ 0.966602] [<ffffffff81af81ac>] ret_from_fork+0x7c/0xb0
[ 0.972652] [<ffffffff810a1730>] ? kthread_create_on_node+0x170/0x170
[ 0.979956] Code: 49 89 fc 4c 89 f7 53 e8 bc 5c a4 00 49 8b 54 24 08 31 c9 49 89 c7 49 8b 44 24 60 4c 89 e7 8b 72 18 ba 08 00 00 00 ff 50 40 89 c2 <49> 0f a3 94 24 e0 02 00 00 19 c9 85 c9 0f 84 34 01 00 00 48 8b
[ 1.001809] RIP [<ffffffff810b15d3>] wake_up_new_task+0x43/0x1b0
[ 1.008641] RSP <ffff88007955dd58>
[ 1.012544] CR2: ffff8800997ea928
[ 1.016279] --[ end trace 9737aaa337a5ca10 ]--

Signed-off-by: zhang jun <jun.zhang@intel.com>
Signed-off-by: Chuansheng Liu <chuansheng.liu@intel.com>
Signed-off-by: Changcheng Liu <changcheng.liu@intel.com>
---
 kernel/sched/fair.c |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 34baa60..123153f 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4587,6 +4587,8 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f
 		if (new_cpu == -1 || new_cpu == cpu) {
 			/* Now try balancing at a lower domain level of cpu */
 			sd = sd->child;
+			if ((!sd) && (new_cpu == -1))
+				new_cpu = smp_processor_id();
 			continue;
 		}
 
-- 
1.7.9.5


^ permalink raw reply	[flat|nested] 9+ messages in thread
end of thread, other threads:[~2014-12-04 12:10 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2014-12-04  9:05 [PATCH] sched/fair: fix select_task_rq_fair return -1 Hillf Danton
2014-12-04  9:22 ` Zhang, Jun
2014-12-04  9:32   ` Hillf Danton
2014-12-04 10:07 ` Vincent Guittot
2014-12-04 10:23   ` Liu, Chuansheng
2014-12-04 10:43     ` Vincent Guittot
2014-12-04 11:10       ` Hillf Danton
2014-12-04 12:10         ` Vincent Guittot
  -- strict thread matches above, loose matches on Subject: below --
2014-12-04  4:27 jun.zhang

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