* [PATCH] sched: remove redundant update_runtime notifier
@ 2012-12-28 10:00 Neil Zhang
2013-01-07 1:16 ` Neil Zhang
2013-01-07 10:39 ` Mike Galbraith
0 siblings, 2 replies; 6+ messages in thread
From: Neil Zhang @ 2012-12-28 10:00 UTC (permalink / raw)
To: mingo, peterz; +Cc: linux-kernel, Neil Zhang, bitbucket
migration_call() will do all the things that update_runtime() does.
So it seems update_runtime() is a redundant notifier, remove it.
Furthermore, there is potential risk that the current code will catch
BUG_ON at line 687 of rt.c when do cpu hotplug while there are realtime
threads running because of enable runtime twice.
Cc: bitbucket@online.de
Signed-off-by: Neil Zhang <zhangwm@marvell.com>
---
kernel/sched/core.c | 3 ---
kernel/sched/rt.c | 40 ----------------------------------------
kernel/sched/sched.h | 1 -
3 files changed, 0 insertions(+), 44 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 257002c..7b6a4d8 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6779,9 +6779,6 @@ void __init sched_init_smp(void)
hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE);
hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE);
- /* RT runtime code needs to handle some hotplug events */
- hotcpu_notifier(update_runtime, 0);
-
init_hrtick();
/* Move init over to a non-isolated CPU */
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 418feb0..1a499d2 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -697,15 +697,6 @@ balanced:
}
}
-static void disable_runtime(struct rq *rq)
-{
- unsigned long flags;
-
- raw_spin_lock_irqsave(&rq->lock, flags);
- __disable_runtime(rq);
- raw_spin_unlock_irqrestore(&rq->lock, flags);
-}
-
static void __enable_runtime(struct rq *rq)
{
rt_rq_iter_t iter;
@@ -730,37 +721,6 @@ static void __enable_runtime(struct rq *rq)
}
}
-static void enable_runtime(struct rq *rq)
-{
- unsigned long flags;
-
- raw_spin_lock_irqsave(&rq->lock, flags);
- __enable_runtime(rq);
- raw_spin_unlock_irqrestore(&rq->lock, flags);
-}
-
-int update_runtime(struct notifier_block *nfb, unsigned long action, void *hcpu)
-{
- int cpu = (int)(long)hcpu;
-
- switch (action) {
- case CPU_DOWN_PREPARE:
- case CPU_DOWN_PREPARE_FROZEN:
- disable_runtime(cpu_rq(cpu));
- return NOTIFY_OK;
-
- case CPU_DOWN_FAILED:
- case CPU_DOWN_FAILED_FROZEN:
- case CPU_ONLINE:
- case CPU_ONLINE_FROZEN:
- enable_runtime(cpu_rq(cpu));
- return NOTIFY_OK;
-
- default:
- return NOTIFY_DONE;
- }
-}
-
static int balance_runtime(struct rt_rq *rt_rq)
{
int more = 0;
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index fc88644..16d18a1 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -890,7 +890,6 @@ extern void sysrq_sched_debug_show(void);
extern void sched_init_granularity(void);
extern void update_max_interval(void);
extern void update_group_power(struct sched_domain *sd, int cpu);
-extern int update_runtime(struct notifier_block *nfb, unsigned long action, void *hcpu);
extern void init_sched_rt_class(void);
extern void init_sched_fair_class(void);
--
1.7.4.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* RE: [PATCH] sched: remove redundant update_runtime notifier
2012-12-28 10:00 [PATCH] sched: remove redundant update_runtime notifier Neil Zhang
@ 2013-01-07 1:16 ` Neil Zhang
2013-01-07 10:39 ` Mike Galbraith
1 sibling, 0 replies; 6+ messages in thread
From: Neil Zhang @ 2013-01-07 1:16 UTC (permalink / raw)
To: Neil Zhang, mingo@kernel.org, peterz@infradead.org
Cc: linux-kernel@vger.kernel.org, bitbucket@online.de
[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset="gb2312", Size: 3518 bytes --]
All,
> -----Original Message-----
> From: Neil Zhang [mailto:zhangwm@marvell.com]
> Sent: 2012Äê12ÔÂ28ÈÕ 18:00
> To: mingo@kernel.org; peterz@infradead.org
> Cc: linux-kernel@vger.kernel.org; Neil Zhang; bitbucket@online.de
> Subject: [PATCH] sched: remove redundant update_runtime notifier
>
> migration_call() will do all the things that update_runtime() does.
> So it seems update_runtime() is a redundant notifier, remove it.
>
> Furthermore, there is potential risk that the current code will catch BUG_ON
> at line 687 of rt.c when do cpu hotplug while there are realtime threads
> running because of enable runtime twice.
>
> Cc: bitbucket@online.de
> Signed-off-by: Neil Zhang <zhangwm@marvell.com>
> ---
> kernel/sched/core.c | 3 ---
> kernel/sched/rt.c | 40 ----------------------------------------
> kernel/sched/sched.h | 1 -
> 3 files changed, 0 insertions(+), 44 deletions(-)
>
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c index
> 257002c..7b6a4d8 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -6779,9 +6779,6 @@ void __init sched_init_smp(void)
> hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE);
> hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE);
>
> - /* RT runtime code needs to handle some hotplug events */
> - hotcpu_notifier(update_runtime, 0);
> -
> init_hrtick();
>
> /* Move init over to a non-isolated CPU */ diff --git a/kernel/sched/rt.c
> b/kernel/sched/rt.c index 418feb0..1a499d2 100644
> --- a/kernel/sched/rt.c
> +++ b/kernel/sched/rt.c
> @@ -697,15 +697,6 @@ balanced:
> }
> }
>
> -static void disable_runtime(struct rq *rq) -{
> - unsigned long flags;
> -
> - raw_spin_lock_irqsave(&rq->lock, flags);
> - __disable_runtime(rq);
> - raw_spin_unlock_irqrestore(&rq->lock, flags);
> -}
> -
> static void __enable_runtime(struct rq *rq) {
> rt_rq_iter_t iter;
> @@ -730,37 +721,6 @@ static void __enable_runtime(struct rq *rq)
> }
> }
>
> -static void enable_runtime(struct rq *rq) -{
> - unsigned long flags;
> -
> - raw_spin_lock_irqsave(&rq->lock, flags);
> - __enable_runtime(rq);
> - raw_spin_unlock_irqrestore(&rq->lock, flags);
> -}
> -
> -int update_runtime(struct notifier_block *nfb, unsigned long action, void
> *hcpu) -{
> - int cpu = (int)(long)hcpu;
> -
> - switch (action) {
> - case CPU_DOWN_PREPARE:
> - case CPU_DOWN_PREPARE_FROZEN:
> - disable_runtime(cpu_rq(cpu));
> - return NOTIFY_OK;
> -
> - case CPU_DOWN_FAILED:
> - case CPU_DOWN_FAILED_FROZEN:
> - case CPU_ONLINE:
> - case CPU_ONLINE_FROZEN:
> - enable_runtime(cpu_rq(cpu));
> - return NOTIFY_OK;
> -
> - default:
> - return NOTIFY_DONE;
> - }
> -}
> -
> static int balance_runtime(struct rt_rq *rt_rq) {
> int more = 0;
> diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index
> fc88644..16d18a1 100644
> --- a/kernel/sched/sched.h
> +++ b/kernel/sched/sched.h
> @@ -890,7 +890,6 @@ extern void sysrq_sched_debug_show(void);
> extern void sched_init_granularity(void); extern void
> update_max_interval(void); extern void update_group_power(struct
> sched_domain *sd, int cpu); -extern int update_runtime(struct notifier_block
> *nfb, unsigned long action, void *hcpu); extern void
> init_sched_rt_class(void); extern void init_sched_fair_class(void);
>
> --
> 1.7.4.1
Any comments about this patch?
Best Regards,
Neil Zhang
ÿôèº{.nÇ+‰·Ÿ®‰†+%ŠËÿ±éݶ\x17¥Šwÿº{.nÇ+‰·¥Š{±þG«éÿŠ{ayº\x1dʇڙë,j\a¢f£¢·hšïêÿ‘êçz_è®\x03(階ŠÝ¢j"ú\x1a¶^[m§ÿÿ¾\a«þG«éÿ¢¸?™¨èÚ&£ø§~á¶iO•æ¬z·švØ^\x14\x04\x1a¶^[m§ÿÿÃ\fÿ¶ìÿ¢¸?–I¥
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [PATCH] sched: remove redundant update_runtime notifier
2012-12-28 10:00 [PATCH] sched: remove redundant update_runtime notifier Neil Zhang
2013-01-07 1:16 ` Neil Zhang
@ 2013-01-07 10:39 ` Mike Galbraith
2013-01-08 1:12 ` Neil Zhang
1 sibling, 1 reply; 6+ messages in thread
From: Mike Galbraith @ 2013-01-07 10:39 UTC (permalink / raw)
To: Neil Zhang; +Cc: mingo, peterz, linux-kernel
On Fri, 2012-12-28 at 18:00 +0800, Neil Zhang wrote:
> migration_call() will do all the things that update_runtime() does.
> So it seems update_runtime() is a redundant notifier, remove it.
>
> Furthermore, there is potential risk that the current code will catch
> BUG_ON at line 687 of rt.c when do cpu hotplug while there are realtime
> threads running because of enable runtime twice.
Hm, box must be reading lkml behind my back.
PID: 14735 TASK: ffff880e75e86500 CPU: 4 COMMAND: "reboot"
#0 [ffff880e74b3d890] machine_kexec at ffffffff8102676e
#1 [ffff880e74b3d8e0] crash_kexec at ffffffff810a3a3a
#2 [ffff880e74b3d9b0] oops_end at ffffffff81446238
#3 [ffff880e74b3d9d0] do_invalid_op at ffffffff810035d4
#4 [ffff880e74b3da70] invalid_op at ffffffff8144d9bb
[exception RIP: __disable_runtime+494] <== BUG_ON(want);
RIP: ffffffff81045dae RSP: ffff880e74b3db28 RFLAGS: 00010082
RAX: 000000000000046a RBX: ffff880e7fcd1310 RCX: ffffffff81d88a90
RDX: 000000000000046a RSI: 0000000000000050 RDI: ffff880e7fcd19b0
RBP: ffff880e74b3db98 R8: 0000000000000010 R9: ffff88047f423408
R10: 0000000000000050 R11: ffffffff81250190 R12: 0000000000000050
R13: fffffffffde9f140 R14: ffff880e7fcd1310 R15: 000000000000122f
ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
#5 [ffff880e74b3dba0] rq_offline_rt at ffffffff8104b36a
#6 [ffff880e74b3dbc0] set_rq_offline at ffffffff81043c9e
#7 [ffff880e74b3dbe0] rq_attach_root at ffffffff8104c130
#8 [ffff880e74b3dc10] cpu_attach_domain at ffffffff81054f44
#9 [ffff880e74b3dc80] build_sched_domains at ffffffff81055525
#10 [ffff880e74b3dcd0] partition_sched_domains at ffffffff81055835
#11 [ffff880e74b3dd70] cpuset_cpu_inactive at ffffffff81055a0d
#12 [ffff880e74b3dd80] notifier_call_chain at ffffffff81448907
#13 [ffff880e74b3ddb0] _cpu_down at ffffffff8142b57b
#14 [ffff880e74b3de10] disable_nonboot_cpus at ffffffff8105ba23
#15 [ffff880e74b3de40] kernel_restart at ffffffff81071dde
#16 [ffff880e74b3de50] sys_reboot at ffffffff81071fc3
#17 [ffff880e74b3df80] system_call_fastpath at ffffffff8144ca12
RIP: 00007fed35778316 RSP: 00007fff23f7e198 RFLAGS: 00010202
RAX: 00000000000000a9 RBX: ffffffff8144ca12 RCX: 00007fed35771130
RDX: 0000000001234567 RSI: 0000000028121969 RDI: fffffffffee1dead
RBP: 0000000000000000 R8: 0000000000020fd0 R9: 000000000060d120
R10: 00007fff23f7df40 R11: 0000000000000202 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000000
ORIG_RAX: 00000000000000a9 CS: 0033 SS: 002b
> Cc: bitbucket@online.de
> Signed-off-by: Neil Zhang <zhangwm@marvell.com>
> ---
> kernel/sched/core.c | 3 ---
> kernel/sched/rt.c | 40 ----------------------------------------
> kernel/sched/sched.h | 1 -
> 3 files changed, 0 insertions(+), 44 deletions(-)
>
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 257002c..7b6a4d8 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -6779,9 +6779,6 @@ void __init sched_init_smp(void)
> hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE);
> hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE);
>
> - /* RT runtime code needs to handle some hotplug events */
> - hotcpu_notifier(update_runtime, 0);
> -
> init_hrtick();
>
> /* Move init over to a non-isolated CPU */
> diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
> index 418feb0..1a499d2 100644
> --- a/kernel/sched/rt.c
> +++ b/kernel/sched/rt.c
> @@ -697,15 +697,6 @@ balanced:
> }
> }
>
> -static void disable_runtime(struct rq *rq)
> -{
> - unsigned long flags;
> -
> - raw_spin_lock_irqsave(&rq->lock, flags);
> - __disable_runtime(rq);
> - raw_spin_unlock_irqrestore(&rq->lock, flags);
> -}
> -
> static void __enable_runtime(struct rq *rq)
> {
> rt_rq_iter_t iter;
> @@ -730,37 +721,6 @@ static void __enable_runtime(struct rq *rq)
> }
> }
>
> -static void enable_runtime(struct rq *rq)
> -{
> - unsigned long flags;
> -
> - raw_spin_lock_irqsave(&rq->lock, flags);
> - __enable_runtime(rq);
> - raw_spin_unlock_irqrestore(&rq->lock, flags);
> -}
> -
> -int update_runtime(struct notifier_block *nfb, unsigned long action, void *hcpu)
> -{
> - int cpu = (int)(long)hcpu;
> -
> - switch (action) {
> - case CPU_DOWN_PREPARE:
> - case CPU_DOWN_PREPARE_FROZEN:
> - disable_runtime(cpu_rq(cpu));
> - return NOTIFY_OK;
> -
> - case CPU_DOWN_FAILED:
> - case CPU_DOWN_FAILED_FROZEN:
> - case CPU_ONLINE:
> - case CPU_ONLINE_FROZEN:
> - enable_runtime(cpu_rq(cpu));
> - return NOTIFY_OK;
> -
> - default:
> - return NOTIFY_DONE;
> - }
> -}
> -
> static int balance_runtime(struct rt_rq *rt_rq)
> {
> int more = 0;
> diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
> index fc88644..16d18a1 100644
> --- a/kernel/sched/sched.h
> +++ b/kernel/sched/sched.h
> @@ -890,7 +890,6 @@ extern void sysrq_sched_debug_show(void);
> extern void sched_init_granularity(void);
> extern void update_max_interval(void);
> extern void update_group_power(struct sched_domain *sd, int cpu);
> -extern int update_runtime(struct notifier_block *nfb, unsigned long action, void *hcpu);
> extern void init_sched_rt_class(void);
> extern void init_sched_fair_class(void);
>
^ permalink raw reply [flat|nested] 6+ messages in thread* RE: [PATCH] sched: remove redundant update_runtime notifier
2013-01-07 10:39 ` Mike Galbraith
@ 2013-01-08 1:12 ` Neil Zhang
0 siblings, 0 replies; 6+ messages in thread
From: Neil Zhang @ 2013-01-08 1:12 UTC (permalink / raw)
To: Mike Galbraith
Cc: mingo@kernel.org, peterz@infradead.org,
linux-kernel@vger.kernel.org
[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset="utf-8", Size: 6114 bytes --]
Mike,
> -----Original Message-----
> From: Mike Galbraith [mailto:bitbucket@online.de]
> Sent: 2013年1月7日 18:40
> To: Neil Zhang
> Cc: mingo@kernel.org; peterz@infradead.org; linux-kernel@vger.kernel.org
> Subject: Re: [PATCH] sched: remove redundant update_runtime notifier
>
> On Fri, 2012-12-28 at 18:00 +0800, Neil Zhang wrote:
> > migration_call() will do all the things that update_runtime() does.
> > So it seems update_runtime() is a redundant notifier, remove it.
> >
> > Furthermore, there is potential risk that the current code will catch
> > BUG_ON at line 687 of rt.c when do cpu hotplug while there are
> > realtime threads running because of enable runtime twice.
>
> Hm, box must be reading lkml behind my back.
>
> PID: 14735 TASK: ffff880e75e86500 CPU: 4 COMMAND: "reboot"
> #0 [ffff880e74b3d890] machine_kexec at ffffffff8102676e
> #1 [ffff880e74b3d8e0] crash_kexec at ffffffff810a3a3a
> #2 [ffff880e74b3d9b0] oops_end at ffffffff81446238
> #3 [ffff880e74b3d9d0] do_invalid_op at ffffffff810035d4
> #4 [ffff880e74b3da70] invalid_op at ffffffff8144d9bb
> [exception RIP: __disable_runtime+494] <== BUG_ON(want);
> RIP: ffffffff81045dae RSP: ffff880e74b3db28 RFLAGS: 00010082
> RAX: 000000000000046a RBX: ffff880e7fcd1310 RCX:
> ffffffff81d88a90
> RDX: 000000000000046a RSI: 0000000000000050 RDI:
> ffff880e7fcd19b0
> RBP: ffff880e74b3db98 R8: 0000000000000010 R9:
> ffff88047f423408
> R10: 0000000000000050 R11: ffffffff81250190 R12:
> 0000000000000050
> R13: fffffffffde9f140 R14: ffff880e7fcd1310 R15:
> 000000000000122f
> ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018
> #5 [ffff880e74b3dba0] rq_offline_rt at ffffffff8104b36a
> #6 [ffff880e74b3dbc0] set_rq_offline at ffffffff81043c9e
> #7 [ffff880e74b3dbe0] rq_attach_root at ffffffff8104c130
> #8 [ffff880e74b3dc10] cpu_attach_domain at ffffffff81054f44
> #9 [ffff880e74b3dc80] build_sched_domains at ffffffff81055525
> #10 [ffff880e74b3dcd0] partition_sched_domains at ffffffff81055835
> #11 [ffff880e74b3dd70] cpuset_cpu_inactive at ffffffff81055a0d
> #12 [ffff880e74b3dd80] notifier_call_chain at ffffffff81448907
> #13 [ffff880e74b3ddb0] _cpu_down at ffffffff8142b57b
> #14 [ffff880e74b3de10] disable_nonboot_cpus at ffffffff8105ba23
> #15 [ffff880e74b3de40] kernel_restart at ffffffff81071dde
> #16 [ffff880e74b3de50] sys_reboot at ffffffff81071fc3
> #17 [ffff880e74b3df80] system_call_fastpath at ffffffff8144ca12
> RIP: 00007fed35778316 RSP: 00007fff23f7e198 RFLAGS: 00010202
> RAX: 00000000000000a9 RBX: ffffffff8144ca12 RCX:
> 00007fed35771130
> RDX: 0000000001234567 RSI: 0000000028121969 RDI:
> fffffffffee1dead
> RBP: 0000000000000000 R8: 0000000000020fd0 R9:
> 000000000060d120
> R10: 00007fff23f7df40 R11: 0000000000000202 R12:
> 0000000000000000
> R13: 0000000000000000 R14: 0000000000000001 R15:
> 0000000000000000
> ORIG_RAX: 00000000000000a9 CS: 0033 SS: 002b
>
So, it seems my first patch is still needed, we should avoid enable runtime twice in case the value is changed between the two times.
> > Cc: bitbucket@online.de
> > Signed-off-by: Neil Zhang <zhangwm@marvell.com>
> > ---
> > kernel/sched/core.c | 3 ---
> > kernel/sched/rt.c | 40 ----------------------------------------
> > kernel/sched/sched.h | 1 -
> > 3 files changed, 0 insertions(+), 44 deletions(-)
> >
> > diff --git a/kernel/sched/core.c b/kernel/sched/core.c index
> > 257002c..7b6a4d8 100644
> > --- a/kernel/sched/core.c
> > +++ b/kernel/sched/core.c
> > @@ -6779,9 +6779,6 @@ void __init sched_init_smp(void)
> > hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE);
> > hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE);
> >
> > - /* RT runtime code needs to handle some hotplug events */
> > - hotcpu_notifier(update_runtime, 0);
> > -
> > init_hrtick();
> >
> > /* Move init over to a non-isolated CPU */ diff --git
> > a/kernel/sched/rt.c b/kernel/sched/rt.c index 418feb0..1a499d2 100644
> > --- a/kernel/sched/rt.c
> > +++ b/kernel/sched/rt.c
> > @@ -697,15 +697,6 @@ balanced:
> > }
> > }
> >
> > -static void disable_runtime(struct rq *rq) -{
> > - unsigned long flags;
> > -
> > - raw_spin_lock_irqsave(&rq->lock, flags);
> > - __disable_runtime(rq);
> > - raw_spin_unlock_irqrestore(&rq->lock, flags);
> > -}
> > -
> > static void __enable_runtime(struct rq *rq) {
> > rt_rq_iter_t iter;
> > @@ -730,37 +721,6 @@ static void __enable_runtime(struct rq *rq)
> > }
> > }
> >
> > -static void enable_runtime(struct rq *rq) -{
> > - unsigned long flags;
> > -
> > - raw_spin_lock_irqsave(&rq->lock, flags);
> > - __enable_runtime(rq);
> > - raw_spin_unlock_irqrestore(&rq->lock, flags);
> > -}
> > -
> > -int update_runtime(struct notifier_block *nfb, unsigned long action,
> > void *hcpu) -{
> > - int cpu = (int)(long)hcpu;
> > -
> > - switch (action) {
> > - case CPU_DOWN_PREPARE:
> > - case CPU_DOWN_PREPARE_FROZEN:
> > - disable_runtime(cpu_rq(cpu));
> > - return NOTIFY_OK;
> > -
> > - case CPU_DOWN_FAILED:
> > - case CPU_DOWN_FAILED_FROZEN:
> > - case CPU_ONLINE:
> > - case CPU_ONLINE_FROZEN:
> > - enable_runtime(cpu_rq(cpu));
> > - return NOTIFY_OK;
> > -
> > - default:
> > - return NOTIFY_DONE;
> > - }
> > -}
> > -
> > static int balance_runtime(struct rt_rq *rt_rq) {
> > int more = 0;
> > diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index
> > fc88644..16d18a1 100644
> > --- a/kernel/sched/sched.h
> > +++ b/kernel/sched/sched.h
> > @@ -890,7 +890,6 @@ extern void sysrq_sched_debug_show(void);
> extern
> > void sched_init_granularity(void); extern void
> > update_max_interval(void); extern void update_group_power(struct
> > sched_domain *sd, int cpu); -extern int update_runtime(struct
> > notifier_block *nfb, unsigned long action, void *hcpu); extern void
> > init_sched_rt_class(void); extern void init_sched_fair_class(void);
> >
>
Best Regards,
Neil Zhang
ÿôèº{.nÇ+‰·Ÿ®‰†+%ŠËÿ±éݶ\x17¥Šwÿº{.nÇ+‰·¥Š{±þG«éÿŠ{ayº\x1dʇڙë,j\a¢f£¢·hšïêÿ‘êçz_è®\x03(階ŠÝ¢j"ú\x1a¶^[m§ÿÿ¾\a«þG«éÿ¢¸?™¨èÚ&£ø§~á¶iO•æ¬z·švØ^\x14\x04\x1a¶^[m§ÿÿÃ\fÿ¶ìÿ¢¸?–I¥
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH] sched: remove redundant update_runtime notifier
@ 2013-04-11 13:04 Neil Zhang
2013-05-14 11:52 ` Peter Zijlstra
0 siblings, 1 reply; 6+ messages in thread
From: Neil Zhang @ 2013-04-11 13:04 UTC (permalink / raw)
To: mingo, peterz, linux-kernel; +Cc: Neil Zhang
migration_call() will do all the things that update_runtime() does.
So let's remove it.
Furthermore, there is potential risk that the current code will catch
BUG_ON at line 689 of rt.c when do cpu hotplug while there are realtime
threads running because of enabling runtime twice while the rt_runtime
may already changed.
Signed-off-by: Neil Zhang <zhangwm@marvell.com>
---
kernel/sched/core.c | 3 ---
kernel/sched/rt.c | 40 ----------------------------------------
kernel/sched/sched.h | 1 -
3 files changed, 0 insertions(+), 44 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 7f12624..3719c3c 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6831,9 +6831,6 @@ void __init sched_init_smp(void)
hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE);
hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE);
- /* RT runtime code needs to handle some hotplug events */
- hotcpu_notifier(update_runtime, 0);
-
init_hrtick();
/* Move init over to a non-isolated CPU */
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 127a2c4..111539a 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -699,15 +699,6 @@ balanced:
}
}
-static void disable_runtime(struct rq *rq)
-{
- unsigned long flags;
-
- raw_spin_lock_irqsave(&rq->lock, flags);
- __disable_runtime(rq);
- raw_spin_unlock_irqrestore(&rq->lock, flags);
-}
-
static void __enable_runtime(struct rq *rq)
{
rt_rq_iter_t iter;
@@ -732,37 +723,6 @@ static void __enable_runtime(struct rq *rq)
}
}
-static void enable_runtime(struct rq *rq)
-{
- unsigned long flags;
-
- raw_spin_lock_irqsave(&rq->lock, flags);
- __enable_runtime(rq);
- raw_spin_unlock_irqrestore(&rq->lock, flags);
-}
-
-int update_runtime(struct notifier_block *nfb, unsigned long action, void *hcpu)
-{
- int cpu = (int)(long)hcpu;
-
- switch (action) {
- case CPU_DOWN_PREPARE:
- case CPU_DOWN_PREPARE_FROZEN:
- disable_runtime(cpu_rq(cpu));
- return NOTIFY_OK;
-
- case CPU_DOWN_FAILED:
- case CPU_DOWN_FAILED_FROZEN:
- case CPU_ONLINE:
- case CPU_ONLINE_FROZEN:
- enable_runtime(cpu_rq(cpu));
- return NOTIFY_OK;
-
- default:
- return NOTIFY_DONE;
- }
-}
-
static int balance_runtime(struct rt_rq *rt_rq)
{
int more = 0;
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index cc03cfd..e73a8bd 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -892,7 +892,6 @@ extern void sysrq_sched_debug_show(void);
extern void sched_init_granularity(void);
extern void update_max_interval(void);
extern void update_group_power(struct sched_domain *sd, int cpu);
-extern int update_runtime(struct notifier_block *nfb, unsigned long action, void *hcpu);
extern void init_sched_rt_class(void);
extern void init_sched_fair_class(void);
--
1.7.4.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH] sched: remove redundant update_runtime notifier
2013-04-11 13:04 Neil Zhang
@ 2013-05-14 11:52 ` Peter Zijlstra
0 siblings, 0 replies; 6+ messages in thread
From: Peter Zijlstra @ 2013-05-14 11:52 UTC (permalink / raw)
To: Neil Zhang; +Cc: mingo, linux-kernel
On Thu, Apr 11, 2013 at 09:04:59PM +0800, Neil Zhang wrote:
> migration_call() will do all the things that update_runtime() does.
> So let's remove it.
>
> Furthermore, there is potential risk that the current code will catch
> BUG_ON at line 689 of rt.c when do cpu hotplug while there are realtime
> threads running because of enabling runtime twice while the rt_runtime
> may already changed.
>
Indeed, it looks like the 'new' sched_class::rq_{on,off}line stuff handles all
that just fine.
Thanks for spotting that.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2013-05-14 11:53 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2012-12-28 10:00 [PATCH] sched: remove redundant update_runtime notifier Neil Zhang
2013-01-07 1:16 ` Neil Zhang
2013-01-07 10:39 ` Mike Galbraith
2013-01-08 1:12 ` Neil Zhang
-- strict thread matches above, loose matches on Subject: below --
2013-04-11 13:04 Neil Zhang
2013-05-14 11:52 ` Peter Zijlstra
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).