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* [PATCH] doc: Fix stale RCU_GP_WAIT_FQS value in stallwarn.rst
@ 2026-10-14  6:31 Yonghao Zhang
  2026-10-14 16:07 ` Randy Dunlap
  0 siblings, 1 reply; 3+ messages in thread
From: Yonghao Zhang @ 2026-10-14  6:31 UTC (permalink / raw)
  To: paulmck, frederic, neeraj.upadhyay, joelagnelf, josh, boqun,
	urezki, rostedt, mathieu.desnoyers, jiangshanlai, qiang.zhang,
	corbet, skhan, rdunlap
  Cc: rcu, linux-doc, Yonghao Zhang

The sample "kthread starved" splat in stallwarn.rst shows
RCU_GP_WAIT_FQS(3), which was correct when the example was captured,
but has been stale since commit fea3f222d352 ("rcu: Record ->gp_state
for both phases of grace-period initialization") inserted
RCU_GP_ONOFF (3) and RCU_GP_INIT (4) ahead of it, shifting
RCU_GP_WAIT_FQS from 3 to 5.

Update the sample output to show (5), matching the current tree.h
values and the later "kthread timer wakeup" example in the same file.

Fixes: fea3f222d352 ("rcu: Record ->gp_state for both phases of grace-period initialization")
Signed-off-by: Yonghao Zhang <hyz3367@gmail.com>
---
 Documentation/RCU/stallwarn.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Documentation/RCU/stallwarn.rst b/Documentation/RCU/stallwarn.rst
index b888e13c02a4..049694b9c681 100644
--- a/Documentation/RCU/stallwarn.rst
+++ b/Documentation/RCU/stallwarn.rst
@@ -379,7 +379,7 @@ If the relevant grace-period kthread has been unable to run prior to
 the stall warning, as was the case in the "All QSes seen" line above,
 the following additional line is printed::
 
-	rcu_sched kthread starved for 23807 jiffies! g7075 f0x0 RCU_GP_WAIT_FQS(3) ->state=0x1 ->cpu=5
+	rcu_sched kthread starved for 23807 jiffies! g7075 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x1 ->cpu=5
 	Unless rcu_sched kthread gets sufficient CPU time, OOM is now expected behavior.
 
 Starving the grace-period kthreads of CPU time can of course result
-- 
2.34.1


^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [PATCH] doc: Fix stale RCU_GP_WAIT_FQS value in stallwarn.rst
  2026-10-14  6:31 [PATCH] doc: Fix stale RCU_GP_WAIT_FQS value in stallwarn.rst Yonghao Zhang
@ 2026-10-14 16:07 ` Randy Dunlap
  2026-10-16 23:54   ` Zqiang
  0 siblings, 1 reply; 3+ messages in thread
From: Randy Dunlap @ 2026-10-14 16:07 UTC (permalink / raw)
  To: Yonghao Zhang, paulmck, frederic, neeraj.upadhyay, joelagnelf,
	josh, boqun, urezki, rostedt, mathieu.desnoyers, jiangshanlai,
	qiang.zhang, corbet, skhan
  Cc: rcu, linux-doc



On 10/13/26 11:31 PM, Yonghao Zhang wrote:
> The sample "kthread starved" splat in stallwarn.rst shows
> RCU_GP_WAIT_FQS(3), which was correct when the example was captured,
> but has been stale since commit fea3f222d352 ("rcu: Record ->gp_state
> for both phases of grace-period initialization") inserted
> RCU_GP_ONOFF (3) and RCU_GP_INIT (4) ahead of it, shifting
> RCU_GP_WAIT_FQS from 3 to 5.
> 
> Update the sample output to show (5), matching the current tree.h
> values and the later "kthread timer wakeup" example in the same file.
> 
> Fixes: fea3f222d352 ("rcu: Record ->gp_state for both phases of grace-period initialization")
> Signed-off-by: Yonghao Zhang <hyz3367@gmail.com>

Acked-by: Randy Dunlap <rdunlap@infradead.org>
Thanks.

> ---
>  Documentation/RCU/stallwarn.rst | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/Documentation/RCU/stallwarn.rst b/Documentation/RCU/stallwarn.rst
> index b888e13c02a4..049694b9c681 100644
> --- a/Documentation/RCU/stallwarn.rst
> +++ b/Documentation/RCU/stallwarn.rst
> @@ -379,7 +379,7 @@ If the relevant grace-period kthread has been unable to run prior to
>  the stall warning, as was the case in the "All QSes seen" line above,
>  the following additional line is printed::
>  
> -	rcu_sched kthread starved for 23807 jiffies! g7075 f0x0 RCU_GP_WAIT_FQS(3) ->state=0x1 ->cpu=5
> +	rcu_sched kthread starved for 23807 jiffies! g7075 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x1 ->cpu=5
>  	Unless rcu_sched kthread gets sufficient CPU time, OOM is now expected behavior.
>  
>  Starving the grace-period kthreads of CPU time can of course result

-- 
~Randy

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] doc: Fix stale RCU_GP_WAIT_FQS value in stallwarn.rst
  2026-10-14 16:07 ` Randy Dunlap
@ 2026-10-16 23:54   ` Zqiang
  0 siblings, 0 replies; 3+ messages in thread
From: Zqiang @ 2026-10-16 23:54 UTC (permalink / raw)
  To: Randy Dunlap, Yonghao Zhang, paulmck, frederic, neeraj.upadhyay,
	joelagnelf, josh, boqun, urezki, rostedt, mathieu.desnoyers,
	jiangshanlai, corbet, skhan
  Cc: rcu, linux-doc

> 
> On 10/13/26 11:31 PM, Yonghao Zhang wrote:
> 
> > 
> > The sample "kthread starved" splat in stallwarn.rst shows
> >  RCU_GP_WAIT_FQS(3), which was correct when the example was captured,
> >  but has been stale since commit fea3f222d352 ("rcu: Record ->gp_state
> >  for both phases of grace-period initialization") inserted
> >  RCU_GP_ONOFF (3) and RCU_GP_INIT (4) ahead of it, shifting
> >  RCU_GP_WAIT_FQS from 3 to 5.
> >  
> >  Update the sample output to show (5), matching the current tree.h
> >  values and the later "kthread timer wakeup" example in the same file.
> >  
> >  Fixes: fea3f222d352 ("rcu: Record ->gp_state for both phases of grace-period initialization")
> >  Signed-off-by: Yonghao Zhang <hyz3367@gmail.com>
> > 
> Acked-by: Randy Dunlap <rdunlap@infradead.org>

Reviewed-by: Zqiang <qiang.zhang@linux.dev>

Thanks
Zqiang

> Thanks.
> 
> > 
> > ---
> >  Documentation/RCU/stallwarn.rst | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >  
> >  diff --git a/Documentation/RCU/stallwarn.rst b/Documentation/RCU/stallwarn.rst
> >  index b888e13c02a4..049694b9c681 100644
> >  --- a/Documentation/RCU/stallwarn.rst
> >  +++ b/Documentation/RCU/stallwarn.rst
> >  @@ -379,7 +379,7 @@ If the relevant grace-period kthread has been unable to run prior to
> >  the stall warning, as was the case in the "All QSes seen" line above,
> >  the following additional line is printed::
> >  
> >  - rcu_sched kthread starved for 23807 jiffies! g7075 f0x0 RCU_GP_WAIT_FQS(3) ->state=0x1 ->cpu=5
> >  + rcu_sched kthread starved for 23807 jiffies! g7075 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x1 ->cpu=5
> >  Unless rcu_sched kthread gets sufficient CPU time, OOM is now expected behavior.
> >  
> >  Starving the grace-period kthreads of CPU time can of course result
> > 
> -- 
> ~Randy
>

^ permalink raw reply	[flat|nested] 3+ messages in thread

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2026-10-14  6:31 [PATCH] doc: Fix stale RCU_GP_WAIT_FQS value in stallwarn.rst Yonghao Zhang
2026-10-14 16:07 ` Randy Dunlap
2026-10-16 23:54   ` Zqiang

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