* [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
end of thread, other threads:[~2026-10-16 23:54 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
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
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.