Re: [PATCH] rcu: Correct cpu offline trace in rcutree_dying_cpu

2021-01-12 Thread Neeraj Upadhyay 




On 1/12/2021 11:01 PM, Paul E. McKenney wrote:

On Mon, Jan 11, 2021 at 05:15:58PM +0530, Neeraj Upadhyay wrote:

Correctly trace whether the outgoing cpu blocks current gp in
rcutree_dying_cpu().

Signed-off-by: Neeraj Upadhyay 


Good catch, queued, thank you!  Please see below for my usual
wordsmithing, and please lat me know if I messed something up.

Thanx, Paul



Thanks Paul, looks good!


Thanks
Neeraj




commit ab6e7609e7590e1bb220ef6b0822a823dde46f6c
Author: Neeraj Upadhyay 
Date:   Mon Jan 11 17:15:58 2021 +0530

 rcu: Fix CPU-offline trace in rcutree_dying_cpu
 
 The condition in the trace_rcu_grace_period() in rcutree_dying_cpu() is

 backwards, so that it uses the string "cpuofl" when the offline CPU is
 blocking the current grace period and "cpuofl-bgp" otherwise.  Given that
 the "-bgp" stands for "blocking grace period", this is at best misleading.
 This commit therefore switches these strings in order to correctly trace
 whether the outgoing cpu blocks the current grace period.
 
 Signed-off-by: Neeraj Upadhyay 

 Signed-off-by: Paul E. McKenney 

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index cc6b6fc..63c6dba 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -2387,7 +2387,7 @@ int rcutree_dying_cpu(unsigned int cpu)
  
  	blkd = !!(rnp->qsmask & rdp->grpmask);

trace_rcu_grace_period(rcu_state.name, READ_ONCE(rnp->gp_seq),
-  blkd ? TPS("cpuofl") : TPS("cpuofl-bgp"));
+  blkd ? TPS("cpuofl-bgp") : TPS("cpuofl"));
return 0;
  }
  



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Re: [PATCH] rcu: Correct cpu offline trace in rcutree_dying_cpu

2021-01-12 Thread Paul E. McKenney 
On Mon, Jan 11, 2021 at 05:15:58PM +0530, Neeraj Upadhyay wrote:
> Correctly trace whether the outgoing cpu blocks current gp in
> rcutree_dying_cpu().
> 
> Signed-off-by: Neeraj Upadhyay 

Good catch, queued, thank you!  Please see below for my usual
wordsmithing, and please lat me know if I messed something up.

Thanx, Paul



commit ab6e7609e7590e1bb220ef6b0822a823dde46f6c
Author: Neeraj Upadhyay 
Date:   Mon Jan 11 17:15:58 2021 +0530

rcu: Fix CPU-offline trace in rcutree_dying_cpu

The condition in the trace_rcu_grace_period() in rcutree_dying_cpu() is
backwards, so that it uses the string "cpuofl" when the offline CPU is
blocking the current grace period and "cpuofl-bgp" otherwise.  Given that
the "-bgp" stands for "blocking grace period", this is at best misleading.
This commit therefore switches these strings in order to correctly trace
whether the outgoing cpu blocks the current grace period.

Signed-off-by: Neeraj Upadhyay 
Signed-off-by: Paul E. McKenney 

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index cc6b6fc..63c6dba 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -2387,7 +2387,7 @@ int rcutree_dying_cpu(unsigned int cpu)
 
blkd = !!(rnp->qsmask & rdp->grpmask);
trace_rcu_grace_period(rcu_state.name, READ_ONCE(rnp->gp_seq),
-  blkd ? TPS("cpuofl") : TPS("cpuofl-bgp"));
+  blkd ? TPS("cpuofl-bgp") : TPS("cpuofl"));
return 0;
 }

[PATCH] rcu: Correct cpu offline trace in rcutree_dying_cpu

2021-01-11 Thread Neeraj Upadhyay 
Correctly trace whether the outgoing cpu blocks current gp in
rcutree_dying_cpu().

Signed-off-by: Neeraj Upadhyay 
---
 kernel/rcu/tree.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 097990a..1f4bff4 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -2364,7 +2364,7 @@ int rcutree_dying_cpu(unsigned int cpu)
 
blkd = !!(rnp->qsmask & rdp->grpmask);
trace_rcu_grace_period(rcu_state.name, READ_ONCE(rnp->gp_seq),
-  blkd ? TPS("cpuofl") : TPS("cpuofl-bgp"));
+  blkd ? TPS("cpuofl-bgp") : TPS("cpuofl"));
return 0;
 }
 
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