[tip/core/rcu,14/23] rcu: Remove now-unused rcu_state fields

Message ID 1346350718-30937-14-git-send-email-paulmck@linux.vnet.ibm.com
State New
Headers show

Commit Message

Paul E. McKenney Aug. 30, 2012, 6:18 p.m.
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>

Moving the RCU grace-period processing to a kthread and adjusting the
tracing resulted in two of the rcu_state structure's fields being unused.
This commit therefore removes them.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
 kernel/rcutree.h |    7 -------
 1 files changed, 0 insertions(+), 7 deletions(-)

Comments

Josh Triplett Sept. 3, 2012, 9:31 a.m. | #1
On Thu, Aug 30, 2012 at 11:18:29AM -0700, Paul E. McKenney wrote:
> From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
> 
> Moving the RCU grace-period processing to a kthread and adjusting the
> tracing resulted in two of the rcu_state structure's fields being unused.
> This commit therefore removes them.
> 
> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

Reviewed-by: Josh Triplett <josh@joshtriplett.org>

>  kernel/rcutree.h |    7 -------
>  1 files changed, 0 insertions(+), 7 deletions(-)
> 
> diff --git a/kernel/rcutree.h b/kernel/rcutree.h
> index 2d4cc18..8f0293c 100644
> --- a/kernel/rcutree.h
> +++ b/kernel/rcutree.h
> @@ -378,13 +378,6 @@ struct rcu_state {
>  
>  	u8	fqs_state ____cacheline_internodealigned_in_smp;
>  						/* Force QS state. */
> -	u8	fqs_active;			/* force_quiescent_state() */
> -						/*  is running. */
> -	u8	fqs_need_gp;			/* A CPU was prevented from */
> -						/*  starting a new grace */
> -						/*  period because */
> -						/*  force_quiescent_state() */
> -						/*  was running. */
>  	u8	boost;				/* Subject to priority boost. */
>  	unsigned long gpnum;			/* Current gp number. */
>  	unsigned long completed;		/* # of last completed gp. */
> -- 
> 1.7.8
>
Peter Zijlstra Sept. 6, 2012, 2:17 p.m. | #2
On Thu, 2012-08-30 at 11:18 -0700, Paul E. McKenney wrote:
> From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
> 
> Moving the RCU grace-period processing to a kthread and adjusting the
> tracing resulted in two of the rcu_state structure's fields being unused.
> This commit therefore removes them.
> 
> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> ---
>  kernel/rcutree.h |    7 -------
>  1 files changed, 0 insertions(+), 7 deletions(-)
> 
> diff --git a/kernel/rcutree.h b/kernel/rcutree.h
> index 2d4cc18..8f0293c 100644
> --- a/kernel/rcutree.h
> +++ b/kernel/rcutree.h
> @@ -378,13 +378,6 @@ struct rcu_state {
>  
>  	u8	fqs_state ____cacheline_internodealigned_in_smp;
>  						/* Force QS state. */
> -	u8	fqs_active;			/* force_quiescent_state() */
> -						/*  is running. */
> -	u8	fqs_need_gp;			/* A CPU was prevented from */
> -						/*  starting a new grace */
> -						/*  period because */
> -						/*  force_quiescent_state() */
> -						/*  was running. */
>  	u8	boost;				/* Subject to priority boost. */
>  	unsigned long gpnum;			/* Current gp number. */
>  	unsigned long completed;		/* # of last completed gp. */

Typically one would fold this change into the patch that caused said
redundancy and not mention it. Save a patch to (post/review/merge) and
makes the patches a more solid whole.
Paul E. McKenney Sept. 6, 2012, 6:02 p.m. | #3
On Thu, Sep 06, 2012 at 04:17:03PM +0200, Peter Zijlstra wrote:
> On Thu, 2012-08-30 at 11:18 -0700, Paul E. McKenney wrote:
> > From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
> > 
> > Moving the RCU grace-period processing to a kthread and adjusting the
> > tracing resulted in two of the rcu_state structure's fields being unused.
> > This commit therefore removes them.
> > 
> > Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> > ---
> >  kernel/rcutree.h |    7 -------
> >  1 files changed, 0 insertions(+), 7 deletions(-)
> > 
> > diff --git a/kernel/rcutree.h b/kernel/rcutree.h
> > index 2d4cc18..8f0293c 100644
> > --- a/kernel/rcutree.h
> > +++ b/kernel/rcutree.h
> > @@ -378,13 +378,6 @@ struct rcu_state {
> >  
> >  	u8	fqs_state ____cacheline_internodealigned_in_smp;
> >  						/* Force QS state. */
> > -	u8	fqs_active;			/* force_quiescent_state() */
> > -						/*  is running. */
> > -	u8	fqs_need_gp;			/* A CPU was prevented from */
> > -						/*  starting a new grace */
> > -						/*  period because */
> > -						/*  force_quiescent_state() */
> > -						/*  was running. */
> >  	u8	boost;				/* Subject to priority boost. */
> >  	unsigned long gpnum;			/* Current gp number. */
> >  	unsigned long completed;		/* # of last completed gp. */
> 
> Typically one would fold this change into the patch that caused said
> redundancy and not mention it. Save a patch to (post/review/merge) and
> makes the patches a more solid whole.

Fair enough.  I still like the idea of pulling the stuff creating
rcu_gp_kthread() into one patch, though.

							Thanx, Paul

Patch

diff --git a/kernel/rcutree.h b/kernel/rcutree.h
index 2d4cc18..8f0293c 100644
--- a/kernel/rcutree.h
+++ b/kernel/rcutree.h
@@ -378,13 +378,6 @@  struct rcu_state {
 
 	u8	fqs_state ____cacheline_internodealigned_in_smp;
 						/* Force QS state. */
-	u8	fqs_active;			/* force_quiescent_state() */
-						/*  is running. */
-	u8	fqs_need_gp;			/* A CPU was prevented from */
-						/*  starting a new grace */
-						/*  period because */
-						/*  force_quiescent_state() */
-						/*  was running. */
 	u8	boost;				/* Subject to priority boost. */
 	unsigned long gpnum;			/* Current gp number. */
 	unsigned long completed;		/* # of last completed gp. */