Re: [PATCH] srcu: Remove dead code in srcu_gp_end()

[Paul E. McKenney]

On Wed, Feb 14, 2018 at 10:00:54AM -0500, Steven Rostedt wrote:
> On Wed, 14 Feb 2018 18:05:24 +0900
> Byungchul Park  wrote:
> 
> > Of course, compilers will optimize out a dead code. Anyway, remove
> > any dead code for better readibility.
> > 
> > Signed-off-by: Byungchul Park 
> > ---
> >  kernel/rcu/srcutree.c | 2 --
> >  1 file changed, 2 deletions(-)
> > 
> > diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
> > index 44bc0fa..829453b 100644
> > --- a/kernel/rcu/srcutree.c
> > +++ b/kernel/rcu/srcutree.c
> > @@ -531,7 +531,6 @@ static void srcu_gp_end(struct srcu_struct *sp)
> > unsigned long flags;
> > unsigned long gpseq;
> > int idx;
> > -   int idxnext;
> 
> Interesting. According to git history, idxnext was never actually used.

Which raises the question of what I intended to do with it.  Reviewing
that function didn't activate any memories, though it did point out a
candidate simplification.

> Reviewed-by: Steven Rostedt (VMware) 

Applied, thank you both!

Thanx, Paul

> -- Steve
> 
> > unsigned long mask;
> > struct srcu_data *sdp;
> > struct srcu_node *snp;
> > @@ -555,7 +554,6 @@ static void srcu_gp_end(struct srcu_struct *sp)
> >  
> > /* Initiate callback invocation as needed. */
> > idx = rcu_seq_ctr(gpseq) % ARRAY_SIZE(snp->srcu_have_cbs);
> > -   idxnext = (idx + 1) % ARRAY_SIZE(snp->srcu_have_cbs);
> > rcu_for_each_node_breadth_first(sp, snp) {
> > spin_lock_irq_rcu_node(snp);
> > cbs = false;
> 

Re: [PATCH] srcu: Remove dead code in srcu_gp_end()

[Paul E. McKenney]

On Wed, Feb 14, 2018 at 10:00:54AM -0500, Steven Rostedt wrote:
> On Wed, 14 Feb 2018 18:05:24 +0900
> Byungchul Park  wrote:
> 
> > Of course, compilers will optimize out a dead code. Anyway, remove
> > any dead code for better readibility.
> > 
> > Signed-off-by: Byungchul Park 
> > ---
> >  kernel/rcu/srcutree.c | 2 --
> >  1 file changed, 2 deletions(-)
> > 
> > diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
> > index 44bc0fa..829453b 100644
> > --- a/kernel/rcu/srcutree.c
> > +++ b/kernel/rcu/srcutree.c
> > @@ -531,7 +531,6 @@ static void srcu_gp_end(struct srcu_struct *sp)
> > unsigned long flags;
> > unsigned long gpseq;
> > int idx;
> > -   int idxnext;
> 
> Interesting. According to git history, idxnext was never actually used.

Which raises the question of what I intended to do with it.  Reviewing
that function didn't activate any memories, though it did point out a
candidate simplification.

> Reviewed-by: Steven Rostedt (VMware) 

Applied, thank you both!

Thanx, Paul

> -- Steve
> 
> > unsigned long mask;
> > struct srcu_data *sdp;
> > struct srcu_node *snp;
> > @@ -555,7 +554,6 @@ static void srcu_gp_end(struct srcu_struct *sp)
> >  
> > /* Initiate callback invocation as needed. */
> > idx = rcu_seq_ctr(gpseq) % ARRAY_SIZE(snp->srcu_have_cbs);
> > -   idxnext = (idx + 1) % ARRAY_SIZE(snp->srcu_have_cbs);
> > rcu_for_each_node_breadth_first(sp, snp) {
> > spin_lock_irq_rcu_node(snp);
> > cbs = false;
> 

Re: [PATCH] srcu: Remove dead code in srcu_gp_end()

[Steven Rostedt]

On Wed, 14 Feb 2018 18:05:24 +0900
Byungchul Park  wrote:

> Of course, compilers will optimize out a dead code. Anyway, remove
> any dead code for better readibility.
> 
> Signed-off-by: Byungchul Park 
> ---
>  kernel/rcu/srcutree.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
> index 44bc0fa..829453b 100644
> --- a/kernel/rcu/srcutree.c
> +++ b/kernel/rcu/srcutree.c
> @@ -531,7 +531,6 @@ static void srcu_gp_end(struct srcu_struct *sp)
>   unsigned long flags;
>   unsigned long gpseq;
>   int idx;
> - int idxnext;

Interesting. According to git history, idxnext was never actually used.

Reviewed-by: Steven Rostedt (VMware) 

-- Steve

>   unsigned long mask;
>   struct srcu_data *sdp;
>   struct srcu_node *snp;
> @@ -555,7 +554,6 @@ static void srcu_gp_end(struct srcu_struct *sp)
>  
>   /* Initiate callback invocation as needed. */
>   idx = rcu_seq_ctr(gpseq) % ARRAY_SIZE(snp->srcu_have_cbs);
> - idxnext = (idx + 1) % ARRAY_SIZE(snp->srcu_have_cbs);
>   rcu_for_each_node_breadth_first(sp, snp) {
>   spin_lock_irq_rcu_node(snp);
>   cbs = false;

Re: [PATCH] srcu: Remove dead code in srcu_gp_end()

[Steven Rostedt]

On Wed, 14 Feb 2018 18:05:24 +0900
Byungchul Park  wrote:

> Of course, compilers will optimize out a dead code. Anyway, remove
> any dead code for better readibility.
> 
> Signed-off-by: Byungchul Park 
> ---
>  kernel/rcu/srcutree.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
> index 44bc0fa..829453b 100644
> --- a/kernel/rcu/srcutree.c
> +++ b/kernel/rcu/srcutree.c
> @@ -531,7 +531,6 @@ static void srcu_gp_end(struct srcu_struct *sp)
>   unsigned long flags;
>   unsigned long gpseq;
>   int idx;
> - int idxnext;

Interesting. According to git history, idxnext was never actually used.

Reviewed-by: Steven Rostedt (VMware) 

-- Steve

>   unsigned long mask;
>   struct srcu_data *sdp;
>   struct srcu_node *snp;
> @@ -555,7 +554,6 @@ static void srcu_gp_end(struct srcu_struct *sp)
>  
>   /* Initiate callback invocation as needed. */
>   idx = rcu_seq_ctr(gpseq) % ARRAY_SIZE(snp->srcu_have_cbs);
> - idxnext = (idx + 1) % ARRAY_SIZE(snp->srcu_have_cbs);
>   rcu_for_each_node_breadth_first(sp, snp) {
>   spin_lock_irq_rcu_node(snp);
>   cbs = false;

[PATCH] srcu: Remove dead code in srcu_gp_end()

[Byungchul Park]

Of course, compilers will optimize out a dead code. Anyway, remove
any dead code for better readibility.

Signed-off-by: Byungchul Park 
---
 kernel/rcu/srcutree.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
index 44bc0fa..829453b 100644
--- a/kernel/rcu/srcutree.c
+++ b/kernel/rcu/srcutree.c
@@ -531,7 +531,6 @@ static void srcu_gp_end(struct srcu_struct *sp)
unsigned long flags;
unsigned long gpseq;
int idx;
-   int idxnext;
unsigned long mask;
struct srcu_data *sdp;
struct srcu_node *snp;
@@ -555,7 +554,6 @@ static void srcu_gp_end(struct srcu_struct *sp)
 
/* Initiate callback invocation as needed. */
idx = rcu_seq_ctr(gpseq) % ARRAY_SIZE(snp->srcu_have_cbs);
-   idxnext = (idx + 1) % ARRAY_SIZE(snp->srcu_have_cbs);
rcu_for_each_node_breadth_first(sp, snp) {
spin_lock_irq_rcu_node(snp);
cbs = false;
-- 
1.9.1

[PATCH] srcu: Remove dead code in srcu_gp_end()

[Byungchul Park]

Of course, compilers will optimize out a dead code. Anyway, remove
any dead code for better readibility.

Signed-off-by: Byungchul Park 
---
 kernel/rcu/srcutree.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
index 44bc0fa..829453b 100644
--- a/kernel/rcu/srcutree.c
+++ b/kernel/rcu/srcutree.c
@@ -531,7 +531,6 @@ static void srcu_gp_end(struct srcu_struct *sp)
unsigned long flags;
unsigned long gpseq;
int idx;
-   int idxnext;
unsigned long mask;
struct srcu_data *sdp;
struct srcu_node *snp;
@@ -555,7 +554,6 @@ static void srcu_gp_end(struct srcu_struct *sp)
 
/* Initiate callback invocation as needed. */
idx = rcu_seq_ctr(gpseq) % ARRAY_SIZE(snp->srcu_have_cbs);
-   idxnext = (idx + 1) % ARRAY_SIZE(snp->srcu_have_cbs);
rcu_for_each_node_breadth_first(sp, snp) {
spin_lock_irq_rcu_node(snp);
cbs = false;
-- 
1.9.1