2022-05-08 16:15:40

by Jason Wang

Subject: [PATCH] arch/ia64: no need to initialise statics to 0

Static variables do not need to be initialised to 0, because compiler
will initialise all uninitialised statics to 0. Thus, remove the
unneeded initializations.

Signed-off-by: Jason Wang <[email protected]>
---
arch/ia64/mm/tlb.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/ia64/mm/tlb.c b/arch/ia64/mm/tlb.c
index 7a2d608fba74..854e90c4e7eb 100644
--- a/arch/ia64/mm/tlb.c
+++ b/arch/ia64/mm/tlb.c
@@ -84,7 +84,7 @@ wrap_mmu_context (struct mm_struct *mm)
flush_bit = xchg(&ia64_ctx.flushmap[i], 0);
ia64_ctx.bitmap[i] ^= flush_bit;
}
-
+
/* use offset at 300 to skip daemons */
ia64_ctx.next = find_next_zero_bit(ia64_ctx.bitmap,
ia64_ctx.max_ctx, 300);
@@ -144,7 +144,7 @@ static inline void up_spin(struct spinaphore *ss)
static struct spinaphore ptcg_sem;
static u16 nptcg = 1;
static int need_ptcg_sem = 1;
-static int toolatetochangeptcgsem = 0;
+static int toolatetochangeptcgsem;

/*
* Kernel parameter "nptcg=" overrides max number of concurrent global TLB
--
2.35.1

2022-05-09 06:36:52

by Yury Norov

Subject: Re: [PATCH] arch/ia64: no need to initialise statics to 0

+ Fenghua Yu <[email protected]>

On Sun, May 08, 2022 at 10:26:28AM +0800, Jason Wang wrote:
> Static variables do not need to be initialised to 0, because compiler
> will initialise all uninitialised statics to 0. Thus, remove the
> unneeded initializations.
>
> Signed-off-by: Jason Wang <[email protected]>

Not sure why checkpatch picked me to be a reviewer for this.
Nevertheless...

> ---
> arch/ia64/mm/tlb.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/ia64/mm/tlb.c b/arch/ia64/mm/tlb.c
> index 7a2d608fba74..854e90c4e7eb 100644
> --- a/arch/ia64/mm/tlb.c
> +++ b/arch/ia64/mm/tlb.c
> @@ -84,7 +84,7 @@ wrap_mmu_context (struct mm_struct *mm)
> flush_bit = xchg(&ia64_ctx.flushmap[i], 0);
> ia64_ctx.bitmap[i] ^= flush_bit;
> }
> -
> +

This one is unrelated to the patch description. Can you split the
patch, or add a couple words about this cleanup?

> /* use offset at 300 to skip daemons */
> ia64_ctx.next = find_next_zero_bit(ia64_ctx.bitmap,
> ia64_ctx.max_ctx, 300);
> @@ -144,7 +144,7 @@ static inline void up_spin(struct spinaphore *ss)
> static struct spinaphore ptcg_sem;
> static u16 nptcg = 1;
> static int need_ptcg_sem = 1;
> -static int toolatetochangeptcgsem = 0;
> +static int toolatetochangeptcgsem;

There are at least 460 global static variables initialized explicitly.

yury:linux$ git grep "^static" | grep "= 0;" | wc -l
460

Are you going to fix them all? If not why this one is so special?

Before applying this, let's ask Fenghua - maybe it was his intention
to underline that the variable is initialized as 0.

Thanks,
Yury

> /*
> * Kernel parameter "nptcg=" overrides max number of concurrent global TLB
> --
> 2.35.1