* Re: [PATCH] x86: remove the useless branch in c_start()
[not found] <1348033343-23658-1-git-send-email-wangyun@linux.vnet.ibm.com>
@ 2012-09-26 3:43 ` Michael Wang
2012-09-26 13:02 ` Borislav Petkov
2012-09-27 6:07 ` [tip:x86/cpu] x86: Remove " tip-bot for Michael Wang
1 sibling, 1 reply; 4+ messages in thread
From: Michael Wang @ 2012-09-26 3:43 UTC (permalink / raw)
To: Michael Wang
Cc: linux-kernel, x86, kjwinchester, borislav.petkov, ak, hpa, mingo,
tglx
On 09/19/2012 01:42 PM, Michael Wang wrote:
> Since 'cpu == -1' in cpumask_next() is legal, no need to handle '*pos == 0'
> specially.
>
> About the comments:
> /* just in case, cpu 0 is not the first */
> A test with a cpumask in which cpu 0 is not the first has been done, and it
> works well.
Could I get some comments on this patch?
Regards,
Michael Wang
>
> This patch will remove that useless branch to clean the code.
>
> Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com>
> ---
> arch/x86/kernel/cpu/proc.c | 5 +----
> 1 files changed, 1 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/proc.c b/arch/x86/kernel/cpu/proc.c
> index 8022c66..fbd8955 100644
> --- a/arch/x86/kernel/cpu/proc.c
> +++ b/arch/x86/kernel/cpu/proc.c
> @@ -140,10 +140,7 @@ static int show_cpuinfo(struct seq_file *m, void *v)
>
> static void *c_start(struct seq_file *m, loff_t *pos)
> {
> - if (*pos == 0) /* just in case, cpu 0 is not the first */
> - *pos = cpumask_first(cpu_online_mask);
> - else
> - *pos = cpumask_next(*pos - 1, cpu_online_mask);
> + *pos = cpumask_next(*pos - 1, cpu_online_mask);
> if ((*pos) < nr_cpu_ids)
> return &cpu_data(*pos);
> return NULL;
>
^ permalink raw reply [flat|nested] 4+ messages in thread* [tip:x86/cpu] x86: Remove the useless branch in c_start()
[not found] <1348033343-23658-1-git-send-email-wangyun@linux.vnet.ibm.com>
2012-09-26 3:43 ` [PATCH] x86: remove the useless branch in c_start() Michael Wang
@ 2012-09-27 6:07 ` tip-bot for Michael Wang
1 sibling, 0 replies; 4+ messages in thread
From: tip-bot for Michael Wang @ 2012-09-27 6:07 UTC (permalink / raw)
To: linux-tip-commits; +Cc: linux-kernel, hpa, mingo, wangyun, tglx
Commit-ID: dec08a837fda146fee498ffc5ecd0d2eeeacd025
Gitweb: http://git.kernel.org/tip/dec08a837fda146fee498ffc5ecd0d2eeeacd025
Author: Michael Wang <wangyun@linux.vnet.ibm.com>
AuthorDate: Wed, 19 Sep 2012 13:42:23 +0800
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 26 Sep 2012 13:27:56 +0200
x86: Remove the useless branch in c_start()
Since 'cpu == -1' in cpumask_next() is legal, no need to handle
'*pos == 0' specially.
About the comments:
/* just in case, cpu 0 is not the first */
A test with a cpumask in which cpu 0 is not the first has been
done, and it works well.
This patch will remove that useless branch to clean the code.
Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com>
Cc: kjwinchester@gmail.com
Cc: borislav.petkov@amd.com
Cc: ak@linux.intel.com
Link: http://lkml.kernel.org/r/1348033343-23658-1-git-send-email-wangyun@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/kernel/cpu/proc.c | 5 +----
1 files changed, 1 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kernel/cpu/proc.c b/arch/x86/kernel/cpu/proc.c
index 8022c66..fbd8955 100644
--- a/arch/x86/kernel/cpu/proc.c
+++ b/arch/x86/kernel/cpu/proc.c
@@ -140,10 +140,7 @@ static int show_cpuinfo(struct seq_file *m, void *v)
static void *c_start(struct seq_file *m, loff_t *pos)
{
- if (*pos == 0) /* just in case, cpu 0 is not the first */
- *pos = cpumask_first(cpu_online_mask);
- else
- *pos = cpumask_next(*pos - 1, cpu_online_mask);
+ *pos = cpumask_next(*pos - 1, cpu_online_mask);
if ((*pos) < nr_cpu_ids)
return &cpu_data(*pos);
return NULL;
^ permalink raw reply related [flat|nested] 4+ messages in thread