2011-03-14 06:54:42

by Xiao Guangrong

Subject: [PATCH] x86, tlb: small cleanup for native_flush_tlb_others

Use smp_processor_id instead of get_cpu and put_cpu since
the caller has already disabled preemption

Signed-off-by: Xiao Guangrong <[email protected]>
---
arch/x86/mm/tlb.c | 3 +--
1 files changed, 1 insertions(+), 2 deletions(-)

diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 6acc724..92849d0 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -211,11 +211,10 @@ void native_flush_tlb_others(const struct cpumask *cpumask,
if (is_uv_system()) {
unsigned int cpu;

- cpu = get_cpu();
+ cpu = smp_processor_id();
cpumask = uv_flush_tlb_others(cpumask, mm, va, cpu);
if (cpumask)
flush_tlb_others_ipi(cpumask, mm, va);
- put_cpu();
return;
}
flush_tlb_others_ipi(cpumask, mm, va);
--
1.7.4

2011-03-14 12:34:08

by Ingo Molnar

Subject: Re: [PATCH] x86, tlb: small cleanup for native_flush_tlb_others

* Xiao Guangrong <[email protected]> wrote:

> Use smp_processor_id instead of get_cpu and put_cpu since
> the caller has already disabled preemption
>
> Signed-off-by: Xiao Guangrong <[email protected]>
> ---
> arch/x86/mm/tlb.c | 3 +--
> 1 files changed, 1 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
> index 6acc724..92849d0 100644
> --- a/arch/x86/mm/tlb.c
> +++ b/arch/x86/mm/tlb.c
> @@ -211,11 +211,10 @@ void native_flush_tlb_others(const struct cpumask *cpumask,
> if (is_uv_system()) {
> unsigned int cpu;
>
> - cpu = get_cpu();
> + cpu = smp_processor_id();
> cpumask = uv_flush_tlb_others(cpumask, mm, va, cpu);
> if (cpumask)
> flush_tlb_others_ipi(cpumask, mm, va);
> - put_cpu();
> return;

There's multiple callers. Could you please update the changelog with the list of
callers and a statement that all of them disable preemption already?

Thanks,

Ingo

2011-03-14 12:40:01

by Ingo Molnar

Subject: Re: [PATCH] x86, tlb: small cleanup for native_flush_tlb_others

Also, the title of the patch should be something like 'small micro-optimization' -
as it's not just a cleanup, it has side-effects on the code.

Thanks,

Ingo

2011-03-15 01:56:44

by Xiao Guangrong

Subject: Re: [PATCH] x86, tlb: small cleanup for native_flush_tlb_others

On 03/14/2011 08:33 PM, Ingo Molnar wrote:
>
> * Xiao Guangrong <[email protected]> wrote:
>
>> Use smp_processor_id instead of get_cpu and put_cpu since
>> the caller has already disabled preemption
>>
>> Signed-off-by: Xiao Guangrong <[email protected]>
>> ---
>> arch/x86/mm/tlb.c | 3 +--
>> 1 files changed, 1 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
>> index 6acc724..92849d0 100644
>> --- a/arch/x86/mm/tlb.c
>> +++ b/arch/x86/mm/tlb.c
>> @@ -211,11 +211,10 @@ void native_flush_tlb_others(const struct cpumask *cpumask,
>> if (is_uv_system()) {
>> unsigned int cpu;
>>
>> - cpu = get_cpu();
>> + cpu = smp_processor_id();
>> cpumask = uv_flush_tlb_others(cpumask, mm, va, cpu);
>> if (cpumask)
>> flush_tlb_others_ipi(cpumask, mm, va);
>> - put_cpu();
>> return;
>
> There's multiple callers. Could you please update the changelog with the list of
> callers and a statement that all of them disable preemption already?
>

Thanks Ingo, there is the new version.

From: Xiao Guangrong <[email protected]>
Subject: [PATCH] x86, tlb: small micro-optimization for native_flush_tlb_others

native_flush_tlb_others is called from:
flush_tlb_current_task
flush_tlb_mm
flush_tlb_page

All these functions disable preemption explicitly, so we can use smp_processor_id
instead of get_cpu and put_cpu

Signed-off-by: Xiao Guangrong <[email protected]>
---
arch/x86/mm/tlb.c | 3 +--
1 files changed, 1 insertions(+), 2 deletions(-)

diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 6acc724..92849d0 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -211,11 +211,10 @@ void native_flush_tlb_others(const struct cpumask *cpumask,
if (is_uv_system()) {
unsigned int cpu;

- cpu = get_cpu();
+ cpu = smp_processor_id();
cpumask = uv_flush_tlb_others(cpumask, mm, va, cpu);
if (cpumask)
flush_tlb_others_ipi(cpumask, mm, va);
- put_cpu();
return;
}
flush_tlb_others_ipi(cpumask, mm, va);
--
1.7.4

2011-03-15 07:49:43

by Xiao Guangrong

Subject: [tip:x86/mm] x86, tlb, UV: Do small micro-optimization for native_flush_tlb_others()

Commit-ID: 25542c646afbf14c43fa7d2b443055cadb73b07a
Gitweb: http://git.kernel.org/tip/25542c646afbf14c43fa7d2b443055cadb73b07a
Author: Xiao Guangrong <[email protected]>
AuthorDate: Tue, 15 Mar 2011 09:57:37 +0800
Committer: Ingo Molnar <[email protected]>
CommitDate: Tue, 15 Mar 2011 08:30:34 +0100

x86, tlb, UV: Do small micro-optimization for native_flush_tlb_others()

native_flush_tlb_others() is called from:

flush_tlb_current_task()
flush_tlb_mm()
flush_tlb_page()

All these functions disable preemption explicitly, so we can use
smp_processor_id() instead of get_cpu() and put_cpu().

Signed-off-by: Xiao Guangrong <[email protected]>
Cc: Cliff Wickman <[email protected]>
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
---
arch/x86/mm/tlb.c | 3 +--
1 files changed, 1 insertions(+), 2 deletions(-)

diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 55272d7..d6c0418 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -208,11 +208,10 @@ void native_flush_tlb_others(const struct cpumask *cpumask,
if (is_uv_system()) {
unsigned int cpu;

- cpu = get_cpu();
+ cpu = smp_processor_id();
cpumask = uv_flush_tlb_others(cpumask, mm, va, cpu);
if (cpumask)
flush_tlb_others_ipi(cpumask, mm, va);
- put_cpu();
return;
}
flush_tlb_others_ipi(cpumask, mm, va);