2012-11-09 02:20:38

by Shan Wei

Subject: [PATCH v3 1/9] net: core: use this_cpu_ptr per-cpu helper

From: Shan Wei <[email protected]>

flush_tasklet is a struct, not a pointer in percpu var.
so use this_cpu_ptr to get the member pointer.

Signed-off-by: Shan Wei <[email protected]>
---
net/core/flow.c | 4 +---
1 files changed, 1 insertions(+), 3 deletions(-)

diff --git a/net/core/flow.c b/net/core/flow.c
index e318c7e..b0901ee 100644
--- a/net/core/flow.c
+++ b/net/core/flow.c
@@ -327,11 +327,9 @@ static void flow_cache_flush_tasklet(unsigned long data)
static void flow_cache_flush_per_cpu(void *data)
{
struct flow_flush_info *info = data;
- int cpu;
struct tasklet_struct *tasklet;

- cpu = smp_processor_id();
- tasklet = &per_cpu_ptr(info->cache->percpu, cpu)->flush_tasklet;
+ tasklet = this_cpu_ptr(&info->cache->percpu->flush_tasklet);
tasklet->data = (unsigned long)info;
tasklet_schedule(tasklet);
}
--
1.7.1

2012-11-09 20:08:47

by Christoph Lameter (Ampere)

Subject: Re: [PATCH v3 1/9] net: core: use this_cpu_ptr per-cpu helper

On Fri, 9 Nov 2012, Shan Wei wrote:

> diff --git a/net/core/flow.c b/net/core/flow.c
> index e318c7e..b0901ee 100644
> --- a/net/core/flow.c
> +++ b/net/core/flow.c
> @@ -327,11 +327,9 @@ static void flow_cache_flush_tasklet(unsigned long data)
> static void flow_cache_flush_per_cpu(void *data)
> {
> struct flow_flush_info *info = data;
> - int cpu;
> struct tasklet_struct *tasklet;
>
> - cpu = smp_processor_id();
> - tasklet = &per_cpu_ptr(info->cache->percpu, cpu)->flush_tasklet;
> + tasklet = this_cpu_ptr(&info->cache->percpu->flush_tasklet);
> tasklet->data = (unsigned long)info;

this_cpu_write(info->cache->percpu->flush_tasklet->data, (unsigned
long)info);

should also do the trick in less instructions and get rid of all temporary
variables as well.

2012-11-09 20:15:47

by Eric Dumazet

Subject: Re: [PATCH v3 1/9] net: core: use this_cpu_ptr per-cpu helper

On Fri, 2012-11-09 at 20:08 +0000, Christoph Lameter wrote:
> On Fri, 9 Nov 2012, Shan Wei wrote:
>
> > diff --git a/net/core/flow.c b/net/core/flow.c
> > index e318c7e..b0901ee 100644
> > --- a/net/core/flow.c
> > +++ b/net/core/flow.c
> > @@ -327,11 +327,9 @@ static void flow_cache_flush_tasklet(unsigned long data)
> > static void flow_cache_flush_per_cpu(void *data)
> > {
> > struct flow_flush_info *info = data;
> > - int cpu;
> > struct tasklet_struct *tasklet;
> >
> > - cpu = smp_processor_id();
> > - tasklet = &per_cpu_ptr(info->cache->percpu, cpu)->flush_tasklet;
> > + tasklet = this_cpu_ptr(&info->cache->percpu->flush_tasklet);
> > tasklet->data = (unsigned long)info;
>
> this_cpu_write(info->cache->percpu->flush_tasklet->data, (unsigned
> long)info);
>
> should also do the trick in less instructions and get rid of all temporary
> variables as well.

Its not the case.

We need the _pointer_ to call :

tasklet_schedule(tasklet);

2012-11-12 23:29:55

by Christoph Lameter (Ampere)

Subject: Re: [PATCH v3 1/9] net: core: use this_cpu_ptr per-cpu helper

On Fri, 9 Nov 2012, Eric Dumazet wrote:

> Its not the case.
>
> We need the _pointer_ to call :
>
> tasklet_schedule(tasklet);

Ah. Ok. In that case

Reviewed-by: Christoph Lameter <[email protected]>