* [PATCH] x86, apm: Make on_cpu0() use workqueue instead of work_on_cpu()
@ 2012-08-24 1:11 Tejun Heo
2012-08-28 22:57 ` Jiri Kosina
0 siblings, 1 reply; 4+ messages in thread
From: Tejun Heo @ 2012-08-24 1:11 UTC (permalink / raw)
To: Jiri Kosina, H. Peter Anvin; +Cc: x86, linux-kernel
Make APM schedule a work item on CPU0 instead of using the expensive
work_on_cpu(); hopefully, this is the last user of work_on_cpu() and
we can take out work_on_cpu() in not too distant future.
Tested both paths. Seems to work fine.
Signed-off-by: Tejun Heo <tj@kernel.org>
---
arch/x86/kernel/apm_32.c | 31 +++++++++++++++++++++++--------
1 file changed, 23 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kernel/apm_32.c b/arch/x86/kernel/apm_32.c
index d65464e..2bdb8c4 100644
--- a/arch/x86/kernel/apm_32.c
+++ b/arch/x86/kernel/apm_32.c
@@ -605,28 +605,43 @@ static long __apm_bios_call(void *_call)
return call->eax & 0xff;
}
+struct on_cpu0_arg {
+ struct work_struct work;
+ long (*fn)(void *);
+ struct apm_bios_call *call;
+ int ret;
+};
+
+static void on_cpu0_workfn(struct work_struct *work)
+{
+ struct on_cpu0_arg *arg = container_of(work, struct on_cpu0_arg, work);
+
+ arg->ret = arg->fn(arg->call);
+}
+
/* Run __apm_bios_call or __apm_bios_call_simple on CPU 0 */
static int on_cpu0(long (*fn)(void *), struct apm_bios_call *call)
{
- int ret;
+ struct on_cpu0_arg arg = { .fn = fn, .call = call };
- /* Don't bother with work_on_cpu in the common case, so we don't
- * have to worry about OOM or overhead. */
+ /* directly invoke on_cpu0_workfn() in the common case */
if (get_cpu() == 0) {
- ret = fn(call);
+ on_cpu0_workfn(&arg.work);
put_cpu();
} else {
put_cpu();
- ret = work_on_cpu(0, fn, call);
+ INIT_WORK_ONSTACK(&arg.work, on_cpu0_workfn);
+ schedule_work_on(0, &arg.work);
+ flush_work(&arg.work);
}
/* work_on_cpu can fail with -ENOMEM */
- if (ret < 0)
- call->err = ret;
+ if (arg.ret < 0)
+ call->err = arg.ret;
else
call->err = (call->eax >> 8) & 0xff;
- return ret;
+ return arg.ret;
}
/**
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] x86, apm: Make on_cpu0() use workqueue instead of work_on_cpu()
2012-08-24 1:11 [PATCH] x86, apm: Make on_cpu0() use workqueue instead of work_on_cpu() Tejun Heo
@ 2012-08-28 22:57 ` Jiri Kosina
2012-09-17 21:38 ` Tejun Heo
0 siblings, 1 reply; 4+ messages in thread
From: Jiri Kosina @ 2012-08-28 22:57 UTC (permalink / raw)
To: Tejun Heo; +Cc: H. Peter Anvin, x86, linux-kernel
On Thu, 23 Aug 2012, Tejun Heo wrote:
> Make APM schedule a work item on CPU0 instead of using the expensive
> work_on_cpu(); hopefully, this is the last user of work_on_cpu() and
> we can take out work_on_cpu() in not too distant future.
>
> Tested both paths. Seems to work fine.
Applying to apm.git, thanks Tejun.
--
Jiri Kosina
SUSE Labs
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] x86, apm: Make on_cpu0() use workqueue instead of work_on_cpu()
2012-08-28 22:57 ` Jiri Kosina
@ 2012-09-17 21:38 ` Tejun Heo
2012-09-18 10:19 ` Jiri Kosina
0 siblings, 1 reply; 4+ messages in thread
From: Tejun Heo @ 2012-09-17 21:38 UTC (permalink / raw)
To: Jiri Kosina; +Cc: H. Peter Anvin, x86, linux-kernel
On Tue, Aug 28, 2012 at 03:57:27PM -0700, Jiri Kosina wrote:
> On Thu, 23 Aug 2012, Tejun Heo wrote:
>
> > Make APM schedule a work item on CPU0 instead of using the expensive
> > work_on_cpu(); hopefully, this is the last user of work_on_cpu() and
> > we can take out work_on_cpu() in not too distant future.
> >
> > Tested both paths. Seems to work fine.
>
> Applying to apm.git, thanks Tejun.
It seems we need work_on_cpu() after all and I'm planning on
reimplementing it in saner way. Can you please drop this one?
Thanks.
--
tejun
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] x86, apm: Make on_cpu0() use workqueue instead of work_on_cpu()
2012-09-17 21:38 ` Tejun Heo
@ 2012-09-18 10:19 ` Jiri Kosina
0 siblings, 0 replies; 4+ messages in thread
From: Jiri Kosina @ 2012-09-18 10:19 UTC (permalink / raw)
To: Tejun Heo; +Cc: H. Peter Anvin, x86, linux-kernel
On Mon, 17 Sep 2012, Tejun Heo wrote:
> > > Make APM schedule a work item on CPU0 instead of using the expensive
> > > work_on_cpu(); hopefully, this is the last user of work_on_cpu() and
> > > we can take out work_on_cpu() in not too distant future.
> > >
> > > Tested both paths. Seems to work fine.
> >
> > Applying to apm.git, thanks Tejun.
>
> It seems we need work_on_cpu() after all and I'm planning on
> reimplementing it in saner way. Can you please drop this one?
Okay, dropped now.
--
Jiri Kosina
SUSE Labs
^ permalink raw reply [flat|nested] 4+ messages in thread
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2012-08-24 1:11 [PATCH] x86, apm: Make on_cpu0() use workqueue instead of work_on_cpu() Tejun Heo
2012-08-28 22:57 ` Jiri Kosina
2012-09-17 21:38 ` Tejun Heo
2012-09-18 10:19 ` Jiri Kosina
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