On Fri, 18 May 2012 09:26:05 +0200
Ingo Molnar wrote:
> I'm not sure we had a usable spin_is_contended() back then, nor
> was the !PREEMPT case in my mind really.
The fact that both spin_needbreak() and spin_is_contended() can be
used outside of sched is a bit confusing.
For example, in mm/com
* Takuya Yoshikawa wrote:
> Replaced Ingo's address with kernel.org one,
>
> On Thu, 03 May 2012 17:47:30 +0200
> Peter Zijlstra wrote:
>
> > On Thu, 2012-05-03 at 22:00 +0900, Takuya Yoshikawa wrote:
> > > But as I could not see why spin_needbreak() was differently
> > > implemented
> > > de
Replaced Ingo's address with kernel.org one,
On Thu, 03 May 2012 17:47:30 +0200
Peter Zijlstra wrote:
> On Thu, 2012-05-03 at 22:00 +0900, Takuya Yoshikawa wrote:
> > But as I could not see why spin_needbreak() was differently
> > implemented
> > depending on CONFIG_PREEMPT, I wanted to understa
On 05/03/2012 09:00 PM, Takuya Yoshikawa wrote:
> On Thu, 03 May 2012 14:29:10 +0200
> Peter Zijlstra wrote:
>
>> On Thu, 2012-05-03 at 21:22 +0900, Takuya Yoshikawa wrote:
>>> Although the real use case is out of this RFC patch, we are now discussing
>>> a case in which we may hold a spin_lock
On Thu, 2012-05-03 at 22:00 +0900, Takuya Yoshikawa wrote:
> But as I could not see why spin_needbreak() was differently
> implemented
> depending on CONFIG_PREEMPT, I wanted to understand the meaning.
Its been that way since before voluntary preemption was introduced, so
its possible Ingo simply
On 05/03/2012 05:27 PM, Avi Kivity wrote:
> On 05/03/2012 05:11 PM, Takuya Yoshikawa wrote:
> > On Thu, 03 May 2012 15:47:26 +0300
> > Avi Kivity wrote:
> >
> > > On 05/03/2012 03:29 PM, Peter Zijlstra wrote:
> > > > On Thu, 2012-05-03 at 21:22 +0900, Takuya Yoshikawa wrote:
> > > > > Although the
On 05/03/2012 05:11 PM, Takuya Yoshikawa wrote:
> On Thu, 03 May 2012 15:47:26 +0300
> Avi Kivity wrote:
>
> > On 05/03/2012 03:29 PM, Peter Zijlstra wrote:
> > > On Thu, 2012-05-03 at 21:22 +0900, Takuya Yoshikawa wrote:
> > > > Although the real use case is out of this RFC patch, we are now
> >
On Thu, 03 May 2012 15:47:26 +0300
Avi Kivity wrote:
> On 05/03/2012 03:29 PM, Peter Zijlstra wrote:
> > On Thu, 2012-05-03 at 21:22 +0900, Takuya Yoshikawa wrote:
> > > Although the real use case is out of this RFC patch, we are now discussing
> > > a case in which we may hold a spin_lock for lo
On Thu, 03 May 2012 14:29:10 +0200
Peter Zijlstra wrote:
> On Thu, 2012-05-03 at 21:22 +0900, Takuya Yoshikawa wrote:
> > Although the real use case is out of this RFC patch, we are now discussing
> > a case in which we may hold a spin_lock for long time, ms order, depending
> > on workload; and
On 05/03/2012 03:29 PM, Peter Zijlstra wrote:
> On Thu, 2012-05-03 at 21:22 +0900, Takuya Yoshikawa wrote:
> > Although the real use case is out of this RFC patch, we are now discussing
> > a case in which we may hold a spin_lock for long time, ms order, depending
> > on workload; and in that case
On Thu, 2012-05-03 at 21:22 +0900, Takuya Yoshikawa wrote:
> Although the real use case is out of this RFC patch, we are now discussing
> a case in which we may hold a spin_lock for long time, ms order, depending
> on workload; and in that case, other threads -- VCPU threads -- should be
> given h
On Thu, 03 May 2012 10:35:27 +0200
Peter Zijlstra wrote:
> On Thu, 2012-05-03 at 17:12 +0900, Takuya Yoshikawa wrote:
> >
> > Although we can do that using spin_is_contended() and cond_resched(),
> > changing cond_resched_lock() to satisfy such a need is another option.
> >
> Yeah, not a pretty
On Thu, 2012-05-03 at 17:12 +0900, Takuya Yoshikawa wrote:
>
> Although we can do that using spin_is_contended() and cond_resched(),
> changing cond_resched_lock() to satisfy such a need is another option.
>
Yeah, not a pretty patch. Changing all cond_resched_lock() sites just to
change one and i
This patch is for showing what I am thinking and only compile tested
on linux-next, so an RFC.
Although I might misread something, I am not sure whether every user of
this API wanted to avoid contention check without CONFIG_PREEMPT.
Any comments will be appreciated.
Thanks,
Takuya
===
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