* [PATCH] xen:rtds: Update last_start whenever cur_budget is updated
@ 2016-10-26 19:06 Meng Xu
2016-10-27 9:14 ` Dario Faggioli
0 siblings, 1 reply; 6+ messages in thread
From: Meng Xu @ 2016-10-26 19:06 UTC (permalink / raw)
To: xen-devel
Cc: Wei Liu, Dagaen Golomb, George Dunlap, Haoran Li, Dario Faggioli,
Linh Thi Xuan Phan, Meng Xu, Meng Xu, Tianyang Chen
We keep last_start updated whenever cur_budget is updated.
This avoids subtle bugs in case burn_budget() will be called
in other places in the future.
Signed-off-by: Meng Xu <mengxu@cis.upenn.edu>
---
Cc: Dario Faggioli <dario.faggioli@citrix.com>
Cc: George Dunlap <George.Dunlap@eu.citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>
Cc: Linh Thi Xuan Phan <linhphan@cis.upenn.edu>
Cc: Haoran Li <lihaoran@wustl.edu>
Cc: Meng Xu <xumengpanda@gmail.com>
Cc: Dagaen Golomb <dgolomb@cis.upenn.edu>
Cc: Tianyang Chen <tiche@cis.upenn.edu>
---
xen/common/sched_rt.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/xen/common/sched_rt.c b/xen/common/sched_rt.c
index 4b4f232..434b773 100644
--- a/xen/common/sched_rt.c
+++ b/xen/common/sched_rt.c
@@ -953,6 +953,7 @@ burn_budget(const struct scheduler *ops, struct rt_vcpu *svc, s_time_t now)
}
svc->cur_budget -= delta;
+ svc->last_start = now;
if ( svc->cur_budget <= 0 )
{
--
1.9.1
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^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] xen:rtds: Update last_start whenever cur_budget is updated
2016-10-26 19:06 [PATCH] xen:rtds: Update last_start whenever cur_budget is updated Meng Xu
@ 2016-10-27 9:14 ` Dario Faggioli
2016-10-27 10:03 ` Wei Liu
0 siblings, 1 reply; 6+ messages in thread
From: Dario Faggioli @ 2016-10-27 9:14 UTC (permalink / raw)
To: Meng Xu, xen-devel
Cc: Wei Liu, Dagaen Golomb, George Dunlap, Haoran Li,
Linh Thi Xuan Phan, Meng Xu, Tianyang Chen
[-- Attachment #1.1: Type: text/plain, Size: 1146 bytes --]
On Wed, 2016-10-26 at 15:06 -0400, Meng Xu wrote:
> We keep last_start updated whenever cur_budget is updated.
> This avoids subtle bugs in case burn_budget() will be called
> in other places in the future.
>
I'd change this into something like:
"Make budget accounting code more consistent by making sure the values
used to compute how much budget has been consumed are updated together.
This makes code resilient to calling burn_budget() from more than just
one place --in case we will need to do that-- without risking subtle
bugs."
Also, when that is the case, like here, you need to explicitly state
that no functional changes are intended.
With all this done to the changelog:
> Signed-off-by: Meng Xu <mengxu@cis.upenn.edu>
>
Acked-by: Dario Faggioli <dario.faggioli@citrix.com>
This can go in 4.8, but can also well wait for 4.9.
Regards,
Dario
--
<<This happens because I choose it to happen!>> (Raistlin Majere)
-----------------------------------------------------------------
Dario Faggioli, Ph.D, http://about.me/dario.faggioli
Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)
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^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] xen:rtds: Update last_start whenever cur_budget is updated
2016-10-27 9:14 ` Dario Faggioli
@ 2016-10-27 10:03 ` Wei Liu
2016-10-27 13:40 ` Meng Xu
2016-10-27 13:42 ` Meng Xu
0 siblings, 2 replies; 6+ messages in thread
From: Wei Liu @ 2016-10-27 10:03 UTC (permalink / raw)
To: Dario Faggioli
Cc: Wei Liu, Dagaen Golomb, George Dunlap, Haoran Li,
Linh Thi Xuan Phan, Meng Xu, Meng Xu, xen-devel, Tianyang Chen
On Thu, Oct 27, 2016 at 11:14:36AM +0200, Dario Faggioli wrote:
> On Wed, 2016-10-26 at 15:06 -0400, Meng Xu wrote:
> > We keep last_start updated whenever cur_budget is updated.
> > This avoids subtle bugs in case burn_budget() will be called
> > in other places in the future.
> >
> I'd change this into something like:
>
> "Make budget accounting code more consistent by making sure the values
> used to compute how much budget has been consumed are updated together.
>
> This makes code resilient to calling burn_budget() from more than just
> one place --in case we will need to do that-- without risking subtle
> bugs."
>
> Also, when that is the case, like here, you need to explicitly state
> that no functional changes are intended.
>
> With all this done to the changelog:
>
> > Signed-off-by: Meng Xu <mengxu@cis.upenn.edu>
> >
> Acked-by: Dario Faggioli <dario.faggioli@citrix.com>
>
> This can go in 4.8, but can also well wait for 4.9.
>
Meng, let me know if you're OK with Dario's suggestion.
Wei.
> Regards,
> Dario
> --
> <<This happens because I choose it to happen!>> (Raistlin Majere)
> -----------------------------------------------------------------
> Dario Faggioli, Ph.D, http://about.me/dario.faggioli
> Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)
_______________________________________________
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https://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] xen:rtds: Update last_start whenever cur_budget is updated
2016-10-27 10:03 ` Wei Liu
@ 2016-10-27 13:40 ` Meng Xu
2016-10-27 13:42 ` Meng Xu
1 sibling, 0 replies; 6+ messages in thread
From: Meng Xu @ 2016-10-27 13:40 UTC (permalink / raw)
To: Wei Liu
Cc: Dagaen Golomb, George Dunlap, Haoran Li, Dario Faggioli,
Linh Thi Xuan Phan, xen-devel, Tianyang Chen
Hi Wei and Dario,
On Thu, Oct 27, 2016 at 6:03 AM, Wei Liu <wei.liu2@citrix.com> wrote:
> On Thu, Oct 27, 2016 at 11:14:36AM +0200, Dario Faggioli wrote:
>> On Wed, 2016-10-26 at 15:06 -0400, Meng Xu wrote:
>> > We keep last_start updated whenever cur_budget is updated.
>> > This avoids subtle bugs in case burn_budget() will be called
>> > in other places in the future.
>> >
>> I'd change this into something like:
>>
>> "Make budget accounting code more consistent by making sure the values
>> used to compute how much budget has been consumed are updated together.
>>
>> This makes code resilient to calling burn_budget() from more than just
>> one place --in case we will need to do that-- without risking subtle
>> bugs."
I agree.
>>
>> Also, when that is the case, like here, you need to explicitly state
>> that no functional changes are intended.
>>
>> With all this done to the changelog:
>>
>> > Signed-off-by: Meng Xu <mengxu@cis.upenn.edu>
>> >
>> Acked-by: Dario Faggioli <dario.faggioli@citrix.com>
>>
>> This can go in 4.8, but can also well wait for 4.9.
>>
>
> Meng, let me know if you're OK with Dario's suggestion.
>
> Wei.
>
>> Regards,
>> Dario
>> --
>> <<This happens because I choose it to happen!>> (Raistlin Majere)
>> -----------------------------------------------------------------
>> Dario Faggioli, Ph.D, http://about.me/dario.faggioli
>> Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)
>
>
--
-----------
Meng Xu
PhD Student in Computer and Information Science
University of Pennsylvania
http://www.cis.upenn.edu/~mengxu/
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] xen:rtds: Update last_start whenever cur_budget is updated
2016-10-27 10:03 ` Wei Liu
2016-10-27 13:40 ` Meng Xu
@ 2016-10-27 13:42 ` Meng Xu
2016-10-27 13:43 ` Wei Liu
1 sibling, 1 reply; 6+ messages in thread
From: Meng Xu @ 2016-10-27 13:42 UTC (permalink / raw)
To: Wei Liu
Cc: Dagaen Golomb, George Dunlap, Haoran Li, Dario Faggioli,
Linh Thi Xuan Phan, xen-devel, Tianyang Chen
Sorry, I accidentally sent out the previous email...
On Thu, Oct 27, 2016 at 6:03 AM, Wei Liu <wei.liu2@citrix.com> wrote:
> On Thu, Oct 27, 2016 at 11:14:36AM +0200, Dario Faggioli wrote:
>> On Wed, 2016-10-26 at 15:06 -0400, Meng Xu wrote:
>> > We keep last_start updated whenever cur_budget is updated.
>> > This avoids subtle bugs in case burn_budget() will be called
>> > in other places in the future.
>> >
>> I'd change this into something like:
>>
>> "Make budget accounting code more consistent by making sure the values
>> used to compute how much budget has been consumed are updated together.
>>
>> This makes code resilient to calling burn_budget() from more than just
>> one place --in case we will need to do that-- without risking subtle
>> bugs."
>>
Agree.
>> Also, when that is the case, like here, you need to explicitly state
>> that no functional changes are intended.
As Dario suggested, it's better to add one more line in the change log
"No functional changes are intended."
>>
>> With all this done to the changelog:
>>
>> > Signed-off-by: Meng Xu <mengxu@cis.upenn.edu>
>> >
>> Acked-by: Dario Faggioli <dario.faggioli@citrix.com>
>>
>> This can go in 4.8, but can also well wait for 4.9.
Agree..
>>
>
> Meng, let me know if you're OK with Dario's suggestion.
I'm OK with his suggestion.
I can send out a new patch with the new commit change log, if needed.
Thanks,
Meng
--
------------
Meng Xu
PhD Student in Computer and Information Science
University of Pennsylvania
http://www.cis.upenn.edu/~mengxu/
_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] xen:rtds: Update last_start whenever cur_budget is updated
2016-10-27 13:42 ` Meng Xu
@ 2016-10-27 13:43 ` Wei Liu
0 siblings, 0 replies; 6+ messages in thread
From: Wei Liu @ 2016-10-27 13:43 UTC (permalink / raw)
To: Meng Xu
Cc: Wei Liu, Dagaen Golomb, George Dunlap, Haoran Li, Dario Faggioli,
Linh Thi Xuan Phan, xen-devel, Tianyang Chen
On Thu, Oct 27, 2016 at 09:42:56AM -0400, Meng Xu wrote:
> Sorry, I accidentally sent out the previous email...
>
> On Thu, Oct 27, 2016 at 6:03 AM, Wei Liu <wei.liu2@citrix.com> wrote:
> > On Thu, Oct 27, 2016 at 11:14:36AM +0200, Dario Faggioli wrote:
> >> On Wed, 2016-10-26 at 15:06 -0400, Meng Xu wrote:
> >> > We keep last_start updated whenever cur_budget is updated.
> >> > This avoids subtle bugs in case burn_budget() will be called
> >> > in other places in the future.
> >> >
> >> I'd change this into something like:
> >>
> >> "Make budget accounting code more consistent by making sure the values
> >> used to compute how much budget has been consumed are updated together.
> >>
> >> This makes code resilient to calling burn_budget() from more than just
> >> one place --in case we will need to do that-- without risking subtle
> >> bugs."
> >>
>
> Agree.
>
> >> Also, when that is the case, like here, you need to explicitly state
> >> that no functional changes are intended.
>
> As Dario suggested, it's better to add one more line in the change log
> "No functional changes are intended."
>
> >>
> >> With all this done to the changelog:
> >>
> >> > Signed-off-by: Meng Xu <mengxu@cis.upenn.edu>
> >> >
> >> Acked-by: Dario Faggioli <dario.faggioli@citrix.com>
> >>
> >> This can go in 4.8, but can also well wait for 4.9.
>
> Agree..
>
> >>
> >
> > Meng, let me know if you're OK with Dario's suggestion.
>
> I'm OK with his suggestion.
> I can send out a new patch with the new commit change log, if needed.
>
No need. I will fix it up.
Wei.
> Thanks,
>
> Meng
>
> --
> ------------
> Meng Xu
> PhD Student in Computer and Information Science
> University of Pennsylvania
> http://www.cis.upenn.edu/~mengxu/
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^ permalink raw reply [flat|nested] 6+ messages in thread
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2016-10-26 19:06 [PATCH] xen:rtds: Update last_start whenever cur_budget is updated Meng Xu
2016-10-27 9:14 ` Dario Faggioli
2016-10-27 10:03 ` Wei Liu
2016-10-27 13:40 ` Meng Xu
2016-10-27 13:42 ` Meng Xu
2016-10-27 13:43 ` Wei Liu
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