[Ksummit-discuss] Nominations for Kernel Summit

[Ksummit-discuss] Nominations for Kernel Summit

[Josh Triplett]

I'd like to nominate the following people:

- Tom Zanussi <tom.zanussi@linux.intel.com> - doing extensive work on
  shrinking the kernel and embedded userspace to fit in shockingly tiny
  spaces.
- Julia Lawall <julia.lawall@lip6.fr> - maintainer of cocinelle, the
  semantic patch tool, which has collectively saved an incredible amount
  of kernel maintainer time and effort.
- Andi Kleen <ak@linux.intel.com> - working on LTO and many other kernel
  projects.

I'd also like to nominate myself; in addition to the kernel tinification
topic I've already proposed, I plan to coordinate RCU topics with Paul
McKenney.

Thanks,
Josh Triplett

Re: [Ksummit-discuss] Nominations for Kernel Summit

[tytso]

On Fri, May 02, 2014 at 09:56:59AM -0700, Josh Triplett wrote:
> I'd like to nominate the following people

Thanks, I've updated the nominations spreadsheet accordingly.

	     	     	 	    		- Ted

Re: [Ksummit-discuss] Nominations for Kernel Summit

[Paul E. McKenney]

On Fri, May 02, 2014 at 09:56:59AM -0700, Josh Triplett wrote:
> I'd like to nominate the following people:
> 
> - Tom Zanussi <tom.zanussi@linux.intel.com> - doing extensive work on
>   shrinking the kernel and embedded userspace to fit in shockingly tiny
>   spaces.
> - Julia Lawall <julia.lawall@lip6.fr> - maintainer of cocinelle, the
>   semantic patch tool, which has collectively saved an incredible amount
>   of kernel maintainer time and effort.
> - Andi Kleen <ak@linux.intel.com> - working on LTO and many other kernel
>   projects.
> 
> I'd also like to nominate myself; in addition to the kernel tinification
> topic I've already proposed, I plan to coordinate RCU topics with Paul
> McKenney.

Sounds very good!  The RCU topics that occur to me immediately include:

o	How do we tell compilers about RCU's memory-ordering requirements?
	Follow up to http://lwn.net/Articles/586838/ and
	https://lwn.net/Articles/588300/.  This could potentially
	converge before August, but the odds do not look all that
	favorable.  Might be an interesting discussion of the
	interaction between the kernel and compiler, though perhaps
	in the Chinese sense.  ;-)

o	What use cases are not supported well, and what should we be
	doing to better support them, in RCU or otherwise?  Without
	some reasonably controversial proposals, this aspect seems
	unlikely to be LKS material.

o	Can we do a better job of automatically catching RCU usage
	bugs?  Or, for that matter, RCU bugs!

Other thoughts for topics?

							Thanx, Paul

Re: [Ksummit-discuss] Nominations for Kernel Summit

[Paul Gortmaker]

On 14-05-07 08:16 PM, Paul E. McKenney wrote:
> On Fri, May 02, 2014 at 09:56:59AM -0700, Josh Triplett wrote:
>> I'd like to nominate the following people:
>>
>> - Tom Zanussi <tom.zanussi@linux.intel.com> - doing extensive work on
>>   shrinking the kernel and embedded userspace to fit in shockingly tiny
>>   spaces.
>> - Julia Lawall <julia.lawall@lip6.fr> - maintainer of cocinelle, the
>>   semantic patch tool, which has collectively saved an incredible amount
>>   of kernel maintainer time and effort.
>> - Andi Kleen <ak@linux.intel.com> - working on LTO and many other kernel
>>   projects.
>>
>> I'd also like to nominate myself; in addition to the kernel tinification
>> topic I've already proposed, I plan to coordinate RCU topics with Paul
>> McKenney.
> 
> Sounds very good!  The RCU topics that occur to me immediately include:
> 
> o	How do we tell compilers about RCU's memory-ordering requirements?
> 	Follow up to http://lwn.net/Articles/586838/ and
> 	https://lwn.net/Articles/588300/.  This could potentially
> 	converge before August, but the odds do not look all that
> 	favorable.  Might be an interesting discussion of the
> 	interaction between the kernel and compiler, though perhaps
> 	in the Chinese sense.  ;-)
> 
> o	What use cases are not supported well, and what should we be
> 	doing to better support them, in RCU or otherwise?  Without
> 	some reasonably controversial proposals, this aspect seems
> 	unlikely to be LKS material.
> 
> o	Can we do a better job of automatically catching RCU usage
> 	bugs?  Or, for that matter, RCU bugs!
> 
> Other thoughts for topics?

It seems, from a user's perspective, that an RCU stall is one
the most user unfriendly things to be on the receiving end of.
Since it trips an NMI to backtrace each core, on a larger system
a person is faced with screens and screens of (mostly irrelevant)
backtrace.  I'm not sure what to suggest to improve things, and
maybe there really isn't anything that can be done, but IMHO it
might be worth discussing...

Paul.
--


> 
> 							Thanx, Paul
> 
> _______________________________________________
> Ksummit-discuss mailing list
> Ksummit-discuss@lists.linuxfoundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/ksummit-discuss
> 

Re: [Ksummit-discuss] Nominations for Kernel Summit

[Paul E. McKenney]

On Fri, May 09, 2014 at 12:46:04PM -0400, Paul Gortmaker wrote:
> On 14-05-07 08:16 PM, Paul E. McKenney wrote:
> > On Fri, May 02, 2014 at 09:56:59AM -0700, Josh Triplett wrote:
> >> I'd like to nominate the following people:
> >>
> >> - Tom Zanussi <tom.zanussi@linux.intel.com> - doing extensive work on
> >>   shrinking the kernel and embedded userspace to fit in shockingly tiny
> >>   spaces.
> >> - Julia Lawall <julia.lawall@lip6.fr> - maintainer of cocinelle, the
> >>   semantic patch tool, which has collectively saved an incredible amount
> >>   of kernel maintainer time and effort.
> >> - Andi Kleen <ak@linux.intel.com> - working on LTO and many other kernel
> >>   projects.
> >>
> >> I'd also like to nominate myself; in addition to the kernel tinification
> >> topic I've already proposed, I plan to coordinate RCU topics with Paul
> >> McKenney.
> > 
> > Sounds very good!  The RCU topics that occur to me immediately include:
> > 
> > o	How do we tell compilers about RCU's memory-ordering requirements?
> > 	Follow up to http://lwn.net/Articles/586838/ and
> > 	https://lwn.net/Articles/588300/.  This could potentially
> > 	converge before August, but the odds do not look all that
> > 	favorable.  Might be an interesting discussion of the
> > 	interaction between the kernel and compiler, though perhaps
> > 	in the Chinese sense.  ;-)
> > 
> > o	What use cases are not supported well, and what should we be
> > 	doing to better support them, in RCU or otherwise?  Without
> > 	some reasonably controversial proposals, this aspect seems
> > 	unlikely to be LKS material.
> > 
> > o	Can we do a better job of automatically catching RCU usage
> > 	bugs?  Or, for that matter, RCU bugs!
> > 
> > Other thoughts for topics?
> 
> It seems, from a user's perspective, that an RCU stall is one
> the most user unfriendly things to be on the receiving end of.
> Since it trips an NMI to backtrace each core, on a larger system
> a person is faced with screens and screens of (mostly irrelevant)
> backtrace.  I'm not sure what to suggest to improve things, and
> maybe there really isn't anything that can be done, but IMHO it
> might be worth discussing...

Certainly an area needing improvement, no argument there!

I could imagine boot-time or run-time selection of the stack-dump
strategy (no stack dump, dump current stack, dump only stacks of
stalled CPUs and/or tasks, dump all CPU stacks, dump all task
stacks, dump randomly selected subset of one of the above) as
well as the mechanism (NMI vs. grovel around in other CPU's/task's
stack).  Maybe other things as well.

Other thoughts?

							Thanx, Paul

> Paul.
> --
> 
> 
> > 
> > 							Thanx, Paul
> > 
> > _______________________________________________
> > Ksummit-discuss mailing list
> > Ksummit-discuss@lists.linuxfoundation.org
> > https://lists.linuxfoundation.org/mailman/listinfo/ksummit-discuss
> > 
>