help in the MM Area of the Linux Kernel

help in the MM Area of the Linux Kernel

[Damian Tometzki]

Hello all,

i'am intrested in helping and Bug Fixing in the mm area of the linux
kernel.?

For driver development is it clear check in the staging area the
TODO's.?

And what is the process for other areas of the kernel for example mm
(Memory management X86) ??

In advance many thanks
Damian

?

help in the MM Area of the Linux Kernel

[Damian Tometzki]

Any suggestions on this topic ?

Am Donnerstag, den 05.10.2017, 18:14 +0200 schrieb Damian Tometzki:
> Hello all,
> 
> i'am intrested in helping and Bug Fixing in the mm area of the linux
> kernel.?
> 
> For driver development is it clear check in the staging area the
> TODO's.?
> 
> And what is the process for other areas of the kernel for example mm
> (Memory management X86) ??
> 
> In advance many thanks
> Damian
> 
> ?

help in the MM Area of the Linux Kernel

[Damian Tometzki]

Any suggestions on this topic ?

BR
Damian

Am Donnerstag, den 05.10.2017, 18:14 +0200 schrieb Damian Tometzki:
> Hello all,
> 
> i'am intrested in helping and Bug Fixing in the mm area of the linux
> kernel.?
> 
> For driver development is it clear check in the staging area the
> TODO's.?
> 
> And what is the process for other areas of the kernel for example mm
> (Memory management X86) ??
> 
> In advance many thanks
> Damian
> 
> ?

help in the MM Area of the Linux Kernel

[valdis.kletnieks at vt.edu]

On Thu, 05 Oct 2017 18:14:08 +0200, Damian Tometzki said:

> i'am intrested in helping and Bug Fixing in the mm area of the linux
> kernel.?
>
> For driver development is it clear check in the staging area the
> TODO's.?
>
> And what is the process for other areas of the kernel for example mm
> (Memory management X86) ??

Rule 1 of kernel hacking:  Not every mechanic gets to work on Formula 1
engines.

For mm, you'll probably need to show some expertise in other kernel areas,
*plus* have a deep understanding of memory management theory. That code has
already been worked over by multiple professionals, which means pretty much all
the easy stuff has already been done.

Oh, and you're probably going to also need knowledge of the kernel
instrumentation - perf, tracepoints, and friends.

If you manage to find an actual bug in that code, it is most likely going to be
some weird corner case, and *much* MM clue will be required to fix it without
breaking some *other* more common corner case.  Remember that the same code has
to Do The Right Thing on everything from an embedded system with 32M of RAM and
only one major process running, to large mainframe class boxes with a terabyte
of RAM, a large Oracle instance, and several hundred Apache / Tomcat / etc
processes flickering in and out of existence, to multi-terabyte systems running
HPC (where the use of RDMA over Infiniband by things like MPI creates
challenges due to a *lot* of locked pages...)

Your best bet?  Find a replicable corner case (this may require access to a
variety of systems), create a test-case that can cause the corner case on
demand.  Figure out what the mm code is doing, and how it could do it better.
Write a patch, test, and then double-check on other systems that you didn't
cause a regression.  Submit the patch.

Good luck. :)



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help in the MM Area of the Linux Kernel

[Damian Tometzki]

Hello Valdis,

thank you you for you reply. I'work for a big company as SAP partner
and i responsible for SAP HANA and the infrastucture.?

My personal intrest is the memory managment. My impression was the same
as you answerded.?

As you said i will try to figure out what the mm code is doing and try
to find out what can we do better.?


Damian



Am Freitag, den 06.10.2017, 12:34 -0400 schrieb
valdis.kletnieks at vt.edu:
> On Thu, 05 Oct 2017 18:14:08 +0200, Damian Tometzki said:
> 
> > 
> > i'am intrested in helping and Bug Fixing in the mm area of the
> > linux
> > kernel.?
> > 
> > For driver development is it clear check in the staging area the
> > TODO's.?
> > 
> > And what is the process for other areas of the kernel for example
> > mm
> > (Memory management X86) ??
> Rule 1 of kernel hacking:??Not every mechanic gets to work on Formula
> 1
> engines.
> 
> For mm, you'll probably need to show some expertise in other kernel
> areas,
> *plus* have a deep understanding of memory management theory. That
> code has
> already been worked over by multiple professionals, which means
> pretty much all
> the easy stuff has already been done.
> 
> Oh, and you're probably going to also need knowledge of the kernel
> instrumentation - perf, tracepoints, and friends.
> 
> If you manage to find an actual bug in that code, it is most likely
> going to be
> some weird corner case, and *much* MM clue will be required to fix it
> without
> breaking some *other* more common corner case.??Remember that the
> same code has
> to Do The Right Thing on everything from an embedded system with 32M
> of RAM and
> only one major process running, to large mainframe class boxes with a
> terabyte
> of RAM, a large Oracle instance, and several hundred Apache / Tomcat
> / etc
> processes flickering in and out of existence, to multi-terabyte
> systems running
> HPC (where the use of RDMA over Infiniband by things like MPI creates
> challenges due to a *lot* of locked pages...)
> 
> Your best bet???Find a replicable corner case (this may require
> access to a
> variety of systems), create a test-case that can cause the corner
> case on
> demand.??Figure out what the mm code is doing, and how it could do it
> better.
> Write a patch, test, and then double-check on other systems that you
> didn't
> cause a regression.??Submit the patch.
> 
> Good luck. :)
> 
> 
> 
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies

help in the MM Area of the Linux Kernel

[Ricardo Ribalda Delgado]

Take a look to this:

https://www.youtube.com/watch?v=6S9DDTFyjrY

I attended a presentation with the same name in the last Kernel
Recipes and was very clarifying.

Cheers!

On Fri, Oct 6, 2017 at 8:29 PM, Damian Tometzki
<damian.tometzki@icloud.com> wrote:
> Hello Valdis,
>
> thank you you for you reply. I'work for a big company as SAP partner
> and i responsible for SAP HANA and the infrastucture.
>
> My personal intrest is the memory managment. My impression was the same
> as you answerded.
>
> As you said i will try to figure out what the mm code is doing and try
> to find out what can we do better.
>
>
> Damian
>
>
>
> Am Freitag, den 06.10.2017, 12:34 -0400 schrieb
> valdis.kletnieks at vt.edu:
>> On Thu, 05 Oct 2017 18:14:08 +0200, Damian Tometzki said:
>>
>> >
>> > i'am intrested in helping and Bug Fixing in the mm area of the
>> > linux
>> > kernel.
>> >
>> > For driver development is it clear check in the staging area the
>> > TODO's.
>> >
>> > And what is the process for other areas of the kernel for example
>> > mm
>> > (Memory management X86) ?
>> Rule 1 of kernel hacking:  Not every mechanic gets to work on Formula
>> 1
>> engines.
>>
>> For mm, you'll probably need to show some expertise in other kernel
>> areas,
>> *plus* have a deep understanding of memory management theory. That
>> code has
>> already been worked over by multiple professionals, which means
>> pretty much all
>> the easy stuff has already been done.
>>
>> Oh, and you're probably going to also need knowledge of the kernel
>> instrumentation - perf, tracepoints, and friends.
>>
>> If you manage to find an actual bug in that code, it is most likely
>> going to be
>> some weird corner case, and *much* MM clue will be required to fix it
>> without
>> breaking some *other* more common corner case.  Remember that the
>> same code has
>> to Do The Right Thing on everything from an embedded system with 32M
>> of RAM and
>> only one major process running, to large mainframe class boxes with a
>> terabyte
>> of RAM, a large Oracle instance, and several hundred Apache / Tomcat
>> / etc
>> processes flickering in and out of existence, to multi-terabyte
>> systems running
>> HPC (where the use of RDMA over Infiniband by things like MPI creates
>> challenges due to a *lot* of locked pages...)
>>
>> Your best bet?  Find a replicable corner case (this may require
>> access to a
>> variety of systems), create a test-case that can cause the corner
>> case on
>> demand.  Figure out what the mm code is doing, and how it could do it
>> better.
>> Write a patch, test, and then double-check on other systems that you
>> didn't
>> cause a regression.  Submit the patch.
>>
>> Good luck. :)
>>
>>
>>
>> _______________________________________________
>> Kernelnewbies mailing list
>> Kernelnewbies at kernelnewbies.org
>> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> https://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies



-- 
Ricardo Ribalda

help in the MM Area of the Linux Kernel

[Yubin Ruan]

2017-10-07 0:34 GMT+08:00  <valdis.kletnieks@vt.edu>:
> On Thu, 05 Oct 2017 18:14:08 +0200, Damian Tometzki said:
>
>> i'am intrested in helping and Bug Fixing in the mm area of the linux
>> kernel.
>>
>> For driver development is it clear check in the staging area the
>> TODO's.
>>
>> And what is the process for other areas of the kernel for example mm
>> (Memory management X86) ?
>
> Rule 1 of kernel hacking:  Not every mechanic gets to work on Formula 1
> engines.
>
> For mm, you'll probably need to show some expertise in other kernel areas,
> *plus* have a deep understanding of memory management theory. That code has
> already been worked over by multiple professionals, which means pretty much all
> the easy stuff has already been done.
>
> Oh, and you're probably going to also need knowledge of the kernel
> instrumentation - perf, tracepoints, and friends.
>
> If you manage to find an actual bug in that code, it is most likely going to be
> some weird corner case, and *much* MM clue will be required to fix it without
> breaking some *other* more common corner case.  Remember that the same code has
> to Do The Right Thing on everything from an embedded system with 32M of RAM and
> only one major process running, to large mainframe class boxes with a terabyte
> of RAM, a large Oracle instance, and several hundred Apache / Tomcat / etc

um...terabyte of RAM? Can you name one of those machine with so much RAM?

Yubin

help in the MM Area of the Linux Kernel

[Jeffrey Walton]

On Mon, Oct 9, 2017 at 9:50 PM, Yubin Ruan <ablacktshirt@gmail.com> wrote:
> ...
>> to Do The Right Thing on everything from an embedded system with 32M of RAM and
>> only one major process running, to large mainframe class boxes with a terabyte
>> of RAM, a large Oracle instance, and several hundred Apache / Tomcat / etc
>
> um...terabyte of RAM? Can you name one of those machine with so much RAM?

4 TB: http://investors.cray.com/phoenix.zhtml?c=98390&p=irol-newsArticle&ID=1855272
64 TB: https://news.ycombinator.com/item?id=7302770
690 TB: https://en.wikipedia.org/wiki/Titan_(supercomputer)
...

Jeff

help in the MM Area of the Linux Kernel

[valdis.kletnieks at vt.edu]

On Mon, 09 Oct 2017 21:58:27 -0400, Jeffrey Walton said:
> On Tue, 10 Oct 2017 09:50:21 +0800, Yubin Ruan said:
> > um...terabyte of RAM? Can you name one of those machine with so much RAM?
>
> 4 TB: http://investors.cray.com/phoenix.zhtml?c=98390&p=irol-newsArticle&ID=1855272
> 64 TB: https://news.ycombinator.com/item?id=7302770
> 690 TB: https://en.wikipedia.org/wiki/Titan_(supercomputer)

Heck, Dell will sell you a 4U rack-mount with 3T in it.  Got probably a half-dozen
of them across the hall from my office for the HPC people.  And we probably got
a hundred or so nodes with 512G of RAM across the various clusters.

And IBM will sell you a System/Z Z14 with 32T of memory, and crazy amounts of
I/O capability (Imagine the equivalent of 320 PCI slots....)

https://www.theregister.co.uk/2017/07/17/ibm_latest_mainframe_z14/
https://www-01.ibm.com/common/ssi/cgi-bin/ssialias?htmlfid=ZSD03046USEN&

And yes, it will run Linux, it's a s390 architecture box.
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