[Lustre-devel] Lustre and cross-platform portability

[Lustre-devel] Lustre and cross-platform portability

[Andreas Dilger]

Whamcloud and EMC are jointly investigating how to be able to contribute the Lustre client code into the upstream Linux kernel.

As a prerequisite to this, EMC is working to clean up the Lustre client code to better match the kernel coding style, and one of the anticipated major obstacles to upstream kernel submission is the heavy use of code abstraction via libcfs for portability to other operating systems (most notably MacOS and WinNT, but also for liblustre, and potentially *BSD).

I have no information that the WinNT project will ever be released by Oracle, and as yet there has not been any code released from the MacOS port, so the libcfs portability layer is potentially exacting a high cost in code maintenance and complexity (CLIO being a prime example) for no apparent benefit.  Similarly, the liblustre client needs a portability layer for userspace, and suffers from the same apparent lack of interest or users.

I'd like to get some feedback from the Lustre community about removing the libcfs abstraction entirely, or possibly restructuring it to look like the Linux kernel API, and having the other platforms code against it as a Linux portability layer, like ZFS on Linux uses the Solaris Portability Layer (SPL) to avoid changing the core ZFS code.  A related topic is whether it would be better to replace all cfs_* functions with standard Linux kernel functions en-masse, or migrate away from cfs_* functions slowly?

Also, we're planning on deprecating the liblustre client code, due to lack of interest/usage.  The current code is in disrepair, and we've been keeping it around for years without any benefit, and while I was one of the strongest advocates for keeping it in our back pocket in case of future needs, I don't see that materializing in the future.

The liblustre code would be left in the tree for now, in case someone from the community is interested to get it working and maintain it, and it may be updated on a best effort basis.  If nobody steps forward to do this work, the liblustre code would be deleted from the development branch in a year or so.


Unfortunately, after starting this thread, I may not be able to reply to questions in a timely manner due to vacation.  I look forward to a thread that concludes with unanimous agreement from all parties. :-)

Cheers, Andreas
--
Andreas Dilger                       Whamcloud, Inc.
Principal Lustre Engineer            http://www.whamcloud.com/

[Lustre-devel] [Twg] Lustre and cross-platform portability

[Ken Hornstein]

>I have no information that the WinNT project will ever be released
>by Oracle, and as yet there has not been any code released from the
>MacOS port, so the libcfs portability layer is potentially exacting
>a high cost in code maintenance and complexity (CLIO being a prime
>example) for no apparent benefit.  Similarly, the liblustre client needs
>a portability layer for userspace, and suffers from the same apparent
>lack of interest or users.

In terms of the MacOS X port, I don't think that's quite fair ...
the code I did is available and anyone can download it.  It was
functional in a very basic way but needed some additonal love.
Okay, I haven't rolled that stuff into the Whamcloud release ...
what happened there was when there was all the uncertainty with
Oracle & Lustre development I lost momentum and got caught up in
other things.  I've talked with the guys at Whamcloud about bringing
at least the portability changes over, and that's all been on me;
it's certainly on my list to work on.

I can say that at least for MacOS X, there has been interest; I can't
speak for the amount of interest, and there's a bit of a chicken and
egg problem ... people don't plan their Lustre use around MacOS X
clients because there isn't one that works well, and people don't put
work into it because there isn't people who plan their Lustre use
around it.

>I'd like to get some feedback from the Lustre community about removing
>the libcfs abstraction entirely, or possibly restructuring it to look
>like the Linux kernel API, and having the other platforms code against
>it as a Linux portability layer, like ZFS on Linux uses the Solaris
>Portability Layer (SPL) to avoid changing the core ZFS code.  A related
>topic is whether it would be better to replace all cfs_* functions with
>standard Linux kernel functions en-masse, or migrate away from cfs_*
>functions slowly?

The only thing I can think of is that if this is done, then officially
Lustre is going to be a Linux-only filesystem.  I understand there are
real costs to maintaining the cfs layer, and I can't speak to whether or
not the loss would be worth the gains.

--Ken

[Lustre-devel] [Twg] Lustre and cross-platform portability

[Andreas Dilger]

On 2012-03-15, at 12:45 PM, Ken Hornstein wrote:
>> I have no information that the WinNT project will ever be released
>> by Oracle, and as yet there has not been any code released from the
>> MacOS port, so the libcfs portability layer is potentially exacting
>> a high cost in code maintenance and complexity (CLIO being a prime
>> example) for no apparent benefit.  Similarly, the liblustre client
>> needs a portability layer for userspace, and suffers from the same
>> apparent lack of interest or users.
> 
> In terms of the MacOS X port, I don't think that's quite fair ...
> the code I did is available and anyone can download it.

Ken, my apologies for this misstatement.  I guess that my faulty memory is to blame for the fact that I didn't recall the MacOS code was made publicly available for download.

>  It was
> functional in a very basic way but needed some additonal love.
> Okay, I haven't rolled that stuff into the Whamcloud release ...

I don't think I've ever seen patches sent from you to either Oracle or Whamcloud, and unfortunately nobody on our side has had the bandwidth or user demand/funding to be pulling such changes either.

> what happened there was when there was all the uncertainty with
> Oracle & Lustre development I lost momentum and got caught up in
> other things.  I've talked with the guys at Whamcloud about bringing
> at least the portability changes over, and that's all been on me;
> it's certainly on my list to work on.
> 
> I can say that at least for MacOS X, there has been interest; I can't
> speak for the amount of interest, and there's a bit of a chicken and
> egg problem ... people don't plan their Lustre use around MacOS X
> clients because there isn't one that works well, and people don't put
> work into it because there isn't people who plan their Lustre use
> around it.

Another alternative that has been proposed is FUSE for MacOS/Solaris.  I'm not sure if FUSE exists for Windows or not.  Of course, this is only useful for casual access, and not for high performance usage.

>> I'd like to get some feedback from the Lustre community about removing
>> the libcfs abstraction entirely, or possibly restructuring it to look
>> like the Linux kernel API, and having the other platforms code against
>> it as a Linux portability layer, like ZFS on Linux uses the Solaris
>> Portability Layer (SPL) to avoid changing the core ZFS code.  A related
>> topic is whether it would be better to replace all cfs_* functions with
>> standard Linux kernel functions en-masse, or migrate away from cfs_*
>> functions slowly?
> 
> The only thing I can think of is that if this is done, then officially
> Lustre is going to be a Linux-only filesystem.  I understand there are
> real costs to maintaining the cfs layer, and I can't speak to whether or
> not the loss would be worth the gains.

This isn't strictly correct.  It would be possible to change the libcfs portability layer to export the same API as the Linux kernel to MacOS and Windows.  This would simplify getting the client into the Linux kernel, but still allow a native client on MacOS.

I'm fine with keeping the abstraction layer if there is legitimate use for it.  Having the MacOS client in the Lustre tree in a state where it can at least be built would allow us to make changes to the code (e.g. function renaming) with some chance of it not being totally broken immediately.

Cheers, Andreas
--
Andreas Dilger                       Whamcloud, Inc.
Principal Lustre Engineer            http://www.whamcloud.com/

[Lustre-devel] [Twg] Lustre and cross-platform portability

[Joshua Walgenbach]

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On 03/15/2012 03:39 PM, Andreas Dilger wrote:

> Another alternative that has been proposed is FUSE for
> MacOS/Solaris. I'm not sure if FUSE exists for Windows or not.  Of
> course, this is only useful for casual access, and not for high
> performance usage.
> 

I think the FUSE for Windows project is defunct, but there is a user
space filesystem project for Windows called Dokan
(http://dokan-dev.net/en/) that had a release a little more than a
year ago.

For my part, a Lustre client on Windows or OS X would be used mostly
for visualization of data, rather than being computed against so a
slower user space implementation would be more than sufficient. There
are a few applications that are using an SMB exported Lustre
filesystem for data collection, but those applications are similarly
low bandwidth. It would be nice to remove the SMB server in the middle.

- -Josh

- --
Joshua Walgenbach, High Performance File Systems, Indiana University
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[Lustre-devel] [wc-discuss] Re: [Twg] Lustre and cross-platform portability

[Gregory Matthews]

On 15/03/12 19:51, Joshua Walgenbach wrote:
> For my part, a Lustre client on Windows or OS X would be used mostly
> for visualization of data, rather than being computed against so a
> slower user space implementation would be more than sufficient.
> There are a few applications that are using an SMB exported Lustre
> filesystem for data collection, but those applications are similarly
> low bandwidth. It would be nice to remove the SMB server in the
> middle.

why bother having a windows client if you lose the performance? We have
windows based detectors and proprietary windows based analysis software
that would definitely benefit from higher performance access to lustre
file systems but replacing existing CIFS servers for no gain seems a bit
pointless.

I understand the problems that a native MS client would have, without
buy-in from Microsoft it would be a nightmare to keep the MS tree and
the Linux tree in sync. One possible future workaround proposed by
Whamcloud at last years LUG is pNFS.

GREG

>
> - -Josh


-- 
Greg Matthews            01235 778658
Senior Computer Systems Administrator
Diamond Light Source, Oxfordshire, UK

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[Lustre-devel] [wc-discuss] Re: [Twg] Lustre and cross-platform portability

[Alexey Lyashkov]

Windows don't have a good OFED port so we anyway will lost a performance.
but using a full client will able to use a striping information and accept a data from a several OST's
with comparing a get a single data stream from a SMB.

Also fuse client will able to run on any OS have a FUSE porting that is any BSD, OpenSolaris, MacOS, in additional to the windows.
That is easy way to maintain a single client for many OS.


On Mar 16, 2012, at 14:11, Gregory Matthews wrote:

> On 15/03/12 19:51, Joshua Walgenbach wrote:
>> For my part, a Lustre client on Windows or OS X would be used mostly
>> for visualization of data, rather than being computed against so a
>> slower user space implementation would be more than sufficient.
>> There are a few applications that are using an SMB exported Lustre
>> filesystem for data collection, but those applications are similarly
>> low bandwidth. It would be nice to remove the SMB server in the
>> middle.
> 
> why bother having a windows client if you lose the performance? We have
> windows based detectors and proprietary windows based analysis software
> that would definitely benefit from higher performance access to lustre
> file systems but replacing existing CIFS servers for no gain seems a bit
> pointless.
> 
> I understand the problems that a native MS client would have, without
> buy-in from Microsoft it would be a nightmare to keep the MS tree and
> the Linux tree in sync. One possible future workaround proposed by
> Whamcloud at last years LUG is pNFS.
> 
> GREG
> 
>> 
>> - -Josh
> 
> 
> -- 
> Greg Matthews            01235 778658
> Senior Computer Systems Administrator
> Diamond Light Source, Oxfordshire, UK
> 
> -- 
> This e-mail and any attachments may contain confidential, copyright and or privileged material, and are for the use of the intended addressee only. If you are not the intended addressee or an authorised recipient of the addressee please notify us of receipt by returning the e-mail and do not use, copy, retain, distribute or disclose the information in or attached to the e-mail.
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> Diamond Light Source Limited (company no. 4375679). Registered in England and Wales with its registered office at Diamond House, Harwell Science and Innovation Campus, Didcot, Oxfordshire, OX11 0DE, United Kingdom
> 
> 
> 

[Lustre-devel] [wc-discuss] Re: [Twg] Lustre and cross-platform portability

[Ken Hornstein]

>Also fuse client will able to run on any OS have a FUSE porting that is
>any BSD, OpenSolaris, MacOS, in additional to the windows.  That is
>easy way to maintain a single client for many OS.

It is, unfortunately, not quite that simple.

I can't claim to be a FUSE expert, but I've been paying attention
to it on other platforms.  From what I can tell, FUSE works great
on Linux, but on other platforms the support is iffy.  Also, it's
not quite implemented the same on other operating systems as it is
on Linux, making porting a Linux FUSE module to other platforms not
trivial; from what I've seen, this is due to the Linux filesystem
interface versus the vnode interface used by every Unix except Linux
(and this is part of what makes Lustre hard to port).

I guess what I'm saying is that don't fall into the underwear gnomes
trap of thinking:

1) Get liblustre working with FUSE
2) ???
3) Lustre client everywhere!

It might make it easier, but I doubt it will make it easy.

--Ken

[Lustre-devel] [wc-discuss] [Twg] Lustre and cross-platform portability

[Alexey Lyashkov]

Trust me.
I (with two friends) write  a FUSE client for a FreeBSD in past.
Most issues related to a porting libcfs/libsysio to FreeBSD, but anyway patch isn''t huge ~200kb.
I have plan to send that patch in near time, as 2.3 landing window open.



On Mar 16, 2012, at 18:46, Ken Hornstein wrote:

>> Also fuse client will able to run on any OS have a FUSE porting that is
>> any BSD, OpenSolaris, MacOS, in additional to the windows.  That is
>> easy way to maintain a single client for many OS.
> 
> It is, unfortunately, not quite that simple.
> 
> I can't claim to be a FUSE expert, but I've been paying attention
> to it on other platforms.  From what I can tell, FUSE works great
> on Linux, but on other platforms the support is iffy.  Also, it's
> not quite implemented the same on other operating systems as it is
> on Linux, making porting a Linux FUSE module to other platforms not
> trivial; from what I've seen, this is due to the Linux filesystem
> interface versus the vnode interface used by every Unix except Linux
> (and this is part of what makes Lustre hard to port).
> 
> I guess what I'm saying is that don't fall into the underwear gnomes
> trap of thinking:
> 
> 1) Get liblustre working with FUSE
> 2) ???
> 3) Lustre client everywhere!
> 
> It might make it easier, but I doubt it will make it easy.
> 
> --Ken

[Lustre-devel] [wc-discuss] Re: [Twg] Lustre and cross-platform portability

[Todd, Allen]

On Friday, March 16, 2012 6:11 AM, Gregory Matthews wrote:
> why bother having a windows client if you lose the performance? We have
> windows based detectors and proprietary windows based analysis software
> that would definitely benefit from higher performance access to lustre
> file systems but replacing existing CIFS servers for no gain seems a bit
> pointless.

From the perspective of my firm, the benefit of a windows lustre client (native or fuse-based), even one that performs at 10% or 20% of the linux client, is the improved scalability that it offers.  Our current solution uses 4 samba gateways per hundred windows servers to achieve acceptable bandwidth, but that bandwidth can be cut to an unacceptable trickle if a large wave of native linux clients simultaneously accesses the filesystem.

We have repeatedly asked our Microsoft HPC contacts to intervene to either fund a native windows client or to get oracle to release the existing one, since scalable storage is a big hole in the Microsoft HPC toolkit.  Obviously, nothing has come out of that.  It seems Microsoft is banking on pNFS, eventually working in this space.

Allen Todd




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[Lustre-devel] [wc-discuss] Re: [Twg] Lustre and cross-platform portability

[Nathan Rutman]

On Mar 16, 2012, at 8:06 AM, Todd, Allen wrote:

> 
> On Friday, March 16, 2012 6:11 AM, Gregory Matthews wrote:
>> why bother having a windows client if you lose the performance? We have
>> windows based detectors and proprietary windows based analysis software
>> that would definitely benefit from higher performance access to lustre
>> file systems but replacing existing CIFS servers for no gain seems a bit
>> pointless.

1. Re-exporting Lustre via CIFS or NFS isn't scalable to very large numbers of Windows clients
2. Re-exporting Lustre via CIFS or NFS can have coherency problems when multiple re-exporters are involved
3. Wide-striped file access would likely have greater performance on a native client than via a re-exported single pipe, for some value of "wide".

> 
>> From the perspective of my firm, the benefit of a windows lustre client (native or fuse-based), even one that performs at 10% or 20% of the linux client, is the improved scalability that it offers.  Our current solution uses 4 samba gateways per hundred windows servers to achieve acceptable bandwidth, but that bandwidth can be cut to an unacceptable trickle if a large wave of native linux clients simultaneously accesses the filesystem.
> 
> We have repeatedly asked our Microsoft HPC contacts to intervene to either fund a native windows client or to get oracle to release the existing one, since scalable storage is a big hole in the Microsoft HPC toolkit.  Obviously, nothing has come out of that.  It seems Microsoft is banking on pNFS, eventually working in this space.
> 
> Allen Todd
> 
> 
> 
> 
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[Lustre-devel] [Twg] Lustre and cross-platform portability

[Ken Hornstein]

>Ken, my apologies for this misstatement.  I guess that my faulty memory
>is to blame for the fact that I didn't recall the MacOS code was made
>publicly available for download.

No problem.  Back when I gave the talk at LUG the source wasn't available
yet due to issues here, but we got that worked out and I was pushing
my changes to a publically available Oracle git repo.  I did send out
email to everyone about that, but I'm sure it was easy to miss.

>I don't think I've ever seen patches sent from you to either Oracle or
>Whamcloud, and unfortunately nobody on our side has had the bandwidth or
>user demand/funding to be pulling such changes either.

Well, I did actually submit patches to Oracle to start the process of
working out at least the portability issues, but I believe that was
when Oracle started to implode the Lustre group so things sort of
stalled.  I'll take 75% of the blame for that if we assign 25% to
Larry Ellison :-)

>This isn't strictly correct.  It would be possible to change the libcfs
>portability layer to export the same API as the Linux kernel to MacOS
>and Windows.  This would simplify getting the client into the Linux
>kernel, but still allow a native client on MacOS.

Well ... that shifts the burden to cross-platform people basically having
to re-implment the Linux kernel.  For some things, that's possible without
too much pain.  For other things, it's not.

--Ken

[Lustre-devel] [EXTERNAL] Lustre and cross-platform portability

[Ward, Lee]

On Mar 14, 2012, at 6:31 PM, Andreas Dilger wrote:

> Whamcloud and EMC are jointly investigating how to be able to contribute the Lustre client code into the upstream Linux kernel.
> 
> As a prerequisite to this, EMC is working to clean up the Lustre client code to better match the kernel coding style, and one of the anticipated major obstacles to upstream kernel submission is the heavy use of code abstraction via libcfs for portability to other operating systems (most notably MacOS and WinNT, but also for liblustre, and potentially *BSD).
> 
> I have no information that the WinNT project will ever be released by Oracle, and as yet there has not been any code released from the MacOS port, so the libcfs portability layer is potentially exacting a high cost in code maintenance and complexity (CLIO being a prime example) for no apparent benefit.  Similarly, the liblustre client needs a portability layer for userspace, and suffers from the same apparent lack of interest or users.
> 
> I'd like to get some feedback from the Lustre community about removing the libcfs abstraction entirely, or possibly restructuring it to look like the Linux kernel API, and having the other platforms code against it as a Linux portability layer, like ZFS on Linux uses the Solaris Portability Layer (SPL) to avoid changing the core ZFS code.  A related topic is whether it would be better to replace all cfs_* functions with standard Linux kernel functions en-masse, or migrate away from cfs_* functions slowly?
> 
> Also, we're planning on deprecating the liblustre client code, due to lack of interest/usage.  The current code is in disrepair, and we've been keeping it around for years without any benefit, and while I was one of the strongest advocates for keeping it in our back pocket in case of future needs, I don't see that materializing in the future.

Relatively true I think, unfortunately. In the past, we provided direct support of Lustre for processes running on light-weight kernels via liblustre. I am aware that DOE/NNSA (more than just Sandia) believes light-weight kernels are the future but it seems that it may be quite a while, yet, before we would be forced into that choice. I don't see NNSA having some sort of heart-attack over your obfuscating liblustre then.

--Lee

> 
> The liblustre code would be left in the tree for now, in case someone from the community is interested to get it working and maintain it, and it may be updated on a best effort basis.  If nobody steps forward to do this work, the liblustre code would be deleted from the development branch in a year or so.
> 
> 
> Unfortunately, after starting this thread, I may not be able to reply to questions in a timely manner due to vacation.  I look forward to a thread that concludes with unanimous agreement from all parties. :-)
> 
> Cheers, Andreas
> --
> Andreas Dilger                       Whamcloud, Inc.
> Principal Lustre Engineer            http://www.whamcloud.com/
> 
> 
> 
> 
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> Lustre-devel mailing list
> Lustre-devel at lists.lustre.org
> http://lists.lustre.org/mailman/listinfo/lustre-devel
> 

[Lustre-devel] [wc-discuss] Re: Lustre and cross-platform portability

[tao.peng at emc.com]

Hi Andreas,

Thank you very much for bringing it up in LUG and getting all these positive support from community.

> -----Original Message-----
> From: Andreas Dilger [mailto:aedilger at gmail.com]
> Sent: Friday, April 27, 2012 7:48 AM
> To: wc-discuss
> Cc: Lustre Devel; lustre-discuss discuss
> Subject: [wc-discuss] Re: Lustre and cross-platform portability
> 
> To revive this thread, based on discussion at the LUG TWG:
> - there was general consensus that cleaning up the Lustre client
>   (and server) code was very desirable to do
> - migrating libcfs to emulate the Linux kernel APIs is also usable.
>   Ken mentioned that there is relatively little conflict between
>   the Linux kernel and the MacOS kernel, and the same for WinNT, so
>   they could use the same function names as Linux without problems.
I created LU-1346 (http://jira.whamcloud.com/browse/LU-1346) to track libcfs cleanup work.

> - there was no objection to converting the Lustre code from spaces
>   to tabs.  My proposal was that build/checkpatch.pl could require
>   tabs immediately, and new patches should be submitted with tabs
>   on all new/modified lines (and optionally all lines on small
>   functions to avoid messy formatting).  This will avoid issues
>   with current patches in flight, and also avoid "git annotate"
>   showing the jumbo replace-all-spaces-with-tabs patch for every
>   line in Lustre, and I think a good fraction of lines will be
>   updated in the next 9-12 months or more.  As we approach the
>   actual time for upstream kernel submission is close, then we can
>   make a final effort to clean up remaining lines in idle code
>   (which will also be unlikely to conflict with existing work).
While tabs are the main coding style difference between Lustre and kernel, there are a few minor change that is needed as well. I think we need to do following to match kernel coding style:
1. Lustre uses expandtab while kernel requires tabs
2. Lustre has vim syntax rules in most source files, which need to be removed
3. Lustre uses a slightly different comment style, which need to be changed to kernel style

I created LU-1347 (http://jira.whamcloud.com/browse/LU-1347) to track the coding style changes.

> 
> There is some hope that the kernel maintainers will not require
> all of the Lustre macros to be removed, but we can deal with this
> on a case-by-case basis.
> 
IMO, we can divide macros to three groups (or more?):
1. Old kernel support macros, kernel maintainers are clear that they won't accept it.
2. For macros to mark out server code, kernel maintainers can accept it. But I think we need to make sure we don't do it too intrusive.
3. Lustre feature macros, we can convert them to Kconfig macros.

Cheers,
Tao
> Cheers, Andreas
> 
> On 2012-03-14, at 7:31 PM, Andreas Dilger wrote:
> > Whamcloud and EMC are jointly investigating how to be able to contribute the Lustre client code into
> the upstream Linux kernel.
> >
> > As a prerequisite to this, EMC is working to clean up the Lustre client code to better match the
> kernel coding style, and one of the anticipated major obstacles to upstream kernel submission is the
> heavy use of code abstraction via libcfs for portability to other operating systems (most notably
> MacOS and WinNT, but also for liblustre, and potentially *BSD).
> >
> > I have no information that the WinNT project will ever be released by Oracle,
> 
> [revised] and the MacOS client needs significant work to update it to the latest version of Lustre,
> and to get it landed into the Lustre repo,
> 
> > so the libcfs portability layer is potentially exacting a high cost in code maintenance and
> complexity (CLIO being a prime example) for no apparent benefit.  Similarly, the liblustre client
> needs a portability layer for userspace, and suffers from the same apparent lack of interest or users.
> >
> > I'd like to get some feedback from the Lustre community about removing the libcfs abstraction
> entirely, or possibly restructuring it to look like the Linux kernel API, and having the other
> platforms code against it as a Linux portability layer, like ZFS on Linux uses the Solaris Portability
> Layer (SPL) to avoid changing the core ZFS code.  A related topic is whether it would be better to
> replace all cfs_* functions with standard Linux kernel functions en-masse, or migrate away from cfs_*
> functions slowly?
> >
> > Also, we're planning on deprecating the liblustre client code, due to lack of interest/usage.  The
> current code is in disrepair, and we've been keeping it around for years without any benefit, and
> while I was one of the strongest advocates for keeping it in our back pocket in case of future needs,
> I don't see that materializing in the future.
> >
> > The liblustre code would be left in the tree for now, in case someone from the community is
> interested to get it working and maintain it, and it may be updated on a best effort basis.  If nobody
> steps forward to do this work, the liblustre code would be deleted from the development branch in a
> year or so.
> >
> >
> > Unfortunately, after starting this thread, I may not be able to reply to questions in a timely
> manner due to vacation.  I look forward to a thread that concludes with unanimous agreement from all
> parties. :-)
> >
> > Cheers, Andreas
> > --
> > Andreas Dilger                       Whamcloud, Inc.
> > Principal Lustre Engineer            http://www.whamcloud.com/
> >
> >
> >
> >
> 
> 
> Cheers, Andreas
> 
> 
> 
> 
> 

[Lustre-devel] [wc-discuss] Re: Lustre and cross-platform portability

[Andreas Dilger]

On 2012-04-26, at 20:23, <tao.peng@emc.com> wrote:
> Thank you very much for bringing it up in LUG and getting all these positive support from community.

Tao,
Yes it does look promising. 

>> To revive this thread, based on discussion at the LUG TWG:
>> - there was general consensus that cleaning up the Lustre client
>>  (and server) code was very desirable to do
>> - migrating libcfs to emulate the Linux kernel APIs is also usable.
>>  Ken mentioned that there is relatively little conflict between
>>  the Linux kernel and the MacOS kernel, and the same for WinNT, so
>>  they could use the same function names as Linux without problems.
> I created LU-1346 (http://jira.whamcloud.com/browse/LU-1346) to track libcfs cleanup work.

OK

>> - there was no objection to converting the Lustre code from spaces
>>  to tabs.  My proposal was that build/checkpatch.pl could require
>>  tabs immediately, and new patches should be submitted with tabs
>>  on all new/modified lines (and optionally all lines on small
>>  functions to avoid messy formatting).  This will avoid issues
>>  with current patches in flight, and also avoid "git annotate"
>>  showing the jumbo replace-all-spaces-with-tabs patch for every
>>  line in Lustre, and I think a good fraction of lines will be
>>  updated in the next 9-12 months or more.  As we approach the
>>  actual time for upstream kernel submission is close, then we can
>>  make a final effort to clean up remaining lines in idle code
>>  (which will also be unlikely to conflict with existing work).
> While tabs are the main coding style difference between Lustre and kernel, there are a few minor change that is needed as well. I think we need to do following to match kernel coding style:
> 1. Lustre uses expandtab while kernel requires tabs

Right.

> 2. Lustre has vim syntax rules in most source files, which need to be removed

They should be replaced with explicit vim and enacts syntax rules that have the kernel indent style instead.  If we could get syntax rules that embodied more of the coding style than just indentation, that would be even better. 

> 3. Lustre uses a slightly different comment style, which need to be changed to kernel style

This is DOxygen style formatting.  I had forgotten about this. We had in the past used this inline formatting for producing some documentation, but I'd need to ask about whether there is still a need for this today. In the meantime, please leave the comment style as-is. 


> I created LU-1347 (http://jira.whamcloud.com/browse/LU-1347) to track the coding style changes.
> 
>> There is some hope that the kernel maintainers will not require
>> all of the Lustre macros to be removed, but we can deal with this
>> on a case-by-case basis.
>> 
> IMO, we can divide macros to three groups (or more?):
> 1. Old kernel support macros, kernel maintainers are clear that they won't accept it.

Yes, but we need to maintain this in the external Lustre tree for years after Lustre would be accepted into mainline, since it would not be in vendor kernels (which a majority of Lustre users would be using). 

For such compat macros we need to make an effort to keep the upstream code as close as possible to the external tree, so patches have the most chance of applying. 

> 2. For macros to mark out server code, kernel maintainers can accept it. But I think we need to make sure we don't do it too intrusive.

Sure, and we also need to make sure the ongoing maintenance effort to keep the code working is not too much either.

I'm OK with incremental patches that more cleanly split the client and server code (structures, headers, etc) if that improves the code structure and readability. 

> 3. Lustre feature macros, we can convert them to Kconfig macros.

Sure. Note that some of them may be obsolete, so before you spend too much time cleaning them up, please post a list to Jira. Maybe some of them can be dropped entirely. 

>> On 2012-03-14, at 7:31 PM, Andreas Dilger wrote:
>>> Whamcloud and EMC are jointly investigating how to be able to contribute the Lustre client code into
>> the upstream Linux kernel.
>>> 
>>> As a prerequisite to this, EMC is working to clean up the Lustre client code to better match the
>> kernel coding style, and one of the anticipated major obstacles to upstream kernel submission is the
>> heavy use of code abstraction via libcfs for portability to other operating systems (most notably
>> MacOS and WinNT, but also for liblustre, and potentially *BSD).
>>> 
>>> I have no information that the WinNT project will ever be released by Oracle,
>> 
>> [revised] and the MacOS client needs significant work to update it to the latest version of Lustre,
>> and to get it landed into the Lustre repo,
>> 
>>> so the libcfs portability layer is potentially exacting a high cost in code maintenance and
>> complexity (CLIO being a prime example) for no apparent benefit.  Similarly, the liblustre client
>> needs a portability layer for userspace, and suffers from the same apparent lack of interest or users.
>>> 
>>> I'd like to get some feedback from the Lustre community about removing the libcfs abstraction
>> entirely, or possibly restructuring it to look like the Linux kernel API, and having the other
>> platforms code against it as a Linux portability layer, like ZFS on Linux uses the Solaris Portability
>> Layer (SPL) to avoid changing the core ZFS code.  A related topic is whether it would be better to
>> replace all cfs_* functions with standard Linux kernel functions en-masse, or migrate away from cfs_*
>> functions slowly?
>>> 
>>> Also, we're planning on deprecating the liblustre client code, due to lack of interest/usage.  The
>> current code is in disrepair, and we've been keeping it around for years without any benefit, and
>> while I was one of the strongest advocates for keeping it in our back pocket in case of future needs,
>> I don't see that materializing in the future.
>>> 
>>> The liblustre code would be left in the tree for now, in case someone from the community is
>> interested to get it working and maintain it, and it may be updated on a best effort basis.  If nobody
>> steps forward to do this work, the liblustre code would be deleted from the development branch in a
>> year or so.
>>> 
>>> 
>>> Unfortunately, after starting this thread, I may not be able to reply to questions in a timely
>> manner due to vacation.  I look forward to a thread that concludes with unanimous agreement from all
>> parties. :-)
>>> 
>>> Cheers, Andreas
>>> --
>>> Andreas Dilger                       Whamcloud, Inc.
>>> Principal Lustre Engineer            http://www.whamcloud.com/
>>> 
>>> 
>>> 
>>> 
>> 
>> 
>> Cheers, Andreas
>> 
>> 
>> 
>> 
>> 
> 

[Lustre-devel] [wc-discuss] Re: Lustre and cross-platform portability

[tao.peng at emc.com]

Hi Andreas,

> -----Original Message-----
> From: Andreas Dilger [mailto:adilger at whamcloud.com]
> Sent: Friday, April 27, 2012 11:54 AM
> To: Peng, Tao
> Cc: <wc-discuss@whamcloud.com>; <lustre-devel@lists.lustre.org>; <lustre-discuss@lists.lustre.org>
> Subject: Re: [wc-discuss] Re: Lustre and cross-platform portability
> 
> On 2012-04-26, at 20:23, <tao.peng@emc.com> wrote:
> > Thank you very much for bringing it up in LUG and getting all these positive support from community.
> 
> Tao,
> Yes it does look promising.
> 
> >> To revive this thread, based on discussion at the LUG TWG:
> >> - there was general consensus that cleaning up the Lustre client
> >>  (and server) code was very desirable to do
> >> - migrating libcfs to emulate the Linux kernel APIs is also usable.
> >>  Ken mentioned that there is relatively little conflict between
> >>  the Linux kernel and the MacOS kernel, and the same for WinNT, so
> >>  they could use the same function names as Linux without problems.
> > I created LU-1346 (http://jira.whamcloud.com/browse/LU-1346) to track libcfs cleanup work.
> 
> OK
> 
> >> - there was no objection to converting the Lustre code from spaces
> >>  to tabs.  My proposal was that build/checkpatch.pl could require
> >>  tabs immediately, and new patches should be submitted with tabs
> >>  on all new/modified lines (and optionally all lines on small
> >>  functions to avoid messy formatting).  This will avoid issues
> >>  with current patches in flight, and also avoid "git annotate"
> >>  showing the jumbo replace-all-spaces-with-tabs patch for every
> >>  line in Lustre, and I think a good fraction of lines will be
> >>  updated in the next 9-12 months or more.  As we approach the
> >>  actual time for upstream kernel submission is close, then we can
> >>  make a final effort to clean up remaining lines in idle code
> >>  (which will also be unlikely to conflict with existing work).
> > While tabs are the main coding style difference between Lustre and kernel, there are a few minor
> change that is needed as well. I think we need to do following to match kernel coding style:
> > 1. Lustre uses expandtab while kernel requires tabs
> 
> Right.
> 
> > 2. Lustre has vim syntax rules in most source files, which need to be removed
> 
> They should be replaced with explicit vim and enacts syntax rules that have the kernel indent style
> instead.  If we could get syntax rules that embodied more of the coding style than just indentation,
> that would be even better.
> 
But we do need to remove them before submitting to kernel, right? And if we enforce checkpatch.pl on every patch applied, IMHO there is not much benefit to have syntax rules on every file, not to mention that it is explicitly forbidden in kernel coding style (Documentation/CodingStyle, Chapter 18:  Editor modelines and other cruft).

BTW, instead of just enabling tabs, how about changing checkpatch.pl to latest kernel version to make sure all future patches follow kernel coding styles?

> > 3. Lustre uses a slightly different comment style, which need to be changed to kernel style
> 
> This is DOxygen style formatting.  I had forgotten about this. We had in the past used this inline
> formatting for producing some documentation, but I'd need to ask about whether there is still a need
> for this today. In the meantime, please leave the comment style as-is.
> 
OK.

> 
> > I created LU-1347 (http://jira.whamcloud.com/browse/LU-1347) to track the coding style changes.
> >
> >> There is some hope that the kernel maintainers will not require
> >> all of the Lustre macros to be removed, but we can deal with this
> >> on a case-by-case basis.
> >>
> > IMO, we can divide macros to three groups (or more?):
> > 1. Old kernel support macros, kernel maintainers are clear that they won't accept it.
> 
> Yes, but we need to maintain this in the external Lustre tree for years after Lustre would be accepted
> into mainline, since it would not be in vendor kernels (which a majority of Lustre users would be
> using).
> 
> For such compat macros we need to make an effort to keep the upstream code as close as possible to the
> external tree, so patches have the most chance of applying.
> 
I agree. We should minimize maintenance effort for it. And as you suggested, we can put as many of these compat macros into places like linux_compat.h as possible and have Lustre code use latest kernel APIs, so that most maintenance effort for old kernel support would be to keep linux_compat.h uptodate. For compact macros that cannot be cleaned up this way, we will have to pay the extra efforts. And of course the cleanup will be an incremental process and macros will be dealt with in a case-by-case basis.

> > 2. For macros to mark out server code, kernel maintainers can accept it. But I think we need to make
> sure we don't do it too intrusive.
> 
> Sure, and we also need to make sure the ongoing maintenance effort to keep the code working is not too
> much either.
> 
> I'm OK with incremental patches that more cleanly split the client and server code (structures,
> headers, etc) if that improves the code structure and readability.
> 
I agree that we can do some incremental patches to split client and server code. But I hope we only do it when it is trivial and simple. IMHO if we want to entirely split client/server code, it will be large code structure change. Since kernel maintainers already agreed on HAVE_SERVER_SUPPORT, how about we keep going that way at first? And we can make some split wherever it is simple and clear. And we will try to make code structure as clear/readable as possible. Then when we summit code for review, if kernel maintainers still don't like it, we do the large restructuring. Does it make sense?

> > 3. Lustre feature macros, we can convert them to Kconfig macros.
> 
> Sure. Note that some of them may be obsolete, so before you spend too much time cleaning them up,
> please post a list to Jira. Maybe some of them can be dropped entirely.
> 
Thanks. I will do as you suggested when it comes to converting them to Kconfig macros.

Cheers,
Tao

> >> On 2012-03-14, at 7:31 PM, Andreas Dilger wrote:
> >>> Whamcloud and EMC are jointly investigating how to be able to contribute the Lustre client code
> into
> >> the upstream Linux kernel.
> >>>
> >>> As a prerequisite to this, EMC is working to clean up the Lustre client code to better match the
> >> kernel coding style, and one of the anticipated major obstacles to upstream kernel submission is
> the
> >> heavy use of code abstraction via libcfs for portability to other operating systems (most notably
> >> MacOS and WinNT, but also for liblustre, and potentially *BSD).
> >>>
> >>> I have no information that the WinNT project will ever be released by Oracle,
> >>
> >> [revised] and the MacOS client needs significant work to update it to the latest version of Lustre,
> >> and to get it landed into the Lustre repo,
> >>
> >>> so the libcfs portability layer is potentially exacting a high cost in code maintenance and
> >> complexity (CLIO being a prime example) for no apparent benefit.  Similarly, the liblustre client
> >> needs a portability layer for userspace, and suffers from the same apparent lack of interest or
> users.
> >>>
> >>> I'd like to get some feedback from the Lustre community about removing the libcfs abstraction
> >> entirely, or possibly restructuring it to look like the Linux kernel API, and having the other
> >> platforms code against it as a Linux portability layer, like ZFS on Linux uses the Solaris
> Portability
> >> Layer (SPL) to avoid changing the core ZFS code.  A related topic is whether it would be better to
> >> replace all cfs_* functions with standard Linux kernel functions en-masse, or migrate away from
> cfs_*
> >> functions slowly?
> >>>
> >>> Also, we're planning on deprecating the liblustre client code, due to lack of interest/usage.  The
> >> current code is in disrepair, and we've been keeping it around for years without any benefit, and
> >> while I was one of the strongest advocates for keeping it in our back pocket in case of future
> needs,
> >> I don't see that materializing in the future.
> >>>
> >>> The liblustre code would be left in the tree for now, in case someone from the community is
> >> interested to get it working and maintain it, and it may be updated on a best effort basis.  If
> nobody
> >> steps forward to do this work, the liblustre code would be deleted from the development branch in a
> >> year or so.
> >>>
> >>>
> >>> Unfortunately, after starting this thread, I may not be able to reply to questions in a timely
> >> manner due to vacation.  I look forward to a thread that concludes with unanimous agreement from
> all
> >> parties. :-)
> >>>
> >>> Cheers, Andreas
> >>> --
> >>> Andreas Dilger                       Whamcloud, Inc.
> >>> Principal Lustre Engineer            http://www.whamcloud.com/
> >>>
> >>>
> >>>
> >>>
> >>
> >>
> >> Cheers, Andreas
> >>
> >>
> >>
> >>
> >>
> >

[Lustre-devel] [Lustre-discuss] [wc-discuss] Re: Lustre and cross-platform portability

[Roman Grigoryev]

Tao,Andreas,all,

What is your plan in test/test framework changes from the point of view
of integration to kernel? As i know, kernel.org has his own test
infrastructure and his own test framework.

I'm sorry if it's incorrect place for this question.

Thanks,
	Roman

On 04/27/2012 02:15 PM, tao.peng at emc.com wrote:
> Hi Andreas,
> 
>> -----Original Message-----
>> From: Andreas Dilger [mailto:adilger at whamcloud.com]
>> Sent: Friday, April 27, 2012 11:54 AM
>> To: Peng, Tao
>> Cc: <wc-discuss@whamcloud.com>; <lustre-devel@lists.lustre.org>; <lustre-discuss@lists.lustre.org>
>> Subject: Re: [wc-discuss] Re: Lustre and cross-platform portability
>>
>> On 2012-04-26, at 20:23, <tao.peng@emc.com> wrote:
>>> Thank you very much for bringing it up in LUG and getting all these positive support from community.
>>
>> Tao,
>> Yes it does look promising.
>>
>>>> To revive this thread, based on discussion at the LUG TWG:
>>>> - there was general consensus that cleaning up the Lustre client
>>>>  (and server) code was very desirable to do
>>>> - migrating libcfs to emulate the Linux kernel APIs is also usable.
>>>>  Ken mentioned that there is relatively little conflict between
>>>>  the Linux kernel and the MacOS kernel, and the same for WinNT, so
>>>>  they could use the same function names as Linux without problems.
>>> I created LU-1346 (http://jira.whamcloud.com/browse/LU-1346) to track libcfs cleanup work.
>>
>> OK
>>
>>>> - there was no objection to converting the Lustre code from spaces
>>>>  to tabs.  My proposal was that build/checkpatch.pl could require
>>>>  tabs immediately, and new patches should be submitted with tabs
>>>>  on all new/modified lines (and optionally all lines on small
>>>>  functions to avoid messy formatting).  This will avoid issues
>>>>  with current patches in flight, and also avoid "git annotate"
>>>>  showing the jumbo replace-all-spaces-with-tabs patch for every
>>>>  line in Lustre, and I think a good fraction of lines will be
>>>>  updated in the next 9-12 months or more.  As we approach the
>>>>  actual time for upstream kernel submission is close, then we can
>>>>  make a final effort to clean up remaining lines in idle code
>>>>  (which will also be unlikely to conflict with existing work).
>>> While tabs are the main coding style difference between Lustre and kernel, there are a few minor
>> change that is needed as well. I think we need to do following to match kernel coding style:
>>> 1. Lustre uses expandtab while kernel requires tabs
>>
>> Right.
>>
>>> 2. Lustre has vim syntax rules in most source files, which need to be removed
>>
>> They should be replaced with explicit vim and enacts syntax rules that have the kernel indent style
>> instead.  If we could get syntax rules that embodied more of the coding style than just indentation,
>> that would be even better.
>>
> But we do need to remove them before submitting to kernel, right? And if we enforce checkpatch.pl on every patch applied, IMHO there is not much benefit to have syntax rules on every file, not to mention that it is explicitly forbidden in kernel coding style (Documentation/CodingStyle, Chapter 18:  Editor modelines and other cruft).
> 
> BTW, instead of just enabling tabs, how about changing checkpatch.pl to latest kernel version to make sure all future patches follow kernel coding styles?
> 
>>> 3. Lustre uses a slightly different comment style, which need to be changed to kernel style
>>
>> This is DOxygen style formatting.  I had forgotten about this. We had in the past used this inline
>> formatting for producing some documentation, but I'd need to ask about whether there is still a need
>> for this today. In the meantime, please leave the comment style as-is.
>>
> OK.
> 
>>
>>> I created LU-1347 (http://jira.whamcloud.com/browse/LU-1347) to track the coding style changes.
>>>
>>>> There is some hope that the kernel maintainers will not require
>>>> all of the Lustre macros to be removed, but we can deal with this
>>>> on a case-by-case basis.
>>>>
>>> IMO, we can divide macros to three groups (or more?):
>>> 1. Old kernel support macros, kernel maintainers are clear that they won't accept it.
>>
>> Yes, but we need to maintain this in the external Lustre tree for years after Lustre would be accepted
>> into mainline, since it would not be in vendor kernels (which a majority of Lustre users would be
>> using).
>>
>> For such compat macros we need to make an effort to keep the upstream code as close as possible to the
>> external tree, so patches have the most chance of applying.
>>
> I agree. We should minimize maintenance effort for it. And as you suggested, we can put as many of these compat macros into places like linux_compat.h as possible and have Lustre code use latest kernel APIs, so that most maintenance effort for old kernel support would be to keep linux_compat.h uptodate. For compact macros that cannot be cleaned up this way, we will have to pay the extra efforts. And of course the cleanup will be an incremental process and macros will be dealt with in a case-by-case basis.
> 
>>> 2. For macros to mark out server code, kernel maintainers can accept it. But I think we need to make
>> sure we don't do it too intrusive.
>>
>> Sure, and we also need to make sure the ongoing maintenance effort to keep the code working is not too
>> much either.
>>
>> I'm OK with incremental patches that more cleanly split the client and server code (structures,
>> headers, etc) if that improves the code structure and readability.
>>
> I agree that we can do some incremental patches to split client and server code. But I hope we only do it when it is trivial and simple. IMHO if we want to entirely split client/server code, it will be large code structure change. Since kernel maintainers already agreed on HAVE_SERVER_SUPPORT, how about we keep going that way at first? And we can make some split wherever it is simple and clear. And we will try to make code structure as clear/readable as possible. Then when we summit code for review, if kernel maintainers still don't like it, we do the large restructuring. Does it make sense?
> 
>>> 3. Lustre feature macros, we can convert them to Kconfig macros.
>>
>> Sure. Note that some of them may be obsolete, so before you spend too much time cleaning them up,
>> please post a list to Jira. Maybe some of them can be dropped entirely.
>>
> Thanks. I will do as you suggested when it comes to converting them to Kconfig macros.
> 
> Cheers,
> Tao
> 
>>>> On 2012-03-14, at 7:31 PM, Andreas Dilger wrote:
>>>>> Whamcloud and EMC are jointly investigating how to be able to contribute the Lustre client code
>> into
>>>> the upstream Linux kernel.
>>>>>
>>>>> As a prerequisite to this, EMC is working to clean up the Lustre client code to better match the
>>>> kernel coding style, and one of the anticipated major obstacles to upstream kernel submission is
>> the
>>>> heavy use of code abstraction via libcfs for portability to other operating systems (most notably
>>>> MacOS and WinNT, but also for liblustre, and potentially *BSD).
>>>>>
>>>>> I have no information that the WinNT project will ever be released by Oracle,
>>>>
>>>> [revised] and the MacOS client needs significant work to update it to the latest version of Lustre,
>>>> and to get it landed into the Lustre repo,
>>>>
>>>>> so the libcfs portability layer is potentially exacting a high cost in code maintenance and
>>>> complexity (CLIO being a prime example) for no apparent benefit.  Similarly, the liblustre client
>>>> needs a portability layer for userspace, and suffers from the same apparent lack of interest or
>> users.
>>>>>
>>>>> I'd like to get some feedback from the Lustre community about removing the libcfs abstraction
>>>> entirely, or possibly restructuring it to look like the Linux kernel API, and having the other
>>>> platforms code against it as a Linux portability layer, like ZFS on Linux uses the Solaris
>> Portability
>>>> Layer (SPL) to avoid changing the core ZFS code.  A related topic is whether it would be better to
>>>> replace all cfs_* functions with standard Linux kernel functions en-masse, or migrate away from
>> cfs_*
>>>> functions slowly?
>>>>>
>>>>> Also, we're planning on deprecating the liblustre client code, due to lack of interest/usage.  The
>>>> current code is in disrepair, and we've been keeping it around for years without any benefit, and
>>>> while I was one of the strongest advocates for keeping it in our back pocket in case of future
>> needs,
>>>> I don't see that materializing in the future.
>>>>>
>>>>> The liblustre code would be left in the tree for now, in case someone from the community is
>>>> interested to get it working and maintain it, and it may be updated on a best effort basis.  If
>> nobody
>>>> steps forward to do this work, the liblustre code would be deleted from the development branch in a
>>>> year or so.
>>>>>
>>>>>
>>>>> Unfortunately, after starting this thread, I may not be able to reply to questions in a timely
>>>> manner due to vacation.  I look forward to a thread that concludes with unanimous agreement from
>> all
>>>> parties. :-)
>>>>>
>>>>> Cheers, Andreas
>>>>> --
>>>>> Andreas Dilger                       Whamcloud, Inc.
>>>>> Principal Lustre Engineer            http://www.whamcloud.com/
>>>>>
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>> Cheers, Andreas
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
> 
> _______________________________________________
> Lustre-discuss mailing list
> Lustre-discuss at lists.lustre.org
> http://lists.lustre.org/mailman/listinfo/lustre-discuss

[Lustre-devel] [Lustre-discuss] [wc-discuss] Re: Lustre and cross-platform portability

[tao.peng at emc.com]

Hi Roman,

Not sure if I misunderstand your question, but we won't push lustre/tests/* files to kernel. We only push client code and any tests will be executed out side of kernel.

Cheers,
Tao
________________________________________
From: Roman Grigoryev [Roman_Grigoryev at xyratex.com]
Sent: Friday, April 27, 2012 6:25 PM
To: Peng, Tao
Cc: adilger at whamcloud.com; wc-discuss at whamcloud.com; lustre-discuss at lists.lustre.org; lustre-devel at lists.lustre.org
Subject: Re: [Lustre-discuss] [wc-discuss] Re: Lustre and cross-platform portability

Tao,Andreas,all,

What is your plan in test/test framework changes from the point of view
of integration to kernel? As i know, kernel.org has his own test
infrastructure and his own test framework.

I'm sorry if it's incorrect place for this question.

Thanks,
        Roman

On 04/27/2012 02:15 PM, tao.peng at emc.com wrote:
> Hi Andreas,
>
>> -----Original Message-----
>> From: Andreas Dilger [mailto:adilger at whamcloud.com]
>> Sent: Friday, April 27, 2012 11:54 AM
>> To: Peng, Tao
>> Cc: <wc-discuss@whamcloud.com>; <lustre-devel@lists.lustre.org>; <lustre-discuss@lists.lustre.org>
>> Subject: Re: [wc-discuss] Re: Lustre and cross-platform portability
>>
>> On 2012-04-26, at 20:23, <tao.peng@emc.com> wrote:
>>> Thank you very much for bringing it up in LUG and getting all these positive support from community.
>>
>> Tao,
>> Yes it does look promising.
>>
>>>> To revive this thread, based on discussion at the LUG TWG:
>>>> - there was general consensus that cleaning up the Lustre client
>>>>  (and server) code was very desirable to do
>>>> - migrating libcfs to emulate the Linux kernel APIs is also usable.
>>>>  Ken mentioned that there is relatively little conflict between
>>>>  the Linux kernel and the MacOS kernel, and the same for WinNT, so
>>>>  they could use the same function names as Linux without problems.
>>> I created LU-1346 (http://jira.whamcloud.com/browse/LU-1346) to track libcfs cleanup work.
>>
>> OK
>>
>>>> - there was no objection to converting the Lustre code from spaces
>>>>  to tabs.  My proposal was that build/checkpatch.pl could require
>>>>  tabs immediately, and new patches should be submitted with tabs
>>>>  on all new/modified lines (and optionally all lines on small
>>>>  functions to avoid messy formatting).  This will avoid issues
>>>>  with current patches in flight, and also avoid "git annotate"
>>>>  showing the jumbo replace-all-spaces-with-tabs patch for every
>>>>  line in Lustre, and I think a good fraction of lines will be
>>>>  updated in the next 9-12 months or more.  As we approach the
>>>>  actual time for upstream kernel submission is close, then we can
>>>>  make a final effort to clean up remaining lines in idle code
>>>>  (which will also be unlikely to conflict with existing work).
>>> While tabs are the main coding style difference between Lustre and kernel, there are a few minor
>> change that is needed as well. I think we need to do following to match kernel coding style:
>>> 1. Lustre uses expandtab while kernel requires tabs
>>
>> Right.
>>
>>> 2. Lustre has vim syntax rules in most source files, which need to be removed
>>
>> They should be replaced with explicit vim and enacts syntax rules that have the kernel indent style
>> instead.  If we could get syntax rules that embodied more of the coding style than just indentation,
>> that would be even better.
>>
> But we do need to remove them before submitting to kernel, right? And if we enforce checkpatch.pl on every patch applied, IMHO there is not much benefit to have syntax rules on every file, not to mention that it is explicitly forbidden in kernel coding style (Documentation/CodingStyle, Chapter 18:  Editor modelines and other cruft).
>
> BTW, instead of just enabling tabs, how about changing checkpatch.pl to latest kernel version to make sure all future patches follow kernel coding styles?
>
>>> 3. Lustre uses a slightly different comment style, which need to be changed to kernel style
>>
>> This is DOxygen style formatting.  I had forgotten about this. We had in the past used this inline
>> formatting for producing some documentation, but I'd need to ask about whether there is still a need
>> for this today. In the meantime, please leave the comment style as-is.
>>
> OK.
>
>>
>>> I created LU-1347 (http://jira.whamcloud.com/browse/LU-1347) to track the coding style changes.
>>>
>>>> There is some hope that the kernel maintainers will not require
>>>> all of the Lustre macros to be removed, but we can deal with this
>>>> on a case-by-case basis.
>>>>
>>> IMO, we can divide macros to three groups (or more?):
>>> 1. Old kernel support macros, kernel maintainers are clear that they won't accept it.
>>
>> Yes, but we need to maintain this in the external Lustre tree for years after Lustre would be accepted
>> into mainline, since it would not be in vendor kernels (which a majority of Lustre users would be
>> using).
>>
>> For such compat macros we need to make an effort to keep the upstream code as close as possible to the
>> external tree, so patches have the most chance of applying.
>>
> I agree. We should minimize maintenance effort for it. And as you suggested, we can put as many of these compat macros into places like linux_compat.h as possible and have Lustre code use latest kernel APIs, so that most maintenance effort for old kernel support would be to keep linux_compat.h uptodate. For compact macros that cannot be cleaned up this way, we will have to pay the extra efforts. And of course the cleanup will be an incremental process and macros will be dealt with in a case-by-case basis.
>
>>> 2. For macros to mark out server code, kernel maintainers can accept it. But I think we need to make
>> sure we don't do it too intrusive.
>>
>> Sure, and we also need to make sure the ongoing maintenance effort to keep the code working is not too
>> much either.
>>
>> I'm OK with incremental patches that more cleanly split the client and server code (structures,
>> headers, etc) if that improves the code structure and readability.
>>
> I agree that we can do some incremental patches to split client and server code. But I hope we only do it when it is trivial and simple. IMHO if we want to entirely split client/server code, it will be large code structure change. Since kernel maintainers already agreed on HAVE_SERVER_SUPPORT, how about we keep going that way at first? And we can make some split wherever it is simple and clear. And we will try to make code structure as clear/readable as possible. Then when we summit code for review, if kernel maintainers still don't like it, we do the large restructuring. Does it make sense?
>
>>> 3. Lustre feature macros, we can convert them to Kconfig macros.
>>
>> Sure. Note that some of them may be obsolete, so before you spend too much time cleaning them up,
>> please post a list to Jira. Maybe some of them can be dropped entirely.
>>
> Thanks. I will do as you suggested when it comes to converting them to Kconfig macros.
>
> Cheers,
> Tao
>
>>>> On 2012-03-14, at 7:31 PM, Andreas Dilger wrote:
>>>>> Whamcloud and EMC are jointly investigating how to be able to contribute the Lustre client code
>> into
>>>> the upstream Linux kernel.
>>>>>
>>>>> As a prerequisite to this, EMC is working to clean up the Lustre client code to better match the
>>>> kernel coding style, and one of the anticipated major obstacles to upstream kernel submission is
>> the
>>>> heavy use of code abstraction via libcfs for portability to other operating systems (most notably
>>>> MacOS and WinNT, but also for liblustre, and potentially *BSD).
>>>>>
>>>>> I have no information that the WinNT project will ever be released by Oracle,
>>>>
>>>> [revised] and the MacOS client needs significant work to update it to the latest version of Lustre,
>>>> and to get it landed into the Lustre repo,
>>>>
>>>>> so the libcfs portability layer is potentially exacting a high cost in code maintenance and
>>>> complexity (CLIO being a prime example) for no apparent benefit.  Similarly, the liblustre client
>>>> needs a portability layer for userspace, and suffers from the same apparent lack of interest or
>> users.
>>>>>
>>>>> I'd like to get some feedback from the Lustre community about removing the libcfs abstraction
>>>> entirely, or possibly restructuring it to look like the Linux kernel API, and having the other
>>>> platforms code against it as a Linux portability layer, like ZFS on Linux uses the Solaris
>> Portability
>>>> Layer (SPL) to avoid changing the core ZFS code.  A related topic is whether it would be better to
>>>> replace all cfs_* functions with standard Linux kernel functions en-masse, or migrate away from
>> cfs_*
>>>> functions slowly?
>>>>>
>>>>> Also, we're planning on deprecating the liblustre client code, due to lack of interest/usage.  The
>>>> current code is in disrepair, and we've been keeping it around for years without any benefit, and
>>>> while I was one of the strongest advocates for keeping it in our back pocket in case of future
>> needs,
>>>> I don't see that materializing in the future.
>>>>>
>>>>> The liblustre code would be left in the tree for now, in case someone from the community is
>>>> interested to get it working and maintain it, and it may be updated on a best effort basis.  If
>> nobody
>>>> steps forward to do this work, the liblustre code would be deleted from the development branch in a
>>>> year or so.
>>>>>
>>>>>
>>>>> Unfortunately, after starting this thread, I may not be able to reply to questions in a timely
>>>> manner due to vacation.  I look forward to a thread that concludes with unanimous agreement from
>> all
>>>> parties. :-)
>>>>>
>>>>> Cheers, Andreas
>>>>> --
>>>>> Andreas Dilger                       Whamcloud, Inc.
>>>>> Principal Lustre Engineer            http://www.whamcloud.com/
>>>>>
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>> Cheers, Andreas
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>
> _______________________________________________
> Lustre-discuss mailing list
> Lustre-discuss at lists.lustre.org
> http://lists.lustre.org/mailman/listinfo/lustre-discuss

[Lustre-devel] [Lustre-discuss] [wc-discuss] Re: Lustre and cross-platform portability

[Roman Grigoryev]

Hi Tao,

I'm not know how linux developers approve patches. But, logically,
because Lustre is big enough project and use kernel subsystems then it
should be tested after kernel changes on kernel side too. In  other case
(without testing) we can observer situation when Lustre built ok but
doesn't work.

I don't know goal of adding Lustre to kernel and, possible,this
situation could be acceptable from your point of view.

Thanks,
	Roman

On 04/27/2012 04:33 PM, tao.peng at emc.com wrote:
> Hi Roman,
> 
> Not sure if I misunderstand your question, but we won't push lustre/tests/* files to kernel.
>We only push client code and any tests will be executed out side of kernel
> 
> Cheers,
> Tao
> ________________________________________
> From: Roman Grigoryev [Roman_Grigoryev at xyratex.com]
> Sent: Friday, April 27, 2012 6:25 PM
> To: Peng, Tao
> Cc: adilger at whamcloud.com; wc-discuss at whamcloud.com; lustre-discuss at lists.lustre.org; lustre-devel at lists.lustre.org
> Subject: Re: [Lustre-discuss] [wc-discuss] Re: Lustre and cross-platform portability
> 
> Tao,Andreas,all,
> 
> What is your plan in test/test framework changes from the point of view
> of integration to kernel? As i know, kernel.org has his own test
> infrastructure and his own test framework.
> 
> I'm sorry if it's incorrect place for this question.
> 
> Thanks,
>         Roman
> 
> On 04/27/2012 02:15 PM, tao.peng at emc.com wrote:
>> Hi Andreas,
>>
>>> -----Original Message-----
>>> From: Andreas Dilger [mailto:adilger at whamcloud.com]
>>> Sent: Friday, April 27, 2012 11:54 AM
>>> To: Peng, Tao
>>> Cc: <wc-discuss@whamcloud.com>; <lustre-devel@lists.lustre.org>; <lustre-discuss@lists.lustre.org>
>>> Subject: Re: [wc-discuss] Re: Lustre and cross-platform portability
>>>
>>> On 2012-04-26, at 20:23, <tao.peng@emc.com> wrote:
>>>> Thank you very much for bringing it up in LUG and getting all these positive support from community.
>>>
>>> Tao,
>>> Yes it does look promising.
>>>
>>>>> To revive this thread, based on discussion at the LUG TWG:
>>>>> - there was general consensus that cleaning up the Lustre client
>>>>>  (and server) code was very desirable to do
>>>>> - migrating libcfs to emulate the Linux kernel APIs is also usable.
>>>>>  Ken mentioned that there is relatively little conflict between
>>>>>  the Linux kernel and the MacOS kernel, and the same for WinNT, so
>>>>>  they could use the same function names as Linux without problems.
>>>> I created LU-1346 (http://jira.whamcloud.com/browse/LU-1346) to track libcfs cleanup work.
>>>
>>> OK
>>>
>>>>> - there was no objection to converting the Lustre code from spaces
>>>>>  to tabs.  My proposal was that build/checkpatch.pl could require
>>>>>  tabs immediately, and new patches should be submitted with tabs
>>>>>  on all new/modified lines (and optionally all lines on small
>>>>>  functions to avoid messy formatting).  This will avoid issues
>>>>>  with current patches in flight, and also avoid "git annotate"
>>>>>  showing the jumbo replace-all-spaces-with-tabs patch for every
>>>>>  line in Lustre, and I think a good fraction of lines will be
>>>>>  updated in the next 9-12 months or more.  As we approach the
>>>>>  actual time for upstream kernel submission is close, then we can
>>>>>  make a final effort to clean up remaining lines in idle code
>>>>>  (which will also be unlikely to conflict with existing work).
>>>> While tabs are the main coding style difference between Lustre and kernel, there are a few minor
>>> change that is needed as well. I think we need to do following to match kernel coding style:
>>>> 1. Lustre uses expandtab while kernel requires tabs
>>>
>>> Right.
>>>
>>>> 2. Lustre has vim syntax rules in most source files, which need to be removed
>>>
>>> They should be replaced with explicit vim and enacts syntax rules that have the kernel indent style
>>> instead.  If we could get syntax rules that embodied more of the coding style than just indentation,
>>> that would be even better.
>>>
>> But we do need to remove them before submitting to kernel, right? And if we enforce checkpatch.pl on every patch applied, IMHO there is not much benefit to have syntax rules on every file, not to mention that it is explicitly forbidden in kernel coding style (Documentation/CodingStyle, Chapter 18:  Editor modelines and other cruft).
>>
>> BTW, instead of just enabling tabs, how about changing checkpatch.pl to latest kernel version to make sure all future patches follow kernel coding styles?
>>
>>>> 3. Lustre uses a slightly different comment style, which need to be changed to kernel style
>>>
>>> This is DOxygen style formatting.  I had forgotten about this. We had in the past used this inline
>>> formatting for producing some documentation, but I'd need to ask about whether there is still a need
>>> for this today. In the meantime, please leave the comment style as-is.
>>>
>> OK.
>>
>>>
>>>> I created LU-1347 (http://jira.whamcloud.com/browse/LU-1347) to track the coding style changes.
>>>>
>>>>> There is some hope that the kernel maintainers will not require
>>>>> all of the Lustre macros to be removed, but we can deal with this
>>>>> on a case-by-case basis.
>>>>>
>>>> IMO, we can divide macros to three groups (or more?):
>>>> 1. Old kernel support macros, kernel maintainers are clear that they won't accept it.
>>>
>>> Yes, but we need to maintain this in the external Lustre tree for years after Lustre would be accepted
>>> into mainline, since it would not be in vendor kernels (which a majority of Lustre users would be
>>> using).
>>>
>>> For such compat macros we need to make an effort to keep the upstream code as close as possible to the
>>> external tree, so patches have the most chance of applying.
>>>
>> I agree. We should minimize maintenance effort for it. And as you suggested, we can put as many of these compat macros into places like linux_compat.h as possible and have Lustre code use latest kernel APIs, so that most maintenance effort for old kernel support would be to keep linux_compat.h uptodate. For compact macros that cannot be cleaned up this way, we will have to pay the extra efforts. And of course the cleanup will be an incremental process and macros will be dealt with in a case-by-case basis.
>>
>>>> 2. For macros to mark out server code, kernel maintainers can accept it. But I think we need to make
>>> sure we don't do it too intrusive.
>>>
>>> Sure, and we also need to make sure the ongoing maintenance effort to keep the code working is not too
>>> much either.
>>>
>>> I'm OK with incremental patches that more cleanly split the client and server code (structures,
>>> headers, etc) if that improves the code structure and readability.
>>>
>> I agree that we can do some incremental patches to split client and server code. But I hope we only do it when it is trivial and simple. IMHO if we want to entirely split client/server code, it will be large code structure change. Since kernel maintainers already agreed on HAVE_SERVER_SUPPORT, how about we keep going that way at first? And we can make some split wherever it is simple and clear. And we will try to make code structure as clear/readable as possible. Then when we summit code for review, if kernel maintainers still don't like it, we do the large restructuring. Does it make sense?
>>
>>>> 3. Lustre feature macros, we can convert them to Kconfig macros.
>>>
>>> Sure. Note that some of them may be obsolete, so before you spend too much time cleaning them up,
>>> please post a list to Jira. Maybe some of them can be dropped entirely.
>>>
>> Thanks. I will do as you suggested when it comes to converting them to Kconfig macros.
>>
>> Cheers,
>> Tao
>>
>>>>> On 2012-03-14, at 7:31 PM, Andreas Dilger wrote:
>>>>>> Whamcloud and EMC are jointly investigating how to be able to contribute the Lustre client code
>>> into
>>>>> the upstream Linux kernel.
>>>>>>
>>>>>> As a prerequisite to this, EMC is working to clean up the Lustre client code to better match the
>>>>> kernel coding style, and one of the anticipated major obstacles to upstream kernel submission is
>>> the
>>>>> heavy use of code abstraction via libcfs for portability to other operating systems (most notably
>>>>> MacOS and WinNT, but also for liblustre, and potentially *BSD).
>>>>>>
>>>>>> I have no information that the WinNT project will ever be released by Oracle,
>>>>>
>>>>> [revised] and the MacOS client needs significant work to update it to the latest version of Lustre,
>>>>> and to get it landed into the Lustre repo,
>>>>>
>>>>>> so the libcfs portability layer is potentially exacting a high cost in code maintenance and
>>>>> complexity (CLIO being a prime example) for no apparent benefit.  Similarly, the liblustre client
>>>>> needs a portability layer for userspace, and suffers from the same apparent lack of interest or
>>> users.
>>>>>>
>>>>>> I'd like to get some feedback from the Lustre community about removing the libcfs abstraction
>>>>> entirely, or possibly restructuring it to look like the Linux kernel API, and having the other
>>>>> platforms code against it as a Linux portability layer, like ZFS on Linux uses the Solaris
>>> Portability
>>>>> Layer (SPL) to avoid changing the core ZFS code.  A related topic is whether it would be better to
>>>>> replace all cfs_* functions with standard Linux kernel functions en-masse, or migrate away from
>>> cfs_*
>>>>> functions slowly?
>>>>>>
>>>>>> Also, we're planning on deprecating the liblustre client code, due to lack of interest/usage.  The
>>>>> current code is in disrepair, and we've been keeping it around for years without any benefit, and
>>>>> while I was one of the strongest advocates for keeping it in our back pocket in case of future
>>> needs,
>>>>> I don't see that materializing in the future.
>>>>>>
>>>>>> The liblustre code would be left in the tree for now, in case someone from the community is
>>>>> interested to get it working and maintain it, and it may be updated on a best effort basis.  If
>>> nobody
>>>>> steps forward to do this work, the liblustre code would be deleted from the development branch in a
>>>>> year or so.
>>>>>>
>>>>>>
>>>>>> Unfortunately, after starting this thread, I may not be able to reply to questions in a timely
>>>>> manner due to vacation.  I look forward to a thread that concludes with unanimous agreement from
>>> all
>>>>> parties. :-)
>>>>>>
>>>>>> Cheers, Andreas
>>>>>> --
>>>>>> Andreas Dilger                       Whamcloud, Inc.
>>>>>> Principal Lustre Engineer            http://www.whamcloud.com/
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>> Cheers, Andreas
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>
>>
>> _______________________________________________
>> Lustre-discuss mailing list
>> Lustre-discuss at lists.lustre.org
>> http://lists.lustre.org/mailman/listinfo/lustre-discuss
> 
> 

[Lustre-devel] [Lustre-discuss] [wc-discuss] Re: Lustre and cross-platform portability

[tao.peng at emc.com]

> -----Original Message-----
> From: Roman Grigoryev [mailto:Roman_Grigoryev at xyratex.com]
> Sent: Thursday, May 03, 2012 5:45 PM
> To: Peng, Tao
> Cc: adilger at whamcloud.com; wc-discuss at whamcloud.com; lustre-discuss at lists.lustre.org; lustre-
> devel at lists.lustre.org
> Subject: Re: [Lustre-discuss] [wc-discuss] Re: Lustre and cross-platform portability
> 
> Hi Tao,
Hi Roman,

> 
> I'm not know how linux developers approve patches. But, logically,
> because Lustre is big enough project and use kernel subsystems then it
> should be tested after kernel changes on kernel side too. In  other case
> (without testing) we can observer situation when Lustre built ok but
> doesn't work.
Now I see what you are worrying about. All code submitted to Linux kernel will be tested, and also patches later merged. It's just that kernel is a different place than Lustre git tree. We are not allowed to put test scripts into kernel tree. So all test code will remain in Whamcloud tree. But we will run the same tests against kernel code as well. One of our goal is to keep kernel client code in sync with Whamcloud tree as much as possible, so that the same code will be tested with older kernels as well.

> 
> I don't know goal of adding Lustre to kernel and, possible,this
> situation could be acceptable from your point of view.
> 
Untested code is buggy and useless. We certainly don't want it either.

Thanks,
Tao

> Thanks,
> 	Roman
> 
> On 04/27/2012 04:33 PM, tao.peng at emc.com wrote:
> > Hi Roman,
> >
> > Not sure if I misunderstand your question, but we won't push lustre/tests/* files to kernel.
> >We only push client code and any tests will be executed out side of kernel
> >
> > Cheers,
> > Tao
> > ________________________________________
> > From: Roman Grigoryev [Roman_Grigoryev at xyratex.com]
> > Sent: Friday, April 27, 2012 6:25 PM
> > To: Peng, Tao
> > Cc: adilger at whamcloud.com; wc-discuss at whamcloud.com; lustre-discuss at lists.lustre.org; lustre-
> devel at lists.lustre.org
> > Subject: Re: [Lustre-discuss] [wc-discuss] Re: Lustre and cross-platform portability
> >
> > Tao,Andreas,all,
> >
> > What is your plan in test/test framework changes from the point of view
> > of integration to kernel? As i know, kernel.org has his own test
> > infrastructure and his own test framework.
> >
> > I'm sorry if it's incorrect place for this question.
> >
> > Thanks,
> >         Roman
> >
> > On 04/27/2012 02:15 PM, tao.peng at emc.com wrote:
> >> Hi Andreas,
> >>
> >>> -----Original Message-----
> >>> From: Andreas Dilger [mailto:adilger at whamcloud.com]
> >>> Sent: Friday, April 27, 2012 11:54 AM
> >>> To: Peng, Tao
> >>> Cc: <wc-discuss@whamcloud.com>; <lustre-devel@lists.lustre.org>; <lustre-discuss@lists.lustre.org>
> >>> Subject: Re: [wc-discuss] Re: Lustre and cross-platform portability
> >>>
> >>> On 2012-04-26, at 20:23, <tao.peng@emc.com> wrote:
> >>>> Thank you very much for bringing it up in LUG and getting all these positive support from
> community.
> >>>
> >>> Tao,
> >>> Yes it does look promising.
> >>>
> >>>>> To revive this thread, based on discussion at the LUG TWG:
> >>>>> - there was general consensus that cleaning up the Lustre client
> >>>>>  (and server) code was very desirable to do
> >>>>> - migrating libcfs to emulate the Linux kernel APIs is also usable.
> >>>>>  Ken mentioned that there is relatively little conflict between
> >>>>>  the Linux kernel and the MacOS kernel, and the same for WinNT, so
> >>>>>  they could use the same function names as Linux without problems.
> >>>> I created LU-1346 (http://jira.whamcloud.com/browse/LU-1346) to track libcfs cleanup work.
> >>>
> >>> OK
> >>>
> >>>>> - there was no objection to converting the Lustre code from spaces
> >>>>>  to tabs.  My proposal was that build/checkpatch.pl could require
> >>>>>  tabs immediately, and new patches should be submitted with tabs
> >>>>>  on all new/modified lines (and optionally all lines on small
> >>>>>  functions to avoid messy formatting).  This will avoid issues
> >>>>>  with current patches in flight, and also avoid "git annotate"
> >>>>>  showing the jumbo replace-all-spaces-with-tabs patch for every
> >>>>>  line in Lustre, and I think a good fraction of lines will be
> >>>>>  updated in the next 9-12 months or more.  As we approach the
> >>>>>  actual time for upstream kernel submission is close, then we can
> >>>>>  make a final effort to clean up remaining lines in idle code
> >>>>>  (which will also be unlikely to conflict with existing work).
> >>>> While tabs are the main coding style difference between Lustre and kernel, there are a few minor
> >>> change that is needed as well. I think we need to do following to match kernel coding style:
> >>>> 1. Lustre uses expandtab while kernel requires tabs
> >>>
> >>> Right.
> >>>
> >>>> 2. Lustre has vim syntax rules in most source files, which need to be removed
> >>>
> >>> They should be replaced with explicit vim and enacts syntax rules that have the kernel indent
> style
> >>> instead.  If we could get syntax rules that embodied more of the coding style than just
> indentation,
> >>> that would be even better.
> >>>
> >> But we do need to remove them before submitting to kernel, right? And if we enforce checkpatch.pl
> on every patch applied, IMHO there is not much benefit to have syntax rules on every file, not to
> mention that it is explicitly forbidden in kernel coding style (Documentation/CodingStyle, Chapter 18:
> Editor modelines and other cruft).
> >>
> >> BTW, instead of just enabling tabs, how about changing checkpatch.pl to latest kernel version to
> make sure all future patches follow kernel coding styles?
> >>
> >>>> 3. Lustre uses a slightly different comment style, which need to be changed to kernel style
> >>>
> >>> This is DOxygen style formatting.  I had forgotten about this. We had in the past used this inline
> >>> formatting for producing some documentation, but I'd need to ask about whether there is still a
> need
> >>> for this today. In the meantime, please leave the comment style as-is.
> >>>
> >> OK.
> >>
> >>>
> >>>> I created LU-1347 (http://jira.whamcloud.com/browse/LU-1347) to track the coding style changes.
> >>>>
> >>>>> There is some hope that the kernel maintainers will not require
> >>>>> all of the Lustre macros to be removed, but we can deal with this
> >>>>> on a case-by-case basis.
> >>>>>
> >>>> IMO, we can divide macros to three groups (or more?):
> >>>> 1. Old kernel support macros, kernel maintainers are clear that they won't accept it.
> >>>
> >>> Yes, but we need to maintain this in the external Lustre tree for years after Lustre would be
> accepted
> >>> into mainline, since it would not be in vendor kernels (which a majority of Lustre users would be
> >>> using).
> >>>
> >>> For such compat macros we need to make an effort to keep the upstream code as close as possible to
> the
> >>> external tree, so patches have the most chance of applying.
> >>>
> >> I agree. We should minimize maintenance effort for it. And as you suggested, we can put as many of
> these compat macros into places like linux_compat.h as possible and have Lustre code use latest kernel
> APIs, so that most maintenance effort for old kernel support would be to keep linux_compat.h uptodate.
> For compact macros that cannot be cleaned up this way, we will have to pay the extra efforts. And of
> course the cleanup will be an incremental process and macros will be dealt with in a case-by-case
> basis.
> >>
> >>>> 2. For macros to mark out server code, kernel maintainers can accept it. But I think we need to
> make
> >>> sure we don't do it too intrusive.
> >>>
> >>> Sure, and we also need to make sure the ongoing maintenance effort to keep the code working is not
> too
> >>> much either.
> >>>
> >>> I'm OK with incremental patches that more cleanly split the client and server code (structures,
> >>> headers, etc) if that improves the code structure and readability.
> >>>
> >> I agree that we can do some incremental patches to split client and server code. But I hope we only
> do it when it is trivial and simple. IMHO if we want to entirely split client/server code, it will be
> large code structure change. Since kernel maintainers already agreed on HAVE_SERVER_SUPPORT, how about
> we keep going that way at first? And we can make some split wherever it is simple and clear. And we
> will try to make code structure as clear/readable as possible. Then when we summit code for review, if
> kernel maintainers still don't like it, we do the large restructuring. Does it make sense?
> >>
> >>>> 3. Lustre feature macros, we can convert them to Kconfig macros.
> >>>
> >>> Sure. Note that some of them may be obsolete, so before you spend too much time cleaning them up,
> >>> please post a list to Jira. Maybe some of them can be dropped entirely.
> >>>
> >> Thanks. I will do as you suggested when it comes to converting them to Kconfig macros.
> >>
> >> Cheers,
> >> Tao
> >>
> >>>>> On 2012-03-14, at 7:31 PM, Andreas Dilger wrote:
> >>>>>> Whamcloud and EMC are jointly investigating how to be able to contribute the Lustre client code
> >>> into
> >>>>> the upstream Linux kernel.
> >>>>>>
> >>>>>> As a prerequisite to this, EMC is working to clean up the Lustre client code to better match
> the
> >>>>> kernel coding style, and one of the anticipated major obstacles to upstream kernel submission is
> >>> the
> >>>>> heavy use of code abstraction via libcfs for portability to other operating systems (most
> notably
> >>>>> MacOS and WinNT, but also for liblustre, and potentially *BSD).
> >>>>>>
> >>>>>> I have no information that the WinNT project will ever be released by Oracle,
> >>>>>
> >>>>> [revised] and the MacOS client needs significant work to update it to the latest version of
> Lustre,
> >>>>> and to get it landed into the Lustre repo,
> >>>>>
> >>>>>> so the libcfs portability layer is potentially exacting a high cost in code maintenance and
> >>>>> complexity (CLIO being a prime example) for no apparent benefit.  Similarly, the liblustre
> client
> >>>>> needs a portability layer for userspace, and suffers from the same apparent lack of interest or
> >>> users.
> >>>>>>
> >>>>>> I'd like to get some feedback from the Lustre community about removing the libcfs abstraction
> >>>>> entirely, or possibly restructuring it to look like the Linux kernel API, and having the other
> >>>>> platforms code against it as a Linux portability layer, like ZFS on Linux uses the Solaris
> >>> Portability
> >>>>> Layer (SPL) to avoid changing the core ZFS code.  A related topic is whether it would be better
> to
> >>>>> replace all cfs_* functions with standard Linux kernel functions en-masse, or migrate away from
> >>> cfs_*
> >>>>> functions slowly?
> >>>>>>
> >>>>>> Also, we're planning on deprecating the liblustre client code, due to lack of interest/usage.
> The
> >>>>> current code is in disrepair, and we've been keeping it around for years without any benefit,
> and
> >>>>> while I was one of the strongest advocates for keeping it in our back pocket in case of future
> >>> needs,
> >>>>> I don't see that materializing in the future.
> >>>>>>
> >>>>>> The liblustre code would be left in the tree for now, in case someone from the community is
> >>>>> interested to get it working and maintain it, and it may be updated on a best effort basis.  If
> >>> nobody
> >>>>> steps forward to do this work, the liblustre code would be deleted from the development branch
> in a
> >>>>> year or so.
> >>>>>>
> >>>>>>
> >>>>>> Unfortunately, after starting this thread, I may not be able to reply to questions in a timely
> >>>>> manner due to vacation.  I look forward to a thread that concludes with unanimous agreement from
> >>> all
> >>>>> parties. :-)
> >>>>>>
> >>>>>> Cheers, Andreas
> >>>>>> --
> >>>>>> Andreas Dilger                       Whamcloud, Inc.
> >>>>>> Principal Lustre Engineer            http://www.whamcloud.com/
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>
> >>>>>
> >>>>> Cheers, Andreas
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>
> >>
> >> _______________________________________________
> >> Lustre-discuss mailing list
> >> Lustre-discuss at lists.lustre.org
> >> http://lists.lustre.org/mailman/listinfo/lustre-discuss
> >
> >
> 
> ______________________________________________________________________
> This email may contain privileged or confidential information, which should only be used for the
> purpose for which it was sent by Xyratex. No further rights or licenses are granted to use such
> information. If you are not the intended recipient of this message, please notify the sender by return
> and delete it. You may not use, copy, disclose or rely on the information contained in it.
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> Xyratex does not accept liability. While we have taken reasonable precautions to ensure that this
> email is free of viruses, Xyratex does not accept liability for the presence of any computer viruses
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> 
> Xyratex Technology Limited (03134912), Registered in England & Wales, Registered Office, Langstone
> Road, Havant, Hampshire, PO9 1SA.
> 
> The Xyratex group of companies also includes, Xyratex Ltd, registered in Bermuda, Xyratex
> International Inc, registered in California, Xyratex (Malaysia) Sdn Bhd registered in Malaysia,
> Xyratex Technology (Wuxi) Co Ltd registered in The People's Republic of China and Xyratex Japan
> Limited registered in Japan.
> ______________________________________________________________________
> 
> 

[Lustre-devel] [Lustre-discuss] [wc-discuss] Re: Lustre and cross-platform portability

[Roman Grigoryev]

On 05/03/2012 02:03 PM, tao.peng at emc.com wrote:
>>
>> I'm not know how linux developers approve patches. But, logically,
>> because Lustre is big enough project and use kernel subsystems then it
>> should be tested after kernel changes on kernel side too. In  other case
>> (without testing) we can observer situation when Lustre built ok but
>> doesn't work.

> Now I see what you are worrying about. All code submitted to Linux kernel 
> will be tested, and also patches later merged. It's just that kernel is a 
> different place than Lustre git tree. We are not allowed to put test scripts 
> into kernel tree. So all test code will remain in Whamcloud tree. But we will 
> run the same tests against kernel code as well. One of our goal is to keep kernel
> client code in sync with Whamcloud tree as much as possible, so that the same 
> code will be tested with older kernels as well.

I just want to point, as I understand situation, keeping kernel client
code in sync with Whamcloud tree without testing on latest
kernels(include unstable) could lead to situation when client on new
kernel doesn't work but built ok. Testing on older kernels doesn't say
about work on new kernels, only give possibility.
Thanks,
	Roman
> 
>>
>> I don't know goal of adding Lustre to kernel and, possible,this
>> situation could be acceptable from your point of view.
>>
> Untested code is buggy and useless. We certainly don't want it either.
> 
> Thanks,
> Tao
> 
>> Thanks,
>> 	Roman
>>
>> On 04/27/2012 04:33 PM, tao.peng at emc.com wrote:
>>> Hi Roman,
>>>
>>> Not sure if I misunderstand your question, but we won't push lustre/tests/* files to kernel.
>>> We only push client code and any tests will be executed out side of kernel
>>>
>>> Cheers,
>>> Tao
>>> ________________________________________
>>> From: Roman Grigoryev [Roman_Grigoryev at xyratex.com]
>>> Sent: Friday, April 27, 2012 6:25 PM
>>> To: Peng, Tao
>>> Cc: adilger at whamcloud.com; wc-discuss at whamcloud.com; lustre-discuss at lists.lustre.org; lustre-
>> devel at lists.lustre.org
>>> Subject: Re: [Lustre-discuss] [wc-discuss] Re: Lustre and cross-platform portability
>>>
>>> Tao,Andreas,all,
>>>
>>> What is your plan in test/test framework changes from the point of view
>>> of integration to kernel? As i know, kernel.org has his own test
>>> infrastructure and his own test framework.
>>>
>>> I'm sorry if it's incorrect place for this question.
>>>
>>> Thanks,
>>>         Roman
>>>
>>> On 04/27/2012 02:15 PM, tao.peng at emc.com wrote:
>>>> Hi Andreas,
>>>>
>>>>> -----Original Message-----
>>>>> From: Andreas Dilger [mailto:adilger at whamcloud.com]
>>>>> Sent: Friday, April 27, 2012 11:54 AM
>>>>> To: Peng, Tao
>>>>> Cc: <wc-discuss@whamcloud.com>; <lustre-devel@lists.lustre.org>; <lustre-discuss@lists.lustre.org>
>>>>> Subject: Re: [wc-discuss] Re: Lustre and cross-platform portability
>>>>>
>>>>> On 2012-04-26, at 20:23, <tao.peng@emc.com> wrote:
>>>>>> Thank you very much for bringing it up in LUG and getting all these positive support from
>> community.
>>>>>
>>>>> Tao,
>>>>> Yes it does look promising.
>>>>>
>>>>>>> To revive this thread, based on discussion at the LUG TWG:
>>>>>>> - there was general consensus that cleaning up the Lustre client
>>>>>>>  (and server) code was very desirable to do
>>>>>>> - migrating libcfs to emulate the Linux kernel APIs is also usable.
>>>>>>>  Ken mentioned that there is relatively little conflict between
>>>>>>>  the Linux kernel and the MacOS kernel, and the same for WinNT, so
>>>>>>>  they could use the same function names as Linux without problems.
>>>>>> I created LU-1346 (http://jira.whamcloud.com/browse/LU-1346) to track libcfs cleanup work.
>>>>>
>>>>> OK
>>>>>
>>>>>>> - there was no objection to converting the Lustre code from spaces
>>>>>>>  to tabs.  My proposal was that build/checkpatch.pl could require
>>>>>>>  tabs immediately, and new patches should be submitted with tabs
>>>>>>>  on all new/modified lines (and optionally all lines on small
>>>>>>>  functions to avoid messy formatting).  This will avoid issues
>>>>>>>  with current patches in flight, and also avoid "git annotate"
>>>>>>>  showing the jumbo replace-all-spaces-with-tabs patch for every
>>>>>>>  line in Lustre, and I think a good fraction of lines will be
>>>>>>>  updated in the next 9-12 months or more.  As we approach the
>>>>>>>  actual time for upstream kernel submission is close, then we can
>>>>>>>  make a final effort to clean up remaining lines in idle code
>>>>>>>  (which will also be unlikely to conflict with existing work).
>>>>>> While tabs are the main coding style difference between Lustre and kernel, there are a few minor
>>>>> change that is needed as well. I think we need to do following to match kernel coding style:
>>>>>> 1. Lustre uses expandtab while kernel requires tabs
>>>>>
>>>>> Right.
>>>>>
>>>>>> 2. Lustre has vim syntax rules in most source files, which need to be removed
>>>>>
>>>>> They should be replaced with explicit vim and enacts syntax rules that have the kernel indent
>> style
>>>>> instead.  If we could get syntax rules that embodied more of the coding style than just
>> indentation,
>>>>> that would be even better.
>>>>>
>>>> But we do need to remove them before submitting to kernel, right? And if we enforce checkpatch.pl
>> on every patch applied, IMHO there is not much benefit to have syntax rules on every file, not to
>> mention that it is explicitly forbidden in kernel coding style (Documentation/CodingStyle, Chapter 18:
>> Editor modelines and other cruft).
>>>>
>>>> BTW, instead of just enabling tabs, how about changing checkpatch.pl to latest kernel version to
>> make sure all future patches follow kernel coding styles?
>>>>
>>>>>> 3. Lustre uses a slightly different comment style, which need to be changed to kernel style
>>>>>
>>>>> This is DOxygen style formatting.  I had forgotten about this. We had in the past used this inline
>>>>> formatting for producing some documentation, but I'd need to ask about whether there is still a
>> need
>>>>> for this today. In the meantime, please leave the comment style as-is.
>>>>>
>>>> OK.
>>>>
>>>>>
>>>>>> I created LU-1347 (http://jira.whamcloud.com/browse/LU-1347) to track the coding style changes.
>>>>>>
>>>>>>> There is some hope that the kernel maintainers will not require
>>>>>>> all of the Lustre macros to be removed, but we can deal with this
>>>>>>> on a case-by-case basis.
>>>>>>>
>>>>>> IMO, we can divide macros to three groups (or more?):
>>>>>> 1. Old kernel support macros, kernel maintainers are clear that they won't accept it.
>>>>>
>>>>> Yes, but we need to maintain this in the external Lustre tree for years after Lustre would be
>> accepted
>>>>> into mainline, since it would not be in vendor kernels (which a majority of Lustre users would be
>>>>> using).
>>>>>
>>>>> For such compat macros we need to make an effort to keep the upstream code as close as possible to
>> the
>>>>> external tree, so patches have the most chance of applying.
>>>>>
>>>> I agree. We should minimize maintenance effort for it. And as you suggested, we can put as many of
>> these compat macros into places like linux_compat.h as possible and have Lustre code use latest kernel
>> APIs, so that most maintenance effort for old kernel support would be to keep linux_compat.h uptodate.
>> For compact macros that cannot be cleaned up this way, we will have to pay the extra efforts. And of
>> course the cleanup will be an incremental process and macros will be dealt with in a case-by-case
>> basis.
>>>>
>>>>>> 2. For macros to mark out server code, kernel maintainers can accept it. But I think we need to
>> make
>>>>> sure we don't do it too intrusive.
>>>>>
>>>>> Sure, and we also need to make sure the ongoing maintenance effort to keep the code working is not
>> too
>>>>> much either.
>>>>>
>>>>> I'm OK with incremental patches that more cleanly split the client and server code (structures,
>>>>> headers, etc) if that improves the code structure and readability.
>>>>>
>>>> I agree that we can do some incremental patches to split client and server code. But I hope we only
>> do it when it is trivial and simple. IMHO if we want to entirely split client/server code, it will be
>> large code structure change. Since kernel maintainers already agreed on HAVE_SERVER_SUPPORT, how about
>> we keep going that way at first? And we can make some split wherever it is simple and clear. And we
>> will try to make code structure as clear/readable as possible. Then when we summit code for review, if
>> kernel maintainers still don't like it, we do the large restructuring. Does it make sense?
>>>>
>>>>>> 3. Lustre feature macros, we can convert them to Kconfig macros.
>>>>>
>>>>> Sure. Note that some of them may be obsolete, so before you spend too much time cleaning them up,
>>>>> please post a list to Jira. Maybe some of them can be dropped entirely.
>>>>>
>>>> Thanks. I will do as you suggested when it comes to converting them to Kconfig macros.
>>>>
>>>> Cheers,
>>>> Tao
>>>>
>>>>>>> On 2012-03-14, at 7:31 PM, Andreas Dilger wrote:
>>>>>>>> Whamcloud and EMC are jointly investigating how to be able to contribute the Lustre client code
>>>>> into
>>>>>>> the upstream Linux kernel.
>>>>>>>>
>>>>>>>> As a prerequisite to this, EMC is working to clean up the Lustre client code to better match
>> the
>>>>>>> kernel coding style, and one of the anticipated major obstacles to upstream kernel submission is
>>>>> the
>>>>>>> heavy use of code abstraction via libcfs for portability to other operating systems (most
>> notably
>>>>>>> MacOS and WinNT, but also for liblustre, and potentially *BSD).
>>>>>>>>
>>>>>>>> I have no information that the WinNT project will ever be released by Oracle,
>>>>>>>
>>>>>>> [revised] and the MacOS client needs significant work to update it to the latest version of
>> Lustre,
>>>>>>> and to get it landed into the Lustre repo,
>>>>>>>
>>>>>>>> so the libcfs portability layer is potentially exacting a high cost in code maintenance and
>>>>>>> complexity (CLIO being a prime example) for no apparent benefit.  Similarly, the liblustre
>> client
>>>>>>> needs a portability layer for userspace, and suffers from the same apparent lack of interest or
>>>>> users.
>>>>>>>>
>>>>>>>> I'd like to get some feedback from the Lustre community about removing the libcfs abstraction
>>>>>>> entirely, or possibly restructuring it to look like the Linux kernel API, and having the other
>>>>>>> platforms code against it as a Linux portability layer, like ZFS on Linux uses the Solaris
>>>>> Portability
>>>>>>> Layer (SPL) to avoid changing the core ZFS code.  A related topic is whether it would be better
>> to
>>>>>>> replace all cfs_* functions with standard Linux kernel functions en-masse, or migrate away from
>>>>> cfs_*
>>>>>>> functions slowly?
>>>>>>>>
>>>>>>>> Also, we're planning on deprecating the liblustre client code, due to lack of interest/usage.
>> The
>>>>>>> current code is in disrepair, and we've been keeping it around for years without any benefit,
>> and
>>>>>>> while I was one of the strongest advocates for keeping it in our back pocket in case of future
>>>>> needs,
>>>>>>> I don't see that materializing in the future.
>>>>>>>>
>>>>>>>> The liblustre code would be left in the tree for now, in case someone from the community is
>>>>>>> interested to get it working and maintain it, and it may be updated on a best effort basis.  If
>>>>> nobody
>>>>>>> steps forward to do this work, the liblustre code would be deleted from the development branch
>> in a
>>>>>>> year or so.
>>>>>>>>
>>>>>>>>
>>>>>>>> Unfortunately, after starting this thread, I may not be able to reply to questions in a timely
>>>>>>> manner due to vacation.  I look forward to a thread that concludes with unanimous agreement from
>>>>> all
>>>>>>> parties. :-)
>>>>>>>>
>>>>>>>> Cheers, Andreas
>>>>>>>> --
>>>>>>>> Andreas Dilger                       Whamcloud, Inc.
>>>>>>>> Principal Lustre Engineer            http://www.whamcloud.com/
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> Cheers, Andreas
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>
>>>>
>>>> _______________________________________________
>>>> Lustre-discuss mailing list
>>>> Lustre-discuss at lists.lustre.org
>>>> http://lists.lustre.org/mailman/listinfo/lustre-discuss
>>>
>>>
>>
>> ______________________________________________________________________
>> This email may contain privileged or confidential information, which should only be used for the
>> purpose for which it was sent by Xyratex. No further rights or licenses are granted to use such
>> information. If you are not the intended recipient of this message, please notify the sender by return
>> and delete it. You may not use, copy, disclose or rely on the information contained in it.
>>
>> Internet email is susceptible to data corruption, interception and unauthorised amendment for which
>> Xyratex does not accept liability. While we have taken reasonable precautions to ensure that this
>> email is free of viruses, Xyratex does not accept liability for the presence of any computer viruses
>> in this email, nor for any losses caused as a result of viruses.
>>
>> Xyratex Technology Limited (03134912), Registered in England & Wales, Registered Office, Langstone
>> Road, Havant, Hampshire, PO9 1SA.
>>
>> The Xyratex group of companies also includes, Xyratex Ltd, registered in Bermuda, Xyratex
>> International Inc, registered in California, Xyratex (Malaysia) Sdn Bhd registered in Malaysia,
>> Xyratex Technology (Wuxi) Co Ltd registered in The People's Republic of China and Xyratex Japan
>> Limited registered in Japan.
>> ______________________________________________________________________
>>
>>
> 

[Lustre-devel] [Lustre-discuss] [wc-discuss] Re: Lustre and cross-platform portability

[tao.peng at emc.com]

________________________________________
From: Roman Grigoryev [Roman_Grigoryev at xyratex.com]
Sent: Thursday, May 03, 2012 6:45 PM
To: Peng, Tao
Cc: adilger at whamcloud.com; wc-discuss at whamcloud.com; lustre-discuss at lists.lustre.org; lustre-devel at lists.lustre.org
Subject: Re: [Lustre-discuss] [wc-discuss] Re: Lustre and cross-platform portability

On 05/03/2012 02:03 PM, tao.peng at emc.com wrote:
>>
>> I'm not know how linux developers approve patches. But, logically,
>> because Lustre is big enough project and use kernel subsystems then it
>> should be tested after kernel changes on kernel side too. In  other case
>> (without testing) we can observer situation when Lustre built ok but
>> doesn't work.

> Now I see what you are worrying about. All code submitted to Linux kernel
> will be tested, and also patches later merged. It's just that kernel is a
> different place than Lustre git tree. We are not allowed to put test scripts
> into kernel tree. So all test code will remain in Whamcloud tree. But we will
> run the same tests against kernel code as well. One of our goal is to keep kernel
> client code in sync with Whamcloud tree as much as possible, so that the same
> code will be tested with older kernels as well.

> I just want to point, as I understand situation, keeping kernel client
> code in sync with Whamcloud tree without testing on latest
> kernels(include unstable) could lead to situation when client on new
> kernel doesn't work but built ok. Testing on older kernels doesn't say
> about work on new kernels, only give possibility.
I agree. We need to test latest kernel from time to time, and it can be a community effort. We will certainly test every patch we put in. And anyone interested can test the code as well. If you are suggesting some public testing infrastructure, maybe Whamcloud will be interested? IMHO, testing every patch in upstream kernel like Maloo does for Whamcloud tree, is a little luxury through.

Thanks,
Tao

[Lustre-devel] [wc-discuss] Re: Lustre and cross-platform portability

[Andreas Dilger]

On 2012-04-27, at 4:15 AM, <tao.peng@emc.com> <tao.peng@emc.com> wrote:
> Andreas Dilger <adilger@whamcloud.com> wrote:
>> On 2012-04-26, at 20:23, <tao.peng@emc.com> wrote:
>>> 2. Lustre has vim syntax rules in most source files, which need
>>> to be removed
>> 
>> They should be replaced with explicit vim and enacts syntax rules that have the kernel indent style instead.  If we could get syntax rules that embodied more of the coding style than just indentation, that would be even better.
>> 
> But we do need to remove them before submitting to kernel, right? And if we enforce checkpatch.pl on every patch applied, IMHO there is not much benefit to have syntax rules on every file, not to mention that it is explicitly forbidden in kernel coding style (Documentation/CodingStyle, Chapter 18:  Editor modelines and other cruft).
> 
> BTW, instead of just enabling tabs, how about changing checkpatch.pl to latest kernel version to make sure all future patches follow kernel coding styles?

The Lustre checkpatch.pl is already based on the kernel one, but with some small modifications.  It will default to checking for spaces vs. tabs, default to "--no-tree", does not require signoffs (since this is added at commit time after the patch is checked).  One other change is to allow no spaces after commas in function parameters if the line is 79 or 80 columns long.  That avoids a line wrap for just a couple of characters.

I have no objection to updating to a newer version of checkpatch.pl if it improves the checking.  Please run it against

>>> IMO, we can divide macros to three groups (or more?):
>>> 1. Old kernel support macros, kernel maintainers are clear that they won't accept it.
> 
>>> 2. For macros to mark out server code, kernel maintainers can accept it. But I think we need to make sure we don't do it too intrusive.
>> 
>> Sure, and we also need to make sure the ongoing maintenance effort to keep the code working is not too much either.
>> 
>> I'm OK with incremental patches that more cleanly split the client and server code (structures, headers, etc) if that improves the code structure and readability.
> 
> I agree that we can do some incremental patches to split client and server code. But I hope we only do it when it is trivial and simple. IMHO if we want to entirely split client/server code, it will be large code structure change. Since kernel maintainers already agreed on HAVE_SERVER_SUPPORT, how about we keep going that way at first?

By all means, we can stick with HAVE_SERVER_SUPPORT for now.  I was just commenting that I'm not against other changes if they improve the code in the long run.

Cheers, Andreas
--
Andreas Dilger                       Whamcloud, Inc.
Principal Lustre Engineer            http://www.whamcloud.com/

[Lustre-devel] [wc-discuss] Re: Lustre and cross-platform portability

[Peng Tao]

On Sat, Apr 28, 2012 at 4:23 AM, Andreas Dilger <adilger@whamcloud.com> wrote:
> On 2012-04-27, at 4:15 AM, <tao.peng@emc.com> <tao.peng@emc.com> wrote:
>> Andreas Dilger <adilger@whamcloud.com> wrote:
>>> On 2012-04-26, at 20:23, <tao.peng@emc.com> wrote:
>>>> 2. Lustre has vim syntax rules in most source files, which need
>>>> to be removed
>>>
>>> They should be replaced with explicit vim and enacts syntax rules that have the kernel indent style instead. ?If we could get syntax rules that embodied more of the coding style than just indentation, that would be even better.
>>>
>> But we do need to remove them before submitting to kernel, right? And if we enforce checkpatch.pl on every patch applied, IMHO there is not much benefit to have syntax rules on every file, not to mention that it is explicitly forbidden in kernel coding style (Documentation/CodingStyle, Chapter 18: ?Editor modelines and other cruft).
>>
>> BTW, instead of just enabling tabs, how about changing checkpatch.pl to latest kernel version to make sure all future patches follow kernel coding styles?
>
> The Lustre checkpatch.pl is already based on the kernel one, but with some small modifications. ?It will default to checking for spaces vs. tabs, default to "--no-tree", does not require signoffs (since this is added at commit time after the patch is checked). ?One other change is to allow no spaces after commas in function parameters if the line is 79 or 80 columns long. ?That avoids a line wrap for just a couple of characters.
>
> I have no objection to updating to a newer version of checkpatch.pl if it improves the checking. ?Please run it against
>
I hope we can use latest kernel version of checkpatch.pl so that it is
more likely future patches can be applied to both kernel and Whamcloud
tree.

I did a diff against kernel checkpatch.pl and it creates ~2k lines of
change. So I think it is worth updating Lustre version of
checkpatch.pl.

I submitted http://review.whamcloud.com/2610 for the change. Please
help to review. Thank you.

>>>> IMO, we can divide macros to three groups (or more?):
>>>> 1. Old kernel support macros, kernel maintainers are clear that they won't accept it.
>>
>>>> 2. For macros to mark out server code, kernel maintainers can accept it. But I think we need to make sure we don't do it too intrusive.
>>>
>>> Sure, and we also need to make sure the ongoing maintenance effort to keep the code working is not too much either.
>>>
>>> I'm OK with incremental patches that more cleanly split the client and server code (structures, headers, etc) if that improves the code structure and readability.
>>
>> I agree that we can do some incremental patches to split client and server code. But I hope we only do it when it is trivial and simple. IMHO if we want to entirely split client/server code, it will be large code structure change. Since kernel maintainers already agreed on HAVE_SERVER_SUPPORT, how about we keep going that way at first?
>
> By all means, we can stick with HAVE_SERVER_SUPPORT for now. ?I was just commenting that I'm not against other changes if they improve the code in the long run.
>
Thanks. We will do the split whenever it is easy. :)

Best,
Tao
> Cheers, Andreas
> --
> Andreas Dilger ? ? ? ? ? ? ? ? ? ? ? Whamcloud, Inc.
> Principal Lustre Engineer ? ? ? ? ? ?http://www.whamcloud.com/
>
>
>
>
> _______________________________________________
> Lustre-devel mailing list
> Lustre-devel at lists.lustre.org
> http://lists.lustre.org/mailman/listinfo/lustre-devel

[Lustre-devel] [wc-discuss] Re: Lustre and cross-platform portability

[Liang Zhen]

On Apr 27, 2012, at 7:48 AM, Andreas Dilger wrote:
> 
> - there was no objection to converting the Lustre code from spaces
>  to tabs.  My proposal was that build/checkpatch.pl could require
>  tabs immediately, and new patches should be submitted with tabs
>  on all new/modified lines (and optionally all lines on small
>  functions to avoid messy formatting).  This will avoid issues
>  with current patches in flight, and also avoid "git annotate"
>  showing the jumbo replace-all-spaces-with-tabs patch for every
>  line in Lustre, and I think a good fraction of lines will be
>  updated in the next 9-12 months or more.  As we approach the
>  actual time for upstream kernel submission is close, then we can
>  make a final effort to clean up remaining lines in idle code
>  (which will also be unlikely to conflict with existing work).

Lustre also requires to align the first alphabet of members while defining a structure, but linux kernel only aligns any first character (for example, * for pointer), then which way we should choose?
we probably should update our coding guidelines ASAP.

Liang

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