[LITMUS^RT] litmus-dev Digest, Vol 56, Issue 11

Mahircan Gul mahircg at mpi-sws.org
Thu Oct 27 20:12:13 CEST 2016 

Hi Nick

In latest version of LITMUS, whether a task is running or not can be 
checked by:

*task->state == IS_RUNNING*

*is_running(task) *function is not available in recent LITMUS distributions.

/Note/: I have ported some LITMUS plug-ins from Linux kernel version 3.x 
to 4.x, and if I remember correctly these are the two (including per-CPU 
macro) kernel-level changes.

In any case, if you get to see more undefined functions or variables, I 
suggest you to check the diff among the latest LITMUS version and the 
version that the plug-in is written for.


Mahir


On 10/27/2016 07:52 PM, litmus-dev-request at lists.litmus-rt.org wrote:
> Send litmus-dev mailing list submissions to
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> Today's Topics:
>
>     1. Re: litmus-dev Digest, Vol 56, Issue 9 (NICHOLAS ALLAN KLEPP)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Thu, 27 Oct 2016 17:51:33 +0000
> From: NICHOLAS ALLAN KLEPP <nickbk at uga.edu>
> To: "litmus-dev at lists.litmus-rt.org" <litmus-dev at lists.litmus-rt.org>
> Subject: Re: [LITMUS^RT] litmus-dev Digest, Vol 56, Issue 9
> Message-ID:
> 	<BL2PR02MB46501F1916EDA6458F3C5AFD5AA0 at BL2PR02MB465.namprd02.prod.outlook.com>
> 	
> Content-Type: text/plain; charset="iso-8859-1"
>
> Thank you for your fast response, everybody!
>
>
> Interestingly, I am still getting the same error even after changing the local_cpu_state() definition from &__get_cpu_var(demo_cpu_state) to this_cpu_ptr(&demo_cpu_state). The implicitly declared function warning for __get_cpu_var() is gone, but the implicitly declared function warning for is_running() is still there, which I find odd.
>
>
> Can anybody say where is_running() is defined? I'm pretty sure I have the correct headers included, but I may be wrong.
>
>
> Is there anything else anyone can think of that may be causing this problem?
>
>
> Thanks! - Nick
>
>
> ________________________________
> From: litmus-dev-bounces at lists.litmus-rt.org <litmus-dev-bounces at lists.litmus-rt.org> on behalf of Mahircan Gul <mahircg at mpi-sws.org>
> Sent: Wednesday, October 26, 2016 5:57 PM
> To: litmus-dev at lists.litmus-rt.org
> Subject: Re: [LITMUS^RT] litmus-dev Digest, Vol 56, Issue 9
>
> Greetings
>
> As mentioned in a previous reply, the issue arises due to changes in
> Linux kernel versions. More specifically, macros for accessing the
> per-CPU variables has changed between kernel v 3.x to 4.x.
>
> I guess those tutorials were written for the LITMUS version that was
> based on Linux 3.x. Therefore, using the old version of macros within
> the current kernel version (I'm assuming you are writing the plug-in on
> Linux v 4.x) yields to the errors you mentioned.
>
> Changing
>
>
>          #define local_cpu_state() (&__get_cpu_var(demo_cpu_state))
>
> to (mind the address-of operator)
>
>          #define local_cpu_state() (this_cpu_ptr(&demo_cpu_state))
>
> should take care of the issue.
>
> The change above should get your development process up and running! The
> tutorials need to be updated at some point, though.
>
> Mahir
>
> On 10/26/2016 07:09 PM, litmus-dev-request at lists.litmus-rt.org wrote:
>> Send litmus-dev mailing list submissions to
>>         litmus-dev at lists.litmus-rt.org
>>
>> To subscribe or unsubscribe via the World Wide Web, visit
>>         https://lists.litmus-rt.org/listinfo/litmus-dev
>> or, via email, send a message with subject or body 'help' to
>>         litmus-dev-request at lists.litmus-rt.org
>>
>> You can reach the person managing the list at
>>         litmus-dev-owner at lists.litmus-rt.org
>>
>> When replying, please edit your Subject line so it is more specific
>> than "Re: Contents of litmus-dev digest..."
>>
>>
>> Today's Topics:
>>
>>      1. Create a Plugin Tutorial Step 5 (NICHOLAS ALLAN KLEPP)
>>      2. Re: Create a Plugin Tutorial Step 5 (shijunjie92)
>>
>>
>> ----------------------------------------------------------------------
>>
>> Message: 1
>> Date: Wed, 26 Oct 2016 17:01:02 +0000
>> From: NICHOLAS ALLAN KLEPP <nickbk at uga.edu>
>> To: "litmus-dev at lists.litmus-rt.org" <litmus-dev at lists.litmus-rt.org>
>> Subject: [LITMUS^RT] Create a Plugin Tutorial Step 5
>> Message-ID:
>>         <BL2PR02MB465FD2B01B25792C2378779D5AB0 at BL2PR02MB465.namprd02.prod.outlook.com>
>>
>> Content-Type: text/plain; charset="iso-8859-1"
>>
>> Hello!
>>
>>
>> I am following the Create a Plugin Tutorial and I am getting a compilation error after I add the scheduling decision logic in step 5. The error seems to be a problem with the demo_requeue() method. Here is the error message generated on compilation:
>>
>>
>> litmus/sched_demo.c: In function 'demo_requeue':
>> litmus/sched_demo.c:32:28: error: dereferencing pointer to incomplete type
>>          __add_ready(&cpu_state->local_queues,tsk);
>>                               ^
>> litmus/sched_demo.c:37:28: error: dereferencing pointer to incomplete type
>>          add_release(&cpu_state->local_queues,tsk);
>>                               ^
>> litmus/sched_demo.c: In function 'demo_schedule':
>> litmus/sched_demo.c:69:10: error: implicit declaration of function '__get_cpu_var' [-Werror=implicit-function-declaration]
>>      struct demo_cpu_state *local_state = local_cpu_state();
>>             ^
>> litmus/sched_demo.c:14:28: error: lvalue required as unary '&' operand
>>    #define local_cpu_state() (&__get_cpu_var(demo_cpu_state))
>>                               ^
>> litmus/sched_demo.c:69:40: note: in expansion of macro 'local_cpu_state'
>>      struct demo_cpu_state *local_state = local_cpu_state();
>>                                           ^
>> litmus/sched_demo.c:83:3: error: implicit declaration of function 'is_running' [-Werror=implicit-function-declaration]
>>      self_suspends = exists && !is_running(prev);
>>      ^
>> cc1: some warnings being treated as errors
>> scripts/Makefile.build:258: recipe for target 'litmus/sched_demo.o' failed
>>
>>
>> In searching the mailing list for similar problems I ran into a thread which did describe the dereferencing pointer to incomplete type error. There are two responses in that thread which I found to be possibly illuminating. One:
>>
>>
>> On May 7, 2013, at 2:11 PM, Bj?rn Brandenburg <bbb at mpi-sws.org> wrote:
>>
>>> On May 7, 2013, at 9:29 AM, Schorr Stefan <stschorr at eit.uni-kl.de> wrote:
>>>> I'm trying to follow the Create A Plugin Tutorial from the webpage.
>>>> The first steps work like a charm, step 4 however doesn't compile :(
>>>>
>>>> I copied the code from the website and I created a new local git
>>>> branch, so I'm absolutely sure that the only file I changed - apart
>>>> from the Makefile - is sched_demo.c (so I don't understand why
>>>> the error messages below point to .h files).
>>>>
>>>> Please give me some hint what goes wrong here...
>>>>
>>>> Best Regards
>>>> Stefan
>>>>
>>>>
>>>> Here's the error I get, when doing make bzImage
>>>>
>>>> In file included from litmus/sched_demo.c:3:
>>>> include/litmus/litmus.h:74: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'litmus_clock'
>>>> include/litmus/litmus.h: In function 'is_kernel_np':
>>>> include/litmus/litmus.h:120: error: dereferencing pointer to incomplete type
>>> Hi Stefan,
>>>
>>> this is a configuration error in LITMUS^RT. Please enable the configuration option CONFIG_NP_SECTION, which should silence the error. Sorry about that...
>> Actually, litmus/litmus.h already has correct dummy implementations for the !CONFIG_NP_SECTION case, so it's something different. Have you tried a 'make clean'?
>> - Bj?rn
>>
>> And two:
>>
>>> On 05/07/2013 02:19 PM, Bj?rn Brandenburg wrote:
>>>> If it doesn't go away, you are probably missing a header file. Here are the one from the reference version. Does it fail with these headers as well?
>>> Hi Bj?rn,
>>> thanks for the fast reply!
>>> There's no change after make clean.
>>> I paste my C code here:
>>>
>> Commit c5248a7288e54c2b5e2bba8aa2677772542bf90e compiles for me. Can you please try compiling c5248a7288e54c2b5e2bba8aa2677772542bf90e and, if it doesn't work, send me your configuration?
>>
>> Thanks,
>> Bj?rn
>>
>> I have verified that CONFIG_NP_SECTION is in fact enabled and as well I have run a 'make clean'. My next option was to try to checkout commit c5248a7288e54c2b5e2bba8aa2677772542bf90e, however, this is not allowed for my local repository. The error:
>>
>> fatal: reference is not a tree: c5248a7288e54c2b5e2bba8aa2677772542bf90e
>>
>> Is there something else I should do to make this work? Thanks!
>>
>> - Nick
>> -------------- next part --------------
>> An HTML attachment was scrubbed...
>> URL: <http://lists.litmus-rt.org/pipermail/litmus-dev/attachments/20161026/4601336b/attachment-0001.html>
>>
>> ------------------------------
>>
>> Message: 2
>> Date: Wed, 26 Oct 2016 19:09:08 +0100
>> From: "shijunjie92" <shijunjie92 at gmail.com>
>> To: "litmus-dev" <litmus-dev at lists.litmus-rt.org>
>> Subject: Re: [LITMUS^RT] Create a Plugin Tutorial Step 5
>> Message-ID: <5810E331.1010709 at gmail.com>
>> Content-Type: text/plain; charset="utf-8"
>>
>> Because of the based linux version has been changed, some functions have been reweitten. You need to compare the tutorial with the latest version of LITMUS-RT's plugin (for example sched_pfp.c) . Rewrite the related functions yourself.
>>
>> 2016-10-26
>>
>> shijunjie92
>>
>>
>>
>> ????NICHOLAS ALLAN KLEPP <nickbk at uga.edu>
>> ?????2016-10-26 19:01
>> ???[LITMUS^RT] Create a Plugin Tutorial Step 5
>> ????"litmus-dev at lists.litmus-rt.org"<litmus-dev at lists.litmus-rt.org>
>> ???
>>
>> Hello!
>>
>>
>>
>> I am following the Create a Plugin Tutorial and I am getting a compilation error after I add the scheduling decision logic in step 5. The error seems to be a problem with the demo_requeue() method. Here is the error message generated on compilation:
>>
>>
>>
>> litmus/sched_demo.c: In function ?demo_requeue?:
>> litmus/sched_demo.c:32:28: error: dereferencing pointer to incomplete type
>>          __add_ready(&cpu_state->local_queues,tsk);
>>                               ^
>> litmus/sched_demo.c:37:28: error: dereferencing pointer to incomplete type
>>          add_release(&cpu_state->local_queues,tsk);
>>                               ^
>> litmus/sched_demo.c: In function ?demo_schedule?:
>> litmus/sched_demo.c:69:10: error: implicit declaration of function ?__get_cpu_var? [-Werror=implicit-function-declaration]
>>      struct demo_cpu_state *local_state = local_cpu_state();
>>             ^
>> litmus/sched_demo.c:14:28: error: lvalue required as unary ?&? operand
>>    #define local_cpu_state() (&__get_cpu_var(demo_cpu_state))
>>                               ^
>> litmus/sched_demo.c:69:40: note: in expansion of macro ?local_cpu_state?
>>      struct demo_cpu_state *local_state = local_cpu_state();
>>                                           ^
>> litmus/sched_demo.c:83:3: error: implicit declaration of function ?is_running? [-Werror=implicit-function-declaration]
>>      self_suspends = exists && !is_running(prev);
>>      ^
>> cc1: some warnings being treated as errors
>> scripts/Makefile.build:258: recipe for target 'litmus/sched_demo.o' failed
>>
>>
>>
>> In searching the mailing list for similar problems I ran into a thread which did describe the dereferencing pointer to incomplete type error. There are two responses in that thread which I found to be possibly illuminating. One:
>>
>>
>>
>> On May 7, 2013, at 2:11 PM, Bj?rn Brandenburg <bbb at mpi-sws.org> wrote:
>>
>>> On May 7, 2013, at 9:29 AM, Schorr Stefan <stschorr at eit.uni-kl.de> wrote:
>>>> I'm trying to follow the Create A Plugin Tutorial from the webpage.
>>>> The first steps work like a charm, step 4 however doesn't compile :(
>>>>
>>>> I copied the code from the website and I created a new local git
>>>> branch, so I'm absolutely sure that the only file I changed - apart
>>>> from the Makefile - is sched_demo.c (so I don't understand why
>>>> the error messages below point to .h files).
>>>>
>>>> Please give me some hint what goes wrong here...
>>>>
>>>> Best Regards
>>>> Stefan
>>>>
>>>>
>>>> Here's the error I get, when doing make bzImage
>>>>
>>>> In file included from litmus/sched_demo.c:3:
>>>> include/litmus/litmus.h:74: error: expected ?=?, ?,?, ?;?, ?asm? or ?__attribute__? before ?litmus_clock?
>>>> include/litmus/litmus.h: In function ?is_kernel_np?:
>>>> include/litmus/litmus.h:120: error: dereferencing pointer to incomplete type
>>> Hi Stefan,
>>>
>>> this is a configuration error in LITMUS^RT. Please enable the configuration option CONFIG_NP_SECTION, which should silence the error. Sorry about that...
>> Actually, litmus/litmus.h already has correct dummy implementations for the !CONFIG_NP_SECTION case, so it's something different. Have you tried a 'make clean'?
>> - Bj?rn
>>
>> And two:
>>
>>
>>> On 05/07/2013 02:19 PM, Bj?rn Brandenburg wrote:
>>>> If it doesn't go away, you are probably missing a header file. Here are the one from the reference version. Does it fail with these headers as well?
>>> Hi Bj?rn,
>>> thanks for the fast reply!
>>> There's no change after make clean.
>>> I paste my C code here:
>>>
>> Commit c5248a7288e54c2b5e2bba8aa2677772542bf90e compiles for me. Can you please try compiling c5248a7288e54c2b5e2bba8aa2677772542bf90e and, if it doesn't work, send me your configuration?
>>
>> Thanks,
>> Bj?rn
>>
>>
>>
>> I have verified that CONFIG_NP_SECTION is in fact enabled and as well I have run a 'make clean'. My next option was to try to checkout commit c5248a7288e54c2b5e2bba8aa2677772542bf90e, however, this is not allowed for my local repository. The error:
>>
>> fatal: reference is not a tree: c5248a7288e54c2b5e2bba8aa2677772542bf90e
>>
>> Is there something else I should do to make this work? Thanks!
>>
>>
>> - Nick
>> -------------- next part --------------
>> An HTML attachment was scrubbed...
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>>
>> ------------------------------
>>
>> _______________________________________________
>> litmus-dev mailing list
>> litmus-dev at lists.litmus-rt.org
>> https://lists.litmus-rt.org/listinfo/litmus-dev
>>
>>
>> End of litmus-dev Digest, Vol 56, Issue 9
>> *****************************************
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