Patch for "strict order mutex"

[Ray]

  Thanks for your work. But pls compress your patch file before send to the maillist.
  And I believe that you did not make the right patch in the attachment. It is hard to merge a patch file of 81,000 lines. It is a better idea to make a diff base on a freeze version (e.g. version 4.7.1 or CVS snapshot 4.7.99.2) because CVS is a moving target. It has to keep in mind that the patch should only contain your changes.


------------------
Thanks & Best Regards!
Ray
2007-10-19

-------------------------------------------------------------
From: xi yang
Date: 2007-10-19 02:15:49
To:   RTEMS Users; Joel Sherrill
CC:
Sub:  Patch for "strict order mutex"

>>
>1)What's strict order mutex ?
>
>  In rtems,when a task release a priority_inheritance or
>  priority ceiling semaphore,the kernel detect whether
>  this task holds priority_inheritance or priority
>  ceiling semaphore, if not, set the priority of task
>  back to real priority of task.
>  This method  is right, but in theory, we would like
>  to reset the priority after releasing the mutex if
>  releasing it in LIFO order.Do it like this can decrease
>  the blocking time of a higher priority task .
>
>2)How to enable "strict order mutex " ?
>
>  When configuring the rtems , add
>  ENABLE_STRICT_ORDER_MUTEX=1
>  to your configure parameter.
>
>I add sp36 to test the function of "strict order mutex"
>3)About this test program
>
> T0,T1,S0,S1
>
> T0,priority 4
> T1,priority 1
>
> S0,priority inheritance
>  S1,priority ceiling,priority ceiling 2
>
> 1,T0 obtain S0 then obtain S1, priority of T0 should be improved to 2
> 2,T0 try to release S0, but not in strict order, return error code
> 3,T0 release S1,the priority of T0 back to 4
> 4,T1 try to obtain S0
> 5,T1 should be blocked and the priority of T0 should be improved to 1
> 6,T0 release S0
> 7,T1 obtain S0
> 8,OVER.
>
>I test it under bochs , this patch is for rtems that check form CVS as
>cvs -d :pserver:anoncvs at www.rtems.com:/usr1/CVS -z 9 co
>-rrtems-4-8-branch  rtems
>
>Regards.
>
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