forked from Imagelibrary/rtems
ae88aa7927
This partially reverts commit 1215fd4d94.
In order to support profiling of SMP locks and provide a future
compatible SMP locks API it is necessary to add an SMP lock destroy
function. Since the commit above adds an SMP lock to each chain control
we would have to add a rtems_chain_destroy() function as well. This
complicates the chain usage dramatically. Thus revert the patch above.
A global SMP lock for all chains is used to implement the protected
chain operations.
Advantages:
* The SAPI chain API is now identical on SMP and non-SMP
configurations.
* The size of the chain control is reduced and is then equal to the
Score chains.
* The protected chain operations work correctly on SMP.
Disadvantage:
* Applications using many different chains and the protected operations
may notice lock contention.
The chain control size drop is a huge benefit (SAPI chain controls are
66% larger than the Score chain controls). The only disadvantage is not
really a problem since these applications can use specific interrupt
locks and unprotected chain operations to avoid this issue.
This is the Real-Time Executive for Multiprocessing Systems (RTEMS). The version number for this software is indicated in the VERSION file. See the documentation manuals in doc/ with daily builds available online at http://rtems.org/onlinedocs/doc-current/share/rtems/html/ and released builds at http://www.rtems.org/onlinedocs/releases/ for information on building, installing, and using RTEMS. The INSTALL file tells you to come back here. See the RTEMS Wiki at http://wiki.rtems.org/wiki/index.php/Main_Page for community knowledge and tutorials. RTEMS Doxygen available at http://www.rtems.org/onlinedocs/doxygen/cpukit/html Get help on the mailing lists: * For general-purpose questions related to using RTEMS, use the rtems-users ml: http://www.rtems.org/mailman/listinfo/rtems-users * For questions and discussion related to development of RTEMS, use the rtems-devel ml: http://www.rtems.org/mailman/listinfo/rtems-devel See http://www.rtems.org/bugzilla/ to report a bug.