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| author | Aun-Ali Zaidi <admin@kodeit.net> | 2015-12-23 14:44:02 -0600 |
|---|---|---|
| committer | Joel Sherrill <joel.sherrill@oarcorp.com> | 2015-12-24 16:52:34 -0600 |
| commit | d5154d0f6a04f3b7ed59d9a09038576fe2640756 (patch) | |
| tree | 4b6dcf6e9b116223903afbc1b1141d28fb751848 /doc/user/userext.t | |
| parent | score: Fix watchdog removal (diff) | |
| download | rtems-d5154d0f6a04f3b7ed59d9a09038576fe2640756.tar.bz2 | |
api: Remove deprecated Notepads
Notepads where a feature of RTEMS' tasks that simply functioned in
the same way as POSIX keys or threaded local storage (TLS). They were
introduced well before per task variables, which are also deprecated,
and were barely used in favor of their POSIX alternatives.
In addition to their scarce usage, Notepads took up unnecessary memory.
For each task:
- 16 32-bit integers were allocated.
- A total of 64 bytes per task per thread.
This is especially critical in low memory and safety-critical applications.
They are also defined as uint32_t, and therefore are not guaranteed to
hold a pointer.
Lastly, they are not portable solutions for SMP and uniprocessor systems,
like POSIX keys and TLS.
updates #2493.
Diffstat (limited to '')
| -rw-r--r-- | doc/user/userext.t | 6 |
1 files changed, 1 insertions, 5 deletions
diff --git a/doc/user/userext.t b/doc/user/userext.t index dc6ad4e5ee..7f4a10180d 100644 --- a/doc/user/userext.t +++ b/doc/user/userext.t @@ -134,11 +134,7 @@ RTEMS provides for a pointer to a user-defined data area for each extension set to be linked to each task's control block. This set of pointers is an extension of the TCB and can be used to store additional data required by the user's -extension functions. It is also possible for a user extension -to utilize the notepad locations associated with each task -although this may conflict with application usage of those -particular notepads. However, notepads are deprecated and will -be removed. +extension functions. The TCB extension is an array of pointers in the TCB. The index into the table can be obtained from the extension id |