jingfei195887 opened a new pull request, #20669:
URL: https://github.com/apache/nuttx/pull/20669
## Summary
Related to the footprint discussion in #20414.
Tasks between setup and activation are added to `g_inactivetasks` and removed
again on activation or teardown, but nothing walks that list: tasks are found
through `g_pidhash`. The extra critical section and list operations add code
to
every task creation path (`nxtask_init`, fork, restart, and their error
paths).
This change stops linking such tasks into the list. `TSTATE_TASK_INACTIVE`
and its (now always empty) list entry in `g_tasklisttable` are kept, so the
generic blocked-list helpers keep working unchanged:
- `nxtask_activate()` and `nxsched_suspend()` remove the TCB through
`nxsched_remove_blocked()` -> `dq_rem()`. A TCB entering the inactive state
always has NULL `flink`/`blink`: new TCBs come from `kmm_zalloc()`, and
`nxtask_restart()` unlinks the TCB with `dq_rem()` (which clears both
links)
before resetting it. `dq_rem()` of such a node from an empty list leaves
the
list empty and the node unchanged.
- Nothing else iterates the list or depends on its contents.
The tasking documentation is updated to match.
## Impact
- No functional change. No API or ABI change.
- Removes one critical section and the list insert/remove from each task
creation and teardown path.
## Testing
Host: Ubuntu x86_64, arm-none-eabi-gcc 10.3.1 20210621, master be9dc4cbaa,
clean CMake builds.
| build | master | this PR | delta |
|---|---:|---:|---:|
| `stm32f103-minimum:nsh` flash (text + data) | 52443 | 52371 | **-72** |
Runtime, with `DEBUG_FEATURES=y` and `DEBUG_ASSERTIONS=y`:
- `sim:ostest`, patched and master side by side: both reached
`timedwait_test`
within a 400 s timeout, ran the same tests in the same order, and the
`task_restart` test completed (`restart_main: Exiting` twice) in both.
No assertion, panic or `ERROR`. ostest did not finish within the timeout in
either build, so this shows no difference rather than a full pass.
- `sim:smp`: boots to `nsh>`, `hello` runs, ostest starts and passes the
`task_restart` test with no assertion.
Other checks:
- `sim:smp` (default config) builds.
- `./tools/checkpatch.sh -g master..HEAD`: all checks pass.
Not tested on hardware.
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