The spawn proxy thread is a special existence in NuttX, usually some developers
spend a lot of time on stack overflow of spawn proxy thread:
https://github.com/apache/nuttx/issues/9046https://github.com/apache/nuttx/pull/9081
In order to avoid similar issues, this PR will remove spawn proxy thread to simplify
the process of task/posix_spawn().
1. Postpone the related processing of spawn file actions until after task_init()
2. Delete the temporary thread of spawn proxy and related global variables
Signed-off-by: chao an <anchao@xiaomi.com>
Store the old environment in a local context so another temporary address
environment can be selected. This can happen especially when a process
is being loaded (the new process's mappings are temporarily instantiated)
and and interrupt occurs.
Summary:
- Support arm64 pmu api, Currently only the cycle counter function is supported.
- Using ARM64 PMU hardware capability to implement perf interface, modify all
perf interface related code.
- Support for pmu init under smp.
Signed-off-by: wangming9 <wangming9@xiaomi.com>
Compilation error occurs after SCHED_CRITMONITOR is enabled
sched/sched_critmonitor.c:315: undefined reference to `serr'
Signed-off-by: yinshengkai <yinshengkai@xiaomi.com>
There is currently a big problem in the address environment handling which
is that the address environment is released too soon when the process is
exiting. The current MMU mappings will always be the exiting process's, which means
the system needs them AT LEAST until the next context switch happens. If
the next thread is a kernel thread, the address environment is needed for
longer.
Kernel threads "lend" the address environment of the previous user process.
This is beneficial in two ways:
- The kernel processes do not need an allocated address environment
- When a context switch happens from user -> kernel or kernel -> kernel,
the TLB does not need to be flushed. This must be done only when
changing to a different user address environment.
Another issue is when a new process is created; the address environment
of the new process must be temporarily instantiated by up_addrenv_select().
However, the system scheduler does not know that the process has a different
address environment to its own and when / if a context restore happens, the
wrong MMU page directory is restored and the process will either crash or
do something horribly wrong.
The following changes are needed to fix the issues:
- Add mm_curr which is the current address environment of the process
- Add a reference counter to safeguard the address environment
- Whenever an address environment is mapped to MMU, its reference counter
is incremented
- Whenever and address environment is unmapped from MMU, its reference
counter is decremented, and tested. If no more references -> drop the
address environment and release the memory as well
- To limit the context switch delay, the address environment is freed in
a separate low priority clean-up thread (LPWORK)
- When a process temporarily instantiates another process's address
environment, the scheduler will now know of this and will restore the
correct mappings to MMU
Why is this not causing more noticeable issues ? The problem only happens
under the aforementioned special conditions, and if a context switch or
IRQ occurs during this time.
Detach the address environment handling from the group structure to the
tcb. This is preparation to fix rare cases where the system (MMU) is left
without a valid page directory, e.g. when a process exits.
NuttX kernel should not use the syscall functions, especially after
enabling CONFIG_SCHED_INSTRUMENTATION_SYSCALL, all system functions
will be traced to backend, which will impact system performance.
Signed-off-by: chao an <anchao@xiaomi.com>
A testcase as following:
child_task()
{
sleep(3);
}
main_task()
{
while (1)
{
ret = task_create("child_task", child_task, );
sleep(1);
task_delete(ret);
}
}
Root casuse:
task_delete hasn's cover the condition that the deleted-task
is justing running on the other CPU.
Fix:
Let the nxsched_remove_readytorun() do the real work
Signed-off-by: ligd <liguiding1@xiaomi.com>
This is preparation for flushing streams from user space, like it should
be done.
- Move tg_streamlist (group, kernel space) ->
ta_streamlist (TLS, user space)
- Access stream list via tg_info in kernel
- Access stream list via TLS in user space
- Remove / rename nxsched_get_streams -> lib_getstreams
- Remove system call for nxsched_get_streams
The user stack is dependent on the user address environment. As the
process exits, this address environment is destroyed anyway, so the
stack does not need to be released separately.
There is also an issue with this when the process exits via exit(). The
problem is that the task group is released prior to this "up_release_stack()"
call along with the address environment, and trying to free the memory
either causes an immediate crash (no valid addrenv), or frees memory into
another process' heap (addrenv from a different process).
Signed-off-by: Ville Juven <ville.juven@unikie.com>
It takes about 10 cycles to obtain the task list according to the task
status. In most cases, we know the task status, so we can directly
add the task from the specified task list to reduce time consuming.
It takes about 10 cycles to obtain the task list according to the task
status. In most cases, we know the task status, so we can directly
delete the task from the specified task list to reduce time consuming.
1.Don't include unwind.h when arch specific backtrace is enable
2.Built arch specific backtrace wrapper only when enable
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Optimize sched_note_begin/end, replace note_printf with note_string
sched_note_begin/end optimized from 50us to 1us per consumption
Signed-off-by: yinshengkai <yinshengkai@xiaomi.com>
Situation:
Assume we have 2 cpus, and busy run task0.
CPU0 CPU1
task0 -> task1 task2 -> task0
1. remove task0 form runninglist
2. take task1 as new tcb
3. add task0 to blocklist
4. clear spinlock
4.1 remove task2 form runninglist
4.2 take task0 as new tcb
4.3 add task2 to blocklist
4.4 use svc ISR swith to task0
4.5 crash
5. use svc ISR swith to task1
Fix:
Move clear spinlock to the end of svc ISR
Signed-off-by: ligd <liguiding1@xiaomi.com>
