onkwon / yaos Goto Github PK

When runtime finer than systick granularity, task runtime doesn't get updated as delta is zero.

• debug() to swo terminal directly
• log(msg)
  • WARN:
  • ERR:
  • INFO:

Consider to change the data structure used in such as device manager, timer list, etc, to save memory

As a real time task preempts idle task, the least priority task, idle task never gets chance to clean zombie tasks freeing data memory used by those zombie tasks. It makes eventually system go into out of memory.

Either of below have to be implemented to solve this problem:

1. idle task gets its priority boosted up to the real time task's priority running at the moment
2. call kill_zombie() function manually in a real time task

All the meta blocks are re-written every time it changes, taking too much time. Let's keep it in memory and write back when it really need to be.

Disabling CONFIG_FS, ramfs gets the root file system and mount /dev/ on it. But /dev/ directory isn't visible to user since it is not actually created in the root file system. There is calling dependency making it hard to create /dev' directory between mountingrootfsanddevfs`.

1. Mount rootfs first
2. Create /dev/ directory
3. Mount devfs now

What makes it difficult is that to get [2] done system call functionality must be activated which only can be activated after devfs mounted.

embedfs also need to get optimized as it creates /dev/ in an incompatible way, not configuable to change its name.

probably because of invalid stack pointer. need to dig out

It will make easier for users to dive into code if following CMSIS on ARM Cortex-M architecture. Consider it though I feel lazy.

It only causes instruction and memory overhead not fully supporting SMP. There is no use as well since YAOS is for single core processor. Let's forget about SMP and get rid of synchronization.

only 64KB embedded flash memory are writable by user since flash sector size is not fixed but variable from 16KB to 128KB.

user must make sure not to exceed the boundary of 64KB writing into embedded flash memory. or the result is unpredictable.

implementing soft reset. don't forget to clean cache buffer first before reset

make the member of the structure in the first place then it can be easily replaced by just assignment operator. Such rq member of struct task, link member of struct page, list member of struct ff_freelist and link of structwaitqueue` are the candidates.

besides consider creating a thread for each event and just make it runnable in the handler, softirq_handler(). That would be more efficient than just calling in turn, waiting for the previous work done.

Return back to the task running if possible fixing the problem or schedule to another task after killing the task.

Reset if system is corrupted entirely.

make sure only saved registers are used during that operations

Superblock and inode synchronization must be implemented

Some static task run just once doing something like initializing and it never returns memory back for system to use the unused memory. As task struct consumes memory the most among others, it is necessary to make that unused memory usable.

There are typos in your README.

Those functions internally call get_sysclk() family functions that access to privileged system registers. Make it usable in user mode providing related system call to user.

It is quite a overhead to keep run queue sorted when adding new tasks using linked list structure.

Change polling method timer of sleep() to cascaded timer wheel.

As a task is resident only in a queue at a time, run queue or wait queue, task's rq list can be used in both of queues.

ldrex and strex don't work on rpi. Find out what is going on.