pthreads - how kernel manage user space threads in linux? -

i have read linux - threads , process

i understood every kernel threads have unique task_struct

but right question how kernel manage user application's thread, suppose user application have 12 thread how kernel manage them , every thread have unique task_struct kernel threads

the kernel manages them when can, ie. whenever entered 'interrupt' changes state of threads.

there 2 flavours of interrupt: either syscall running thread, or call driver has been entered 'real' hardware interrupt kb, nic, disk, timer etc, can change state of threads , initiate sceduling algorithm run may change set of threads run on available cores.

in between interrupts, kernel manages nothing because not entered.

the task_struct raised when running thread makes syscall create new thread. new thread created ready, , run whenever scheduling algorithm dispatches onto core.