Can kernel handle two syscalls at the same time by doing multithreading? -

when user applications system call, program enters kernel mode , os handles user requests. if @ same time 2 processes syscall, can os multithreading? example there 2 layer of kernel, second layer handle user requests doing multithreading, , first layer control second layer. impossible? or it's not @ practical use?

thanks.

it's done routinely. when process (thread of process) traps kernel, kernel "borrows" user thread run kernel code. it's been long time (decades?) since still had "unique kernel lock" forced sequential executions of threads inside kernel. beside kernel typically running multiple threads own work (paging, write-back, ....).