Hi Daniel.... On Sat, Jan 16, 2010 at 6:28 PM, Daniel (Youngwhan) Song <breadncup@xxxxxxxxx> wrote: > To confirm again, > > Since kernel thread by kernel_thread() is created by do_fork() in the > kernel, pthread_create() uses clone() system call which eventually calls > do_fork() in the kernel, and fork() in user space calls eventually do_fork() > as well, all threads/process are manged by task_struct with different > configuration(flags). Is this correct? I think it's the other way around...do_fork() eventuall calls clone() with various flags, depending on the intention of the caller. > If then, is my understanding that the implementation of do_fork() is by NPTL > in linux 2.6 correct? NPTL is a complete implementation of threading both in user space (mostly in glibc AFAIK) and kernel space (by system calls and related kernel infrastructure), including signal handling etc etc. do_fork() is just a part of it > If so, there is no heavy process in the linux in typical. Right? If you're using the logic that forking is relatively "cheap" due to using COW, then yes it's quite cheap. However, I believe the label LWP is strictly connected to thread due to one property: threads are sharing process address space, thus during context switch between threads in the same thread group, it could be done fast because there is no need to flush TLB and switch to another PGD. -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
