Re: furwocks: Fast Userspace Read/Write Locks

Peter Wächtler (pwaechtler@loewe-komp.de)
Thu, 07 Mar 2002 13:40:49 +0100


Rusty Russell wrote:

> This is a userspace implementation of rwlocks on top of futexes.
>

With the futex approach in mind: Does anybody think it's desirable to have

pthread_cond_wait/signal and pthread_mutex_* with inter process scope build
into the kernel as system call?

The only issue I see so far, is that libpthread should get a "reserved" namespace
entry ( /dev/shm/.linuxthreads-locks ?) to hold all the PTHREAD_PROCESS_SHARE
locks/condvars.

OTOH Irix seems to implement inter process locks as syscall, so that the kernel does
all the bookkeeping. That approach denies a malicious program to trash all locks
in the system...

Hmh, then we could implement a per user /dev/shm/.linuxthreads-lock-<uid> with
tight permissions?

What do you think?

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/