Subject: NetBSD kernels - Are critical sections possible?
To: None <firstname.lastname@example.org>
From: Marc D Bumble <email@example.com>
Date: 03/19/1999 16:46:59
>From NetBSD kernel space, I have a driver which attempts to access
data across the PCI bus. There is an ioctl call which makes the info
request across the PCI bus and then puts the kernel to sleep, using
tsleep(), while it waits for the data to be retrieved. In my system,
it does make sense for more than one user process to request this same
data, so if possible, in the kernel space, I would like to allow one
PCI call to retrieve data whose results more than one user process
Is the NetBSD kernel multi-threaded? Or is there any value in
allowing other processes which need the same data to queue and wait on
the same wakeup call? If so, do I have a critical section below? Or
is the waitvar variable deadweight.
For instance, does this code make sense for the NetBSD kernel?
if (waitvar == 0)
If it does make sense, is it a critical section, as in does it need some
sort of semaphore blocking?
I would just love some pointers to the appropriate manual or
documentation which covers this kernel process topic for NetBSD.
thanks in advance,
Ennovate Networks, Inc.
330 Codman Hill Rd
Boxboro MA 01719
USA Tel 978-263-2002 (ext. 147 or 225)