I put these in to match the use of spl*() in the NetBSD code I was basing this
on, but it appears to cause problems.
I'm doing this in a separate commit so as to be able to refer back if locking
becomes an issue at a later stage.
Define the atm_dev_free() routine so that its OK to free stuff that is defined
as volatile. Note this doesn't FORCE the arguemnts to be volatile,
just says that it's not an error if it is..
and isn't strictly required. However, it lowers the number of false
positives found when grep'ing the kernel sources for p_ucred to ensure
proper locking.
the pipe is locked and shouldn't be.
initialize pipe->pipe_mtxp to NULL when creating pipes in order not
to trip the above assertions.
swap pipe lock with giant around calls to pipe_destroy_write_buffer()
pipe_destroy_write_buffer issue noticed by: jhb
fully protect p_ucred yet so Giant is needed until all the p_ucred
locking is done. This is the original reason td_ucred was not used
immediately after its addition. Unfortunately, not using td_ucred is
not enough to avoid problems. Since p_ucred could be stale, we could
actually be dereferencing a stale pointer to dink with the refcount, so
we really need Giant to avoid foot-shooting. This allows td_ucred to
be safely used as well.
In order to determine what to page out, the vm_daemon checks
reference bits on all pages belonging to all processes. Unfortunately,
the algorithm used reacted badly with shared pages; each shared page
would be checked once per process sharing it; this caused an O(N^2)
growth of tlb invalidations. The algorithm has been changed so that
each page will be checked only 16 times.
Prior to this change, a fork/sleepbomb of 1300 processes could cause
the vm_daemon to take over 60 seconds to complete, effectively
freezing the system for that time period. With this change
in place, the vm_daemon completes in less than a second. Any system
with hundreds of processes sharing pages should benefit from this change.
Note that the vm_daemon is only run when the system is under extreme
memory pressure. It is likely that many people with loaded systems saw
no symptoms of this problem until they reached the point where swapping
began.
Special thanks go to dillon, peter, and Chuck Cranor, who helped me
get up to speed with vm internals.
PR: 33542, 20393
Reviewed by: dillon
MFC after: 1 week
in most machines of the Sun Ultra series. This is a port of the NetBSD
driver which I enhanced to make use of the gather functionality and the
configurable RX buffer offset to avoid copying all received/sent packet
(instead, packets will be directly DMAd from mbuf chains and into mbuf
clusters now).
device drivers for bus system with other endinesses than the CPU (using
interfaces compatible to NetBSD):
- bwap16() and bswap32(). These have optimized implementations on some
architectures; for those that don't, there exist generic implementations.
- macros to convert from a certain byte order to host byte order and vice
versa, using a naming scheme like le16toh(), htole16().
These are implemented using the bswap functions.
- stream bus space access functions, which do not perform a byte order
conversion (while the normal access functions would if the bus endianess
differs from the CPU endianess).
htons(), htonl(), ntohs() and ntohl() are implemented using the new
functions above for kernel usage. None of the above interfaces is currently
exported to user land.
Make use of the new functions in a few places where local implementations
of the same functionality existed.
Reviewed by: mike, bde
Tested on alpha by: mike
