virtual memory reservation and a private pool of memory pages -- by a scheme
based on memory pools.
This allows better utilization of memory because buffers can now be allocated
with a granularity finer than the system's native page size (useful for
filesystems with e.g. 1k or 2k fragment sizes). It also avoids fragmentation
of virtual to physical memory mappings (due to the former fixed virtual
address reservation) resulting in better utilization of MMU resources on some
platforms. Finally, the scheme is more flexible by allowing run-time decisions
on the amount of memory to be used for buffers.
On the other hand, the effectiveness of the LRU queue for buffer recycling
may be somewhat reduced compared to the traditional method since, due to the
nature of the pool based memory allocation, the actual least recently used
buffer may release its memory to a pool different from the one needed by a
newly allocated buffer. However, this effect will kick in only if the
system is under memory pressure.
Gone are the old kern_sysctl(), cpu_sysctl(), hw_sysctl(),
vfs_sysctl(), etc, routines, along with sysctl_int() et al. Now all
nodes are registered with the tree, and nodes can be added (or
removed) easily, and I/O to and from the tree is handled generically.
Since the nodes are registered with the tree, the mapping from name to
number (and back again) can now be discovered, instead of having to be
hard coded. Adding new nodes to the tree is likewise much simpler --
the new infrastructure handles almost all the work for simple types,
and just about anything else can be done with a small helper function.
All existing nodes are where they were before (numerically speaking),
so all existing consumers of sysctl information should notice no
difference.
PS - I'm sorry, but there's a distinct lack of documentation at the
moment. I'm working on sysctl(3/8/9) right now, and I promise to
watch out for buses.
While we are here, try to tag machine dependent functions in header files.
also transformed darwin_ppc_*_state into mach_ppc_*_state, as this is
what they really are (COMPAT_DARWIN is on the top of COMPAT_MACH, not the
other way around)
Remove p_raslock and rename p_lwplock p_lock (one lock is enough).
Simplify window test when adding a ras and correct test on VM_MAXUSER_ADDRESS.
Avoid unpredictable branch in i386 locore.S
(pad fields left in struct proc to avoid kernel bump)
containing signal posting, kernel-exit handling and sa_upcall processing.
XXX the pc532, sparc, sparc64 and vax ports should have their
XXX userret() code rearranged to use this.
Use <powerpc/oea/bat.h> exclusively and remove <machine/bat.h> and
<powerpc/bat.h>. Remove unneeded <machine/cpufunc.h>. To insure
1:1 correspondence of <powerpc/FOO.h> to <machine/FOO.h> include
"../../powerpc/include/Makefile" in "arch/FOO/include/Makefile".
Incororpate <byte_swap.h> into <bswap.h> and then byte_swap.h
aymeric