Primary purpose of change: to support the mmap implementation, VM must
know both (a) about some block metadata for FS cache blocks, i.e. inode
numbers and inode offsets where applicable; and (b) know about *all*
cache blocks, i.e. also of the FS primary caches and not just the
blocks that spill into the secondary one. This changes the interface and
VM data structures.
This change is only for the interface (libminixfs) and VM data
structures; the filesystem code is unmodified, so although the secondary
cache will be used as normal, blocks will not be annotated with inode
information until the FS is modified to provide this information. Until
it is modified, mmap of files will fail gracefully on such filesystems.
This is indicated to VFS/VM by returning ENOSYS for REQ_PEEK.
Change-Id: I1d2df6c485e6c5e89eb28d9055076cc02629594e
. make vm be able to use malloc() by overriding brk()
and minix_mmap() functions
. phys regions can then be malloc()ed and free()d instead
of being in an avl tree, which is slightly faster
. 'offset' field in phys_region can go too (offset is implied
by position in array) but leads to bigger code changes
Introduce explicit abstractions for different mapping types,
handling the instantiation, forking, pagefaults and freeing of
anonymous memory, direct physical mappings, shared memory and
physically contiguous anonymous memory as separate types, making
region.c more generic.
Also some other genericification like merging the 3 munmap cases
into one.
COW and SMAP safemap code is still implicit in region.c.
complete munmap implementation; single-page references made
a general munmap() implementation possible to write cleanly.
. memory: let the MIOCRAMSIZE ioctl set the imgrd device
size (but only to 0)
. let the ramdisk command set sizes to 0
. use this command to set /dev/imgrd to 0 after mounting /usr
in /etc/rc, so the boot time ramdisk is freed (about 4MB
currently)
