ref: 207a4bb4a39ff7eac23018e5b8b9734a6d00171b
dir: /alloc.myr/
use "sys.use"
pkg std =
type size = uint
generic alloc : ( -> @a*)
generic free : (v:@a* -> void)
const bytealloc : (sz:size -> byte*)
const bytefree : (ptr:byte* -> void)
;;
/* null pointers */
const Zbyte = 0 castto(byte*)
const Zslab = 0 castto(slab*)
const Zbin = 0 castto(bin*)
const Pagesz = 4096 /* on the systems this supports, anyways... */
type bucket = struct
sz : size /* aligned size */
nper : size /* max number of elements per slab */
slabs : slab* /* partially filled or free slabs */
cache : slab* /* cache of empty slabs, to prevent thrashing */
ncache : size /* size of cache */
;;
type slab = struct
freehd : bin*
next : slab*
nfree : int
;;
type bin = struct
next : bin*
;;
const allocinit = {b : bucket*, sz
b.sz = align(sz, 16)
b.nper = (Pagesz - sizeof(slab))/b.sz
b.slabs = Zslab
b.cache = Zslab
b.ncache = 0
}
const mkslab = {b : bucket*
var p
var s
p = mmap(Zbyte, Mprotrw, Mpriv | Manon, -1, 0)
if p == Mapbad
die("Unable to mmap")
;;
s = p castto(slab*)
s.nfree = b.nper
}
const delslab = {s : slab*
}
const align = {v, align
-> (v + align - 1) & ~(align - 1)
}