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runtime: delete MHeapMapCache, which is useless

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because free needs to mark the block as freed to
coordinate with the garbage collector.

(in C++ free can blindly put the block on the free list,
no questions asked, so the cache saves some work.)

R=iant
CC=golang-dev
https://golang.org/cl/206069
This commit is contained in:
Russ Cox 2010-02-10 21:23:08 -08:00
parent fc8e3d4004
commit 22a7f2a14d
7 changed files with 33 additions and 133 deletions
Download patch file Download diff file Expand all files Collapse all files

67
src/pkg/runtime/malloc.cgo
View file

@ -48,6 +48,12 @@ mallocgc(uintptr size, uint32 refflag, int32 dogc, int32 zeroed)
mstats.alloc += size;
mstats.total_alloc += size;
mstats.by_size[sizeclass].nmalloc++;
if(!mlookup(v, nil, nil, nil, &ref)) {
printf("malloc %D; mlookup failed\n", (uint64)size);
throw("malloc mlookup");
}
*ref = RefNone | refflag;
} else {
// TODO(rsc): Report tracebacks for very large allocations.
@ -61,14 +67,10 @@ mallocgc(uintptr size, uint32 refflag, int32 dogc, int32 zeroed)
mstats.alloc += npages<<PageShift;
mstats.total_alloc += npages<<PageShift;
v = (void*)(s->start << PageShift);
}
// setup for mark sweep
if(!mlookup(v, nil, nil, &ref)) {
printf("malloc %D; mlookup failed\n", (uint64)size);
throw("malloc mlookup");
// setup for mark sweep
s->gcref0 = RefNone | refflag;
}
*ref = RefNone | refflag;
m->mallocing = 0;
@ -88,7 +90,6 @@ void
free(void *v)
{
int32 sizeclass, size;
uintptr page, tmp;
MSpan *s;
MCache *c;
uint32 *ref;
@ -100,46 +101,34 @@ free(void *v)
throw("malloc/free - deadlock");
m->mallocing = 1;
if(!mlookup(v, nil, nil, &ref)) {
if(!mlookup(v, nil, nil, &s, &ref)) {
printf("free %p: not an allocated block\n", v);
throw("free mlookup");
}
*ref = RefFree;
// Find size class for v.
page = (uintptr)v >> PageShift;
sizeclass = MHeapMapCache_GET(&mheap.mapcache, page, tmp);
sizeclass = s->sizeclass;
if(sizeclass == 0) {
// Missed in cache.
s = MHeap_Lookup(&mheap, page);
if(s == nil)
throw("free - invalid pointer");
sizeclass = s->sizeclass;
if(sizeclass == 0) {
// Large object.
mstats.alloc -= s->npages<<PageShift;
runtime_memclr(v, s->npages<<PageShift);
MHeap_Free(&mheap, s);
goto out;
}
MHeapMapCache_SET(&mheap.mapcache, page, sizeclass);
// Large object.
mstats.alloc -= s->npages<<PageShift;
runtime_memclr(v, s->npages<<PageShift);
MHeap_Free(&mheap, s);
} else {
// Small object.
c = m->mcache;
size = class_to_size[sizeclass];
if(size > sizeof(uintptr))
((uintptr*)v)[1] = 1; // mark as "needs to be zeroed"
mstats.alloc -= size;
mstats.by_size[sizeclass].nfree++;
MCache_Free(c, v, sizeclass, size);
}
// Small object.
c = m->mcache;
size = class_to_size[sizeclass];
if(size > sizeof(uintptr))
((uintptr*)v)[1] = 1; // mark as "needs to be zeroed"
mstats.alloc -= size;
mstats.by_size[sizeclass].nfree++;
MCache_Free(c, v, sizeclass, size);
out:
m->mallocing = 0;
}
int32
mlookup(void *v, byte **base, uintptr *size, uint32 **ref)
mlookup(void *v, byte **base, uintptr *size, MSpan **sp, uint32 **ref)
{
uintptr n, nobj, i;
byte *p;
@ -147,6 +136,8 @@ mlookup(void *v, byte **base, uintptr *size, uint32 **ref)
mstats.nlookup++;
s = MHeap_LookupMaybe(&mheap, (uintptr)v>>PageShift);
if(sp)
*sp = s;
if(s == nil) {
if(base)
*base = nil;
@ -256,7 +247,7 @@ stackalloc(uint32 n)
return v;
}
v = mallocgc(n, 0, 0, 0);
if(!mlookup(v, nil, nil, &ref))
if(!mlookup(v, nil, nil, nil, &ref))
throw("stackalloc mlookup");
*ref = RefStack;
return v;
@ -283,7 +274,7 @@ func Free(p *byte) {
}
func Lookup(p *byte) (base *byte, size uintptr) {
mlookup(p, &base, &size, nil);
mlookup(p, &base, &size, nil, nil);
}
func GC() {
@ -306,7 +297,7 @@ func SetFinalizer(obj Eface, finalizer Eface) {
printf("runtime.SetFinalizer: first argument is %S, not pointer\n", *obj.type->string);
goto throw;
}
if(!mlookup(obj.data, &base, &size, nil) || obj.data != base) {
if(!mlookup(obj.data, &base, &size, nil, nil) || obj.data != base) {
printf("runtime.SetFinalizer: pointer not at beginning of allocated block\n");
goto throw;
}