runtime: faster allocator, garbage collector
GC is still single-threaded.
Multiple threads will happen in another CL.
Garbage collection pauses are typically
about half as long as they were before this CL.
R=brainman, iant, r
CC=golang-dev
https://golang.org/cl/3975046
diff --git a/src/pkg/runtime/mcentral.c b/src/pkg/runtime/mcentral.c
index f1ad119..29b03b5 100644
--- a/src/pkg/runtime/mcentral.c
+++ b/src/pkg/runtime/mcentral.c
@@ -113,8 +113,7 @@
MCentral_Free(MCentral *c, void *v)
{
MSpan *s;
- PageID page;
- MLink *p, *next;
+ MLink *p;
int32 size;
// Find span for v.
@@ -138,16 +137,8 @@
if(--s->ref == 0) {
size = runtime·class_to_size[c->sizeclass];
runtime·MSpanList_Remove(s);
- // The second word of each freed block indicates
- // whether it needs to be zeroed. The first word
- // is the link pointer and must always be cleared.
- for(p=s->freelist; p; p=next) {
- next = p->next;
- if(size > sizeof(uintptr) && ((uintptr*)p)[1] != 0)
- runtime·memclr((byte*)p, size);
- else
- p->next = nil;
- }
+ runtime·unmarkspan((byte*)(s->start<<PageShift), s->npages<<PageShift);
+ *(uintptr*)(s->start<<PageShift) = 1; // needs zeroing
s->freelist = nil;
c->nfree -= (s->npages << PageShift) / size;
runtime·unlock(c);
@@ -157,7 +148,7 @@
}
void
-runtime·MGetSizeClassInfo(int32 sizeclass, int32 *sizep, int32 *npagesp, int32 *nobj)
+runtime·MGetSizeClassInfo(int32 sizeclass, uintptr *sizep, int32 *npagesp, int32 *nobj)
{
int32 size;
int32 npages;
@@ -166,7 +157,7 @@
size = runtime·class_to_size[sizeclass];
*npagesp = npages;
*sizep = size;
- *nobj = (npages << PageShift) / (size + RefcountOverhead);
+ *nobj = (npages << PageShift) / size;
}
// Fetch a new span from the heap and
@@ -174,7 +165,8 @@
static bool
MCentral_Grow(MCentral *c)
{
- int32 i, n, npages, size;
+ int32 i, n, npages;
+ uintptr size;
MLink **tailp, *v;
byte *p;
MSpan *s;
@@ -191,7 +183,7 @@
// Carve span into sequence of blocks.
tailp = &s->freelist;
p = (byte*)(s->start << PageShift);
- s->gcref = (uint32*)(p + size*n);
+ s->limit = p + size*n;
for(i=0; i<n; i++) {
v = (MLink*)p;
*tailp = v;
@@ -199,6 +191,7 @@
p += size;
}
*tailp = nil;
+ runtime·markspan((byte*)(s->start<<PageShift), size, n, size*n < (s->npages<<PageShift));
runtime·lock(c);
c->nfree += n;
