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runtime: avoid unnecessary zeroization of huge memory blocks

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+move zeroization out of the heap mutex

R=golang-dev, iant, rsc
CC=golang-dev
https://golang.org/cl/6094050
This commit is contained in:
Dmitriy Vyukov 2012-05-02 18:01:11 +04:00
parent 0d55d9832f
commit c1c851bbe8
4 changed files with 6 additions and 7 deletions
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2
src/pkg/runtime/malloc.goc
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@ -60,7 +60,7 @@ runtime·mallocgc(uintptr size, uint32 flag, int32 dogc, int32 zeroed)
npages = size >> PageShift;
if((size & PageMask) != 0)
npages++;
s = runtime·MHeap_Alloc(&runtime·mheap, npages, 0, 1);
s = runtime·MHeap_Alloc(&runtime·mheap, npages, 0, 1, zeroed);
if(s == nil)
runtime·throw("out of memory");
size = npages<<PageShift;

2
src/pkg/runtime/malloc.h
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@ -380,7 +380,7 @@ struct MHeap
extern MHeap runtime·mheap;
void runtime·MHeap_Init(MHeap *h, void *(*allocator)(uintptr));
MSpan* runtime·MHeap_Alloc(MHeap *h, uintptr npage, int32 sizeclass, int32 acct);
MSpan* runtime·MHeap_Alloc(MHeap *h, uintptr npage, int32 sizeclass, int32 acct, int32 zeroed);
void runtime·MHeap_Free(MHeap *h, MSpan *s, int32 acct);
MSpan* runtime·MHeap_Lookup(MHeap *h, void *v);
MSpan* runtime·MHeap_LookupMaybe(MHeap *h, void *v);

2
src/pkg/runtime/mcentral.c
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@ -207,7 +207,7 @@ MCentral_Grow(MCentral *c)
runtime·unlock(c);
runtime·MGetSizeClassInfo(c->sizeclass, &size, &npages, &n);
s = runtime·MHeap_Alloc(&runtime·mheap, npages, c->sizeclass, 0);
s = runtime·MHeap_Alloc(&runtime·mheap, npages, c->sizeclass, 0, 1);
if(s == nil) {
// TODO(rsc): Log out of memory
runtime·lock(c);

7
src/pkg/runtime/mheap.c
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@ -66,7 +66,7 @@ runtime·MHeap_Init(MHeap *h, void *(*alloc)(uintptr))
// Allocate a new span of npage pages from the heap
// and record its size class in the HeapMap and HeapMapCache.
MSpan*
runtime·MHeap_Alloc(MHeap *h, uintptr npage, int32 sizeclass, int32 acct)
runtime·MHeap_Alloc(MHeap *h, uintptr npage, int32 sizeclass, int32 acct, int32 zeroed)
{
MSpan *s;
@ -81,6 +81,8 @@ runtime·MHeap_Alloc(MHeap *h, uintptr npage, int32 sizeclass, int32 acct)
}
}
runtime·unlock(h);
if(s != nil && *(uintptr*)(s->start<<PageShift) != 0 && zeroed)
runtime·memclr((byte*)(s->start<<PageShift), s->npages<<PageShift);
return s;
}
@ -138,9 +140,6 @@ HaveSpan:
MHeap_FreeLocked(h, t);
}
if(*(uintptr*)(s->start<<PageShift) != 0)
runtime·memclr((byte*)(s->start<<PageShift), s->npages<<PageShift);
// Record span info, because gc needs to be
// able to map interior pointer to containing span.
s->sizeclass = sizeclass;