Imported Upstream version 60upstream/60

1 files changed, 482 insertions, 0 deletions

diff --git a/src/pkg/runtime/malloc.goc b/src/pkg/runtime/malloc.goc
new file mode 100644
index 000000000..b9fe36db6
--- /dev/null
+++ b/src/pkg/runtime/malloc.goc
@@ -0,0 +1,482 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// See malloc.h for overview.
+//
+// TODO(rsc): double-check stats.
+
+package runtime
+#include "runtime.h"
+#include "stack.h"
+#include "malloc.h"
+#include "defs.h"
+#include "type.h"
+
+MHeap runtime·mheap;
+extern MStats mstats;	// defined in extern.go
+
+extern volatile int32 runtime·MemProfileRate;
+
+// Allocate an object of at least size bytes.
+// Small objects are allocated from the per-thread cache's free lists.
+// Large objects (> 32 kB) are allocated straight from the heap.
+void*
+runtime·mallocgc(uintptr size, uint32 flag, int32 dogc, int32 zeroed)
+{
+	int32 sizeclass, rate;
+	MCache *c;
+	uintptr npages;
+	MSpan *s;
+	void *v;
+
+	if(runtime·gcwaiting && g != m->g0 && m->locks == 0)
+		runtime·gosched();
+	if(m->mallocing)
+		runtime·throw("malloc/free - deadlock");
+	m->mallocing = 1;
+	if(size == 0)
+		size = 1;
+
+	c = m->mcache;
+	c->local_nmalloc++;
+	if(size <= MaxSmallSize) {
+		// Allocate from mcache free lists.
+		sizeclass = runtime·SizeToClass(size);
+		size = runtime·class_to_size[sizeclass];
+		v = runtime·MCache_Alloc(c, sizeclass, size, zeroed);
+		if(v == nil)
+			runtime·throw("out of memory");
+		c->local_alloc += size;
+		c->local_total_alloc += size;
+		c->local_by_size[sizeclass].nmalloc++;
+	} else {
+		// TODO(rsc): Report tracebacks for very large allocations.
+
+		// Allocate directly from heap.
+		npages = size >> PageShift;
+		if((size & PageMask) != 0)
+			npages++;
+		s = runtime·MHeap_Alloc(&runtime·mheap, npages, 0, 1);
+		if(s == nil)
+			runtime·throw("out of memory");
+		size = npages<<PageShift;
+		c->local_alloc += size;
+		c->local_total_alloc += size;
+		v = (void*)(s->start << PageShift);
+
+		// setup for mark sweep
+		runtime·markspan(v, 0, 0, true);
+	}
+	if(!(flag & FlagNoGC))
+		runtime·markallocated(v, size, (flag&FlagNoPointers) != 0);
+
+	m->mallocing = 0;
+
+	if(!(flag & FlagNoProfiling) && (rate = runtime·MemProfileRate) > 0) {
+		if(size >= rate)
+			goto profile;
+		if(m->mcache->next_sample > size)
+			m->mcache->next_sample -= size;
+		else {
+			// pick next profile time
+			if(rate > 0x3fffffff)	// make 2*rate not overflow
+				rate = 0x3fffffff;
+			m->mcache->next_sample = runtime·fastrand1() % (2*rate);
+		profile:
+			runtime·setblockspecial(v);
+			runtime·MProf_Malloc(v, size);
+		}
+	}
+
+	if(dogc && mstats.heap_alloc >= mstats.next_gc)
+		runtime·gc(0);
+	return v;
+}
+
+void*
+runtime·malloc(uintptr size)
+{
+	return runtime·mallocgc(size, 0, 0, 1);
+}
+
+// Free the object whose base pointer is v.
+void
+runtime·free(void *v)
+{
+	int32 sizeclass;
+	MSpan *s;
+	MCache *c;
+	uint32 prof;
+	uintptr size;
+
+	if(v == nil)
+		return;
+	
+	// If you change this also change mgc0.c:/^sweepspan,
+	// which has a copy of the guts of free.
+
+	if(m->mallocing)
+		runtime·throw("malloc/free - deadlock");
+	m->mallocing = 1;
+
+	if(!runtime·mlookup(v, nil, nil, &s)) {
+		runtime·printf("free %p: not an allocated block\n", v);
+		runtime·throw("free runtime·mlookup");
+	}
+	prof = runtime·blockspecial(v);
+
+	// Find size class for v.
+	sizeclass = s->sizeclass;
+	c = m->mcache;
+	if(sizeclass == 0) {
+		// Large object.
+		size = s->npages<<PageShift;
+		*(uintptr*)(s->start<<PageShift) = 1;	// mark as "needs to be zeroed"
+		// Must mark v freed before calling unmarkspan and MHeap_Free:
+		// they might coalesce v into other spans and change the bitmap further.
+		runtime·markfreed(v, size);
+		runtime·unmarkspan(v, 1<<PageShift);
+		runtime·MHeap_Free(&runtime·mheap, s, 1);
+	} else {
+		// Small object.
+		size = runtime·class_to_size[sizeclass];
+		if(size > sizeof(uintptr))
+			((uintptr*)v)[1] = 1;	// mark as "needs to be zeroed"
+		// Must mark v freed before calling MCache_Free:
+		// it might coalesce v and other blocks into a bigger span
+		// and change the bitmap further.
+		runtime·markfreed(v, size);
+		c->local_by_size[sizeclass].nfree++;
+		runtime·MCache_Free(c, v, sizeclass, size);
+	}
+	c->local_alloc -= size;
+	if(prof)
+		runtime·MProf_Free(v, size);
+	m->mallocing = 0;
+}
+
+int32
+runtime·mlookup(void *v, byte **base, uintptr *size, MSpan **sp)
+{
+	uintptr n, i;
+	byte *p;
+	MSpan *s;
+
+	m->mcache->local_nlookup++;
+	s = runtime·MHeap_LookupMaybe(&runtime·mheap, v);
+	if(sp)
+		*sp = s;
+	if(s == nil) {
+		runtime·checkfreed(v, 1);
+		if(base)
+			*base = nil;
+		if(size)
+			*size = 0;
+		return 0;
+	}
+
+	p = (byte*)((uintptr)s->start<<PageShift);
+	if(s->sizeclass == 0) {
+		// Large object.
+		if(base)
+			*base = p;
+		if(size)
+			*size = s->npages<<PageShift;
+		return 1;
+	}
+
+	if((byte*)v >= (byte*)s->limit) {
+		// pointers past the last block do not count as pointers.
+		return 0;
+	}
+
+	n = runtime·class_to_size[s->sizeclass];
+	if(base) {
+		i = ((byte*)v - p)/n;
+		*base = p + i*n;
+	}
+	if(size)
+		*size = n;
+
+	return 1;
+}
+
+MCache*
+runtime·allocmcache(void)
+{
+	MCache *c;
+
+	runtime·lock(&runtime·mheap);
+	c = runtime·FixAlloc_Alloc(&runtime·mheap.cachealloc);
+	mstats.mcache_inuse = runtime·mheap.cachealloc.inuse;
+	mstats.mcache_sys = runtime·mheap.cachealloc.sys;
+	runtime·unlock(&runtime·mheap);
+	return c;
+}
+
+void
+runtime·purgecachedstats(M* m)
+{
+	MCache *c;
+
+	// Protected by either heap or GC lock.
+	c = m->mcache;
+	mstats.heap_alloc += c->local_cachealloc;
+	c->local_cachealloc = 0;
+	mstats.heap_objects += c->local_objects;
+	c->local_objects = 0;
+	mstats.nmalloc += c->local_nmalloc;
+	c->local_nmalloc = 0;
+	mstats.nfree += c->local_nfree;
+	c->local_nfree = 0;
+	mstats.nlookup += c->local_nlookup;
+	c->local_nlookup = 0;
+	mstats.alloc += c->local_alloc;
+	c->local_alloc= 0;
+	mstats.total_alloc += c->local_total_alloc;
+	c->local_total_alloc= 0;
+}
+
+uintptr runtime·sizeof_C_MStats = sizeof(MStats);
+
+#define MaxArena32 (2U<<30)
+
+void
+runtime·mallocinit(void)
+{
+	byte *p;
+	uintptr arena_size, bitmap_size;
+	extern byte end[];
+
+	runtime·InitSizes();
+
+	// Set up the allocation arena, a contiguous area of memory where
+	// allocated data will be found.  The arena begins with a bitmap large
+	// enough to hold 4 bits per allocated word.
+	if(sizeof(void*) == 8) {
+		// On a 64-bit machine, allocate from a single contiguous reservation.
+		// 16 GB should be big enough for now.
+		//
+		// The code will work with the reservation at any address, but ask
+		// SysReserve to use 0x000000f800000000 if possible.
+		// Allocating a 16 GB region takes away 36 bits, and the amd64
+		// doesn't let us choose the top 17 bits, so that leaves the 11 bits
+		// in the middle of 0x00f8 for us to choose.  Choosing 0x00f8 means
+		// that the valid memory addresses will begin 0x00f8, 0x00f9, 0x00fa, 0x00fb.
+		// None of the bytes f8 f9 fa fb can appear in valid UTF-8, and
+		// they are otherwise as far from ff (likely a common byte) as possible.
+		// Choosing 0x00 for the leading 6 bits was more arbitrary, but it
+		// is not a common ASCII code point either.  Using 0x11f8 instead
+		// caused out of memory errors on OS X during thread allocations.
+		// These choices are both for debuggability and to reduce the
+		// odds of the conservative garbage collector not collecting memory
+		// because some non-pointer block of memory had a bit pattern
+		// that matched a memory address.
+		//
+		// Actually we reserve 17 GB (because the bitmap ends up being 1 GB)
+		// but it hardly matters: fc is not valid UTF-8 either, and we have to
+		// allocate 15 GB before we get that far.
+		arena_size = 16LL<<30;
+		bitmap_size = arena_size / (sizeof(void*)*8/4);
+		p = runtime·SysReserve((void*)(0x00f8ULL<<32), bitmap_size + arena_size);
+		if(p == nil)
+			runtime·throw("runtime: cannot reserve arena virtual address space");
+	} else {
+		// On a 32-bit machine, we can't typically get away
+		// with a giant virtual address space reservation.
+		// Instead we map the memory information bitmap
+		// immediately after the data segment, large enough
+		// to handle another 2GB of mappings (256 MB),
+		// along with a reservation for another 512 MB of memory.
+		// When that gets used up, we'll start asking the kernel
+		// for any memory anywhere and hope it's in the 2GB
+		// following the bitmap (presumably the executable begins
+		// near the bottom of memory, so we'll have to use up
+		// most of memory before the kernel resorts to giving out
+		// memory before the beginning of the text segment).
+		//
+		// Alternatively we could reserve 512 MB bitmap, enough
+		// for 4GB of mappings, and then accept any memory the
+		// kernel threw at us, but normally that's a waste of 512 MB
+		// of address space, which is probably too much in a 32-bit world.
+		bitmap_size = MaxArena32 / (sizeof(void*)*8/4);
+		arena_size = 512<<20;
+		
+		// SysReserve treats the address we ask for, end, as a hint,
+		// not as an absolute requirement.  If we ask for the end
+		// of the data segment but the operating system requires
+		// a little more space before we can start allocating, it will
+		// give out a slightly higher pointer.  That's fine.  
+		// Run with what we get back.
+		p = runtime·SysReserve(end, bitmap_size + arena_size);
+		if(p == nil)
+			runtime·throw("runtime: cannot reserve arena virtual address space");
+	}
+	if((uintptr)p & (((uintptr)1<<PageShift)-1))
+		runtime·throw("runtime: SysReserve returned unaligned address");
+
+	runtime·mheap.bitmap = p;
+	runtime·mheap.arena_start = p + bitmap_size;
+	runtime·mheap.arena_used = runtime·mheap.arena_start;
+	runtime·mheap.arena_end = runtime·mheap.arena_start + arena_size;
+
+	// Initialize the rest of the allocator.	
+	runtime·MHeap_Init(&runtime·mheap, runtime·SysAlloc);
+	m->mcache = runtime·allocmcache();
+
+	// See if it works.
+	runtime·free(runtime·malloc(1));
+}
+
+void*
+runtime·MHeap_SysAlloc(MHeap *h, uintptr n)
+{
+	byte *p;
+
+	if(n <= h->arena_end - h->arena_used) {
+		// Keep taking from our reservation.
+		p = h->arena_used;
+		runtime·SysMap(p, n);
+		h->arena_used += n;
+		runtime·MHeap_MapBits(h);
+		return p;
+	}
+	
+	// On 64-bit, our reservation is all we have.
+	if(sizeof(void*) == 8)
+		return nil;
+
+	// On 32-bit, once the reservation is gone we can
+	// try to get memory at a location chosen by the OS
+	// and hope that it is in the range we allocated bitmap for.
+	p = runtime·SysAlloc(n);
+	if(p == nil)
+		return nil;
+
+	if(p < h->arena_start || p+n - h->arena_start >= MaxArena32) {
+		runtime·printf("runtime: memory allocated by OS not in usable range\n");
+		runtime·SysFree(p, n);
+		return nil;
+	}
+
+	if(p+n > h->arena_used) {
+		h->arena_used = p+n;
+		if(h->arena_used > h->arena_end)
+			h->arena_end = h->arena_used;
+		runtime·MHeap_MapBits(h);
+	}
+	
+	return p;
+}
+
+// Runtime stubs.
+
+void*
+runtime·mal(uintptr n)
+{
+	return runtime·mallocgc(n, 0, 1, 1);
+}
+
+func new(n uint32) (ret *uint8) {
+	ret = runtime·mal(n);
+}
+
+void*
+runtime·stackalloc(uint32 n)
+{
+	// Stackalloc must be called on scheduler stack, so that we
+	// never try to grow the stack during the code that stackalloc runs.
+	// Doing so would cause a deadlock (issue 1547).
+	if(g != m->g0)
+		runtime·throw("stackalloc not on scheduler stack");
+
+	// Stack allocator uses malloc/free most of the time,
+	// but if we're in the middle of malloc and need stack,
+	// we have to do something else to avoid deadlock.
+	// In that case, we fall back on a fixed-size free-list
+	// allocator, assuming that inside malloc all the stack
+	// frames are small, so that all the stack allocations
+	// will be a single size, the minimum (right now, 5k).
+	if(m->mallocing || m->gcing || n == FixedStack) {
+		if(n != FixedStack) {
+			runtime·printf("stackalloc: in malloc, size=%d want %d", FixedStack, n);
+			runtime·throw("stackalloc");
+		}
+		return runtime·FixAlloc_Alloc(m->stackalloc);
+	}
+	return runtime·mallocgc(n, FlagNoProfiling|FlagNoGC, 0, 0);
+}
+
+void
+runtime·stackfree(void *v, uintptr n)
+{
+	if(m->mallocing || m->gcing || n == FixedStack) {
+		runtime·FixAlloc_Free(m->stackalloc, v);
+		return;
+	}
+	runtime·free(v);
+}
+
+func Alloc(n uintptr) (p *byte) {
+	p = runtime·malloc(n);
+}
+
+func Free(p *byte) {
+	runtime·free(p);
+}
+
+func Lookup(p *byte) (base *byte, size uintptr) {
+	runtime·mlookup(p, &base, &size, nil);
+}
+
+func GC() {
+	runtime·gc(1);
+}
+
+func SetFinalizer(obj Eface, finalizer Eface) {
+	byte *base;
+	uintptr size;
+	FuncType *ft;
+	int32 i, nret;
+	Type *t;
+
+	if(obj.type == nil) {
+		runtime·printf("runtime.SetFinalizer: first argument is nil interface\n");
+	throw:
+		runtime·throw("runtime.SetFinalizer");
+	}
+	if(obj.type->kind != KindPtr) {
+		runtime·printf("runtime.SetFinalizer: first argument is %S, not pointer\n", *obj.type->string);
+		goto throw;
+	}
+	if(!runtime·mlookup(obj.data, &base, &size, nil) || obj.data != base) {
+		runtime·printf("runtime.SetFinalizer: pointer not at beginning of allocated block\n");
+		goto throw;
+	}
+	nret = 0;
+	if(finalizer.type != nil) {
+		if(finalizer.type->kind != KindFunc) {
+		badfunc:
+			runtime·printf("runtime.SetFinalizer: second argument is %S, not func(%S)\n", *finalizer.type->string, *obj.type->string);
+			goto throw;
+		}
+		ft = (FuncType*)finalizer.type;
+		if(ft->dotdotdot || ft->in.len != 1 || *(Type**)ft->in.array != obj.type)
+			goto badfunc;
+
+		// compute size needed for return parameters
+		for(i=0; i<ft->out.len; i++) {
+			t = ((Type**)ft->out.array)[i];
+			nret = (nret + t->align - 1) & ~(t->align - 1);
+			nret += t->size;
+		}
+		nret = (nret + sizeof(void*)-1) & ~(sizeof(void*)-1);
+
+		if(runtime·getfinalizer(obj.data, 0)) {
+			runtime·printf("runtime.SetFinalizer: finalizer already set\n");
+			goto throw;
+		}
+	}
+	runtime·addfinalizer(obj.data, finalizer.data, nret);
+}