1000 lines
30 KiB
Plaintext
1000 lines
30 KiB
Plaintext
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// See malloc.h for overview.
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//
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// TODO(rsc): double-check stats.
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package runtime
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#include <stddef.h>
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#include <errno.h>
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#include <stdlib.h>
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#include "go-alloc.h"
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#include "runtime.h"
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#include "arch.h"
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#include "malloc.h"
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#include "interface.h"
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#include "go-type.h"
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#include "race.h"
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// Map gccgo field names to gc field names.
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// Eface aka __go_empty_interface.
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#define type __type_descriptor
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// Type aka __go_type_descriptor
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#define kind __code
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#define string __reflection
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#define KindPtr GO_PTR
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#define KindNoPointers GO_NO_POINTERS
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// GCCGO SPECIFIC CHANGE
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//
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// There is a long comment in runtime_mallocinit about where to put the heap
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// on a 64-bit system. It makes assumptions that are not valid on linux/arm64
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// -- it assumes user space can choose the lower 47 bits of a pointer, but on
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// linux/arm64 we can only choose the lower 39 bits. This means the heap is
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// roughly a quarter of the available address space and we cannot choose a bit
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// pattern that all pointers will have -- luckily the GC is mostly precise
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// these days so this doesn't matter all that much. The kernel (as of 3.13)
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// will allocate address space starting either down from 0x7fffffffff or up
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// from 0x2000000000, so we put the heap roughly in the middle of these two
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// addresses to minimize the chance that a non-heap allocation will get in the
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// way of the heap.
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//
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// This all means that there isn't much point in trying 256 different
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// locations for the heap on such systems.
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#ifdef __aarch64__
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#define HeapBase(i) ((void*)(uintptr)(0x40ULL<<32))
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#define HeapBaseOptions 1
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#else
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#define HeapBase(i) ((void*)(uintptr)(i<<40|0x00c0ULL<<32))
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#define HeapBaseOptions 0x80
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#endif
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// END GCCGO SPECIFIC CHANGE
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// Mark mheap as 'no pointers', it does not contain interesting pointers but occupies ~45K.
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MHeap runtime_mheap;
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MStats mstats;
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int32 runtime_checking;
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extern MStats mstats; // defined in zruntime_def_$GOOS_$GOARCH.go
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extern volatile intgo runtime_MemProfileRate
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__asm__ (GOSYM_PREFIX "runtime.MemProfileRate");
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static MSpan* largealloc(uint32, uintptr*);
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static void profilealloc(void *v, uintptr size);
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static void settype(MSpan *s, void *v, uintptr typ);
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// Allocate an object of at least size bytes.
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// Small objects are allocated from the per-thread cache's free lists.
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// Large objects (> 32 kB) are allocated straight from the heap.
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// If the block will be freed with runtime_free(), typ must be 0.
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void*
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runtime_mallocgc(uintptr size, uintptr typ, uint32 flag)
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{
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M *m;
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G *g;
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int32 sizeclass;
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uintptr tinysize, size1;
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intgo rate;
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MCache *c;
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MSpan *s;
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MLink *v, *next;
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byte *tiny;
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bool incallback;
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if(size == 0) {
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// All 0-length allocations use this pointer.
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// The language does not require the allocations to
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// have distinct values.
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return &runtime_zerobase;
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}
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m = runtime_m();
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g = runtime_g();
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incallback = false;
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if(m->mcache == nil && g->ncgo > 0) {
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// For gccgo this case can occur when a cgo or SWIG function
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// has an interface return type and the function
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// returns a non-pointer, so memory allocation occurs
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// after syscall.Cgocall but before syscall.CgocallDone.
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// We treat it as a callback.
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runtime_exitsyscall();
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m = runtime_m();
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incallback = true;
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flag |= FlagNoInvokeGC;
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}
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if(runtime_gcwaiting() && g != m->g0 && m->locks == 0 && !(flag & FlagNoInvokeGC)) {
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runtime_gosched();
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m = runtime_m();
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}
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if(m->mallocing)
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runtime_throw("malloc/free - deadlock");
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// Disable preemption during settype.
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// We can not use m->mallocing for this, because settype calls mallocgc.
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m->locks++;
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m->mallocing = 1;
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if(DebugTypeAtBlockEnd)
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size += sizeof(uintptr);
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c = m->mcache;
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if(!runtime_debug.efence && size <= MaxSmallSize) {
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if((flag&(FlagNoScan|FlagNoGC)) == FlagNoScan && size < TinySize) {
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// Tiny allocator.
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//
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// Tiny allocator combines several tiny allocation requests
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// into a single memory block. The resulting memory block
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// is freed when all subobjects are unreachable. The subobjects
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// must be FlagNoScan (don't have pointers), this ensures that
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// the amount of potentially wasted memory is bounded.
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//
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// Size of the memory block used for combining (TinySize) is tunable.
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// Current setting is 16 bytes, which relates to 2x worst case memory
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// wastage (when all but one subobjects are unreachable).
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// 8 bytes would result in no wastage at all, but provides less
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// opportunities for combining.
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// 32 bytes provides more opportunities for combining,
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// but can lead to 4x worst case wastage.
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// The best case winning is 8x regardless of block size.
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//
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// Objects obtained from tiny allocator must not be freed explicitly.
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// So when an object will be freed explicitly, we ensure that
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// its size >= TinySize.
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//
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// SetFinalizer has a special case for objects potentially coming
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// from tiny allocator, it such case it allows to set finalizers
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// for an inner byte of a memory block.
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//
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// The main targets of tiny allocator are small strings and
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// standalone escaping variables. On a json benchmark
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// the allocator reduces number of allocations by ~12% and
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// reduces heap size by ~20%.
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tinysize = c->tinysize;
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if(size <= tinysize) {
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tiny = c->tiny;
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// Align tiny pointer for required (conservative) alignment.
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if((size&7) == 0)
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tiny = (byte*)ROUND((uintptr)tiny, 8);
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else if((size&3) == 0)
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tiny = (byte*)ROUND((uintptr)tiny, 4);
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else if((size&1) == 0)
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tiny = (byte*)ROUND((uintptr)tiny, 2);
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size1 = size + (tiny - c->tiny);
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if(size1 <= tinysize) {
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// The object fits into existing tiny block.
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v = (MLink*)tiny;
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c->tiny += size1;
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c->tinysize -= size1;
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m->mallocing = 0;
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m->locks--;
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if(incallback)
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runtime_entersyscall();
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return v;
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}
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}
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// Allocate a new TinySize block.
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s = c->alloc[TinySizeClass];
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if(s->freelist == nil)
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s = runtime_MCache_Refill(c, TinySizeClass);
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v = s->freelist;
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next = v->next;
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s->freelist = next;
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s->ref++;
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if(next != nil) // prefetching nil leads to a DTLB miss
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PREFETCH(next);
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((uint64*)v)[0] = 0;
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((uint64*)v)[1] = 0;
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// See if we need to replace the existing tiny block with the new one
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// based on amount of remaining free space.
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if(TinySize-size > tinysize) {
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c->tiny = (byte*)v + size;
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c->tinysize = TinySize - size;
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}
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size = TinySize;
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goto done;
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}
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// Allocate from mcache free lists.
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// Inlined version of SizeToClass().
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if(size <= 1024-8)
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sizeclass = runtime_size_to_class8[(size+7)>>3];
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else
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sizeclass = runtime_size_to_class128[(size-1024+127) >> 7];
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size = runtime_class_to_size[sizeclass];
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s = c->alloc[sizeclass];
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if(s->freelist == nil)
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s = runtime_MCache_Refill(c, sizeclass);
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v = s->freelist;
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next = v->next;
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s->freelist = next;
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s->ref++;
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if(next != nil) // prefetching nil leads to a DTLB miss
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PREFETCH(next);
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if(!(flag & FlagNoZero)) {
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v->next = nil;
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// block is zeroed iff second word is zero ...
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if(size > 2*sizeof(uintptr) && ((uintptr*)v)[1] != 0)
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runtime_memclr((byte*)v, size);
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}
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done:
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c->local_cachealloc += size;
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} else {
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// Allocate directly from heap.
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s = largealloc(flag, &size);
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v = (void*)(s->start << PageShift);
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}
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if(flag & FlagNoGC)
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runtime_marknogc(v);
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else if(!(flag & FlagNoScan))
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runtime_markscan(v);
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if(DebugTypeAtBlockEnd)
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*(uintptr*)((uintptr)v+size-sizeof(uintptr)) = typ;
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m->mallocing = 0;
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// TODO: save type even if FlagNoScan? Potentially expensive but might help
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// heap profiling/tracing.
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if(UseSpanType && !(flag & FlagNoScan) && typ != 0)
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settype(s, v, typ);
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if(raceenabled)
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runtime_racemalloc(v, size);
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if(runtime_debug.allocfreetrace)
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runtime_tracealloc(v, size, typ);
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if(!(flag & FlagNoProfiling) && (rate = runtime_MemProfileRate) > 0) {
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if(size < (uintptr)rate && size < (uintptr)(uint32)c->next_sample)
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c->next_sample -= size;
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else
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profilealloc(v, size);
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}
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m->locks--;
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if(!(flag & FlagNoInvokeGC) && mstats.heap_alloc >= mstats.next_gc)
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runtime_gc(0);
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if(incallback)
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runtime_entersyscall();
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return v;
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}
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static MSpan*
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largealloc(uint32 flag, uintptr *sizep)
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{
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uintptr npages, size;
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MSpan *s;
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void *v;
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// Allocate directly from heap.
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size = *sizep;
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if(size + PageSize < size)
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runtime_throw("out of memory");
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npages = size >> PageShift;
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if((size & PageMask) != 0)
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npages++;
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s = runtime_MHeap_Alloc(&runtime_mheap, npages, 0, 1, !(flag & FlagNoZero));
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if(s == nil)
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runtime_throw("out of memory");
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s->limit = (byte*)(s->start<<PageShift) + size;
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*sizep = npages<<PageShift;
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v = (void*)(s->start << PageShift);
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// setup for mark sweep
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runtime_markspan(v, 0, 0, true);
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return s;
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}
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static void
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profilealloc(void *v, uintptr size)
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{
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uintptr rate;
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int32 next;
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MCache *c;
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c = runtime_m()->mcache;
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rate = runtime_MemProfileRate;
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if(size < rate) {
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// pick next profile time
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// If you change this, also change allocmcache.
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if(rate > 0x3fffffff) // make 2*rate not overflow
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rate = 0x3fffffff;
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next = runtime_fastrand1() % (2*rate);
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// Subtract the "remainder" of the current allocation.
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// Otherwise objects that are close in size to sampling rate
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// will be under-sampled, because we consistently discard this remainder.
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next -= (size - c->next_sample);
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if(next < 0)
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next = 0;
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c->next_sample = next;
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}
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runtime_MProf_Malloc(v, size);
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}
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void*
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__go_alloc(uintptr size)
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{
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return runtime_mallocgc(size, 0, FlagNoInvokeGC);
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}
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// Free the object whose base pointer is v.
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void
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__go_free(void *v)
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{
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M *m;
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int32 sizeclass;
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MSpan *s;
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MCache *c;
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uintptr size;
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if(v == nil)
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return;
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// If you change this also change mgc0.c:/^sweep,
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// which has a copy of the guts of free.
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m = runtime_m();
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if(m->mallocing)
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runtime_throw("malloc/free - deadlock");
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m->mallocing = 1;
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if(!runtime_mlookup(v, nil, nil, &s)) {
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runtime_printf("free %p: not an allocated block\n", v);
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runtime_throw("free runtime_mlookup");
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}
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size = s->elemsize;
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sizeclass = s->sizeclass;
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// Objects that are smaller than TinySize can be allocated using tiny alloc,
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// if then such object is combined with an object with finalizer, we will crash.
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if(size < TinySize)
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runtime_throw("freeing too small block");
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if(runtime_debug.allocfreetrace)
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runtime_tracefree(v, size);
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// Ensure that the span is swept.
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// If we free into an unswept span, we will corrupt GC bitmaps.
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runtime_MSpan_EnsureSwept(s);
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if(s->specials != nil)
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runtime_freeallspecials(s, v, size);
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c = m->mcache;
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if(sizeclass == 0) {
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// Large object.
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s->needzero = 1;
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// Must mark v freed before calling unmarkspan and MHeap_Free:
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// they might coalesce v into other spans and change the bitmap further.
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runtime_markfreed(v);
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runtime_unmarkspan(v, 1<<PageShift);
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// NOTE(rsc,dvyukov): The original implementation of efence
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// in CL 22060046 used SysFree instead of SysFault, so that
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// the operating system would eventually give the memory
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// back to us again, so that an efence program could run
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// longer without running out of memory. Unfortunately,
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// calling SysFree here without any kind of adjustment of the
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// heap data structures means that when the memory does
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// come back to us, we have the wrong metadata for it, either in
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// the MSpan structures or in the garbage collection bitmap.
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// Using SysFault here means that the program will run out of
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// memory fairly quickly in efence mode, but at least it won't
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// have mysterious crashes due to confused memory reuse.
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// It should be possible to switch back to SysFree if we also
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// implement and then call some kind of MHeap_DeleteSpan.
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if(runtime_debug.efence)
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runtime_SysFault((void*)(s->start<<PageShift), size);
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else
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runtime_MHeap_Free(&runtime_mheap, s, 1);
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c->local_nlargefree++;
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c->local_largefree += size;
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} else {
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// Small object.
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if(size > 2*sizeof(uintptr))
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((uintptr*)v)[1] = (uintptr)0xfeedfeedfeedfeedll; // mark as "needs to be zeroed"
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else if(size > sizeof(uintptr))
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((uintptr*)v)[1] = 0;
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// Must mark v freed before calling MCache_Free:
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// it might coalesce v and other blocks into a bigger span
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// and change the bitmap further.
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c->local_nsmallfree[sizeclass]++;
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c->local_cachealloc -= size;
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if(c->alloc[sizeclass] == s) {
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// We own the span, so we can just add v to the freelist
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runtime_markfreed(v);
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((MLink*)v)->next = s->freelist;
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s->freelist = v;
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s->ref--;
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} else {
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// Someone else owns this span. Add to free queue.
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runtime_MCache_Free(c, v, sizeclass, size);
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}
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}
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m->mallocing = 0;
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}
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int32
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runtime_mlookup(void *v, byte **base, uintptr *size, MSpan **sp)
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{
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M *m;
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uintptr n, i;
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byte *p;
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MSpan *s;
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m = runtime_m();
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m->mcache->local_nlookup++;
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if (sizeof(void*) == 4 && m->mcache->local_nlookup >= (1<<30)) {
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// purge cache stats to prevent overflow
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runtime_lock(&runtime_mheap);
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runtime_purgecachedstats(m->mcache);
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runtime_unlock(&runtime_mheap);
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}
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s = runtime_MHeap_LookupMaybe(&runtime_mheap, v);
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if(sp)
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*sp = s;
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if(s == nil) {
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runtime_checkfreed(v, 1);
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if(base)
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*base = nil;
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if(size)
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*size = 0;
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return 0;
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}
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p = (byte*)((uintptr)s->start<<PageShift);
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if(s->sizeclass == 0) {
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// Large object.
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if(base)
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*base = p;
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if(size)
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*size = s->npages<<PageShift;
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return 1;
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}
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n = s->elemsize;
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if(base) {
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i = ((byte*)v - p)/n;
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*base = p + i*n;
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}
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if(size)
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*size = n;
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return 1;
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}
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void
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runtime_purgecachedstats(MCache *c)
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{
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MHeap *h;
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int32 i;
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// Protected by either heap or GC lock.
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h = &runtime_mheap;
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mstats.heap_alloc += c->local_cachealloc;
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c->local_cachealloc = 0;
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mstats.nlookup += c->local_nlookup;
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c->local_nlookup = 0;
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h->largefree += c->local_largefree;
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c->local_largefree = 0;
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h->nlargefree += c->local_nlargefree;
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c->local_nlargefree = 0;
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for(i=0; i<(int32)nelem(c->local_nsmallfree); i++) {
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h->nsmallfree[i] += c->local_nsmallfree[i];
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c->local_nsmallfree[i] = 0;
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}
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}
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extern uintptr runtime_sizeof_C_MStats
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__asm__ (GOSYM_PREFIX "runtime.Sizeof_C_MStats");
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// Size of the trailing by_size array differs between Go and C,
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// NumSizeClasses was changed, but we can not change Go struct because of backward compatibility.
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// sizeof_C_MStats is what C thinks about size of Go struct.
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// Initialized in mallocinit because it's defined in go/runtime/mem.go.
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#define MaxArena32 (2U<<30)
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void
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runtime_mallocinit(void)
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{
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byte *p, *p1;
|
|
uintptr arena_size, bitmap_size, spans_size, p_size;
|
|
extern byte _end[];
|
|
uintptr limit;
|
|
uint64 i;
|
|
bool reserved;
|
|
|
|
runtime_sizeof_C_MStats = sizeof(MStats) - (NumSizeClasses - 61) * sizeof(mstats.by_size[0]);
|
|
|
|
p = nil;
|
|
p_size = 0;
|
|
arena_size = 0;
|
|
bitmap_size = 0;
|
|
spans_size = 0;
|
|
reserved = false;
|
|
|
|
// for 64-bit build
|
|
USED(p);
|
|
USED(p_size);
|
|
USED(arena_size);
|
|
USED(bitmap_size);
|
|
USED(spans_size);
|
|
|
|
runtime_InitSizes();
|
|
|
|
if(runtime_class_to_size[TinySizeClass] != TinySize)
|
|
runtime_throw("bad TinySizeClass");
|
|
|
|
// limit = runtime_memlimit();
|
|
// See https://code.google.com/p/go/issues/detail?id=5049
|
|
// TODO(rsc): Fix after 1.1.
|
|
limit = 0;
|
|
|
|
// 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 && (limit == 0 || limit > (1<<30))) {
|
|
// On a 64-bit machine, allocate from a single contiguous reservation.
|
|
// 128 GB (MaxMem) should be big enough for now.
|
|
//
|
|
// The code will work with the reservation at any address, but ask
|
|
// SysReserve to use 0x0000XXc000000000 if possible (XX=00...7f).
|
|
// Allocating a 128 GB region takes away 37 bits, and the amd64
|
|
// doesn't let us choose the top 17 bits, so that leaves the 11 bits
|
|
// in the middle of 0x00c0 for us to choose. Choosing 0x00c0 means
|
|
// that the valid memory addresses will begin 0x00c0, 0x00c1, ..., 0x00df.
|
|
// In little-endian, that's c0 00, c1 00, ..., df 00. None of those are valid
|
|
// UTF-8 sequences, and they are otherwise as far away from
|
|
// ff (likely a common byte) as possible. If that fails, we try other 0xXXc0
|
|
// addresses. An earlier attempt to use 0x11f8 caused out of memory errors
|
|
// on OS X during thread allocations. 0x00c0 causes conflicts with
|
|
// AddressSanitizer which reserves all memory up to 0x0100.
|
|
// 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 136 GB (because the bitmap ends up being 8 GB)
|
|
// but it hardly matters: e0 00 is not valid UTF-8 either.
|
|
//
|
|
// If this fails we fall back to the 32 bit memory mechanism
|
|
arena_size = MaxMem;
|
|
bitmap_size = arena_size / (sizeof(void*)*8/4);
|
|
spans_size = arena_size / PageSize * sizeof(runtime_mheap.spans[0]);
|
|
spans_size = ROUND(spans_size, PageSize);
|
|
for(i = 0; i < HeapBaseOptions; i++) {
|
|
p = HeapBase(i);
|
|
p_size = bitmap_size + spans_size + arena_size + PageSize;
|
|
p = runtime_SysReserve(p, p_size, &reserved);
|
|
if(p != nil)
|
|
break;
|
|
}
|
|
}
|
|
if (p == nil) {
|
|
// 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;
|
|
spans_size = MaxArena32 / PageSize * sizeof(runtime_mheap.spans[0]);
|
|
if(limit > 0 && arena_size+bitmap_size+spans_size > limit) {
|
|
bitmap_size = (limit / 9) & ~((1<<PageShift) - 1);
|
|
arena_size = bitmap_size * 8;
|
|
spans_size = arena_size / PageSize * sizeof(runtime_mheap.spans[0]);
|
|
}
|
|
spans_size = ROUND(spans_size, PageSize);
|
|
|
|
// 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. Except QEMU, which
|
|
// is buggy, as usual: it won't adjust the pointer upward.
|
|
// So adjust it upward a little bit ourselves: 1/4 MB to get
|
|
// away from the running binary image and then round up
|
|
// to a MB boundary.
|
|
p = (byte*)ROUND((uintptr)_end + (1<<18), 1<<20);
|
|
p_size = bitmap_size + spans_size + arena_size + PageSize;
|
|
p = runtime_SysReserve(p, p_size, &reserved);
|
|
if(p == nil)
|
|
runtime_throw("runtime: cannot reserve arena virtual address space");
|
|
}
|
|
|
|
// PageSize can be larger than OS definition of page size,
|
|
// so SysReserve can give us a PageSize-unaligned pointer.
|
|
// To overcome this we ask for PageSize more and round up the pointer.
|
|
p1 = (byte*)ROUND((uintptr)p, PageSize);
|
|
|
|
runtime_mheap.spans = (MSpan**)p1;
|
|
runtime_mheap.bitmap = p1 + spans_size;
|
|
runtime_mheap.arena_start = p1 + spans_size + bitmap_size;
|
|
runtime_mheap.arena_used = runtime_mheap.arena_start;
|
|
runtime_mheap.arena_end = p + p_size;
|
|
runtime_mheap.arena_reserved = reserved;
|
|
|
|
if(((uintptr)runtime_mheap.arena_start & (PageSize-1)) != 0)
|
|
runtime_throw("misrounded allocation in mallocinit");
|
|
|
|
// Initialize the rest of the allocator.
|
|
runtime_MHeap_Init(&runtime_mheap);
|
|
runtime_m()->mcache = runtime_allocmcache();
|
|
|
|
// See if it works.
|
|
runtime_free(runtime_malloc(TinySize));
|
|
}
|
|
|
|
void*
|
|
runtime_MHeap_SysAlloc(MHeap *h, uintptr n)
|
|
{
|
|
byte *p, *p_end;
|
|
uintptr p_size;
|
|
bool reserved;
|
|
|
|
|
|
if(n > (uintptr)(h->arena_end - h->arena_used)) {
|
|
// We are in 32-bit mode, maybe we didn't use all possible address space yet.
|
|
// Reserve some more space.
|
|
byte *new_end;
|
|
|
|
p_size = ROUND(n + PageSize, 256<<20);
|
|
new_end = h->arena_end + p_size;
|
|
if(new_end <= h->arena_start + MaxArena32) {
|
|
// TODO: It would be bad if part of the arena
|
|
// is reserved and part is not.
|
|
p = runtime_SysReserve(h->arena_end, p_size, &reserved);
|
|
if(p == h->arena_end) {
|
|
h->arena_end = new_end;
|
|
h->arena_reserved = reserved;
|
|
}
|
|
else if(p+p_size <= h->arena_start + MaxArena32) {
|
|
// Keep everything page-aligned.
|
|
// Our pages are bigger than hardware pages.
|
|
h->arena_end = p+p_size;
|
|
h->arena_used = p + (-(uintptr)p&(PageSize-1));
|
|
h->arena_reserved = reserved;
|
|
} else {
|
|
uint64 stat;
|
|
stat = 0;
|
|
runtime_SysFree(p, p_size, &stat);
|
|
}
|
|
}
|
|
}
|
|
if(n <= (uintptr)(h->arena_end - h->arena_used)) {
|
|
// Keep taking from our reservation.
|
|
p = h->arena_used;
|
|
runtime_SysMap(p, n, h->arena_reserved, &mstats.heap_sys);
|
|
h->arena_used += n;
|
|
runtime_MHeap_MapBits(h);
|
|
runtime_MHeap_MapSpans(h);
|
|
if(raceenabled)
|
|
runtime_racemapshadow(p, n);
|
|
|
|
if(((uintptr)p & (PageSize-1)) != 0)
|
|
runtime_throw("misrounded allocation in MHeap_SysAlloc");
|
|
return p;
|
|
}
|
|
|
|
// If using 64-bit, our reservation is all we have.
|
|
if((uintptr)(h->arena_end - h->arena_start) >= MaxArena32)
|
|
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_size = ROUND(n, PageSize) + PageSize;
|
|
p = runtime_SysAlloc(p_size, &mstats.heap_sys);
|
|
if(p == nil)
|
|
return nil;
|
|
|
|
if(p < h->arena_start || (uintptr)(p+p_size - h->arena_start) >= MaxArena32) {
|
|
runtime_printf("runtime: memory allocated by OS (%p) not in usable range [%p,%p)\n",
|
|
p, h->arena_start, h->arena_start+MaxArena32);
|
|
runtime_SysFree(p, p_size, &mstats.heap_sys);
|
|
return nil;
|
|
}
|
|
|
|
p_end = p + p_size;
|
|
p += -(uintptr)p & (PageSize-1);
|
|
if(p+n > h->arena_used) {
|
|
h->arena_used = p+n;
|
|
if(p_end > h->arena_end)
|
|
h->arena_end = p_end;
|
|
runtime_MHeap_MapBits(h);
|
|
runtime_MHeap_MapSpans(h);
|
|
if(raceenabled)
|
|
runtime_racemapshadow(p, n);
|
|
}
|
|
|
|
if(((uintptr)p & (PageSize-1)) != 0)
|
|
runtime_throw("misrounded allocation in MHeap_SysAlloc");
|
|
return p;
|
|
}
|
|
|
|
static struct
|
|
{
|
|
Lock;
|
|
byte* pos;
|
|
byte* end;
|
|
} persistent;
|
|
|
|
enum
|
|
{
|
|
PersistentAllocChunk = 256<<10,
|
|
PersistentAllocMaxBlock = 64<<10, // VM reservation granularity is 64K on windows
|
|
};
|
|
|
|
// Wrapper around SysAlloc that can allocate small chunks.
|
|
// There is no associated free operation.
|
|
// Intended for things like function/type/debug-related persistent data.
|
|
// If align is 0, uses default align (currently 8).
|
|
void*
|
|
runtime_persistentalloc(uintptr size, uintptr align, uint64 *stat)
|
|
{
|
|
byte *p;
|
|
|
|
if(align != 0) {
|
|
if(align&(align-1))
|
|
runtime_throw("persistentalloc: align is not a power of 2");
|
|
if(align > PageSize)
|
|
runtime_throw("persistentalloc: align is too large");
|
|
} else
|
|
align = 8;
|
|
if(size >= PersistentAllocMaxBlock)
|
|
return runtime_SysAlloc(size, stat);
|
|
runtime_lock(&persistent);
|
|
persistent.pos = (byte*)ROUND((uintptr)persistent.pos, align);
|
|
if(persistent.pos + size > persistent.end) {
|
|
persistent.pos = runtime_SysAlloc(PersistentAllocChunk, &mstats.other_sys);
|
|
if(persistent.pos == nil) {
|
|
runtime_unlock(&persistent);
|
|
runtime_throw("runtime: cannot allocate memory");
|
|
}
|
|
persistent.end = persistent.pos + PersistentAllocChunk;
|
|
}
|
|
p = persistent.pos;
|
|
persistent.pos += size;
|
|
runtime_unlock(&persistent);
|
|
if(stat != &mstats.other_sys) {
|
|
// reaccount the allocation against provided stat
|
|
runtime_xadd64(stat, size);
|
|
runtime_xadd64(&mstats.other_sys, -(uint64)size);
|
|
}
|
|
return p;
|
|
}
|
|
|
|
static void
|
|
settype(MSpan *s, void *v, uintptr typ)
|
|
{
|
|
uintptr size, ofs, j, t;
|
|
uintptr ntypes, nbytes2, nbytes3;
|
|
uintptr *data2;
|
|
byte *data3;
|
|
|
|
if(s->sizeclass == 0) {
|
|
s->types.compression = MTypes_Single;
|
|
s->types.data = typ;
|
|
return;
|
|
}
|
|
size = s->elemsize;
|
|
ofs = ((uintptr)v - (s->start<<PageShift)) / size;
|
|
|
|
switch(s->types.compression) {
|
|
case MTypes_Empty:
|
|
ntypes = (s->npages << PageShift) / size;
|
|
nbytes3 = 8*sizeof(uintptr) + 1*ntypes;
|
|
data3 = runtime_mallocgc(nbytes3, 0, FlagNoProfiling|FlagNoScan|FlagNoInvokeGC);
|
|
s->types.compression = MTypes_Bytes;
|
|
s->types.data = (uintptr)data3;
|
|
((uintptr*)data3)[1] = typ;
|
|
data3[8*sizeof(uintptr) + ofs] = 1;
|
|
break;
|
|
|
|
case MTypes_Words:
|
|
((uintptr*)s->types.data)[ofs] = typ;
|
|
break;
|
|
|
|
case MTypes_Bytes:
|
|
data3 = (byte*)s->types.data;
|
|
for(j=1; j<8; j++) {
|
|
if(((uintptr*)data3)[j] == typ) {
|
|
break;
|
|
}
|
|
if(((uintptr*)data3)[j] == 0) {
|
|
((uintptr*)data3)[j] = typ;
|
|
break;
|
|
}
|
|
}
|
|
if(j < 8) {
|
|
data3[8*sizeof(uintptr) + ofs] = j;
|
|
} else {
|
|
ntypes = (s->npages << PageShift) / size;
|
|
nbytes2 = ntypes * sizeof(uintptr);
|
|
data2 = runtime_mallocgc(nbytes2, 0, FlagNoProfiling|FlagNoScan|FlagNoInvokeGC);
|
|
s->types.compression = MTypes_Words;
|
|
s->types.data = (uintptr)data2;
|
|
|
|
// Move the contents of data3 to data2. Then deallocate data3.
|
|
for(j=0; j<ntypes; j++) {
|
|
t = data3[8*sizeof(uintptr) + j];
|
|
t = ((uintptr*)data3)[t];
|
|
data2[j] = t;
|
|
}
|
|
data2[ofs] = typ;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
|
|
uintptr
|
|
runtime_gettype(void *v)
|
|
{
|
|
MSpan *s;
|
|
uintptr t, ofs;
|
|
byte *data;
|
|
|
|
s = runtime_MHeap_LookupMaybe(&runtime_mheap, v);
|
|
if(s != nil) {
|
|
t = 0;
|
|
switch(s->types.compression) {
|
|
case MTypes_Empty:
|
|
break;
|
|
case MTypes_Single:
|
|
t = s->types.data;
|
|
break;
|
|
case MTypes_Words:
|
|
ofs = (uintptr)v - (s->start<<PageShift);
|
|
t = ((uintptr*)s->types.data)[ofs/s->elemsize];
|
|
break;
|
|
case MTypes_Bytes:
|
|
ofs = (uintptr)v - (s->start<<PageShift);
|
|
data = (byte*)s->types.data;
|
|
t = data[8*sizeof(uintptr) + ofs/s->elemsize];
|
|
t = ((uintptr*)data)[t];
|
|
break;
|
|
default:
|
|
runtime_throw("runtime_gettype: invalid compression kind");
|
|
}
|
|
if(0) {
|
|
runtime_printf("%p -> %d,%X\n", v, (int32)s->types.compression, (int64)t);
|
|
}
|
|
return t;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
// Runtime stubs.
|
|
|
|
void*
|
|
runtime_mal(uintptr n)
|
|
{
|
|
return runtime_mallocgc(n, 0, 0);
|
|
}
|
|
|
|
func new(typ *Type) (ret *uint8) {
|
|
ret = runtime_mallocgc(typ->__size, (uintptr)typ | TypeInfo_SingleObject, typ->kind&KindNoPointers ? FlagNoScan : 0);
|
|
}
|
|
|
|
static void*
|
|
cnew(const Type *typ, intgo n, int32 objtyp)
|
|
{
|
|
if((objtyp&(PtrSize-1)) != objtyp)
|
|
runtime_throw("runtime: invalid objtyp");
|
|
if(n < 0 || (typ->__size > 0 && (uintptr)n > (MaxMem/typ->__size)))
|
|
runtime_panicstring("runtime: allocation size out of range");
|
|
return runtime_mallocgc(typ->__size*n, (uintptr)typ | objtyp, typ->kind&KindNoPointers ? FlagNoScan : 0);
|
|
}
|
|
|
|
// same as runtime_new, but callable from C
|
|
void*
|
|
runtime_cnew(const Type *typ)
|
|
{
|
|
return cnew(typ, 1, TypeInfo_SingleObject);
|
|
}
|
|
|
|
void*
|
|
runtime_cnewarray(const Type *typ, intgo n)
|
|
{
|
|
return cnew(typ, n, TypeInfo_Array);
|
|
}
|
|
|
|
func GC() {
|
|
runtime_gc(2); // force GC and do eager sweep
|
|
}
|
|
|
|
func SetFinalizer(obj Eface, finalizer Eface) {
|
|
byte *base;
|
|
uintptr size;
|
|
const FuncType *ft;
|
|
const Type *fint;
|
|
const PtrType *ot;
|
|
|
|
if(obj.__type_descriptor == nil) {
|
|
runtime_printf("runtime.SetFinalizer: first argument is nil interface\n");
|
|
goto throw;
|
|
}
|
|
if(obj.__type_descriptor->__code != GO_PTR) {
|
|
runtime_printf("runtime.SetFinalizer: first argument is %S, not pointer\n", *obj.__type_descriptor->__reflection);
|
|
goto throw;
|
|
}
|
|
ot = (const PtrType*)obj.type;
|
|
// As an implementation detail we do not run finalizers for zero-sized objects,
|
|
// because we use &runtime_zerobase for all such allocations.
|
|
if(ot->__element_type != nil && ot->__element_type->__size == 0)
|
|
return;
|
|
// The following check is required for cases when a user passes a pointer to composite literal,
|
|
// but compiler makes it a pointer to global. For example:
|
|
// var Foo = &Object{}
|
|
// func main() {
|
|
// runtime.SetFinalizer(Foo, nil)
|
|
// }
|
|
// See issue 7656.
|
|
if((byte*)obj.__object < runtime_mheap.arena_start || runtime_mheap.arena_used <= (byte*)obj.__object)
|
|
return;
|
|
if(!runtime_mlookup(obj.__object, &base, &size, nil) || obj.__object != base) {
|
|
// As an implementation detail we allow to set finalizers for an inner byte
|
|
// of an object if it could come from tiny alloc (see mallocgc for details).
|
|
if(ot->__element_type == nil || (ot->__element_type->__code&KindNoPointers) == 0 || ot->__element_type->__size >= TinySize) {
|
|
runtime_printf("runtime.SetFinalizer: pointer not at beginning of allocated block (%p)\n", obj.__object);
|
|
goto throw;
|
|
}
|
|
}
|
|
if(finalizer.__type_descriptor != nil) {
|
|
runtime_createfing();
|
|
if(finalizer.__type_descriptor->__code != GO_FUNC)
|
|
goto badfunc;
|
|
ft = (const FuncType*)finalizer.__type_descriptor;
|
|
if(ft->__dotdotdot || ft->__in.__count != 1)
|
|
goto badfunc;
|
|
fint = *(Type**)ft->__in.__values;
|
|
if(__go_type_descriptors_equal(fint, obj.__type_descriptor)) {
|
|
// ok - same type
|
|
} else if(fint->__code == GO_PTR && (fint->__uncommon == nil || fint->__uncommon->__name == nil || obj.type->__uncommon == nil || obj.type->__uncommon->__name == nil) && __go_type_descriptors_equal(((const PtrType*)fint)->__element_type, ((const PtrType*)obj.type)->__element_type)) {
|
|
// ok - not same type, but both pointers,
|
|
// one or the other is unnamed, and same element type, so assignable.
|
|
} else if(fint->kind == GO_INTERFACE && ((const InterfaceType*)fint)->__methods.__count == 0) {
|
|
// ok - satisfies empty interface
|
|
} else if(fint->kind == GO_INTERFACE && __go_convert_interface_2(fint, obj.__type_descriptor, 1) != nil) {
|
|
// ok - satisfies non-empty interface
|
|
} else
|
|
goto badfunc;
|
|
|
|
ot = (const PtrType*)obj.__type_descriptor;
|
|
if(!runtime_addfinalizer(obj.__object, *(FuncVal**)finalizer.__object, ft, ot)) {
|
|
runtime_printf("runtime.SetFinalizer: finalizer already set\n");
|
|
goto throw;
|
|
}
|
|
} else {
|
|
// NOTE: asking to remove a finalizer when there currently isn't one set is OK.
|
|
runtime_removefinalizer(obj.__object);
|
|
}
|
|
return;
|
|
|
|
badfunc:
|
|
runtime_printf("runtime.SetFinalizer: cannot pass %S to finalizer %S\n", *obj.__type_descriptor->__reflection, *finalizer.__type_descriptor->__reflection);
|
|
throw:
|
|
runtime_throw("runtime.SetFinalizer");
|
|
}
|