468 lines
13 KiB
Plaintext
468 lines
13 KiB
Plaintext
// 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 <stddef.h>
|
|
#include <errno.h>
|
|
#include <stdlib.h>
|
|
#include "go-alloc.h"
|
|
#include "runtime.h"
|
|
#include "malloc.h"
|
|
#include "go-string.h"
|
|
#include "interface.h"
|
|
#include "go-type.h"
|
|
typedef struct __go_empty_interface Eface;
|
|
typedef struct __go_type_descriptor Type;
|
|
typedef struct __go_func_type FuncType;
|
|
|
|
MHeap runtime_mheap;
|
|
extern MStats mstats; // defined in extern.go
|
|
|
|
extern volatile int32 runtime_MemProfileRate
|
|
__asm__ ("libgo_runtime.runtime.MemProfileRate");
|
|
|
|
// Same algorithm from chan.c, but a different
|
|
// instance of the static uint32 x.
|
|
// Not protected by a lock - let the threads use
|
|
// the same random number if they like.
|
|
static uint32
|
|
fastrand1(void)
|
|
{
|
|
static uint32 x = 0x49f6428aUL;
|
|
|
|
x += x;
|
|
if(x & 0x80000000L)
|
|
x ^= 0x88888eefUL;
|
|
return x;
|
|
}
|
|
|
|
// 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(!__sync_bool_compare_and_swap(&m->mallocing, 0, 1))
|
|
runtime_throw("malloc/free - deadlock");
|
|
if(size == 0)
|
|
size = 1;
|
|
|
|
mstats.nmalloc++;
|
|
if(size <= MaxSmallSize) {
|
|
// Allocate from mcache free lists.
|
|
sizeclass = runtime_SizeToClass(size);
|
|
size = runtime_class_to_size[sizeclass];
|
|
c = m->mcache;
|
|
v = runtime_MCache_Alloc(c, sizeclass, size, zeroed);
|
|
if(v == nil)
|
|
runtime_throw("out of memory");
|
|
mstats.alloc += size;
|
|
mstats.total_alloc += size;
|
|
mstats.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;
|
|
mstats.alloc += size;
|
|
mstats.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);
|
|
|
|
__sync_bool_compare_and_swap(&m->mallocing, 1, 0);
|
|
|
|
if(__sync_bool_compare_and_swap(&m->gcing, 1, 0)) {
|
|
if(!(flag & FlagNoProfiling))
|
|
__go_run_goroutine_gc(0);
|
|
else {
|
|
// We are being called from the profiler. Tell it
|
|
// to invoke the garbage collector when it is
|
|
// done. No need to use a sync function here.
|
|
m->gcing_for_prof = 1;
|
|
}
|
|
}
|
|
|
|
if(!(flag & FlagNoProfiling) && (rate = runtime_MemProfileRate) > 0) {
|
|
if(size >= (uint32) rate)
|
|
goto profile;
|
|
if((uint32) 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 = 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*
|
|
__go_alloc(uintptr size)
|
|
{
|
|
return runtime_mallocgc(size, 0, 0, 1);
|
|
}
|
|
|
|
// Free the object whose base pointer is v.
|
|
void
|
|
__go_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(!__sync_bool_compare_and_swap(&m->mallocing, 0, 1))
|
|
runtime_throw("malloc/free - deadlock");
|
|
|
|
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;
|
|
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.
|
|
c = m->mcache;
|
|
size = runtime_class_to_size[sizeclass];
|
|
if(size > (int32)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);
|
|
mstats.by_size[sizeclass].nfree++;
|
|
runtime_MCache_Free(c, v, sizeclass, size);
|
|
}
|
|
mstats.alloc -= size;
|
|
if(prof)
|
|
runtime_MProf_Free(v, size);
|
|
|
|
__sync_bool_compare_and_swap(&m->mallocing, 1, 0);
|
|
|
|
if(__sync_bool_compare_and_swap(&m->gcing, 1, 0))
|
|
__go_run_goroutine_gc(1);
|
|
}
|
|
|
|
int32
|
|
runtime_mlookup(void *v, byte **base, uintptr *size, MSpan **sp)
|
|
{
|
|
uintptr n, i;
|
|
byte *p;
|
|
MSpan *s;
|
|
|
|
mstats.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];
|
|
i = ((byte*)v - p)/n;
|
|
if(base)
|
|
*base = p + i*n;
|
|
if(size)
|
|
*size = n;
|
|
|
|
return 1;
|
|
}
|
|
|
|
MCache*
|
|
runtime_allocmcache(void)
|
|
{
|
|
MCache *c;
|
|
|
|
if(!__sync_bool_compare_and_swap(&m->mallocing, 0, 1))
|
|
runtime_throw("allocmcache - deadlock");
|
|
|
|
runtime_lock(&runtime_mheap);
|
|
c = runtime_FixAlloc_Alloc(&runtime_mheap.cachealloc);
|
|
|
|
// Clear the free list used by FixAlloc; assume the rest is zeroed.
|
|
c->list[0].list = nil;
|
|
|
|
mstats.mcache_inuse = runtime_mheap.cachealloc.inuse;
|
|
mstats.mcache_sys = runtime_mheap.cachealloc.sys;
|
|
runtime_unlock(&runtime_mheap);
|
|
|
|
__sync_bool_compare_and_swap(&m->mallocing, 1, 0);
|
|
if(__sync_bool_compare_and_swap(&m->gcing, 1, 0))
|
|
__go_run_goroutine_gc(2);
|
|
|
|
return c;
|
|
}
|
|
|
|
extern int32 runtime_sizeof_C_MStats
|
|
__asm__ ("libgo_runtime.runtime.Sizeof_C_MStats");
|
|
|
|
#define MaxArena32 (2U<<30)
|
|
|
|
void
|
|
runtime_mallocinit(void)
|
|
{
|
|
byte *p;
|
|
uintptr arena_size, bitmap_size;
|
|
extern byte end[];
|
|
|
|
runtime_sizeof_C_MStats = sizeof(MStats);
|
|
|
|
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 = (uintptr)(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();
|
|
|
|
// Initialize malloc profiling.
|
|
runtime_Mprof_Init();
|
|
|
|
// Initialize finalizer.
|
|
runtime_initfintab();
|
|
|
|
// See if it works.
|
|
runtime_free(runtime_malloc(1));
|
|
}
|
|
|
|
void*
|
|
runtime_MHeap_SysAlloc(MHeap *h, uintptr n)
|
|
{
|
|
byte *p;
|
|
|
|
if(n <= (uintptr)(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 || (uintptr)(p+n - h->arena_start) >= MaxArena32) {
|
|
runtime_printf("runtime: memory allocated by OS not in usable range");
|
|
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);
|
|
}
|
|
|
|
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;
|
|
const FuncType *ft;
|
|
|
|
if(obj.__type_descriptor == nil) {
|
|
// runtime_printf("runtime.SetFinalizer: first argument is nil interface\n");
|
|
throw:
|
|
runtime_throw("runtime.SetFinalizer");
|
|
}
|
|
if(obj.__type_descriptor->__code != GO_PTR) {
|
|
// runtime_printf("runtime.SetFinalizer: first argument is %S, not pointer\n", *obj.type->string);
|
|
goto throw;
|
|
}
|
|
if(!runtime_mlookup(obj.__object, &base, &size, nil) || obj.__object != base) {
|
|
// runtime_printf("runtime.SetFinalizer: pointer not at beginning of allocated block\n");
|
|
goto throw;
|
|
}
|
|
ft = nil;
|
|
if(finalizer.__type_descriptor != nil) {
|
|
if(finalizer.__type_descriptor->__code != GO_FUNC) {
|
|
badfunc:
|
|
// runtime_printf("runtime.SetFinalizer: second argument is %S, not func(%S)\n", *finalizer.type->string, *obj.type->string);
|
|
goto throw;
|
|
}
|
|
ft = (const FuncType*)finalizer.__type_descriptor;
|
|
if(ft->__dotdotdot || ft->__in.__count != 1 || !__go_type_descriptors_equal(*(Type**)ft->__in.__values, obj.__type_descriptor))
|
|
goto badfunc;
|
|
|
|
if(runtime_getfinalizer(obj.__object, 0)) {
|
|
// runtime_printf("runtime.SetFinalizer: finalizer already set");
|
|
goto throw;
|
|
}
|
|
}
|
|
runtime_addfinalizer(obj.__object, finalizer.__type_descriptor != nil ? *(void**)finalizer.__object : nil, ft);
|
|
}
|