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// 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 

#include 

#include 

#include "go-alloc.h"

#include "runtime.h"

#include "arch.h"

#include "malloc.h"

#include "go-string.h"

#include "interface.h"

#include "go-type.h"

MHeap runtime_mheap;

extern MStats mstats;   // defined in extern.go

extern volatile int32 runtime_MemProfileRate

  __asm__ ("libgo_runtime.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)

{

        M *m;

        G *g;

        int32 sizeclass, rate;

        MCache *c;

        uintptr npages;

        MSpan *s;

        void *v;

        m = runtime_m();

        g = runtime_g();

        if(g->status == Gsyscall)

                dogc = 0;

        if(runtime_gcwaiting && g != m->g0 && m->locks == 0 && g->status != Gsyscall) {

                runtime_gosched();

                m = runtime_m();

        }

        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, !(flag & FlagNoGC));

                if(s == nil)

                        runtime_throw("out of memory");

                size = npages<

                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 >= (uint32) rate)

                        goto profile;

                if((uint32) m->mcache->next_sample > size)

                        m->mcache->next_sample -= size;

                else {

                        // pick next profile time

                        // If you change this, also change allocmcache.

                        if(rate > 0x3fffffff)   // make 2*rate not overflow

                                rate = 0x3fffffff;

                        m->mcache->next_sample = runtime_fastrand1() % (2*rate);

                profile:

                        runtime_setblockspecial(v, true);

                        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)

{

        M *m;

        int32 sizeclass;

        MSpan *s;

        MCache *c;

        uint32 prof;

        uintptr size;

        if(v == nil)

                return;

        // If you change this also change mgc0.c:/^sweep,

        // which has a copy of the guts of free.

        m = runtime_m();

        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<

                *(uintptr*)(s->start<

                // 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<

                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;

        runtime_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<

        if(s->sizeclass == 0) {

                // Large object.

                if(base)

                        *base = p;

                if(size)

                        *size = s->npages<

                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)

{

        int32 rate;

        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);

        // Set first allocation sample size.

        rate = runtime_MemProfileRate;

        if(rate > 0x3fffffff)   // make 2*rate not overflow

                rate = 0x3fffffff;

        if(rate != 0)

                c->next_sample = runtime_fastrand1() % (2*rate);

        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;

}

extern uintptr 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[];

        byte *want;

        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.  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.

                want = (byte*)(((uintptr)end + (1<<18) + (1<<20) - 1)&~((1<<20)-1));

                if(0xffffffff - (uintptr)want <= bitmap_size + arena_size)

                  want = 0;

                p = runtime_SysReserve(want, bitmap_size + arena_size);

                if(p == nil)

                        runtime_throw("runtime: cannot reserve arena virtual address space");

        }

        if((uintptr)p & (((uintptr)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);

        runtime_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 <= (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\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(typ *Type) (ret *uint8) {

        uint32 flag = typ->__code&GO_NO_POINTERS ? FlagNoPointers : 0;

        ret = runtime_mallocgc(typ->__size, flag, 1, 1);

}

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");

                goto throw;

        }

        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)

                        goto badfunc;

                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_addfinalizer(obj.__object, finalizer.__type_descriptor != nil ? *(void**)finalizer.__object : nil, ft)) {

                runtime_printf("runtime.SetFinalizer: finalizer already set\n");

                goto throw;

        }

        return;

badfunc:

        // runtime_printf("runtime.SetFinalizer: second argument is %S, not func(%S)\n", *finalizer.type->string, *obj.type->string);

throw:

        runtime_throw("runtime.SetFinalizer");

}