First pieces of malloc.
R=r
DELTA=756 (754 added, 0 deleted, 2 changed)
OCL=19266
CL=19378
diff --git a/src/runtime/runtime.c b/src/runtime/runtime.c
index 766f16f..5dd4336 100644
--- a/src/runtime/runtime.c
+++ b/src/runtime/runtime.c
@@ -63,7 +63,7 @@
MAP_SHARED = 0x0001,
MAP_PRIVATE = 0x0002,
MAP_FIXED = 0x0010,
- MAP_ANON = 0x1000,
+ MAP_ANON = 0x1000, // not on Linux - TODO(rsc)
};
void
diff --git a/src/runtime/runtime.h b/src/runtime/runtime.h
index 5f2ad18..842ac8e 100644
--- a/src/runtime/runtime.h
+++ b/src/runtime/runtime.h
@@ -15,6 +15,7 @@
typedef unsigned long long int uint64;
typedef float float32;
typedef double float64;
+typedef uint64 uintptr;
/*
* get rid of C types
@@ -69,6 +70,10 @@
true = 1,
false = 0,
};
+enum
+{
+ SmallFreeClasses = 168, // number of small free lists in malloc
+};
/*
* structures
@@ -103,7 +108,7 @@
{ // must not move anything
byte* array; // actual data
uint32 nel; // number of elements
- uint32 cap; // allocate3d number of elements
+ uint32 cap; // allocated number of elements
byte b[8]; // actual array - may not be contig
};
struct Gobuf
@@ -152,6 +157,7 @@
M* schedlink;
Mem mem;
uint32 machport; // Return address for Mach IPC (OS X)
+ void* freelist[SmallFreeClasses];
};
struct Stktop
{
diff --git a/usr/rsc/mem/Makefile b/usr/rsc/mem/Makefile
new file mode 100644
index 0000000..8f2eace
--- /dev/null
+++ b/usr/rsc/mem/Makefile
@@ -0,0 +1,33 @@
+# 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.
+
+CC=6c -w
+GC=6g
+LD=6l
+O=6
+
+TARG=testrandom testrepeat testsizetoclass
+
+default: $(TARG)
+
+%.$O: %.c malloc.h
+ $(CC) $*.c
+
+%.$O: %.go
+ $(GC) $*.go
+
+OFILES=\
+ allocator.$O\
+ malloc.$O\
+ pagemap.$O\
+ triv.$O\
+
+testrandom.$O: allocator.$O
+testrepeat.$O: allocator.$O
+
+test%: test%.$O $(OFILES)
+ $(LD) -o $@ $^
+
+clean:
+ rm -f *.$O $(TARG)
diff --git a/usr/rsc/mem/allocator.go b/usr/rsc/mem/allocator.go
new file mode 100644
index 0000000..da624fc
--- /dev/null
+++ b/usr/rsc/mem/allocator.go
@@ -0,0 +1,12 @@
+// 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.
+
+package allocator
+
+export func free(*byte)
+export func malloc(int) *byte
+export func memset(*byte, int, int)
+export var footprint int64
+export var frozen bool
+export func testsizetoclass()
diff --git a/usr/rsc/mem/malloc.c b/usr/rsc/mem/malloc.c
new file mode 100644
index 0000000..f5461cd
--- /dev/null
+++ b/usr/rsc/mem/malloc.c
@@ -0,0 +1,443 @@
+// 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.
+
+// General C malloc/free, but intended for Go.
+// Same design as tcmalloc:
+// see https://www/eng/designdocs/tcmalloc/tcmalloc.html
+
+// TODO:
+// * Central free lists.
+// * Thread cache stealing.
+// * Return memory to the OS.
+// * Memory footprint during testrandom is too big.
+// * Need to coalesce adjacent free spans.
+//
+// *** Some way to avoid the ``malloc overflows the stack
+// during the stack overflow malloc'' problem.
+
+#include "malloc.h"
+
+typedef struct Span Span;
+typedef struct Central Central;
+
+// A Span contains metadata about a range of pages.
+enum {
+ SpanInUse = 0, // span has been handed out by allocator
+ SpanFree = 1, // span is in central free list
+};
+struct Span
+{
+ Span *next; // in free lists
+ byte *base; // first byte in span
+ uintptr length; // number of pages in span
+ int32 cl;
+ int32 state; // state (enum above)
+// int ref; // reference count if state == SpanInUse (for GC)
+// void *type; // object type if state == SpanInUse (for GC)
+};
+
+// The Central cache contains a list of free spans,
+// as well as free lists of small blocks.
+struct Central
+{
+ Lock;
+ Span *free[256];
+ Span *large; // free spans >= MaxPage pages
+};
+
+static Central central;
+static PageMap spanmap;
+
+// Insert a new span into the map.
+static void
+insertspan(Span *s)
+{
+ int32 i;
+ uintptr base;
+
+ // TODO: This is likely too slow for large spans.
+ base = (uintptr)s->base >> PageShift;
+ for(i=0; i<s->length; i++)
+ pminsert(&spanmap, base+i, s);
+}
+
+// Record that a span has gotten smaller.
+static void
+shrinkspan(Span *s, int32 newlength)
+{
+ int32 i;
+ uintptr base;
+
+ // TODO: This is unnecessary, because an insertspan is next.
+ base = (uintptr)s->base >> PageShift;
+ for(i=newlength; i<s->length; i++)
+ pminsert(&spanmap, base+i, nil);
+
+ s->length = newlength;
+}
+
+// Find the span for a given pointer.
+static Span*
+spanofptr(void *v)
+{
+ return pmlookup(&spanmap, (uintptr)v >> PageShift);
+}
+
+static void freespan(Span*);
+
+// Allocate a span of at least n pages.
+static Span*
+allocspan(int32 npage)
+{
+ Span *s, **l, *s1;
+ int32 allocnpage, i;
+
+ // Look in the n-page free lists for big enough n.
+ for(i=npage; i<nelem(central.free); i++) {
+ s = central.free[i];
+ if(s != nil) {
+ central.free[i] = s->next;
+ goto havespan;
+ }
+ }
+
+ // Look in the large list, which has large runs of pages.
+ for(l=¢ral.large; (s=*l) != nil; l=&s->next) {
+ if(s->length >= npage) {
+ *l = s->next;
+ s->next = nil;
+if(s->length > npage) {
+prints("Chop span");
+sys·printint(s->length);
+prints(" for ");
+sys·printint(npage);
+prints("\n");
+}
+ goto havespan;
+ }
+ }
+
+ // Otherwise we need more memory.
+ // TODO: Could try to release this lock while asking for memory.
+ s = trivalloc(sizeof *s);
+ allocnpage = npage;
+ if(allocnpage < (1<<20>>PageShift)) // TODO: Tune
+ allocnpage = (1<<20>>PageShift);
+ s->length = allocnpage;
+prints("New span ");
+sys·printint(allocnpage);
+prints(" for ");
+sys·printint(npage);
+prints("\n");
+ s->base = trivalloc(allocnpage<<PageShift);
+ insertspan(s);
+
+havespan:
+ // If span is bigger than needed, redistribute the remainder.
+ if(s->length > npage) {
+ s1 = trivalloc(sizeof *s);
+ s1->base = s->base + (npage << PageShift);
+ s1->length = s->length - npage;
+ shrinkspan(s, npage);
+ insertspan(s1);
+ freespan(s1);
+ }
+ s->state = SpanInUse;
+ return s;
+}
+
+// Free a span.
+static void
+freespan(Span *s)
+{
+ Span **l;
+ Span *ss;
+
+ s->state = SpanFree;
+ if(s->length < nelem(central.free)) {
+ s->next = central.free[s->length];
+ central.free[s->length] = s;
+ } else {
+ // Keep central.large sorted in
+ // increasing size for best-fit allocation.
+ for(l = ¢ral.large; (ss=*l) != nil; l=&ss->next)
+ if(ss->length >= s->length)
+ break;
+ s->next = *l;
+ *l = s;
+ }
+}
+
+// Small objects are kept on per-size free lists in the M.
+// There are SmallFreeClasses (defined in runtime.h) different lists.
+static int32 classtosize[SmallFreeClasses] = {
+ /*
+ seq 8 8 127 | sed 's/$/,/' | fmt
+ seq 128 16 255 | sed 's/$/,/' | fmt
+ seq 256 32 511 | sed 's/$/,/' | fmt
+ seq 512 64 1023 | sed 's/$/,/' | fmt
+ seq 1024 128 2047 | sed 's/$/,/' | fmt
+ seq 2048 256 32768 | sed 's/$/,/' | fmt
+ */
+ 8, 16, 24, 32, 40, 48, 56, 64, 72, 80, 88, 96, 104, 112, 120,
+ 128, 144, 160, 176, 192, 208, 224, 240,
+ 256, 288, 320, 352, 384, 416, 448, 480,
+ 512, 576, 640, 704, 768, 832, 896, 960,
+ 1024, 1152, 1280, 1408, 1536, 1664, 1792, 1920,
+ 2048, 2304, 2560, 2816, 3072, 3328, 3584, 3840, 4096, 4352, 4608,
+ 4864, 5120, 5376, 5632, 5888, 6144, 6400, 6656, 6912, 7168, 7424,
+ 7680, 7936, 8192, 8448, 8704, 8960, 9216, 9472, 9728, 9984, 10240,
+ 10496, 10752, 11008, 11264, 11520, 11776, 12032, 12288, 12544,
+ 12800, 13056, 13312, 13568, 13824, 14080, 14336, 14592, 14848,
+ 15104, 15360, 15616, 15872, 16128, 16384, 16640, 16896, 17152,
+ 17408, 17664, 17920, 18176, 18432, 18688, 18944, 19200, 19456,
+ 19712, 19968, 20224, 20480, 20736, 20992, 21248, 21504, 21760,
+ 22016, 22272, 22528, 22784, 23040, 23296, 23552, 23808, 24064,
+ 24320, 24576, 24832, 25088, 25344, 25600, 25856, 26112, 26368,
+ 26624, 26880, 27136, 27392, 27648, 27904, 28160, 28416, 28672,
+ 28928, 29184, 29440, 29696, 29952, 30208, 30464, 30720, 30976,
+ 31232, 31488, 31744, 32000, 32256, 32512, 32768,
+};
+enum {
+ LargeSize = 32768
+};
+
+// Trigger compile error if nelem(classtosize) != SmallFreeClasses.
+static int32 zzz1[SmallFreeClasses-nelem(classtosize)+1];
+static int32 zzz2[nelem(classtosize)-SmallFreeClasses+1];
+
+static int32
+sizetoclass(int32 siz)
+{
+ if(siz <= 0)
+ return 0;
+ if(siz <= 128)
+ return (siz-1) >> 3;
+ if(siz <= 256)
+ return ((siz-1) >> 4) + 8;
+ if(siz <= 512)
+ return ((siz-1) >> 5) + 16;
+ if(siz <= 1024)
+ return ((siz-1) >> 6) + 24;
+ if(siz <= 2048)
+ return ((siz-1) >> 7) + 32;
+ if(siz <= 32768)
+ return ((siz-1) >> 8) + 40;
+ throw("sizetoclass - invalid size");
+ return -1;
+}
+
+void
+allocator·testsizetoclass(void)
+{
+ int32 i, n;
+
+ n = 0;
+ for(i=0; i<nelem(classtosize); i++) {
+ for(; n <= classtosize[i]; n++) {
+ if(sizetoclass(n) != i) {
+ prints("sizetoclass ");
+ sys·printint(n);
+ prints(" = ");
+ sys·printint(sizetoclass(n));
+ prints(" want ");
+ sys·printint(i);
+ prints("\n");
+ throw("testsizetoclass");
+ }
+ }
+ }
+ if (n != 32768+1) {
+ prints("testsizetoclass stopped at ");
+ sys·printint(n);
+ prints("\n");
+ throw("testsizetoclass");
+ }
+}
+
+// Grab a bunch of objects of size class cl off the central free list.
+// Set *pn to the number of objects returned.
+static void*
+centralgrab(int32 cl, int32 *pn)
+{
+ byte *p;
+ Span *s;
+ int32 chunk, i, n, siz;
+
+ // For now there is no central free list.
+ // Fall back to allocating a new span
+ // and chopping it up.
+ chunk = classtosize[cl] * 1024;
+ if(chunk > 1<<20) {
+ chunk = 1<<20;
+ }
+ chunk = (chunk+PageMask) & ~PageMask;
+ s = allocspan(chunk>>PageShift);
+prints("New Class ");
+sys·printint(cl);
+prints("\n");
+ s->state = SpanInUse;
+ s->cl = cl;
+ siz = classtosize[cl];
+ n = chunk/siz;
+ p = s->base;
+ for(i=0; i<n-1; i++) {
+ *(void**)p = p+siz;
+ p += siz;
+ }
+ *pn = n;
+ return p;
+}
+
+// Allocate a small object of size class cl.
+void*
+allocsmall(int32 cl)
+{
+ void **p;
+ int32 n;
+
+ if(cl < 0 || cl >= SmallFreeClasses)
+ throw("allocsmall - invalid class");
+
+ // try m-local cache.
+ p = m->freelist[cl];
+ if(p == nil) {
+ // otherwise grab some blocks from central cache.
+ lock(¢ral);
+ p = centralgrab(cl, &n);
+ // TODO: update local counters using n
+ unlock(¢ral);
+ }
+
+ // advance linked list.
+ m->freelist[cl] = *p;
+
+ // Blocks on free list are zeroed except for
+ // the linked list pointer that we just used. Zero it.
+ *p = 0;
+
+ return p;
+}
+
+// Allocate large object of np pages.
+void*
+alloclarge(int32 np)
+{
+ Span *s;
+
+ lock(¢ral);
+//prints("Alloc span ");
+//sys·printint(np);
+//prints("\n");
+ s = allocspan(np);
+ unlock(¢ral);
+ s->state = SpanInUse;
+ s->cl = -1;
+ return s->base;
+}
+
+// Allocate object of n bytes.
+void*
+alloc(int32 n)
+{
+ int32 cl, np;
+
+ if(n < LargeSize) {
+ cl = sizetoclass(n);
+ if(cl < 0 || cl >= SmallFreeClasses) {
+ sys·printint(n);
+ prints(" -> ");
+ sys·printint(cl);
+ prints("\n");
+ throw("alloc - logic error");
+ }
+ return allocsmall(sizetoclass(n));
+ }
+
+ // count number of pages; careful about overflow for big n.
+ np = (n>>PageShift) + (((n&PageMask)+PageMask)>>PageShift);
+ return alloclarge(np);
+}
+
+void
+allocator·malloc(int32 n, byte *out)
+{
+ out = alloc(n);
+ FLUSH(&out);
+}
+
+// Free object with base pointer v.
+void
+free(void *v)
+{
+ void **p;
+ Span *s;
+ int32 siz, off;
+
+ s = spanofptr(v);
+ if(s->state != SpanInUse)
+ throw("free - invalid pointer1");
+
+ // Big object should be s->base.
+ if(s->cl < 0) {
+ if(v != s->base)
+ throw("free - invalid pointer2");
+ // TODO: For large spans, maybe just return the
+ // memory to the operating system and let it zero it.
+ sys·memclr(s->base, s->length << PageShift);
+//prints("Free big ");
+//sys·printint(s->length);
+//prints("\n");
+ lock(¢ral);
+ freespan(s);
+ unlock(¢ral);
+ return;
+ }
+
+ // Small object should be aligned properly.
+ siz = classtosize[s->cl];
+ off = (byte*)v - (byte*)s->base;
+ if(off%siz)
+ throw("free - invalid pointer3");
+
+ // Zero and add to free list.
+ sys·memclr(v, siz);
+ p = v;
+ *p = m->freelist[s->cl];
+ m->freelist[s->cl] = p;
+}
+
+void
+allocator·free(byte *v)
+{
+ free(v);
+}
+
+void
+allocator·memset(byte *v, int32 c, int32 n)
+{
+ int32 i;
+
+ for(i=0; i<n; i++)
+ v[i] = c;
+}
+
+// Allocate stack segment.
+// Must be done without holding locks, because
+// calling any function might trigger another stack segment allocation.
+void*
+allocstack(int32 n)
+{
+ // TODO
+ USED(n);
+ return nil;
+}
+
+void
+freestack(void *v)
+{
+ // TODO
+ USED(v);
+}
+
diff --git a/usr/rsc/mem/malloc.h b/usr/rsc/mem/malloc.h
new file mode 100644
index 0000000..aa3bed2
--- /dev/null
+++ b/usr/rsc/mem/malloc.h
@@ -0,0 +1,32 @@
+// 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.
+
+#include "../../../src/runtime/runtime.h"
+
+typedef struct PageMap PageMap;
+
+enum
+{
+ PageShift = 12,
+ PageMask = (1<<PageShift) - 1,
+};
+
+enum {
+ PMBits = 64 - PageShift,
+ PMLevels = 4,
+ PMLevelBits = 13,
+ PMLevelSize = 1<<PMLevelBits,
+ PMLevelMask = PMLevelSize - 1,
+};
+struct PageMap
+{
+ void *level0[PMLevelSize];
+};
+
+extern int64 allocator·footprint;
+extern bool allocator·frozen;
+
+void* trivalloc(int32);
+void* pmlookup(PageMap*, uintptr);
+void* pminsert(PageMap*, uintptr, void*);
diff --git a/usr/rsc/mem/pagemap.c b/usr/rsc/mem/pagemap.c
new file mode 100644
index 0000000..4d903a2
--- /dev/null
+++ b/usr/rsc/mem/pagemap.c
@@ -0,0 +1,66 @@
+// 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.
+
+#include "malloc.h"
+
+// A PageMap maps page numbers to void* pointers.
+// The AMD64 has 64-bit addresses and 4096-byte pages, so
+// the page numbers are 52 bits. We use a four-level radix tree,
+// with 13 bits for each level. This requires 32 kB per level or
+// 128 kB for a table with one entry. Moving to three levels of 18 bits
+// would require 3 MB for a table with one entry, which seems too expensive.
+// This is easy to change.
+// It may be that a balanced tree would be better anyway.
+
+// Return the entry for page number pn in m.
+void*
+pmlookup(PageMap *m, uintptr pn)
+{
+ int32 i, x;
+ void **v;
+
+ v = &m->level0[0];
+ for(i=0; i<PMLevels; i++) {
+ // Pick off top PMLevelBits bits as index and shift up.
+ x = (pn >> (PMBits - PMLevelBits)) & PMLevelMask;
+ pn <<= PMLevelBits;
+
+ // Walk down using index.
+ v = v[x];
+ if(v == nil)
+ return nil;
+ }
+ return v;
+}
+
+// Set the entry for page number pn in m to s.
+// Return the old value.
+void*
+pminsert(PageMap *m, uintptr pn, void *value)
+{
+ int32 i, x;
+ void **v, **l;
+
+ l = nil; // shut up 6c
+ v = &m->level0[0];
+ for(i=0; i<PMLevels; i++) {
+ // Pick off top PMLevelBits bits as index and shift up.
+ x = (pn >> (PMBits - PMLevelBits)) & PMLevelMask;
+ pn <<= PMLevelBits;
+
+ // Walk down using index, but remember location of pointer.
+ l = &v[x];
+ v = *l;
+
+ // Allocate new level if needed.
+ if(v == nil && i < PMLevels-1) {
+ v = trivalloc(PMLevelSize * sizeof v[0]);
+ *l = v;
+ }
+ }
+
+ // Record new value and return old.
+ *l = value;
+ return v;
+}
diff --git a/usr/rsc/mem/testrandom.go b/usr/rsc/mem/testrandom.go
new file mode 100644
index 0000000..7115afd
--- /dev/null
+++ b/usr/rsc/mem/testrandom.go
@@ -0,0 +1,62 @@
+// 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.
+
+package main
+
+import (
+ "allocator";
+ "rand"
+)
+
+var footprint int64;
+var allocated int64;
+func bigger() {
+ if footprint < allocator.footprint {
+ footprint = allocator.footprint;
+ println("Footprint", footprint, " for ", allocated);
+ if footprint > 1e9 {
+ panicln("too big");
+ }
+ }
+}
+
+// Prime the data structures by allocating one of
+// each block in order. After this, there should be
+// little reason to ask for more memory from the OS.
+func prime() {
+ for i := 0; i < 16; i++ {
+ b := allocator.malloc(1<<uint(i));
+ allocator.free(b);
+ }
+ for i := 0; i < 256; i++ {
+ b := allocator.malloc(i<<12);
+ allocator.free(b);
+ }
+}
+
+func main() {
+// prime();
+ var blocks [1] struct { base *byte; siz int; };
+ for i := 0; i < 1 << 20; i++ {
+ if i%(1<<10) == 0 {
+ println(i);
+ }
+ b := rand.rand() % len(blocks);
+ if blocks[b].base != nil {
+ // println("Free", blocks[b].siz, blocks[b].base);
+ allocator.free(blocks[b].base);
+ blocks[b].base = nil;
+ allocated -= int64(blocks[b].siz);
+ continue
+ }
+ siz := rand.rand() >> (11 + rand.urand32() % 20);
+ base := allocator.malloc(siz);
+ blocks[b].base = base;
+ blocks[b].siz = siz;
+ allocated += int64(siz);
+ // println("Alloc", siz, base);
+ allocator.memset(base, 0xbb, siz);
+ bigger();
+ }
+}
diff --git a/usr/rsc/mem/testrepeat.go b/usr/rsc/mem/testrepeat.go
new file mode 100644
index 0000000..caa9653
--- /dev/null
+++ b/usr/rsc/mem/testrepeat.go
@@ -0,0 +1,37 @@
+// 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.
+
+package main
+
+import (
+ "allocator"
+)
+
+var footprint int64
+func bigger() {
+ if footprint < allocator.footprint {
+ footprint = allocator.footprint;
+ println("Footprint", footprint);
+ }
+}
+
+func main() {
+ for i := 0; i < 1<<16; i++ {
+ for j := 1; j <= 1<<22; j<<=1 {
+ if i == 0 {
+ println("First alloc:", j);
+ }
+ b := allocator.malloc(j);
+ allocator.free(b);
+ bigger();
+ }
+ if i%(1<<10) == 0 {
+ println(i);
+ }
+ if i == 0 {
+ println("Primed", i);
+ allocator.frozen = true;
+ }
+ }
+}
diff --git a/usr/rsc/mem/testsizetoclass.go b/usr/rsc/mem/testsizetoclass.go
new file mode 100644
index 0000000..f92d843
--- /dev/null
+++ b/usr/rsc/mem/testsizetoclass.go
@@ -0,0 +1,11 @@
+// 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.
+
+package main
+
+import "allocator"
+
+func main() {
+ allocator.testsizetoclass()
+}
diff --git a/usr/rsc/mem/triv.c b/usr/rsc/mem/triv.c
new file mode 100644
index 0000000..631e93a
--- /dev/null
+++ b/usr/rsc/mem/triv.c
@@ -0,0 +1,64 @@
+// 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.
+
+// Trivial base allocator.
+
+#include "malloc.h"
+
+// TODO: The call to sys·mmap should be a call to an assembly
+// function sys·mmapnew that takes only a size parameter.
+enum
+{
+ PROT_NONE = 0x00,
+ PROT_READ = 0x01,
+ PROT_WRITE = 0x02,
+ PROT_EXEC = 0x04,
+
+ MAP_FILE = 0x0000,
+ MAP_SHARED = 0x0001,
+ MAP_PRIVATE = 0x0002,
+ MAP_FIXED = 0x0010,
+ MAP_ANON = 0x1000,
+};
+
+// Allocate and return zeroed memory.
+// Simple allocator for small things like Span structures,
+// and also used to grab large amounts of memory for
+// the real allocator to hand out.
+enum
+{
+ Round = 15,
+};
+void*
+trivalloc(int32 size)
+{
+ static byte *p;
+ static int32 n;
+ byte *v;
+
+ if(allocator·frozen)
+ throw("allocator frozen");
+
+//prints("Newmem: ");
+//sys·printint(size);
+//prints("\n");
+
+ if(size < 4096) { // TODO: Tune constant.
+ size = (size + Round) & ~Round;
+ if(size > n) {
+ n = 1<<20; // TODO: Tune constant.
+ p = sys·mmap(nil, n, PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, 0, 0);
+ allocator·footprint += n;
+ }
+ v = p;
+ p += size;
+ return v;
+ }
+ if(size & PageMask)
+ size += (1<<PageShift) - (size & PageMask);
+ v = sys·mmap(nil, size, PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE, 0, 0);
+ allocator·footprint += size;
+ return v;
+}
+
