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747 |
jeremybenn |
// 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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// Garbage collector.
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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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#ifdef USING_SPLIT_STACK
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extern void * __splitstack_find (void *, void *, size_t *, void **, void **,
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void **);
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extern void * __splitstack_find_context (void *context[10], size_t *, void **,
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void **, void **);
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#endif
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enum {
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Debug = 0,
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PtrSize = sizeof(void*),
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DebugMark = 0, // run second pass to check mark
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// Four bits per word (see #defines below).
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wordsPerBitmapWord = sizeof(void*)*8/4,
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bitShift = sizeof(void*)*8/4,
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};
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// Bits in per-word bitmap.
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// #defines because enum might not be able to hold the values.
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//
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// Each word in the bitmap describes wordsPerBitmapWord words
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// of heap memory. There are 4 bitmap bits dedicated to each heap word,
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// so on a 64-bit system there is one bitmap word per 16 heap words.
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// The bits in the word are packed together by type first, then by
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// heap location, so each 64-bit bitmap word consists of, from top to bottom,
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// the 16 bitSpecial bits for the corresponding heap words, then the 16 bitMarked bits,
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// then the 16 bitNoPointers/bitBlockBoundary bits, then the 16 bitAllocated bits.
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// This layout makes it easier to iterate over the bits of a given type.
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//
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// The bitmap starts at mheap.arena_start and extends *backward* from
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// there. On a 64-bit system the off'th word in the arena is tracked by
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// the off/16+1'th word before mheap.arena_start. (On a 32-bit system,
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// the only difference is that the divisor is 8.)
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//
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// To pull out the bits corresponding to a given pointer p, we use:
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//
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// off = p - (uintptr*)mheap.arena_start; // word offset
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// b = (uintptr*)mheap.arena_start - off/wordsPerBitmapWord - 1;
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// shift = off % wordsPerBitmapWord
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// bits = *b >> shift;
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// /* then test bits & bitAllocated, bits & bitMarked, etc. */
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//
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#define bitAllocated ((uintptr)1<<(bitShift*0))
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#define bitNoPointers ((uintptr)1<<(bitShift*1)) /* when bitAllocated is set */
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#define bitMarked ((uintptr)1<<(bitShift*2)) /* when bitAllocated is set */
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#define bitSpecial ((uintptr)1<<(bitShift*3)) /* when bitAllocated is set - has finalizer or being profiled */
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#define bitBlockBoundary ((uintptr)1<<(bitShift*1)) /* when bitAllocated is NOT set */
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#define bitMask (bitBlockBoundary | bitAllocated | bitMarked | bitSpecial)
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// TODO: Make these per-M.
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static uint64 nhandoff;
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static int32 gctrace;
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typedef struct Workbuf Workbuf;
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struct Workbuf
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{
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Workbuf *next;
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uintptr nobj;
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byte *obj[512-2];
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};
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typedef struct Finalizer Finalizer;
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struct Finalizer
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{
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void (*fn)(void*);
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void *arg;
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const struct __go_func_type *ft;
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};
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typedef struct FinBlock FinBlock;
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struct FinBlock
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{
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FinBlock *alllink;
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FinBlock *next;
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int32 cnt;
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int32 cap;
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Finalizer fin[1];
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};
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static G *fing;
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static FinBlock *finq; // list of finalizers that are to be executed
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static FinBlock *finc; // cache of free blocks
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static FinBlock *allfin; // list of all blocks
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static Lock finlock;
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static int32 fingwait;
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static void runfinq(void*);
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static Workbuf* getempty(Workbuf*);
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static Workbuf* getfull(Workbuf*);
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static void putempty(Workbuf*);
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static Workbuf* handoff(Workbuf*);
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static struct {
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Lock fmu;
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Workbuf *full;
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Lock emu;
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Workbuf *empty;
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uint32 nproc;
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volatile uint32 nwait;
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volatile uint32 ndone;
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Note alldone;
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Lock markgate;
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Lock sweepgate;
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MSpan *spans;
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Lock;
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byte *chunk;
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uintptr nchunk;
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} work;
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// scanblock scans a block of n bytes starting at pointer b for references
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// to other objects, scanning any it finds recursively until there are no
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// unscanned objects left. Instead of using an explicit recursion, it keeps
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// a work list in the Workbuf* structures and loops in the main function
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// body. Keeping an explicit work list is easier on the stack allocator and
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// more efficient.
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static void
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scanblock(byte *b, int64 n)
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{
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byte *obj, *arena_start, *arena_used, *p;
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void **vp;
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uintptr size, *bitp, bits, shift, i, j, x, xbits, off, nobj, nproc;
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MSpan *s;
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PageID k;
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void **wp;
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Workbuf *wbuf;
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bool keepworking;
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if((int64)(uintptr)n != n || n < 0) {
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// runtime_printf("scanblock %p %lld\n", b, (long long)n);
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runtime_throw("scanblock");
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}
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// Memory arena parameters.
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arena_start = runtime_mheap.arena_start;
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arena_used = runtime_mheap.arena_used;
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nproc = work.nproc;
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wbuf = nil; // current work buffer
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wp = nil; // storage for next queued pointer (write pointer)
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nobj = 0; // number of queued objects
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// Scanblock helpers pass b==nil.
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// The main proc needs to return to make more
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// calls to scanblock. But if work.nproc==1 then
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// might as well process blocks as soon as we
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// have them.
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keepworking = b == nil || work.nproc == 1;
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// Align b to a word boundary.
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off = (uintptr)b & (PtrSize-1);
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if(off != 0) {
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b += PtrSize - off;
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n -= PtrSize - off;
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}
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for(;;) {
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// Each iteration scans the block b of length n, queueing pointers in
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// the work buffer.
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if(Debug > 1)
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runtime_printf("scanblock %p %lld\n", b, (long long) n);
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vp = (void**)b;
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n >>= (2+PtrSize/8); /* n /= PtrSize (4 or 8) */
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for(i=0; i<(uintptr)n; i++) {
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obj = (byte*)vp[i];
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// Words outside the arena cannot be pointers.
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if((byte*)obj < arena_start || (byte*)obj >= arena_used)
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continue;
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// obj may be a pointer to a live object.
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// Try to find the beginning of the object.
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// Round down to word boundary.
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obj = (void*)((uintptr)obj & ~((uintptr)PtrSize-1));
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// Find bits for this word.
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off = (uintptr*)obj - (uintptr*)arena_start;
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bitp = (uintptr*)arena_start - off/wordsPerBitmapWord - 1;
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shift = off % wordsPerBitmapWord;
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xbits = *bitp;
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bits = xbits >> shift;
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// Pointing at the beginning of a block?
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if((bits & (bitAllocated|bitBlockBoundary)) != 0)
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goto found;
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// Pointing just past the beginning?
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// Scan backward a little to find a block boundary.
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for(j=shift; j-->0; ) {
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if(((xbits>>j) & (bitAllocated|bitBlockBoundary)) != 0) {
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obj = (byte*)obj - (shift-j)*PtrSize;
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shift = j;
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bits = xbits>>shift;
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goto found;
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}
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}
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// Otherwise consult span table to find beginning.
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// (Manually inlined copy of MHeap_LookupMaybe.)
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k = (uintptr)obj>>PageShift;
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x = k;
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if(sizeof(void*) == 8)
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x -= (uintptr)arena_start>>PageShift;
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s = runtime_mheap.map[x];
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if(s == nil || k < s->start || k - s->start >= s->npages || s->state != MSpanInUse)
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continue;
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p = (byte*)((uintptr)s->start<<PageShift);
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if(s->sizeclass == 0) {
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obj = p;
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} else {
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if((byte*)obj >= (byte*)s->limit)
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continue;
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size = runtime_class_to_size[s->sizeclass];
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int32 i = ((byte*)obj - p)/size;
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obj = p+i*size;
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}
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// Now that we know the object header, reload bits.
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off = (uintptr*)obj - (uintptr*)arena_start;
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bitp = (uintptr*)arena_start - off/wordsPerBitmapWord - 1;
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shift = off % wordsPerBitmapWord;
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xbits = *bitp;
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bits = xbits >> shift;
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found:
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// Now we have bits, bitp, and shift correct for
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// obj pointing at the base of the object.
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// Only care about allocated and not marked.
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if((bits & (bitAllocated|bitMarked)) != bitAllocated)
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continue;
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if(nproc == 1)
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*bitp |= bitMarked<<shift;
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else {
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for(;;) {
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x = *bitp;
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if(x & (bitMarked<<shift))
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goto continue_obj;
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if(runtime_casp((void**)bitp, (void*)x, (void*)(x|(bitMarked<<shift))))
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break;
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}
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}
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// If object has no pointers, don't need to scan further.
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if((bits & bitNoPointers) != 0)
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continue;
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// If another proc wants a pointer, give it some.
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if(nobj > 4 && work.nwait > 0 && work.full == nil) {
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wbuf->nobj = nobj;
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wbuf = handoff(wbuf);
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nobj = wbuf->nobj;
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wp = (void**)(wbuf->obj + nobj);
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}
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// If buffer is full, get a new one.
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if(wbuf == nil || nobj >= nelem(wbuf->obj)) {
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if(wbuf != nil)
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wbuf->nobj = nobj;
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wbuf = getempty(wbuf);
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wp = (void**)(wbuf->obj);
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nobj = 0;
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| 280 |
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}
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*wp++ = obj;
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nobj++;
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continue_obj:;
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| 284 |
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}
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| 286 |
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// Done scanning [b, b+n). Prepare for the next iteration of
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| 287 |
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// the loop by setting b and n to the parameters for the next block.
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| 288 |
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| 289 |
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// Fetch b from the work buffer.
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| 290 |
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if(nobj == 0) {
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| 291 |
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if(!keepworking) {
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| 292 |
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putempty(wbuf);
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| 293 |
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return;
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| 294 |
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}
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| 295 |
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// Emptied our buffer: refill.
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| 296 |
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wbuf = getfull(wbuf);
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| 297 |
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if(wbuf == nil)
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| 298 |
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return;
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| 299 |
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nobj = wbuf->nobj;
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| 300 |
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wp = (void**)(wbuf->obj + wbuf->nobj);
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| 301 |
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}
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| 302 |
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b = *--wp;
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| 303 |
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nobj--;
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| 304 |
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| 305 |
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// Ask span about size class.
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| 306 |
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// (Manually inlined copy of MHeap_Lookup.)
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| 307 |
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x = (uintptr)b>>PageShift;
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| 308 |
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if(sizeof(void*) == 8)
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| 309 |
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x -= (uintptr)arena_start>>PageShift;
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| 310 |
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s = runtime_mheap.map[x];
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| 311 |
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if(s->sizeclass == 0)
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| 312 |
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n = s->npages<<PageShift;
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| 313 |
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else
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| 314 |
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n = runtime_class_to_size[s->sizeclass];
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| 315 |
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}
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| 316 |
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}
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| 317 |
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| 318 |
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// debug_scanblock is the debug copy of scanblock.
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| 319 |
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// it is simpler, slower, single-threaded, recursive,
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| 320 |
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// and uses bitSpecial as the mark bit.
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| 321 |
|
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static void
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| 322 |
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debug_scanblock(byte *b, int64 n)
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| 323 |
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{
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| 324 |
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byte *obj, *p;
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| 325 |
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void **vp;
|
| 326 |
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uintptr size, *bitp, bits, shift, i, xbits, off;
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| 327 |
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MSpan *s;
|
| 328 |
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| 329 |
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if(!DebugMark)
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| 330 |
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runtime_throw("debug_scanblock without DebugMark");
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| 331 |
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| 332 |
|
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if((int64)(uintptr)n != n || n < 0) {
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| 333 |
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//runtime_printf("debug_scanblock %p %D\n", b, n);
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| 334 |
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runtime_throw("debug_scanblock");
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| 335 |
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}
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| 336 |
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| 337 |
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// Align b to a word boundary.
|
| 338 |
|
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off = (uintptr)b & (PtrSize-1);
|
| 339 |
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if(off != 0) {
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| 340 |
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b += PtrSize - off;
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| 341 |
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n -= PtrSize - off;
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| 342 |
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}
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| 343 |
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|
|
| 344 |
|
|
vp = (void**)b;
|
| 345 |
|
|
n /= PtrSize;
|
| 346 |
|
|
for(i=0; i<(uintptr)n; i++) {
|
| 347 |
|
|
obj = (byte*)vp[i];
|
| 348 |
|
|
|
| 349 |
|
|
// Words outside the arena cannot be pointers.
|
| 350 |
|
|
if((byte*)obj < runtime_mheap.arena_start || (byte*)obj >= runtime_mheap.arena_used)
|
| 351 |
|
|
continue;
|
| 352 |
|
|
|
| 353 |
|
|
// Round down to word boundary.
|
| 354 |
|
|
obj = (void*)((uintptr)obj & ~((uintptr)PtrSize-1));
|
| 355 |
|
|
|
| 356 |
|
|
// Consult span table to find beginning.
|
| 357 |
|
|
s = runtime_MHeap_LookupMaybe(&runtime_mheap, obj);
|
| 358 |
|
|
if(s == nil)
|
| 359 |
|
|
continue;
|
| 360 |
|
|
|
| 361 |
|
|
|
| 362 |
|
|
p = (byte*)((uintptr)s->start<<PageShift);
|
| 363 |
|
|
if(s->sizeclass == 0) {
|
| 364 |
|
|
obj = p;
|
| 365 |
|
|
size = (uintptr)s->npages<<PageShift;
|
| 366 |
|
|
} else {
|
| 367 |
|
|
if((byte*)obj >= (byte*)s->limit)
|
| 368 |
|
|
continue;
|
| 369 |
|
|
size = runtime_class_to_size[s->sizeclass];
|
| 370 |
|
|
int32 i = ((byte*)obj - p)/size;
|
| 371 |
|
|
obj = p+i*size;
|
| 372 |
|
|
}
|
| 373 |
|
|
|
| 374 |
|
|
// Now that we know the object header, reload bits.
|
| 375 |
|
|
off = (uintptr*)obj - (uintptr*)runtime_mheap.arena_start;
|
| 376 |
|
|
bitp = (uintptr*)runtime_mheap.arena_start - off/wordsPerBitmapWord - 1;
|
| 377 |
|
|
shift = off % wordsPerBitmapWord;
|
| 378 |
|
|
xbits = *bitp;
|
| 379 |
|
|
bits = xbits >> shift;
|
| 380 |
|
|
|
| 381 |
|
|
// Now we have bits, bitp, and shift correct for
|
| 382 |
|
|
// obj pointing at the base of the object.
|
| 383 |
|
|
// If not allocated or already marked, done.
|
| 384 |
|
|
if((bits & bitAllocated) == 0 || (bits & bitSpecial) != 0) // NOTE: bitSpecial not bitMarked
|
| 385 |
|
|
continue;
|
| 386 |
|
|
*bitp |= bitSpecial<<shift;
|
| 387 |
|
|
if(!(bits & bitMarked))
|
| 388 |
|
|
runtime_printf("found unmarked block %p in %p\n", obj, vp+i);
|
| 389 |
|
|
|
| 390 |
|
|
// If object has no pointers, don't need to scan further.
|
| 391 |
|
|
if((bits & bitNoPointers) != 0)
|
| 392 |
|
|
continue;
|
| 393 |
|
|
|
| 394 |
|
|
debug_scanblock(obj, size);
|
| 395 |
|
|
}
|
| 396 |
|
|
}
|
| 397 |
|
|
|
| 398 |
|
|
// Get an empty work buffer off the work.empty list,
|
| 399 |
|
|
// allocating new buffers as needed.
|
| 400 |
|
|
static Workbuf*
|
| 401 |
|
|
getempty(Workbuf *b)
|
| 402 |
|
|
{
|
| 403 |
|
|
if(work.nproc == 1) {
|
| 404 |
|
|
// Put b on full list.
|
| 405 |
|
|
if(b != nil) {
|
| 406 |
|
|
b->next = work.full;
|
| 407 |
|
|
work.full = b;
|
| 408 |
|
|
}
|
| 409 |
|
|
// Grab from empty list if possible.
|
| 410 |
|
|
b = work.empty;
|
| 411 |
|
|
if(b != nil) {
|
| 412 |
|
|
work.empty = b->next;
|
| 413 |
|
|
goto haveb;
|
| 414 |
|
|
}
|
| 415 |
|
|
} else {
|
| 416 |
|
|
// Put b on full list.
|
| 417 |
|
|
if(b != nil) {
|
| 418 |
|
|
runtime_lock(&work.fmu);
|
| 419 |
|
|
b->next = work.full;
|
| 420 |
|
|
work.full = b;
|
| 421 |
|
|
runtime_unlock(&work.fmu);
|
| 422 |
|
|
}
|
| 423 |
|
|
// Grab from empty list if possible.
|
| 424 |
|
|
runtime_lock(&work.emu);
|
| 425 |
|
|
b = work.empty;
|
| 426 |
|
|
if(b != nil)
|
| 427 |
|
|
work.empty = b->next;
|
| 428 |
|
|
runtime_unlock(&work.emu);
|
| 429 |
|
|
if(b != nil)
|
| 430 |
|
|
goto haveb;
|
| 431 |
|
|
}
|
| 432 |
|
|
|
| 433 |
|
|
// Need to allocate.
|
| 434 |
|
|
runtime_lock(&work);
|
| 435 |
|
|
if(work.nchunk < sizeof *b) {
|
| 436 |
|
|
work.nchunk = 1<<20;
|
| 437 |
|
|
work.chunk = runtime_SysAlloc(work.nchunk);
|
| 438 |
|
|
}
|
| 439 |
|
|
b = (Workbuf*)work.chunk;
|
| 440 |
|
|
work.chunk += sizeof *b;
|
| 441 |
|
|
work.nchunk -= sizeof *b;
|
| 442 |
|
|
runtime_unlock(&work);
|
| 443 |
|
|
|
| 444 |
|
|
haveb:
|
| 445 |
|
|
b->nobj = 0;
|
| 446 |
|
|
return b;
|
| 447 |
|
|
}
|
| 448 |
|
|
|
| 449 |
|
|
static void
|
| 450 |
|
|
putempty(Workbuf *b)
|
| 451 |
|
|
{
|
| 452 |
|
|
if(b == nil)
|
| 453 |
|
|
return;
|
| 454 |
|
|
|
| 455 |
|
|
if(work.nproc == 1) {
|
| 456 |
|
|
b->next = work.empty;
|
| 457 |
|
|
work.empty = b;
|
| 458 |
|
|
return;
|
| 459 |
|
|
}
|
| 460 |
|
|
|
| 461 |
|
|
runtime_lock(&work.emu);
|
| 462 |
|
|
b->next = work.empty;
|
| 463 |
|
|
work.empty = b;
|
| 464 |
|
|
runtime_unlock(&work.emu);
|
| 465 |
|
|
}
|
| 466 |
|
|
|
| 467 |
|
|
// Get a full work buffer off the work.full list, or return nil.
|
| 468 |
|
|
static Workbuf*
|
| 469 |
|
|
getfull(Workbuf *b)
|
| 470 |
|
|
{
|
| 471 |
|
|
int32 i;
|
| 472 |
|
|
Workbuf *b1;
|
| 473 |
|
|
|
| 474 |
|
|
if(work.nproc == 1) {
|
| 475 |
|
|
// Put b on empty list.
|
| 476 |
|
|
if(b != nil) {
|
| 477 |
|
|
b->next = work.empty;
|
| 478 |
|
|
work.empty = b;
|
| 479 |
|
|
}
|
| 480 |
|
|
// Grab from full list if possible.
|
| 481 |
|
|
// Since work.nproc==1, no one else is
|
| 482 |
|
|
// going to give us work.
|
| 483 |
|
|
b = work.full;
|
| 484 |
|
|
if(b != nil)
|
| 485 |
|
|
work.full = b->next;
|
| 486 |
|
|
return b;
|
| 487 |
|
|
}
|
| 488 |
|
|
|
| 489 |
|
|
putempty(b);
|
| 490 |
|
|
|
| 491 |
|
|
// Grab buffer from full list if possible.
|
| 492 |
|
|
for(;;) {
|
| 493 |
|
|
b1 = work.full;
|
| 494 |
|
|
if(b1 == nil)
|
| 495 |
|
|
break;
|
| 496 |
|
|
runtime_lock(&work.fmu);
|
| 497 |
|
|
if(work.full != nil) {
|
| 498 |
|
|
b1 = work.full;
|
| 499 |
|
|
work.full = b1->next;
|
| 500 |
|
|
runtime_unlock(&work.fmu);
|
| 501 |
|
|
return b1;
|
| 502 |
|
|
}
|
| 503 |
|
|
runtime_unlock(&work.fmu);
|
| 504 |
|
|
}
|
| 505 |
|
|
|
| 506 |
|
|
runtime_xadd(&work.nwait, +1);
|
| 507 |
|
|
for(i=0;; i++) {
|
| 508 |
|
|
b1 = work.full;
|
| 509 |
|
|
if(b1 != nil) {
|
| 510 |
|
|
runtime_lock(&work.fmu);
|
| 511 |
|
|
if(work.full != nil) {
|
| 512 |
|
|
runtime_xadd(&work.nwait, -1);
|
| 513 |
|
|
b1 = work.full;
|
| 514 |
|
|
work.full = b1->next;
|
| 515 |
|
|
runtime_unlock(&work.fmu);
|
| 516 |
|
|
return b1;
|
| 517 |
|
|
}
|
| 518 |
|
|
runtime_unlock(&work.fmu);
|
| 519 |
|
|
continue;
|
| 520 |
|
|
}
|
| 521 |
|
|
if(work.nwait == work.nproc)
|
| 522 |
|
|
return nil;
|
| 523 |
|
|
if(i < 10)
|
| 524 |
|
|
runtime_procyield(20);
|
| 525 |
|
|
else if(i < 20)
|
| 526 |
|
|
runtime_osyield();
|
| 527 |
|
|
else
|
| 528 |
|
|
runtime_usleep(100);
|
| 529 |
|
|
}
|
| 530 |
|
|
}
|
| 531 |
|
|
|
| 532 |
|
|
static Workbuf*
|
| 533 |
|
|
handoff(Workbuf *b)
|
| 534 |
|
|
{
|
| 535 |
|
|
int32 n;
|
| 536 |
|
|
Workbuf *b1;
|
| 537 |
|
|
|
| 538 |
|
|
// Make new buffer with half of b's pointers.
|
| 539 |
|
|
b1 = getempty(nil);
|
| 540 |
|
|
n = b->nobj/2;
|
| 541 |
|
|
b->nobj -= n;
|
| 542 |
|
|
b1->nobj = n;
|
| 543 |
|
|
runtime_memmove(b1->obj, b->obj+b->nobj, n*sizeof b1->obj[0]);
|
| 544 |
|
|
nhandoff += n;
|
| 545 |
|
|
|
| 546 |
|
|
// Put b on full list - let first half of b get stolen.
|
| 547 |
|
|
runtime_lock(&work.fmu);
|
| 548 |
|
|
b->next = work.full;
|
| 549 |
|
|
work.full = b;
|
| 550 |
|
|
runtime_unlock(&work.fmu);
|
| 551 |
|
|
|
| 552 |
|
|
return b1;
|
| 553 |
|
|
}
|
| 554 |
|
|
|
| 555 |
|
|
// Scanstack calls scanblock on each of gp's stack segments.
|
| 556 |
|
|
static void
|
| 557 |
|
|
scanstack(void (*scanblock)(byte*, int64), G *gp)
|
| 558 |
|
|
{
|
| 559 |
|
|
#ifdef USING_SPLIT_STACK
|
| 560 |
|
|
M *mp;
|
| 561 |
|
|
void* sp;
|
| 562 |
|
|
size_t spsize;
|
| 563 |
|
|
void* next_segment;
|
| 564 |
|
|
void* next_sp;
|
| 565 |
|
|
void* initial_sp;
|
| 566 |
|
|
|
| 567 |
|
|
if(gp == runtime_g()) {
|
| 568 |
|
|
// Scanning our own stack.
|
| 569 |
|
|
sp = __splitstack_find(nil, nil, &spsize, &next_segment,
|
| 570 |
|
|
&next_sp, &initial_sp);
|
| 571 |
|
|
} else if((mp = gp->m) != nil && mp->helpgc) {
|
| 572 |
|
|
// gchelper's stack is in active use and has no interesting pointers.
|
| 573 |
|
|
return;
|
| 574 |
|
|
} else {
|
| 575 |
|
|
// Scanning another goroutine's stack.
|
| 576 |
|
|
// The goroutine is usually asleep (the world is stopped).
|
| 577 |
|
|
|
| 578 |
|
|
// The exception is that if the goroutine is about to enter or might
|
| 579 |
|
|
// have just exited a system call, it may be executing code such
|
| 580 |
|
|
// as schedlock and may have needed to start a new stack segment.
|
| 581 |
|
|
// Use the stack segment and stack pointer at the time of
|
| 582 |
|
|
// the system call instead, since that won't change underfoot.
|
| 583 |
|
|
if(gp->gcstack != nil) {
|
| 584 |
|
|
sp = gp->gcstack;
|
| 585 |
|
|
spsize = gp->gcstack_size;
|
| 586 |
|
|
next_segment = gp->gcnext_segment;
|
| 587 |
|
|
next_sp = gp->gcnext_sp;
|
| 588 |
|
|
initial_sp = gp->gcinitial_sp;
|
| 589 |
|
|
} else {
|
| 590 |
|
|
sp = __splitstack_find_context(&gp->stack_context[0],
|
| 591 |
|
|
&spsize, &next_segment,
|
| 592 |
|
|
&next_sp, &initial_sp);
|
| 593 |
|
|
}
|
| 594 |
|
|
}
|
| 595 |
|
|
if(sp != nil) {
|
| 596 |
|
|
scanblock(sp, spsize);
|
| 597 |
|
|
while((sp = __splitstack_find(next_segment, next_sp,
|
| 598 |
|
|
&spsize, &next_segment,
|
| 599 |
|
|
&next_sp, &initial_sp)) != nil)
|
| 600 |
|
|
scanblock(sp, spsize);
|
| 601 |
|
|
}
|
| 602 |
|
|
#else
|
| 603 |
|
|
M *mp;
|
| 604 |
|
|
byte* bottom;
|
| 605 |
|
|
byte* top;
|
| 606 |
|
|
|
| 607 |
|
|
if(gp == runtime_g()) {
|
| 608 |
|
|
// Scanning our own stack.
|
| 609 |
|
|
bottom = (byte*)&gp;
|
| 610 |
|
|
} else if((mp = gp->m) != nil && mp->helpgc) {
|
| 611 |
|
|
// gchelper's stack is in active use and has no interesting pointers.
|
| 612 |
|
|
return;
|
| 613 |
|
|
} else {
|
| 614 |
|
|
// Scanning another goroutine's stack.
|
| 615 |
|
|
// The goroutine is usually asleep (the world is stopped).
|
| 616 |
|
|
bottom = (byte*)gp->gcnext_sp;
|
| 617 |
|
|
if(bottom == nil)
|
| 618 |
|
|
return;
|
| 619 |
|
|
}
|
| 620 |
|
|
top = (byte*)gp->gcinitial_sp + gp->gcstack_size;
|
| 621 |
|
|
if(top > bottom)
|
| 622 |
|
|
scanblock(bottom, top - bottom);
|
| 623 |
|
|
else
|
| 624 |
|
|
scanblock(top, bottom - top);
|
| 625 |
|
|
#endif
|
| 626 |
|
|
}
|
| 627 |
|
|
|
| 628 |
|
|
// Markfin calls scanblock on the blocks that have finalizers:
|
| 629 |
|
|
// the things pointed at cannot be freed until the finalizers have run.
|
| 630 |
|
|
static void
|
| 631 |
|
|
markfin(void *v)
|
| 632 |
|
|
{
|
| 633 |
|
|
uintptr size;
|
| 634 |
|
|
|
| 635 |
|
|
size = 0;
|
| 636 |
|
|
if(!runtime_mlookup(v, (byte**)&v, &size, nil) || !runtime_blockspecial(v))
|
| 637 |
|
|
runtime_throw("mark - finalizer inconsistency");
|
| 638 |
|
|
|
| 639 |
|
|
// do not mark the finalizer block itself. just mark the things it points at.
|
| 640 |
|
|
scanblock(v, size);
|
| 641 |
|
|
}
|
| 642 |
|
|
|
| 643 |
|
|
struct root_list {
|
| 644 |
|
|
struct root_list *next;
|
| 645 |
|
|
struct root {
|
| 646 |
|
|
void *decl;
|
| 647 |
|
|
size_t size;
|
| 648 |
|
|
} roots[];
|
| 649 |
|
|
};
|
| 650 |
|
|
|
| 651 |
|
|
static struct root_list* roots;
|
| 652 |
|
|
|
| 653 |
|
|
void
|
| 654 |
|
|
__go_register_gc_roots (struct root_list* r)
|
| 655 |
|
|
{
|
| 656 |
|
|
// FIXME: This needs locking if multiple goroutines can call
|
| 657 |
|
|
// dlopen simultaneously.
|
| 658 |
|
|
r->next = roots;
|
| 659 |
|
|
roots = r;
|
| 660 |
|
|
}
|
| 661 |
|
|
|
| 662 |
|
|
static void
|
| 663 |
|
|
debug_markfin(void *v)
|
| 664 |
|
|
{
|
| 665 |
|
|
uintptr size;
|
| 666 |
|
|
|
| 667 |
|
|
if(!runtime_mlookup(v, (byte**)&v, &size, nil))
|
| 668 |
|
|
runtime_throw("debug_mark - finalizer inconsistency");
|
| 669 |
|
|
debug_scanblock(v, size);
|
| 670 |
|
|
}
|
| 671 |
|
|
|
| 672 |
|
|
// Mark
|
| 673 |
|
|
static void
|
| 674 |
|
|
mark(void (*scan)(byte*, int64))
|
| 675 |
|
|
{
|
| 676 |
|
|
struct root_list *pl;
|
| 677 |
|
|
G *gp;
|
| 678 |
|
|
FinBlock *fb;
|
| 679 |
|
|
|
| 680 |
|
|
// mark data+bss.
|
| 681 |
|
|
for(pl = roots; pl != nil; pl = pl->next) {
|
| 682 |
|
|
struct root* pr = &pl->roots[0];
|
| 683 |
|
|
while(1) {
|
| 684 |
|
|
void *decl = pr->decl;
|
| 685 |
|
|
if(decl == nil)
|
| 686 |
|
|
break;
|
| 687 |
|
|
scanblock(decl, pr->size);
|
| 688 |
|
|
pr++;
|
| 689 |
|
|
}
|
| 690 |
|
|
}
|
| 691 |
|
|
|
| 692 |
|
|
scan((byte*)&runtime_m0, sizeof runtime_m0);
|
| 693 |
|
|
scan((byte*)&runtime_g0, sizeof runtime_g0);
|
| 694 |
|
|
scan((byte*)&runtime_allg, sizeof runtime_allg);
|
| 695 |
|
|
scan((byte*)&runtime_allm, sizeof runtime_allm);
|
| 696 |
|
|
runtime_MProf_Mark(scan);
|
| 697 |
|
|
runtime_time_scan(scan);
|
| 698 |
|
|
|
| 699 |
|
|
// mark stacks
|
| 700 |
|
|
for(gp=runtime_allg; gp!=nil; gp=gp->alllink) {
|
| 701 |
|
|
switch(gp->status){
|
| 702 |
|
|
default:
|
| 703 |
|
|
runtime_printf("unexpected G.status %d\n", gp->status);
|
| 704 |
|
|
runtime_throw("mark - bad status");
|
| 705 |
|
|
case Gdead:
|
| 706 |
|
|
break;
|
| 707 |
|
|
case Grunning:
|
| 708 |
|
|
if(gp != runtime_g())
|
| 709 |
|
|
runtime_throw("mark - world not stopped");
|
| 710 |
|
|
scanstack(scan, gp);
|
| 711 |
|
|
break;
|
| 712 |
|
|
case Grunnable:
|
| 713 |
|
|
case Gsyscall:
|
| 714 |
|
|
case Gwaiting:
|
| 715 |
|
|
scanstack(scan, gp);
|
| 716 |
|
|
break;
|
| 717 |
|
|
}
|
| 718 |
|
|
}
|
| 719 |
|
|
|
| 720 |
|
|
// mark things pointed at by objects with finalizers
|
| 721 |
|
|
if(scan == debug_scanblock)
|
| 722 |
|
|
runtime_walkfintab(debug_markfin, scan);
|
| 723 |
|
|
else
|
| 724 |
|
|
runtime_walkfintab(markfin, scan);
|
| 725 |
|
|
|
| 726 |
|
|
for(fb=allfin; fb; fb=fb->alllink)
|
| 727 |
|
|
scanblock((byte*)fb->fin, fb->cnt*sizeof(fb->fin[0]));
|
| 728 |
|
|
|
| 729 |
|
|
// in multiproc mode, join in the queued work.
|
| 730 |
|
|
scan(nil, 0);
|
| 731 |
|
|
}
|
| 732 |
|
|
|
| 733 |
|
|
static bool
|
| 734 |
|
|
handlespecial(byte *p, uintptr size)
|
| 735 |
|
|
{
|
| 736 |
|
|
void (*fn)(void*);
|
| 737 |
|
|
const struct __go_func_type *ft;
|
| 738 |
|
|
FinBlock *block;
|
| 739 |
|
|
Finalizer *f;
|
| 740 |
|
|
|
| 741 |
|
|
if(!runtime_getfinalizer(p, true, &fn, &ft)) {
|
| 742 |
|
|
runtime_setblockspecial(p, false);
|
| 743 |
|
|
runtime_MProf_Free(p, size);
|
| 744 |
|
|
return false;
|
| 745 |
|
|
}
|
| 746 |
|
|
|
| 747 |
|
|
runtime_lock(&finlock);
|
| 748 |
|
|
if(finq == nil || finq->cnt == finq->cap) {
|
| 749 |
|
|
if(finc == nil) {
|
| 750 |
|
|
finc = runtime_SysAlloc(PageSize);
|
| 751 |
|
|
finc->cap = (PageSize - sizeof(FinBlock)) / sizeof(Finalizer) + 1;
|
| 752 |
|
|
finc->alllink = allfin;
|
| 753 |
|
|
allfin = finc;
|
| 754 |
|
|
}
|
| 755 |
|
|
block = finc;
|
| 756 |
|
|
finc = block->next;
|
| 757 |
|
|
block->next = finq;
|
| 758 |
|
|
finq = block;
|
| 759 |
|
|
}
|
| 760 |
|
|
f = &finq->fin[finq->cnt];
|
| 761 |
|
|
finq->cnt++;
|
| 762 |
|
|
f->fn = fn;
|
| 763 |
|
|
f->ft = ft;
|
| 764 |
|
|
f->arg = p;
|
| 765 |
|
|
runtime_unlock(&finlock);
|
| 766 |
|
|
return true;
|
| 767 |
|
|
}
|
| 768 |
|
|
|
| 769 |
|
|
// Sweep frees or collects finalizers for blocks not marked in the mark phase.
|
| 770 |
|
|
// It clears the mark bits in preparation for the next GC round.
|
| 771 |
|
|
static void
|
| 772 |
|
|
sweep(void)
|
| 773 |
|
|
{
|
| 774 |
|
|
M *m;
|
| 775 |
|
|
MSpan *s;
|
| 776 |
|
|
int32 cl, n, npages;
|
| 777 |
|
|
uintptr size;
|
| 778 |
|
|
byte *p;
|
| 779 |
|
|
MCache *c;
|
| 780 |
|
|
byte *arena_start;
|
| 781 |
|
|
|
| 782 |
|
|
m = runtime_m();
|
| 783 |
|
|
arena_start = runtime_mheap.arena_start;
|
| 784 |
|
|
|
| 785 |
|
|
for(;;) {
|
| 786 |
|
|
s = work.spans;
|
| 787 |
|
|
if(s == nil)
|
| 788 |
|
|
break;
|
| 789 |
|
|
if(!runtime_casp(&work.spans, s, s->allnext))
|
| 790 |
|
|
continue;
|
| 791 |
|
|
|
| 792 |
|
|
if(s->state != MSpanInUse)
|
| 793 |
|
|
continue;
|
| 794 |
|
|
|
| 795 |
|
|
p = (byte*)(s->start << PageShift);
|
| 796 |
|
|
cl = s->sizeclass;
|
| 797 |
|
|
if(cl == 0) {
|
| 798 |
|
|
size = s->npages<<PageShift;
|
| 799 |
|
|
n = 1;
|
| 800 |
|
|
} else {
|
| 801 |
|
|
// Chunk full of small blocks.
|
| 802 |
|
|
size = runtime_class_to_size[cl];
|
| 803 |
|
|
npages = runtime_class_to_allocnpages[cl];
|
| 804 |
|
|
n = (npages << PageShift) / size;
|
| 805 |
|
|
}
|
| 806 |
|
|
|
| 807 |
|
|
// Sweep through n objects of given size starting at p.
|
| 808 |
|
|
// This thread owns the span now, so it can manipulate
|
| 809 |
|
|
// the block bitmap without atomic operations.
|
| 810 |
|
|
for(; n > 0; n--, p += size) {
|
| 811 |
|
|
uintptr off, *bitp, shift, bits;
|
| 812 |
|
|
|
| 813 |
|
|
off = (uintptr*)p - (uintptr*)arena_start;
|
| 814 |
|
|
bitp = (uintptr*)arena_start - off/wordsPerBitmapWord - 1;
|
| 815 |
|
|
shift = off % wordsPerBitmapWord;
|
| 816 |
|
|
bits = *bitp>>shift;
|
| 817 |
|
|
|
| 818 |
|
|
if((bits & bitAllocated) == 0)
|
| 819 |
|
|
continue;
|
| 820 |
|
|
|
| 821 |
|
|
if((bits & bitMarked) != 0) {
|
| 822 |
|
|
if(DebugMark) {
|
| 823 |
|
|
if(!(bits & bitSpecial))
|
| 824 |
|
|
runtime_printf("found spurious mark on %p\n", p);
|
| 825 |
|
|
*bitp &= ~(bitSpecial<<shift);
|
| 826 |
|
|
}
|
| 827 |
|
|
*bitp &= ~(bitMarked<<shift);
|
| 828 |
|
|
continue;
|
| 829 |
|
|
}
|
| 830 |
|
|
|
| 831 |
|
|
// Special means it has a finalizer or is being profiled.
|
| 832 |
|
|
// In DebugMark mode, the bit has been coopted so
|
| 833 |
|
|
// we have to assume all blocks are special.
|
| 834 |
|
|
if(DebugMark || (bits & bitSpecial) != 0) {
|
| 835 |
|
|
if(handlespecial(p, size))
|
| 836 |
|
|
continue;
|
| 837 |
|
|
}
|
| 838 |
|
|
|
| 839 |
|
|
// Mark freed; restore block boundary bit.
|
| 840 |
|
|
*bitp = (*bitp & ~(bitMask<<shift)) | (bitBlockBoundary<<shift);
|
| 841 |
|
|
|
| 842 |
|
|
c = m->mcache;
|
| 843 |
|
|
if(s->sizeclass == 0) {
|
| 844 |
|
|
// Free large span.
|
| 845 |
|
|
runtime_unmarkspan(p, 1<<PageShift);
|
| 846 |
|
|
*(uintptr*)p = 1; // needs zeroing
|
| 847 |
|
|
runtime_MHeap_Free(&runtime_mheap, s, 1);
|
| 848 |
|
|
} else {
|
| 849 |
|
|
// Free small object.
|
| 850 |
|
|
if(size > sizeof(uintptr))
|
| 851 |
|
|
((uintptr*)p)[1] = 1; // mark as "needs to be zeroed"
|
| 852 |
|
|
c->local_by_size[s->sizeclass].nfree++;
|
| 853 |
|
|
runtime_MCache_Free(c, p, s->sizeclass, size);
|
| 854 |
|
|
}
|
| 855 |
|
|
c->local_alloc -= size;
|
| 856 |
|
|
c->local_nfree++;
|
| 857 |
|
|
}
|
| 858 |
|
|
}
|
| 859 |
|
|
}
|
| 860 |
|
|
|
| 861 |
|
|
void
|
| 862 |
|
|
runtime_gchelper(void)
|
| 863 |
|
|
{
|
| 864 |
|
|
// Wait until main proc is ready for mark help.
|
| 865 |
|
|
runtime_lock(&work.markgate);
|
| 866 |
|
|
runtime_unlock(&work.markgate);
|
| 867 |
|
|
scanblock(nil, 0);
|
| 868 |
|
|
|
| 869 |
|
|
// Wait until main proc is ready for sweep help.
|
| 870 |
|
|
runtime_lock(&work.sweepgate);
|
| 871 |
|
|
runtime_unlock(&work.sweepgate);
|
| 872 |
|
|
sweep();
|
| 873 |
|
|
|
| 874 |
|
|
if(runtime_xadd(&work.ndone, +1) == work.nproc-1)
|
| 875 |
|
|
runtime_notewakeup(&work.alldone);
|
| 876 |
|
|
}
|
| 877 |
|
|
|
| 878 |
|
|
// Semaphore, not Lock, so that the goroutine
|
| 879 |
|
|
// reschedules when there is contention rather
|
| 880 |
|
|
// than spinning.
|
| 881 |
|
|
static uint32 gcsema = 1;
|
| 882 |
|
|
|
| 883 |
|
|
// Initialized from $GOGC. GOGC=off means no gc.
|
| 884 |
|
|
//
|
| 885 |
|
|
// Next gc is after we've allocated an extra amount of
|
| 886 |
|
|
// memory proportional to the amount already in use.
|
| 887 |
|
|
// If gcpercent=100 and we're using 4M, we'll gc again
|
| 888 |
|
|
// when we get to 8M. This keeps the gc cost in linear
|
| 889 |
|
|
// proportion to the allocation cost. Adjusting gcpercent
|
| 890 |
|
|
// just changes the linear constant (and also the amount of
|
| 891 |
|
|
// extra memory used).
|
| 892 |
|
|
static int32 gcpercent = -2;
|
| 893 |
|
|
|
| 894 |
|
|
static void
|
| 895 |
|
|
stealcache(void)
|
| 896 |
|
|
{
|
| 897 |
|
|
M *m;
|
| 898 |
|
|
|
| 899 |
|
|
for(m=runtime_allm; m; m=m->alllink)
|
| 900 |
|
|
runtime_MCache_ReleaseAll(m->mcache);
|
| 901 |
|
|
}
|
| 902 |
|
|
|
| 903 |
|
|
static void
|
| 904 |
|
|
cachestats(void)
|
| 905 |
|
|
{
|
| 906 |
|
|
M *m;
|
| 907 |
|
|
MCache *c;
|
| 908 |
|
|
uint32 i;
|
| 909 |
|
|
uint64 stacks_inuse;
|
| 910 |
|
|
uint64 stacks_sys;
|
| 911 |
|
|
|
| 912 |
|
|
stacks_inuse = 0;
|
| 913 |
|
|
stacks_sys = 0;
|
| 914 |
|
|
for(m=runtime_allm; m; m=m->alllink) {
|
| 915 |
|
|
runtime_purgecachedstats(m);
|
| 916 |
|
|
// stacks_inuse += m->stackalloc->inuse;
|
| 917 |
|
|
// stacks_sys += m->stackalloc->sys;
|
| 918 |
|
|
c = m->mcache;
|
| 919 |
|
|
for(i=0; i<nelem(c->local_by_size); i++) {
|
| 920 |
|
|
mstats.by_size[i].nmalloc += c->local_by_size[i].nmalloc;
|
| 921 |
|
|
c->local_by_size[i].nmalloc = 0;
|
| 922 |
|
|
mstats.by_size[i].nfree += c->local_by_size[i].nfree;
|
| 923 |
|
|
c->local_by_size[i].nfree = 0;
|
| 924 |
|
|
}
|
| 925 |
|
|
}
|
| 926 |
|
|
mstats.stacks_inuse = stacks_inuse;
|
| 927 |
|
|
mstats.stacks_sys = stacks_sys;
|
| 928 |
|
|
}
|
| 929 |
|
|
|
| 930 |
|
|
void
|
| 931 |
|
|
runtime_gc(int32 force)
|
| 932 |
|
|
{
|
| 933 |
|
|
M *m;
|
| 934 |
|
|
int64 t0, t1, t2, t3;
|
| 935 |
|
|
uint64 heap0, heap1, obj0, obj1;
|
| 936 |
|
|
const byte *p;
|
| 937 |
|
|
bool extra;
|
| 938 |
|
|
|
| 939 |
|
|
// Make sure all registers are saved on stack so that
|
| 940 |
|
|
// scanstack sees them.
|
| 941 |
|
|
__builtin_unwind_init();
|
| 942 |
|
|
|
| 943 |
|
|
// The gc is turned off (via enablegc) until
|
| 944 |
|
|
// the bootstrap has completed.
|
| 945 |
|
|
// Also, malloc gets called in the guts
|
| 946 |
|
|
// of a number of libraries that might be
|
| 947 |
|
|
// holding locks. To avoid priority inversion
|
| 948 |
|
|
// problems, don't bother trying to run gc
|
| 949 |
|
|
// while holding a lock. The next mallocgc
|
| 950 |
|
|
// without a lock will do the gc instead.
|
| 951 |
|
|
m = runtime_m();
|
| 952 |
|
|
if(!mstats.enablegc || m->locks > 0 || runtime_panicking)
|
| 953 |
|
|
return;
|
| 954 |
|
|
|
| 955 |
|
|
if(gcpercent == -2) { // first time through
|
| 956 |
|
|
p = runtime_getenv("GOGC");
|
| 957 |
|
|
if(p == nil || p[0] == '\0')
|
| 958 |
|
|
gcpercent = 100;
|
| 959 |
|
|
else if(runtime_strcmp((const char*)p, "off") == 0)
|
| 960 |
|
|
gcpercent = -1;
|
| 961 |
|
|
else
|
| 962 |
|
|
gcpercent = runtime_atoi(p);
|
| 963 |
|
|
|
| 964 |
|
|
p = runtime_getenv("GOGCTRACE");
|
| 965 |
|
|
if(p != nil)
|
| 966 |
|
|
gctrace = runtime_atoi(p);
|
| 967 |
|
|
}
|
| 968 |
|
|
if(gcpercent < 0)
|
| 969 |
|
|
return;
|
| 970 |
|
|
|
| 971 |
|
|
runtime_semacquire(&gcsema);
|
| 972 |
|
|
if(!force && mstats.heap_alloc < mstats.next_gc) {
|
| 973 |
|
|
runtime_semrelease(&gcsema);
|
| 974 |
|
|
return;
|
| 975 |
|
|
}
|
| 976 |
|
|
|
| 977 |
|
|
t0 = runtime_nanotime();
|
| 978 |
|
|
nhandoff = 0;
|
| 979 |
|
|
|
| 980 |
|
|
m->gcing = 1;
|
| 981 |
|
|
runtime_stoptheworld();
|
| 982 |
|
|
|
| 983 |
|
|
cachestats();
|
| 984 |
|
|
heap0 = mstats.heap_alloc;
|
| 985 |
|
|
obj0 = mstats.nmalloc - mstats.nfree;
|
| 986 |
|
|
|
| 987 |
|
|
runtime_lock(&work.markgate);
|
| 988 |
|
|
runtime_lock(&work.sweepgate);
|
| 989 |
|
|
|
| 990 |
|
|
extra = false;
|
| 991 |
|
|
work.nproc = 1;
|
| 992 |
|
|
if(runtime_gomaxprocs > 1 && runtime_ncpu > 1) {
|
| 993 |
|
|
runtime_noteclear(&work.alldone);
|
| 994 |
|
|
work.nproc += runtime_helpgc(&extra);
|
| 995 |
|
|
}
|
| 996 |
|
|
work.nwait = 0;
|
| 997 |
|
|
work.ndone = 0;
|
| 998 |
|
|
|
| 999 |
|
|
runtime_unlock(&work.markgate); // let the helpers in
|
| 1000 |
|
|
mark(scanblock);
|
| 1001 |
|
|
if(DebugMark)
|
| 1002 |
|
|
mark(debug_scanblock);
|
| 1003 |
|
|
t1 = runtime_nanotime();
|
| 1004 |
|
|
|
| 1005 |
|
|
work.spans = runtime_mheap.allspans;
|
| 1006 |
|
|
runtime_unlock(&work.sweepgate); // let the helpers in
|
| 1007 |
|
|
sweep();
|
| 1008 |
|
|
if(work.nproc > 1)
|
| 1009 |
|
|
runtime_notesleep(&work.alldone);
|
| 1010 |
|
|
t2 = runtime_nanotime();
|
| 1011 |
|
|
|
| 1012 |
|
|
stealcache();
|
| 1013 |
|
|
cachestats();
|
| 1014 |
|
|
|
| 1015 |
|
|
mstats.next_gc = mstats.heap_alloc+mstats.heap_alloc*gcpercent/100;
|
| 1016 |
|
|
m->gcing = 0;
|
| 1017 |
|
|
|
| 1018 |
|
|
m->locks++; // disable gc during the mallocs in newproc
|
| 1019 |
|
|
if(finq != nil) {
|
| 1020 |
|
|
// kick off or wake up goroutine to run queued finalizers
|
| 1021 |
|
|
if(fing == nil)
|
| 1022 |
|
|
fing = __go_go(runfinq, nil);
|
| 1023 |
|
|
else if(fingwait) {
|
| 1024 |
|
|
fingwait = 0;
|
| 1025 |
|
|
runtime_ready(fing);
|
| 1026 |
|
|
}
|
| 1027 |
|
|
}
|
| 1028 |
|
|
m->locks--;
|
| 1029 |
|
|
|
| 1030 |
|
|
cachestats();
|
| 1031 |
|
|
heap1 = mstats.heap_alloc;
|
| 1032 |
|
|
obj1 = mstats.nmalloc - mstats.nfree;
|
| 1033 |
|
|
|
| 1034 |
|
|
t3 = runtime_nanotime();
|
| 1035 |
|
|
mstats.pause_ns[mstats.numgc%nelem(mstats.pause_ns)] = t3 - t0;
|
| 1036 |
|
|
mstats.pause_total_ns += t3 - t0;
|
| 1037 |
|
|
mstats.numgc++;
|
| 1038 |
|
|
if(mstats.debuggc)
|
| 1039 |
|
|
runtime_printf("pause %llu\n", (unsigned long long)t3-t0);
|
| 1040 |
|
|
|
| 1041 |
|
|
if(gctrace) {
|
| 1042 |
|
|
runtime_printf("gc%d(%d): %llu+%llu+%llu ms %llu -> %llu MB %llu -> %llu (%llu-%llu) objects %llu handoff\n",
|
| 1043 |
|
|
mstats.numgc, work.nproc, (unsigned long long)(t1-t0)/1000000, (unsigned long long)(t2-t1)/1000000, (unsigned long long)(t3-t2)/1000000,
|
| 1044 |
|
|
(unsigned long long)heap0>>20, (unsigned long long)heap1>>20, (unsigned long long)obj0, (unsigned long long)obj1,
|
| 1045 |
|
|
(unsigned long long) mstats.nmalloc, (unsigned long long)mstats.nfree,
|
| 1046 |
|
|
(unsigned long long) nhandoff);
|
| 1047 |
|
|
}
|
| 1048 |
|
|
|
| 1049 |
|
|
runtime_semrelease(&gcsema);
|
| 1050 |
|
|
|
| 1051 |
|
|
// If we could have used another helper proc, start one now,
|
| 1052 |
|
|
// in the hope that it will be available next time.
|
| 1053 |
|
|
// It would have been even better to start it before the collection,
|
| 1054 |
|
|
// but doing so requires allocating memory, so it's tricky to
|
| 1055 |
|
|
// coordinate. This lazy approach works out in practice:
|
| 1056 |
|
|
// we don't mind if the first couple gc rounds don't have quite
|
| 1057 |
|
|
// the maximum number of procs.
|
| 1058 |
|
|
runtime_starttheworld(extra);
|
| 1059 |
|
|
|
| 1060 |
|
|
// give the queued finalizers, if any, a chance to run
|
| 1061 |
|
|
if(finq != nil)
|
| 1062 |
|
|
runtime_gosched();
|
| 1063 |
|
|
|
| 1064 |
|
|
if(gctrace > 1 && !force)
|
| 1065 |
|
|
runtime_gc(1);
|
| 1066 |
|
|
}
|
| 1067 |
|
|
|
| 1068 |
|
|
void runtime_ReadMemStats(MStats *)
|
| 1069 |
|
|
__asm__("libgo_runtime.runtime.ReadMemStats");
|
| 1070 |
|
|
|
| 1071 |
|
|
void
|
| 1072 |
|
|
runtime_ReadMemStats(MStats *stats)
|
| 1073 |
|
|
{
|
| 1074 |
|
|
M *m;
|
| 1075 |
|
|
|
| 1076 |
|
|
// Have to acquire gcsema to stop the world,
|
| 1077 |
|
|
// because stoptheworld can only be used by
|
| 1078 |
|
|
// one goroutine at a time, and there might be
|
| 1079 |
|
|
// a pending garbage collection already calling it.
|
| 1080 |
|
|
runtime_semacquire(&gcsema);
|
| 1081 |
|
|
m = runtime_m();
|
| 1082 |
|
|
m->gcing = 1;
|
| 1083 |
|
|
runtime_stoptheworld();
|
| 1084 |
|
|
cachestats();
|
| 1085 |
|
|
*stats = mstats;
|
| 1086 |
|
|
m->gcing = 0;
|
| 1087 |
|
|
runtime_semrelease(&gcsema);
|
| 1088 |
|
|
runtime_starttheworld(false);
|
| 1089 |
|
|
}
|
| 1090 |
|
|
|
| 1091 |
|
|
static void
|
| 1092 |
|
|
runfinq(void* dummy __attribute__ ((unused)))
|
| 1093 |
|
|
{
|
| 1094 |
|
|
G* gp;
|
| 1095 |
|
|
Finalizer *f;
|
| 1096 |
|
|
FinBlock *fb, *next;
|
| 1097 |
|
|
uint32 i;
|
| 1098 |
|
|
|
| 1099 |
|
|
gp = runtime_g();
|
| 1100 |
|
|
for(;;) {
|
| 1101 |
|
|
// There's no need for a lock in this section
|
| 1102 |
|
|
// because it only conflicts with the garbage
|
| 1103 |
|
|
// collector, and the garbage collector only
|
| 1104 |
|
|
// runs when everyone else is stopped, and
|
| 1105 |
|
|
// runfinq only stops at the gosched() or
|
| 1106 |
|
|
// during the calls in the for loop.
|
| 1107 |
|
|
fb = finq;
|
| 1108 |
|
|
finq = nil;
|
| 1109 |
|
|
if(fb == nil) {
|
| 1110 |
|
|
fingwait = 1;
|
| 1111 |
|
|
gp->status = Gwaiting;
|
| 1112 |
|
|
gp->waitreason = "finalizer wait";
|
| 1113 |
|
|
runtime_gosched();
|
| 1114 |
|
|
continue;
|
| 1115 |
|
|
}
|
| 1116 |
|
|
for(; fb; fb=next) {
|
| 1117 |
|
|
next = fb->next;
|
| 1118 |
|
|
for(i=0; i<(uint32)fb->cnt; i++) {
|
| 1119 |
|
|
void *params[1];
|
| 1120 |
|
|
|
| 1121 |
|
|
f = &fb->fin[i];
|
| 1122 |
|
|
params[0] = &f->arg;
|
| 1123 |
|
|
runtime_setblockspecial(f->arg, false);
|
| 1124 |
|
|
reflect_call(f->ft, (void*)f->fn, 0, 0, params, nil);
|
| 1125 |
|
|
f->fn = nil;
|
| 1126 |
|
|
f->arg = nil;
|
| 1127 |
|
|
}
|
| 1128 |
|
|
fb->cnt = 0;
|
| 1129 |
|
|
fb->next = finc;
|
| 1130 |
|
|
finc = fb;
|
| 1131 |
|
|
}
|
| 1132 |
|
|
runtime_gc(1); // trigger another gc to clean up the finalized objects, if possible
|
| 1133 |
|
|
}
|
| 1134 |
|
|
}
|
| 1135 |
|
|
|
| 1136 |
|
|
// mark the block at v of size n as allocated.
|
| 1137 |
|
|
// If noptr is true, mark it as having no pointers.
|
| 1138 |
|
|
void
|
| 1139 |
|
|
runtime_markallocated(void *v, uintptr n, bool noptr)
|
| 1140 |
|
|
{
|
| 1141 |
|
|
uintptr *b, obits, bits, off, shift;
|
| 1142 |
|
|
|
| 1143 |
|
|
// if(0)
|
| 1144 |
|
|
// runtime_printf("markallocated %p+%p\n", v, n);
|
| 1145 |
|
|
|
| 1146 |
|
|
if((byte*)v+n > (byte*)runtime_mheap.arena_used || (byte*)v < runtime_mheap.arena_start)
|
| 1147 |
|
|
runtime_throw("markallocated: bad pointer");
|
| 1148 |
|
|
|
| 1149 |
|
|
off = (uintptr*)v - (uintptr*)runtime_mheap.arena_start; // word offset
|
| 1150 |
|
|
b = (uintptr*)runtime_mheap.arena_start - off/wordsPerBitmapWord - 1;
|
| 1151 |
|
|
shift = off % wordsPerBitmapWord;
|
| 1152 |
|
|
|
| 1153 |
|
|
for(;;) {
|
| 1154 |
|
|
obits = *b;
|
| 1155 |
|
|
bits = (obits & ~(bitMask<<shift)) | (bitAllocated<<shift);
|
| 1156 |
|
|
if(noptr)
|
| 1157 |
|
|
bits |= bitNoPointers<<shift;
|
| 1158 |
|
|
if(runtime_singleproc) {
|
| 1159 |
|
|
*b = bits;
|
| 1160 |
|
|
break;
|
| 1161 |
|
|
} else {
|
| 1162 |
|
|
// more than one goroutine is potentially running: use atomic op
|
| 1163 |
|
|
if(runtime_casp((void**)b, (void*)obits, (void*)bits))
|
| 1164 |
|
|
break;
|
| 1165 |
|
|
}
|
| 1166 |
|
|
}
|
| 1167 |
|
|
}
|
| 1168 |
|
|
|
| 1169 |
|
|
// mark the block at v of size n as freed.
|
| 1170 |
|
|
void
|
| 1171 |
|
|
runtime_markfreed(void *v, uintptr n)
|
| 1172 |
|
|
{
|
| 1173 |
|
|
uintptr *b, obits, bits, off, shift;
|
| 1174 |
|
|
|
| 1175 |
|
|
// if(0)
|
| 1176 |
|
|
// runtime_printf("markallocated %p+%p\n", v, n);
|
| 1177 |
|
|
|
| 1178 |
|
|
if((byte*)v+n > (byte*)runtime_mheap.arena_used || (byte*)v < runtime_mheap.arena_start)
|
| 1179 |
|
|
runtime_throw("markallocated: bad pointer");
|
| 1180 |
|
|
|
| 1181 |
|
|
off = (uintptr*)v - (uintptr*)runtime_mheap.arena_start; // word offset
|
| 1182 |
|
|
b = (uintptr*)runtime_mheap.arena_start - off/wordsPerBitmapWord - 1;
|
| 1183 |
|
|
shift = off % wordsPerBitmapWord;
|
| 1184 |
|
|
|
| 1185 |
|
|
for(;;) {
|
| 1186 |
|
|
obits = *b;
|
| 1187 |
|
|
bits = (obits & ~(bitMask<<shift)) | (bitBlockBoundary<<shift);
|
| 1188 |
|
|
if(runtime_singleproc) {
|
| 1189 |
|
|
*b = bits;
|
| 1190 |
|
|
break;
|
| 1191 |
|
|
} else {
|
| 1192 |
|
|
// more than one goroutine is potentially running: use atomic op
|
| 1193 |
|
|
if(runtime_casp((void**)b, (void*)obits, (void*)bits))
|
| 1194 |
|
|
break;
|
| 1195 |
|
|
}
|
| 1196 |
|
|
}
|
| 1197 |
|
|
}
|
| 1198 |
|
|
|
| 1199 |
|
|
// check that the block at v of size n is marked freed.
|
| 1200 |
|
|
void
|
| 1201 |
|
|
runtime_checkfreed(void *v, uintptr n)
|
| 1202 |
|
|
{
|
| 1203 |
|
|
uintptr *b, bits, off, shift;
|
| 1204 |
|
|
|
| 1205 |
|
|
if(!runtime_checking)
|
| 1206 |
|
|
return;
|
| 1207 |
|
|
|
| 1208 |
|
|
if((byte*)v+n > (byte*)runtime_mheap.arena_used || (byte*)v < runtime_mheap.arena_start)
|
| 1209 |
|
|
return; // not allocated, so okay
|
| 1210 |
|
|
|
| 1211 |
|
|
off = (uintptr*)v - (uintptr*)runtime_mheap.arena_start; // word offset
|
| 1212 |
|
|
b = (uintptr*)runtime_mheap.arena_start - off/wordsPerBitmapWord - 1;
|
| 1213 |
|
|
shift = off % wordsPerBitmapWord;
|
| 1214 |
|
|
|
| 1215 |
|
|
bits = *b>>shift;
|
| 1216 |
|
|
if((bits & bitAllocated) != 0) {
|
| 1217 |
|
|
runtime_printf("checkfreed %p+%p: off=%p have=%p\n",
|
| 1218 |
|
|
v, (void*)n, (void*)off, (void*)(bits & bitMask));
|
| 1219 |
|
|
runtime_throw("checkfreed: not freed");
|
| 1220 |
|
|
}
|
| 1221 |
|
|
}
|
| 1222 |
|
|
|
| 1223 |
|
|
// mark the span of memory at v as having n blocks of the given size.
|
| 1224 |
|
|
// if leftover is true, there is left over space at the end of the span.
|
| 1225 |
|
|
void
|
| 1226 |
|
|
runtime_markspan(void *v, uintptr size, uintptr n, bool leftover)
|
| 1227 |
|
|
{
|
| 1228 |
|
|
uintptr *b, off, shift;
|
| 1229 |
|
|
byte *p;
|
| 1230 |
|
|
|
| 1231 |
|
|
if((byte*)v+size*n > (byte*)runtime_mheap.arena_used || (byte*)v < runtime_mheap.arena_start)
|
| 1232 |
|
|
runtime_throw("markspan: bad pointer");
|
| 1233 |
|
|
|
| 1234 |
|
|
p = v;
|
| 1235 |
|
|
if(leftover) // mark a boundary just past end of last block too
|
| 1236 |
|
|
n++;
|
| 1237 |
|
|
for(; n-- > 0; p += size) {
|
| 1238 |
|
|
// Okay to use non-atomic ops here, because we control
|
| 1239 |
|
|
// the entire span, and each bitmap word has bits for only
|
| 1240 |
|
|
// one span, so no other goroutines are changing these
|
| 1241 |
|
|
// bitmap words.
|
| 1242 |
|
|
off = (uintptr*)p - (uintptr*)runtime_mheap.arena_start; // word offset
|
| 1243 |
|
|
b = (uintptr*)runtime_mheap.arena_start - off/wordsPerBitmapWord - 1;
|
| 1244 |
|
|
shift = off % wordsPerBitmapWord;
|
| 1245 |
|
|
*b = (*b & ~(bitMask<<shift)) | (bitBlockBoundary<<shift);
|
| 1246 |
|
|
}
|
| 1247 |
|
|
}
|
| 1248 |
|
|
|
| 1249 |
|
|
// unmark the span of memory at v of length n bytes.
|
| 1250 |
|
|
void
|
| 1251 |
|
|
runtime_unmarkspan(void *v, uintptr n)
|
| 1252 |
|
|
{
|
| 1253 |
|
|
uintptr *p, *b, off;
|
| 1254 |
|
|
|
| 1255 |
|
|
if((byte*)v+n > (byte*)runtime_mheap.arena_used || (byte*)v < runtime_mheap.arena_start)
|
| 1256 |
|
|
runtime_throw("markspan: bad pointer");
|
| 1257 |
|
|
|
| 1258 |
|
|
p = v;
|
| 1259 |
|
|
off = p - (uintptr*)runtime_mheap.arena_start; // word offset
|
| 1260 |
|
|
if(off % wordsPerBitmapWord != 0)
|
| 1261 |
|
|
runtime_throw("markspan: unaligned pointer");
|
| 1262 |
|
|
b = (uintptr*)runtime_mheap.arena_start - off/wordsPerBitmapWord - 1;
|
| 1263 |
|
|
n /= PtrSize;
|
| 1264 |
|
|
if(n%wordsPerBitmapWord != 0)
|
| 1265 |
|
|
runtime_throw("unmarkspan: unaligned length");
|
| 1266 |
|
|
// Okay to use non-atomic ops here, because we control
|
| 1267 |
|
|
// the entire span, and each bitmap word has bits for only
|
| 1268 |
|
|
// one span, so no other goroutines are changing these
|
| 1269 |
|
|
// bitmap words.
|
| 1270 |
|
|
n /= wordsPerBitmapWord;
|
| 1271 |
|
|
while(n-- > 0)
|
| 1272 |
|
|
*b-- = 0;
|
| 1273 |
|
|
}
|
| 1274 |
|
|
|
| 1275 |
|
|
bool
|
| 1276 |
|
|
runtime_blockspecial(void *v)
|
| 1277 |
|
|
{
|
| 1278 |
|
|
uintptr *b, off, shift;
|
| 1279 |
|
|
|
| 1280 |
|
|
if(DebugMark)
|
| 1281 |
|
|
return true;
|
| 1282 |
|
|
|
| 1283 |
|
|
off = (uintptr*)v - (uintptr*)runtime_mheap.arena_start;
|
| 1284 |
|
|
b = (uintptr*)runtime_mheap.arena_start - off/wordsPerBitmapWord - 1;
|
| 1285 |
|
|
shift = off % wordsPerBitmapWord;
|
| 1286 |
|
|
|
| 1287 |
|
|
return (*b & (bitSpecial<<shift)) != 0;
|
| 1288 |
|
|
}
|
| 1289 |
|
|
|
| 1290 |
|
|
void
|
| 1291 |
|
|
runtime_setblockspecial(void *v, bool s)
|
| 1292 |
|
|
{
|
| 1293 |
|
|
uintptr *b, off, shift, bits, obits;
|
| 1294 |
|
|
|
| 1295 |
|
|
if(DebugMark)
|
| 1296 |
|
|
return;
|
| 1297 |
|
|
|
| 1298 |
|
|
off = (uintptr*)v - (uintptr*)runtime_mheap.arena_start;
|
| 1299 |
|
|
b = (uintptr*)runtime_mheap.arena_start - off/wordsPerBitmapWord - 1;
|
| 1300 |
|
|
shift = off % wordsPerBitmapWord;
|
| 1301 |
|
|
|
| 1302 |
|
|
for(;;) {
|
| 1303 |
|
|
obits = *b;
|
| 1304 |
|
|
if(s)
|
| 1305 |
|
|
bits = obits | (bitSpecial<<shift);
|
| 1306 |
|
|
else
|
| 1307 |
|
|
bits = obits & ~(bitSpecial<<shift);
|
| 1308 |
|
|
if(runtime_singleproc) {
|
| 1309 |
|
|
*b = bits;
|
| 1310 |
|
|
break;
|
| 1311 |
|
|
} else {
|
| 1312 |
|
|
// more than one goroutine is potentially running: use atomic op
|
| 1313 |
|
|
if(runtime_casp((void**)b, (void*)obits, (void*)bits))
|
| 1314 |
|
|
break;
|
| 1315 |
|
|
}
|
| 1316 |
|
|
}
|
| 1317 |
|
|
}
|
| 1318 |
|
|
|
| 1319 |
|
|
void
|
| 1320 |
|
|
runtime_MHeap_MapBits(MHeap *h)
|
| 1321 |
|
|
{
|
| 1322 |
|
|
// Caller has added extra mappings to the arena.
|
| 1323 |
|
|
// Add extra mappings of bitmap words as needed.
|
| 1324 |
|
|
// We allocate extra bitmap pieces in chunks of bitmapChunk.
|
| 1325 |
|
|
enum {
|
| 1326 |
|
|
bitmapChunk = 8192
|
| 1327 |
|
|
};
|
| 1328 |
|
|
uintptr n;
|
| 1329 |
|
|
|
| 1330 |
|
|
n = (h->arena_used - h->arena_start) / wordsPerBitmapWord;
|
| 1331 |
|
|
n = (n+bitmapChunk-1) & ~(bitmapChunk-1);
|
| 1332 |
|
|
if(h->bitmap_mapped >= n)
|
| 1333 |
|
|
return;
|
| 1334 |
|
|
|
| 1335 |
|
|
runtime_SysMap(h->arena_start - n, n - h->bitmap_mapped);
|
| 1336 |
|
|
h->bitmap_mapped = n;
|
| 1337 |
|
|
}
|
