mirror of
https://github.com/golang/go.git
synced 2025-10-31 16:50:58 +00:00
build: merge the great pkg/ rename into dev.power64
This also removes pkg/runtime/traceback_lr.c, which was ported to Go in an earlier commit and then moved to runtime/traceback.go. Reviewer: rsc@golang.org rsc: LGTM
This commit is contained in:
Austin Clements
commit
2bd616b1a7
2208 changed files with 400 additions and 852 deletions
814
src/runtime/malloc.go
Normal file
814
src/runtime/malloc.go
Normal file
|
|
@ -0,0 +1,814 @@
|
|||
// Copyright 2014 The Go Authors. All rights reserved.
|
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// Use of this source code is governed by a BSD-style
|
||||
// license that can be found in the LICENSE file.
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||||
|
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package runtime
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||||
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import "unsafe"
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const (
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debugMalloc = false
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flagNoScan = 1 << 0 // GC doesn't have to scan object
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||||
flagNoZero = 1 << 1 // don't zero memory
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||||
|
||||
maxTinySize = 16
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||||
tinySizeClass = 2
|
||||
maxSmallSize = 32 << 10
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||||
|
||||
pageShift = 13
|
||||
pageSize = 1 << pageShift
|
||||
pageMask = pageSize - 1
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||||
|
||||
bitsPerPointer = 2
|
||||
bitsMask = 1<<bitsPerPointer - 1
|
||||
pointersPerByte = 8 / bitsPerPointer
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bitPtrMask = bitsMask << 2
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maxGCMask = 64
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bitsDead = 0
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bitsPointer = 2
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||||
|
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bitBoundary = 1
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bitMarked = 2
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bitMask = bitBoundary | bitMarked
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mSpanInUse = 0
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)
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||||
// Page number (address>>pageShift)
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type pageID uintptr
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||||
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||||
// All zero-sized allocations return a pointer to this byte.
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var zeroObject byte
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||||
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||||
// Maximum possible heap size.
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||||
var maxMem uintptr
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||||
|
||||
// Allocate an object of size bytes.
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||||
// Small objects are allocated from the per-P cache's free lists.
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||||
// Large objects (> 32 kB) are allocated straight from the heap.
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||||
func gomallocgc(size uintptr, typ *_type, flags int) unsafe.Pointer {
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||||
if size == 0 {
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||||
return unsafe.Pointer(&zeroObject)
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||||
}
|
||||
size0 := size
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||||
|
||||
// This function must be atomic wrt GC, but for performance reasons
|
||||
// we don't acquirem/releasem on fast path. The code below does not have
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||||
// split stack checks, so it can't be preempted by GC.
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||||
// Functions like roundup/add are inlined. And onM/racemalloc are nosplit.
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// If debugMalloc = true, these assumptions are checked below.
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if debugMalloc {
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mp := acquirem()
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if mp.mallocing != 0 {
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gothrow("malloc deadlock")
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}
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mp.mallocing = 1
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if mp.curg != nil {
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||||
mp.curg.stackguard0 = ^uintptr(0xfff) | 0xbad
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||||
}
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}
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c := gomcache()
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||||
var s *mspan
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||||
var x unsafe.Pointer
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||||
if size <= maxSmallSize {
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||||
if flags&flagNoScan != 0 && size < maxTinySize {
|
||||
// Tiny allocator.
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||||
//
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||||
// Tiny allocator combines several tiny allocation requests
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||||
// into a single memory block. The resulting memory block
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||||
// is freed when all subobjects are unreachable. The subobjects
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||||
// must be FlagNoScan (don't have pointers), this ensures that
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||||
// the amount of potentially wasted memory is bounded.
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||||
//
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||||
// Size of the memory block used for combining (maxTinySize) is tunable.
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||||
// Current setting is 16 bytes, which relates to 2x worst case memory
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||||
// wastage (when all but one subobjects are unreachable).
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// 8 bytes would result in no wastage at all, but provides less
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||||
// opportunities for combining.
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// 32 bytes provides more opportunities for combining,
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||||
// but can lead to 4x worst case wastage.
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||||
// The best case winning is 8x regardless of block size.
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||||
//
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||||
// Objects obtained from tiny allocator must not be freed explicitly.
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||||
// So when an object will be freed explicitly, we ensure that
|
||||
// its size >= maxTinySize.
|
||||
//
|
||||
// SetFinalizer has a special case for objects potentially coming
|
||||
// from tiny allocator, it such case it allows to set finalizers
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||||
// for an inner byte of a memory block.
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||||
//
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||||
// The main targets of tiny allocator are small strings and
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||||
// standalone escaping variables. On a json benchmark
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||||
// the allocator reduces number of allocations by ~12% and
|
||||
// reduces heap size by ~20%.
|
||||
|
||||
tinysize := uintptr(c.tinysize)
|
||||
if size <= tinysize {
|
||||
tiny := unsafe.Pointer(c.tiny)
|
||||
// Align tiny pointer for required (conservative) alignment.
|
||||
if size&7 == 0 {
|
||||
tiny = roundup(tiny, 8)
|
||||
} else if size&3 == 0 {
|
||||
tiny = roundup(tiny, 4)
|
||||
} else if size&1 == 0 {
|
||||
tiny = roundup(tiny, 2)
|
||||
}
|
||||
size1 := size + (uintptr(tiny) - uintptr(unsafe.Pointer(c.tiny)))
|
||||
if size1 <= tinysize {
|
||||
// The object fits into existing tiny block.
|
||||
x = tiny
|
||||
c.tiny = (*byte)(add(x, size))
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||||
c.tinysize -= uintptr(size1)
|
||||
if debugMalloc {
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||||
mp := acquirem()
|
||||
if mp.mallocing == 0 {
|
||||
gothrow("bad malloc")
|
||||
}
|
||||
mp.mallocing = 0
|
||||
if mp.curg != nil {
|
||||
mp.curg.stackguard0 = mp.curg.stackguard
|
||||
}
|
||||
releasem(mp)
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||||
releasem(mp)
|
||||
}
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||||
return x
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||||
}
|
||||
}
|
||||
// Allocate a new maxTinySize block.
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||||
s = c.alloc[tinySizeClass]
|
||||
v := s.freelist
|
||||
if v == nil {
|
||||
mp := acquirem()
|
||||
mp.scalararg[0] = tinySizeClass
|
||||
onM(mcacheRefill_m)
|
||||
releasem(mp)
|
||||
s = c.alloc[tinySizeClass]
|
||||
v = s.freelist
|
||||
}
|
||||
s.freelist = v.next
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||||
s.ref++
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||||
//TODO: prefetch v.next
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||||
x = unsafe.Pointer(v)
|
||||
(*[2]uint64)(x)[0] = 0
|
||||
(*[2]uint64)(x)[1] = 0
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||||
// See if we need to replace the existing tiny block with the new one
|
||||
// based on amount of remaining free space.
|
||||
if maxTinySize-size > tinysize {
|
||||
c.tiny = (*byte)(add(x, size))
|
||||
c.tinysize = uintptr(maxTinySize - size)
|
||||
}
|
||||
size = maxTinySize
|
||||
} else {
|
||||
var sizeclass int8
|
||||
if size <= 1024-8 {
|
||||
sizeclass = size_to_class8[(size+7)>>3]
|
||||
} else {
|
||||
sizeclass = size_to_class128[(size-1024+127)>>7]
|
||||
}
|
||||
size = uintptr(class_to_size[sizeclass])
|
||||
s = c.alloc[sizeclass]
|
||||
v := s.freelist
|
||||
if v == nil {
|
||||
mp := acquirem()
|
||||
mp.scalararg[0] = uintptr(sizeclass)
|
||||
onM(mcacheRefill_m)
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||||
releasem(mp)
|
||||
s = c.alloc[sizeclass]
|
||||
v = s.freelist
|
||||
}
|
||||
s.freelist = v.next
|
||||
s.ref++
|
||||
//TODO: prefetch
|
||||
x = unsafe.Pointer(v)
|
||||
if flags&flagNoZero == 0 {
|
||||
v.next = nil
|
||||
if size > 2*ptrSize && ((*[2]uintptr)(x))[1] != 0 {
|
||||
memclr(unsafe.Pointer(v), size)
|
||||
}
|
||||
}
|
||||
}
|
||||
c.local_cachealloc += intptr(size)
|
||||
} else {
|
||||
mp := acquirem()
|
||||
mp.scalararg[0] = uintptr(size)
|
||||
mp.scalararg[1] = uintptr(flags)
|
||||
onM(largeAlloc_m)
|
||||
s = (*mspan)(mp.ptrarg[0])
|
||||
mp.ptrarg[0] = nil
|
||||
releasem(mp)
|
||||
x = unsafe.Pointer(uintptr(s.start << pageShift))
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||||
size = uintptr(s.elemsize)
|
||||
}
|
||||
|
||||
if flags&flagNoScan != 0 {
|
||||
// All objects are pre-marked as noscan.
|
||||
goto marked
|
||||
}
|
||||
|
||||
// From here till marked label marking the object as allocated
|
||||
// and storing type info in the GC bitmap.
|
||||
{
|
||||
arena_start := uintptr(unsafe.Pointer(mheap_.arena_start))
|
||||
off := (uintptr(x) - arena_start) / ptrSize
|
||||
xbits := (*uint8)(unsafe.Pointer(arena_start - off/wordsPerBitmapByte - 1))
|
||||
shift := (off % wordsPerBitmapByte) * gcBits
|
||||
if debugMalloc && ((*xbits>>shift)&(bitMask|bitPtrMask)) != bitBoundary {
|
||||
println("runtime: bits =", (*xbits>>shift)&(bitMask|bitPtrMask))
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||||
gothrow("bad bits in markallocated")
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||||
}
|
||||
|
||||
var ti, te uintptr
|
||||
var ptrmask *uint8
|
||||
if size == ptrSize {
|
||||
// It's one word and it has pointers, it must be a pointer.
|
||||
*xbits |= (bitsPointer << 2) << shift
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||||
goto marked
|
||||
}
|
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if typ.kind&kindGCProg != 0 {
|
||||
nptr := (uintptr(typ.size) + ptrSize - 1) / ptrSize
|
||||
masksize := nptr
|
||||
if masksize%2 != 0 {
|
||||
masksize *= 2 // repeated
|
||||
}
|
||||
masksize = masksize * pointersPerByte / 8 // 4 bits per word
|
||||
masksize++ // unroll flag in the beginning
|
||||
if masksize > maxGCMask && typ.gc[1] != 0 {
|
||||
// If the mask is too large, unroll the program directly
|
||||
// into the GC bitmap. It's 7 times slower than copying
|
||||
// from the pre-unrolled mask, but saves 1/16 of type size
|
||||
// memory for the mask.
|
||||
mp := acquirem()
|
||||
mp.ptrarg[0] = x
|
||||
mp.ptrarg[1] = unsafe.Pointer(typ)
|
||||
mp.scalararg[0] = uintptr(size)
|
||||
mp.scalararg[1] = uintptr(size0)
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||||
onM(unrollgcproginplace_m)
|
||||
releasem(mp)
|
||||
goto marked
|
||||
}
|
||||
ptrmask = (*uint8)(unsafe.Pointer(uintptr(typ.gc[0])))
|
||||
// Check whether the program is already unrolled
|
||||
// by checking if the unroll flag byte is set
|
||||
maskword := uintptr(atomicloadp(unsafe.Pointer(ptrmask)))
|
||||
if *(*uint8)(unsafe.Pointer(&maskword)) == 0 {
|
||||
mp := acquirem()
|
||||
mp.ptrarg[0] = unsafe.Pointer(typ)
|
||||
onM(unrollgcprog_m)
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||||
releasem(mp)
|
||||
}
|
||||
ptrmask = (*uint8)(add(unsafe.Pointer(ptrmask), 1)) // skip the unroll flag byte
|
||||
} else {
|
||||
ptrmask = (*uint8)(unsafe.Pointer(&typ.gc[0])) // embed mask
|
||||
}
|
||||
if size == 2*ptrSize {
|
||||
*xbits = *ptrmask | bitBoundary
|
||||
goto marked
|
||||
}
|
||||
te = uintptr(typ.size) / ptrSize
|
||||
// If the type occupies odd number of words, its mask is repeated.
|
||||
if te%2 == 0 {
|
||||
te /= 2
|
||||
}
|
||||
// Copy pointer bitmask into the bitmap.
|
||||
for i := uintptr(0); i < size0; i += 2 * ptrSize {
|
||||
v := *(*uint8)(add(unsafe.Pointer(ptrmask), ti))
|
||||
ti++
|
||||
if ti == te {
|
||||
ti = 0
|
||||
}
|
||||
if i == 0 {
|
||||
v |= bitBoundary
|
||||
}
|
||||
if i+ptrSize == size0 {
|
||||
v &^= uint8(bitPtrMask << 4)
|
||||
}
|
||||
|
||||
*xbits = v
|
||||
xbits = (*byte)(add(unsafe.Pointer(xbits), ^uintptr(0)))
|
||||
}
|
||||
if size0%(2*ptrSize) == 0 && size0 < size {
|
||||
// Mark the word after last object's word as bitsDead.
|
||||
*xbits = bitsDead << 2
|
||||
}
|
||||
}
|
||||
marked:
|
||||
if raceenabled {
|
||||
racemalloc(x, size)
|
||||
}
|
||||
|
||||
if debugMalloc {
|
||||
mp := acquirem()
|
||||
if mp.mallocing == 0 {
|
||||
gothrow("bad malloc")
|
||||
}
|
||||
mp.mallocing = 0
|
||||
if mp.curg != nil {
|
||||
mp.curg.stackguard0 = mp.curg.stackguard
|
||||
}
|
||||
releasem(mp)
|
||||
releasem(mp)
|
||||
}
|
||||
|
||||
if debug.allocfreetrace != 0 {
|
||||
tracealloc(x, size, typ)
|
||||
}
|
||||
|
||||
if rate := MemProfileRate; rate > 0 {
|
||||
if size < uintptr(rate) && int32(size) < c.next_sample {
|
||||
c.next_sample -= int32(size)
|
||||
} else {
|
||||
mp := acquirem()
|
||||
profilealloc(mp, x, size)
|
||||
releasem(mp)
|
||||
}
|
||||
}
|
||||
|
||||
if memstats.heap_alloc >= memstats.next_gc {
|
||||
gogc(0)
|
||||
}
|
||||
|
||||
return x
|
||||
}
|
||||
|
||||
// cmallocgc is a trampoline used to call the Go malloc from C.
|
||||
func cmallocgc(size uintptr, typ *_type, flags int, ret *unsafe.Pointer) {
|
||||
*ret = gomallocgc(size, typ, flags)
|
||||
}
|
||||
|
||||
// implementation of new builtin
|
||||
func newobject(typ *_type) unsafe.Pointer {
|
||||
flags := 0
|
||||
if typ.kind&kindNoPointers != 0 {
|
||||
flags |= flagNoScan
|
||||
}
|
||||
return gomallocgc(uintptr(typ.size), typ, flags)
|
||||
}
|
||||
|
||||
// implementation of make builtin for slices
|
||||
func newarray(typ *_type, n uintptr) unsafe.Pointer {
|
||||
flags := 0
|
||||
if typ.kind&kindNoPointers != 0 {
|
||||
flags |= flagNoScan
|
||||
}
|
||||
if int(n) < 0 || (typ.size > 0 && n > maxMem/uintptr(typ.size)) {
|
||||
panic("runtime: allocation size out of range")
|
||||
}
|
||||
return gomallocgc(uintptr(typ.size)*n, typ, flags)
|
||||
}
|
||||
|
||||
// rawmem returns a chunk of pointerless memory. It is
|
||||
// not zeroed.
|
||||
func rawmem(size uintptr) unsafe.Pointer {
|
||||
return gomallocgc(size, nil, flagNoScan|flagNoZero)
|
||||
}
|
||||
|
||||
// round size up to next size class
|
||||
func goroundupsize(size uintptr) uintptr {
|
||||
if size < maxSmallSize {
|
||||
if size <= 1024-8 {
|
||||
return uintptr(class_to_size[size_to_class8[(size+7)>>3]])
|
||||
}
|
||||
return uintptr(class_to_size[size_to_class128[(size-1024+127)>>7]])
|
||||
}
|
||||
if size+pageSize < size {
|
||||
return size
|
||||
}
|
||||
return (size + pageSize - 1) &^ pageMask
|
||||
}
|
||||
|
||||
func profilealloc(mp *m, x unsafe.Pointer, size uintptr) {
|
||||
c := mp.mcache
|
||||
rate := MemProfileRate
|
||||
if size < uintptr(rate) {
|
||||
// pick next profile time
|
||||
// If you change this, also change allocmcache.
|
||||
if rate > 0x3fffffff { // make 2*rate not overflow
|
||||
rate = 0x3fffffff
|
||||
}
|
||||
next := int32(fastrand1()) % (2 * int32(rate))
|
||||
// Subtract the "remainder" of the current allocation.
|
||||
// Otherwise objects that are close in size to sampling rate
|
||||
// will be under-sampled, because we consistently discard this remainder.
|
||||
next -= (int32(size) - c.next_sample)
|
||||
if next < 0 {
|
||||
next = 0
|
||||
}
|
||||
c.next_sample = next
|
||||
}
|
||||
|
||||
mProf_Malloc(x, size)
|
||||
}
|
||||
|
||||
// force = 1 - do GC regardless of current heap usage
|
||||
// force = 2 - go GC and eager sweep
|
||||
func gogc(force int32) {
|
||||
// The gc is turned off (via enablegc) until the bootstrap has completed.
|
||||
// Also, malloc gets called in the guts of a number of libraries that might be
|
||||
// holding locks. To avoid deadlocks during stoptheworld, don't bother
|
||||
// trying to run gc while holding a lock. The next mallocgc without a lock
|
||||
// will do the gc instead.
|
||||
mp := acquirem()
|
||||
if gp := getg(); gp == mp.g0 || mp.locks > 1 || !memstats.enablegc || panicking != 0 || gcpercent < 0 {
|
||||
releasem(mp)
|
||||
return
|
||||
}
|
||||
releasem(mp)
|
||||
mp = nil
|
||||
|
||||
semacquire(&worldsema, false)
|
||||
|
||||
if force == 0 && memstats.heap_alloc < memstats.next_gc {
|
||||
// typically threads which lost the race to grab
|
||||
// worldsema exit here when gc is done.
|
||||
semrelease(&worldsema)
|
||||
return
|
||||
}
|
||||
|
||||
// Ok, we're doing it! Stop everybody else
|
||||
startTime := nanotime()
|
||||
mp = acquirem()
|
||||
mp.gcing = 1
|
||||
releasem(mp)
|
||||
onM(stoptheworld)
|
||||
if mp != acquirem() {
|
||||
gothrow("gogc: rescheduled")
|
||||
}
|
||||
|
||||
clearpools()
|
||||
|
||||
// Run gc on the g0 stack. We do this so that the g stack
|
||||
// we're currently running on will no longer change. Cuts
|
||||
// the root set down a bit (g0 stacks are not scanned, and
|
||||
// we don't need to scan gc's internal state). We also
|
||||
// need to switch to g0 so we can shrink the stack.
|
||||
n := 1
|
||||
if debug.gctrace > 1 {
|
||||
n = 2
|
||||
}
|
||||
for i := 0; i < n; i++ {
|
||||
if i > 0 {
|
||||
startTime = nanotime()
|
||||
}
|
||||
// switch to g0, call gc, then switch back
|
||||
mp.scalararg[0] = uintptr(uint32(startTime)) // low 32 bits
|
||||
mp.scalararg[1] = uintptr(startTime >> 32) // high 32 bits
|
||||
if force >= 2 {
|
||||
mp.scalararg[2] = 1 // eagersweep
|
||||
} else {
|
||||
mp.scalararg[2] = 0
|
||||
}
|
||||
onM(gc_m)
|
||||
}
|
||||
|
||||
// all done
|
||||
mp.gcing = 0
|
||||
semrelease(&worldsema)
|
||||
onM(starttheworld)
|
||||
releasem(mp)
|
||||
mp = nil
|
||||
|
||||
// now that gc is done, kick off finalizer thread if needed
|
||||
if !concurrentSweep {
|
||||
// give the queued finalizers, if any, a chance to run
|
||||
gosched()
|
||||
}
|
||||
}
|
||||
|
||||
// GC runs a garbage collection.
|
||||
func GC() {
|
||||
gogc(2)
|
||||
}
|
||||
|
||||
// SetFinalizer sets the finalizer associated with x to f.
|
||||
// When the garbage collector finds an unreachable block
|
||||
// with an associated finalizer, it clears the association and runs
|
||||
// f(x) in a separate goroutine. This makes x reachable again, but
|
||||
// now without an associated finalizer. Assuming that SetFinalizer
|
||||
// is not called again, the next time the garbage collector sees
|
||||
// that x is unreachable, it will free x.
|
||||
//
|
||||
// SetFinalizer(x, nil) clears any finalizer associated with x.
|
||||
//
|
||||
// The argument x must be a pointer to an object allocated by
|
||||
// calling new or by taking the address of a composite literal.
|
||||
// The argument f must be a function that takes a single argument
|
||||
// to which x's type can be assigned, and can have arbitrary ignored return
|
||||
// values. If either of these is not true, SetFinalizer aborts the
|
||||
// program.
|
||||
//
|
||||
// Finalizers are run in dependency order: if A points at B, both have
|
||||
// finalizers, and they are otherwise unreachable, only the finalizer
|
||||
// for A runs; once A is freed, the finalizer for B can run.
|
||||
// If a cyclic structure includes a block with a finalizer, that
|
||||
// cycle is not guaranteed to be garbage collected and the finalizer
|
||||
// is not guaranteed to run, because there is no ordering that
|
||||
// respects the dependencies.
|
||||
//
|
||||
// The finalizer for x is scheduled to run at some arbitrary time after
|
||||
// x becomes unreachable.
|
||||
// There is no guarantee that finalizers will run before a program exits,
|
||||
// so typically they are useful only for releasing non-memory resources
|
||||
// associated with an object during a long-running program.
|
||||
// For example, an os.File object could use a finalizer to close the
|
||||
// associated operating system file descriptor when a program discards
|
||||
// an os.File without calling Close, but it would be a mistake
|
||||
// to depend on a finalizer to flush an in-memory I/O buffer such as a
|
||||
// bufio.Writer, because the buffer would not be flushed at program exit.
|
||||
//
|
||||
// It is not guaranteed that a finalizer will run if the size of *x is
|
||||
// zero bytes.
|
||||
//
|
||||
// A single goroutine runs all finalizers for a program, sequentially.
|
||||
// If a finalizer must run for a long time, it should do so by starting
|
||||
// a new goroutine.
|
||||
func SetFinalizer(obj interface{}, finalizer interface{}) {
|
||||
e := (*eface)(unsafe.Pointer(&obj))
|
||||
etyp := e._type
|
||||
if etyp == nil {
|
||||
gothrow("runtime.SetFinalizer: first argument is nil")
|
||||
}
|
||||
if etyp.kind&kindMask != kindPtr {
|
||||
gothrow("runtime.SetFinalizer: first argument is " + *etyp._string + ", not pointer")
|
||||
}
|
||||
ot := (*ptrtype)(unsafe.Pointer(etyp))
|
||||
if ot.elem == nil {
|
||||
gothrow("nil elem type!")
|
||||
}
|
||||
|
||||
// As an implementation detail we do not run finalizers for zero-sized objects,
|
||||
// because we use &runtime·zerobase for all such allocations.
|
||||
if ot.elem.size == 0 {
|
||||
return
|
||||
}
|
||||
|
||||
// find the containing object
|
||||
_, base, _ := findObject(e.data)
|
||||
|
||||
// The following check is required for cases when a user passes a pointer to composite
|
||||
// literal, but compiler makes it a pointer to global. For example:
|
||||
// var Foo = &Object{}
|
||||
// func main() {
|
||||
// runtime.SetFinalizer(Foo, nil)
|
||||
// }
|
||||
// See issue 7656.
|
||||
if base == nil {
|
||||
return
|
||||
}
|
||||
|
||||
if e.data != base {
|
||||
// As an implementation detail we allow to set finalizers for an inner byte
|
||||
// of an object if it could come from tiny alloc (see mallocgc for details).
|
||||
if ot.elem == nil || ot.elem.kind&kindNoPointers == 0 || ot.elem.size >= maxTinySize {
|
||||
gothrow("runtime.SetFinalizer: pointer not at beginning of allocated block")
|
||||
}
|
||||
}
|
||||
|
||||
f := (*eface)(unsafe.Pointer(&finalizer))
|
||||
ftyp := f._type
|
||||
if ftyp == nil {
|
||||
// switch to M stack and remove finalizer
|
||||
mp := acquirem()
|
||||
mp.ptrarg[0] = e.data
|
||||
onM(removeFinalizer_m)
|
||||
releasem(mp)
|
||||
return
|
||||
}
|
||||
|
||||
if ftyp.kind&kindMask != kindFunc {
|
||||
gothrow("runtime.SetFinalizer: second argument is " + *ftyp._string + ", not a function")
|
||||
}
|
||||
ft := (*functype)(unsafe.Pointer(ftyp))
|
||||
ins := *(*[]*_type)(unsafe.Pointer(&ft.in))
|
||||
if ft.dotdotdot || len(ins) != 1 {
|
||||
gothrow("runtime.SetFinalizer: cannot pass " + *etyp._string + " to finalizer " + *ftyp._string)
|
||||
}
|
||||
fint := ins[0]
|
||||
switch {
|
||||
case fint == etyp:
|
||||
// ok - same type
|
||||
goto okarg
|
||||
case fint.kind&kindMask == kindPtr:
|
||||
if (fint.x == nil || fint.x.name == nil || etyp.x == nil || etyp.x.name == nil) && (*ptrtype)(unsafe.Pointer(fint)).elem == ot.elem {
|
||||
// ok - not same type, but both pointers,
|
||||
// one or the other is unnamed, and same element type, so assignable.
|
||||
goto okarg
|
||||
}
|
||||
case fint.kind&kindMask == kindInterface:
|
||||
ityp := (*interfacetype)(unsafe.Pointer(fint))
|
||||
if len(ityp.mhdr) == 0 {
|
||||
// ok - satisfies empty interface
|
||||
goto okarg
|
||||
}
|
||||
if _, ok := assertE2I2(ityp, obj); ok {
|
||||
goto okarg
|
||||
}
|
||||
}
|
||||
gothrow("runtime.SetFinalizer: cannot pass " + *etyp._string + " to finalizer " + *ftyp._string)
|
||||
okarg:
|
||||
// compute size needed for return parameters
|
||||
nret := uintptr(0)
|
||||
for _, t := range *(*[]*_type)(unsafe.Pointer(&ft.out)) {
|
||||
nret = round(nret, uintptr(t.align)) + uintptr(t.size)
|
||||
}
|
||||
nret = round(nret, ptrSize)
|
||||
|
||||
// make sure we have a finalizer goroutine
|
||||
createfing()
|
||||
|
||||
// switch to M stack to add finalizer record
|
||||
mp := acquirem()
|
||||
mp.ptrarg[0] = f.data
|
||||
mp.ptrarg[1] = e.data
|
||||
mp.scalararg[0] = nret
|
||||
mp.ptrarg[2] = unsafe.Pointer(fint)
|
||||
mp.ptrarg[3] = unsafe.Pointer(ot)
|
||||
onM(setFinalizer_m)
|
||||
if mp.scalararg[0] != 1 {
|
||||
gothrow("runtime.SetFinalizer: finalizer already set")
|
||||
}
|
||||
releasem(mp)
|
||||
}
|
||||
|
||||
// round n up to a multiple of a. a must be a power of 2.
|
||||
func round(n, a uintptr) uintptr {
|
||||
return (n + a - 1) &^ (a - 1)
|
||||
}
|
||||
|
||||
// Look up pointer v in heap. Return the span containing the object,
|
||||
// the start of the object, and the size of the object. If the object
|
||||
// does not exist, return nil, nil, 0.
|
||||
func findObject(v unsafe.Pointer) (s *mspan, x unsafe.Pointer, n uintptr) {
|
||||
c := gomcache()
|
||||
c.local_nlookup++
|
||||
if ptrSize == 4 && c.local_nlookup >= 1<<30 {
|
||||
// purge cache stats to prevent overflow
|
||||
lock(&mheap_.lock)
|
||||
purgecachedstats(c)
|
||||
unlock(&mheap_.lock)
|
||||
}
|
||||
|
||||
// find span
|
||||
arena_start := uintptr(unsafe.Pointer(mheap_.arena_start))
|
||||
arena_used := uintptr(unsafe.Pointer(mheap_.arena_used))
|
||||
if uintptr(v) < arena_start || uintptr(v) >= arena_used {
|
||||
return
|
||||
}
|
||||
p := uintptr(v) >> pageShift
|
||||
q := p - arena_start>>pageShift
|
||||
s = *(**mspan)(add(unsafe.Pointer(mheap_.spans), q*ptrSize))
|
||||
if s == nil {
|
||||
return
|
||||
}
|
||||
x = unsafe.Pointer(uintptr(s.start) << pageShift)
|
||||
|
||||
if uintptr(v) < uintptr(x) || uintptr(v) >= uintptr(unsafe.Pointer(s.limit)) || s.state != mSpanInUse {
|
||||
s = nil
|
||||
x = nil
|
||||
return
|
||||
}
|
||||
|
||||
n = uintptr(s.elemsize)
|
||||
if s.sizeclass != 0 {
|
||||
x = add(x, (uintptr(v)-uintptr(x))/n*n)
|
||||
}
|
||||
return
|
||||
}
|
||||
|
||||
var fingCreate uint32
|
||||
|
||||
func createfing() {
|
||||
// start the finalizer goroutine exactly once
|
||||
if fingCreate == 0 && cas(&fingCreate, 0, 1) {
|
||||
go runfinq()
|
||||
}
|
||||
}
|
||||
|
||||
// This is the goroutine that runs all of the finalizers
|
||||
func runfinq() {
|
||||
var (
|
||||
frame unsafe.Pointer
|
||||
framecap uintptr
|
||||
)
|
||||
|
||||
for {
|
||||
lock(&finlock)
|
||||
fb := finq
|
||||
finq = nil
|
||||
if fb == nil {
|
||||
gp := getg()
|
||||
fing = gp
|
||||
fingwait = true
|
||||
gp.issystem = true
|
||||
goparkunlock(&finlock, "finalizer wait")
|
||||
gp.issystem = false
|
||||
continue
|
||||
}
|
||||
unlock(&finlock)
|
||||
if raceenabled {
|
||||
racefingo()
|
||||
}
|
||||
for fb != nil {
|
||||
for i := int32(0); i < fb.cnt; i++ {
|
||||
f := (*finalizer)(add(unsafe.Pointer(&fb.fin), uintptr(i)*unsafe.Sizeof(finalizer{})))
|
||||
|
||||
framesz := unsafe.Sizeof((interface{})(nil)) + uintptr(f.nret)
|
||||
if framecap < framesz {
|
||||
// The frame does not contain pointers interesting for GC,
|
||||
// all not yet finalized objects are stored in finq.
|
||||
// If we do not mark it as FlagNoScan,
|
||||
// the last finalized object is not collected.
|
||||
frame = gomallocgc(framesz, nil, flagNoScan)
|
||||
framecap = framesz
|
||||
}
|
||||
|
||||
if f.fint == nil {
|
||||
gothrow("missing type in runfinq")
|
||||
}
|
||||
switch f.fint.kind & kindMask {
|
||||
case kindPtr:
|
||||
// direct use of pointer
|
||||
*(*unsafe.Pointer)(frame) = f.arg
|
||||
case kindInterface:
|
||||
ityp := (*interfacetype)(unsafe.Pointer(f.fint))
|
||||
// set up with empty interface
|
||||
(*eface)(frame)._type = &f.ot.typ
|
||||
(*eface)(frame).data = f.arg
|
||||
if len(ityp.mhdr) != 0 {
|
||||
// convert to interface with methods
|
||||
// this conversion is guaranteed to succeed - we checked in SetFinalizer
|
||||
*(*fInterface)(frame) = assertE2I(ityp, *(*interface{})(frame))
|
||||
}
|
||||
default:
|
||||
gothrow("bad kind in runfinq")
|
||||
}
|
||||
reflectcall(unsafe.Pointer(f.fn), frame, uint32(framesz), uint32(framesz))
|
||||
|
||||
// drop finalizer queue references to finalized object
|
||||
f.fn = nil
|
||||
f.arg = nil
|
||||
f.ot = nil
|
||||
}
|
||||
fb.cnt = 0
|
||||
next := fb.next
|
||||
lock(&finlock)
|
||||
fb.next = finc
|
||||
finc = fb
|
||||
unlock(&finlock)
|
||||
fb = next
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
var persistent struct {
|
||||
lock mutex
|
||||
pos unsafe.Pointer
|
||||
end unsafe.Pointer
|
||||
}
|
||||
|
||||
// Wrapper around sysAlloc that can allocate small chunks.
|
||||
// There is no associated free operation.
|
||||
// Intended for things like function/type/debug-related persistent data.
|
||||
// If align is 0, uses default align (currently 8).
|
||||
func persistentalloc(size, align uintptr, stat *uint64) unsafe.Pointer {
|
||||
const (
|
||||
chunk = 256 << 10
|
||||
maxBlock = 64 << 10 // VM reservation granularity is 64K on windows
|
||||
)
|
||||
|
||||
if align != 0 {
|
||||
if align&(align-1) != 0 {
|
||||
gothrow("persistentalloc: align is not a power of 2")
|
||||
}
|
||||
if align > _PageSize {
|
||||
gothrow("persistentalloc: align is too large")
|
||||
}
|
||||
} else {
|
||||
align = 8
|
||||
}
|
||||
|
||||
if size >= maxBlock {
|
||||
return sysAlloc(size, stat)
|
||||
}
|
||||
|
||||
lock(&persistent.lock)
|
||||
persistent.pos = roundup(persistent.pos, align)
|
||||
if uintptr(persistent.pos)+size > uintptr(persistent.end) {
|
||||
persistent.pos = sysAlloc(chunk, &memstats.other_sys)
|
||||
if persistent.pos == nil {
|
||||
unlock(&persistent.lock)
|
||||
gothrow("runtime: cannot allocate memory")
|
||||
}
|
||||
persistent.end = add(persistent.pos, chunk)
|
||||
}
|
||||
p := persistent.pos
|
||||
persistent.pos = add(persistent.pos, size)
|
||||
unlock(&persistent.lock)
|
||||
|
||||
if stat != &memstats.other_sys {
|
||||
xadd64(stat, int64(size))
|
||||
xadd64(&memstats.other_sys, -int64(size))
|
||||
}
|
||||
return p
|
||||
}
|
||||
Loading…
Add table
Add a link
Reference in a new issue