Adding upstream version 1.21.8.upstream/1.21.8

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1278 insertions, 0 deletions

diff --git a/src/runtime/mprof.go b/src/runtime/mprof.go
new file mode 100644
index 0000000..308ebae
--- /dev/null
+++ b/src/runtime/mprof.go
@@ -0,0 +1,1278 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Malloc profiling.
+// Patterned after tcmalloc's algorithms; shorter code.
+
+package runtime
+
+import (
+	"internal/abi"
+	"runtime/internal/atomic"
+	"runtime/internal/sys"
+	"unsafe"
+)
+
+// NOTE(rsc): Everything here could use cas if contention became an issue.
+var (
+	// profInsertLock protects changes to the start of all *bucket linked lists
+	profInsertLock mutex
+	// profBlockLock protects the contents of every blockRecord struct
+	profBlockLock mutex
+	// profMemActiveLock protects the active field of every memRecord struct
+	profMemActiveLock mutex
+	// profMemFutureLock is a set of locks that protect the respective elements
+	// of the future array of every memRecord struct
+	profMemFutureLock [len(memRecord{}.future)]mutex
+)
+
+// All memory allocations are local and do not escape outside of the profiler.
+// The profiler is forbidden from referring to garbage-collected memory.
+
+const (
+	// profile types
+	memProfile bucketType = 1 + iota
+	blockProfile
+	mutexProfile
+
+	// size of bucket hash table
+	buckHashSize = 179999
+
+	// max depth of stack to record in bucket
+	maxStack = 32
+)
+
+type bucketType int
+
+// A bucket holds per-call-stack profiling information.
+// The representation is a bit sleazy, inherited from C.
+// This struct defines the bucket header. It is followed in
+// memory by the stack words and then the actual record
+// data, either a memRecord or a blockRecord.
+//
+// Per-call-stack profiling information.
+// Lookup by hashing call stack into a linked-list hash table.
+//
+// None of the fields in this bucket header are modified after
+// creation, including its next and allnext links.
+//
+// No heap pointers.
+type bucket struct {
+	_       sys.NotInHeap
+	next    *bucket
+	allnext *bucket
+	typ     bucketType // memBucket or blockBucket (includes mutexProfile)
+	hash    uintptr
+	size    uintptr
+	nstk    uintptr
+}
+
+// A memRecord is the bucket data for a bucket of type memProfile,
+// part of the memory profile.
+type memRecord struct {
+	// The following complex 3-stage scheme of stats accumulation
+	// is required to obtain a consistent picture of mallocs and frees
+	// for some point in time.
+	// The problem is that mallocs come in real time, while frees
+	// come only after a GC during concurrent sweeping. So if we would
+	// naively count them, we would get a skew toward mallocs.
+	//
+	// Hence, we delay information to get consistent snapshots as
+	// of mark termination. Allocations count toward the next mark
+	// termination's snapshot, while sweep frees count toward the
+	// previous mark termination's snapshot:
+	//
+	//              MT          MT          MT          MT
+	//             .·|         .·|         .·|         .·|
+	//          .·˙  |      .·˙  |      .·˙  |      .·˙  |
+	//       .·˙     |   .·˙     |   .·˙     |   .·˙     |
+	//    .·˙        |.·˙        |.·˙        |.·˙        |
+	//
+	//       alloc → ▲ ← free
+	//               ┠┅┅┅┅┅┅┅┅┅┅┅P
+	//       C+2     →    C+1    →  C
+	//
+	//                   alloc → ▲ ← free
+	//                           ┠┅┅┅┅┅┅┅┅┅┅┅P
+	//                   C+2     →    C+1    →  C
+	//
+	// Since we can't publish a consistent snapshot until all of
+	// the sweep frees are accounted for, we wait until the next
+	// mark termination ("MT" above) to publish the previous mark
+	// termination's snapshot ("P" above). To do this, allocation
+	// and free events are accounted to *future* heap profile
+	// cycles ("C+n" above) and we only publish a cycle once all
+	// of the events from that cycle must be done. Specifically:
+	//
+	// Mallocs are accounted to cycle C+2.
+	// Explicit frees are accounted to cycle C+2.
+	// GC frees (done during sweeping) are accounted to cycle C+1.
+	//
+	// After mark termination, we increment the global heap
+	// profile cycle counter and accumulate the stats from cycle C
+	// into the active profile.
+
+	// active is the currently published profile. A profiling
+	// cycle can be accumulated into active once its complete.
+	active memRecordCycle
+
+	// future records the profile events we're counting for cycles
+	// that have not yet been published. This is ring buffer
+	// indexed by the global heap profile cycle C and stores
+	// cycles C, C+1, and C+2. Unlike active, these counts are
+	// only for a single cycle; they are not cumulative across
+	// cycles.
+	//
+	// We store cycle C here because there's a window between when
+	// C becomes the active cycle and when we've flushed it to
+	// active.
+	future [3]memRecordCycle
+}
+
+// memRecordCycle
+type memRecordCycle struct {
+	allocs, frees           uintptr
+	alloc_bytes, free_bytes uintptr
+}
+
+// add accumulates b into a. It does not zero b.
+func (a *memRecordCycle) add(b *memRecordCycle) {
+	a.allocs += b.allocs
+	a.frees += b.frees
+	a.alloc_bytes += b.alloc_bytes
+	a.free_bytes += b.free_bytes
+}
+
+// A blockRecord is the bucket data for a bucket of type blockProfile,
+// which is used in blocking and mutex profiles.
+type blockRecord struct {
+	count  float64
+	cycles int64
+}
+
+var (
+	mbuckets atomic.UnsafePointer // *bucket, memory profile buckets
+	bbuckets atomic.UnsafePointer // *bucket, blocking profile buckets
+	xbuckets atomic.UnsafePointer // *bucket, mutex profile buckets
+	buckhash atomic.UnsafePointer // *buckhashArray
+
+	mProfCycle mProfCycleHolder
+)
+
+type buckhashArray [buckHashSize]atomic.UnsafePointer // *bucket
+
+const mProfCycleWrap = uint32(len(memRecord{}.future)) * (2 << 24)
+
+// mProfCycleHolder holds the global heap profile cycle number (wrapped at
+// mProfCycleWrap, stored starting at bit 1), and a flag (stored at bit 0) to
+// indicate whether future[cycle] in all buckets has been queued to flush into
+// the active profile.
+type mProfCycleHolder struct {
+	value atomic.Uint32
+}
+
+// read returns the current cycle count.
+func (c *mProfCycleHolder) read() (cycle uint32) {
+	v := c.value.Load()
+	cycle = v >> 1
+	return cycle
+}
+
+// setFlushed sets the flushed flag. It returns the current cycle count and the
+// previous value of the flushed flag.
+func (c *mProfCycleHolder) setFlushed() (cycle uint32, alreadyFlushed bool) {
+	for {
+		prev := c.value.Load()
+		cycle = prev >> 1
+		alreadyFlushed = (prev & 0x1) != 0
+		next := prev | 0x1
+		if c.value.CompareAndSwap(prev, next) {
+			return cycle, alreadyFlushed
+		}
+	}
+}
+
+// increment increases the cycle count by one, wrapping the value at
+// mProfCycleWrap. It clears the flushed flag.
+func (c *mProfCycleHolder) increment() {
+	// We explicitly wrap mProfCycle rather than depending on
+	// uint wraparound because the memRecord.future ring does not
+	// itself wrap at a power of two.
+	for {
+		prev := c.value.Load()
+		cycle := prev >> 1
+		cycle = (cycle + 1) % mProfCycleWrap
+		next := cycle << 1
+		if c.value.CompareAndSwap(prev, next) {
+			break
+		}
+	}
+}
+
+// newBucket allocates a bucket with the given type and number of stack entries.
+func newBucket(typ bucketType, nstk int) *bucket {
+	size := unsafe.Sizeof(bucket{}) + uintptr(nstk)*unsafe.Sizeof(uintptr(0))
+	switch typ {
+	default:
+		throw("invalid profile bucket type")
+	case memProfile:
+		size += unsafe.Sizeof(memRecord{})
+	case blockProfile, mutexProfile:
+		size += unsafe.Sizeof(blockRecord{})
+	}
+
+	b := (*bucket)(persistentalloc(size, 0, &memstats.buckhash_sys))
+	b.typ = typ
+	b.nstk = uintptr(nstk)
+	return b
+}
+
+// stk returns the slice in b holding the stack.
+func (b *bucket) stk() []uintptr {
+	stk := (*[maxStack]uintptr)(add(unsafe.Pointer(b), unsafe.Sizeof(*b)))
+	return stk[:b.nstk:b.nstk]
+}
+
+// mp returns the memRecord associated with the memProfile bucket b.
+func (b *bucket) mp() *memRecord {
+	if b.typ != memProfile {
+		throw("bad use of bucket.mp")
+	}
+	data := add(unsafe.Pointer(b), unsafe.Sizeof(*b)+b.nstk*unsafe.Sizeof(uintptr(0)))
+	return (*memRecord)(data)
+}
+
+// bp returns the blockRecord associated with the blockProfile bucket b.
+func (b *bucket) bp() *blockRecord {
+	if b.typ != blockProfile && b.typ != mutexProfile {
+		throw("bad use of bucket.bp")
+	}
+	data := add(unsafe.Pointer(b), unsafe.Sizeof(*b)+b.nstk*unsafe.Sizeof(uintptr(0)))
+	return (*blockRecord)(data)
+}
+
+// Return the bucket for stk[0:nstk], allocating new bucket if needed.
+func stkbucket(typ bucketType, size uintptr, stk []uintptr, alloc bool) *bucket {
+	bh := (*buckhashArray)(buckhash.Load())
+	if bh == nil {
+		lock(&profInsertLock)
+		// check again under the lock
+		bh = (*buckhashArray)(buckhash.Load())
+		if bh == nil {
+			bh = (*buckhashArray)(sysAlloc(unsafe.Sizeof(buckhashArray{}), &memstats.buckhash_sys))
+			if bh == nil {
+				throw("runtime: cannot allocate memory")
+			}
+			buckhash.StoreNoWB(unsafe.Pointer(bh))
+		}
+		unlock(&profInsertLock)
+	}
+
+	// Hash stack.
+	var h uintptr
+	for _, pc := range stk {
+		h += pc
+		h += h << 10
+		h ^= h >> 6
+	}
+	// hash in size
+	h += size
+	h += h << 10
+	h ^= h >> 6
+	// finalize
+	h += h << 3
+	h ^= h >> 11
+
+	i := int(h % buckHashSize)
+	// first check optimistically, without the lock
+	for b := (*bucket)(bh[i].Load()); b != nil; b = b.next {
+		if b.typ == typ && b.hash == h && b.size == size && eqslice(b.stk(), stk) {
+			return b
+		}
+	}
+
+	if !alloc {
+		return nil
+	}
+
+	lock(&profInsertLock)
+	// check again under the insertion lock
+	for b := (*bucket)(bh[i].Load()); b != nil; b = b.next {
+		if b.typ == typ && b.hash == h && b.size == size && eqslice(b.stk(), stk) {
+			unlock(&profInsertLock)
+			return b
+		}
+	}
+
+	// Create new bucket.
+	b := newBucket(typ, len(stk))
+	copy(b.stk(), stk)
+	b.hash = h
+	b.size = size
+
+	var allnext *atomic.UnsafePointer
+	if typ == memProfile {
+		allnext = &mbuckets
+	} else if typ == mutexProfile {
+		allnext = &xbuckets
+	} else {
+		allnext = &bbuckets
+	}
+
+	b.next = (*bucket)(bh[i].Load())
+	b.allnext = (*bucket)(allnext.Load())
+
+	bh[i].StoreNoWB(unsafe.Pointer(b))
+	allnext.StoreNoWB(unsafe.Pointer(b))
+
+	unlock(&profInsertLock)
+	return b
+}
+
+func eqslice(x, y []uintptr) bool {
+	if len(x) != len(y) {
+		return false
+	}
+	for i, xi := range x {
+		if xi != y[i] {
+			return false
+		}
+	}
+	return true
+}
+
+// mProf_NextCycle publishes the next heap profile cycle and creates a
+// fresh heap profile cycle. This operation is fast and can be done
+// during STW. The caller must call mProf_Flush before calling
+// mProf_NextCycle again.
+//
+// This is called by mark termination during STW so allocations and
+// frees after the world is started again count towards a new heap
+// profiling cycle.
+func mProf_NextCycle() {
+	mProfCycle.increment()
+}
+
+// mProf_Flush flushes the events from the current heap profiling
+// cycle into the active profile. After this it is safe to start a new
+// heap profiling cycle with mProf_NextCycle.
+//
+// This is called by GC after mark termination starts the world. In
+// contrast with mProf_NextCycle, this is somewhat expensive, but safe
+// to do concurrently.
+func mProf_Flush() {
+	cycle, alreadyFlushed := mProfCycle.setFlushed()
+	if alreadyFlushed {
+		return
+	}
+
+	index := cycle % uint32(len(memRecord{}.future))
+	lock(&profMemActiveLock)
+	lock(&profMemFutureLock[index])
+	mProf_FlushLocked(index)
+	unlock(&profMemFutureLock[index])
+	unlock(&profMemActiveLock)
+}
+
+// mProf_FlushLocked flushes the events from the heap profiling cycle at index
+// into the active profile. The caller must hold the lock for the active profile
+// (profMemActiveLock) and for the profiling cycle at index
+// (profMemFutureLock[index]).
+func mProf_FlushLocked(index uint32) {
+	assertLockHeld(&profMemActiveLock)
+	assertLockHeld(&profMemFutureLock[index])
+	head := (*bucket)(mbuckets.Load())
+	for b := head; b != nil; b = b.allnext {
+		mp := b.mp()
+
+		// Flush cycle C into the published profile and clear
+		// it for reuse.
+		mpc := &mp.future[index]
+		mp.active.add(mpc)
+		*mpc = memRecordCycle{}
+	}
+}
+
+// mProf_PostSweep records that all sweep frees for this GC cycle have
+// completed. This has the effect of publishing the heap profile
+// snapshot as of the last mark termination without advancing the heap
+// profile cycle.
+func mProf_PostSweep() {
+	// Flush cycle C+1 to the active profile so everything as of
+	// the last mark termination becomes visible. *Don't* advance
+	// the cycle, since we're still accumulating allocs in cycle
+	// C+2, which have to become C+1 in the next mark termination
+	// and so on.
+	cycle := mProfCycle.read() + 1
+
+	index := cycle % uint32(len(memRecord{}.future))
+	lock(&profMemActiveLock)
+	lock(&profMemFutureLock[index])
+	mProf_FlushLocked(index)
+	unlock(&profMemFutureLock[index])
+	unlock(&profMemActiveLock)
+}
+
+// Called by malloc to record a profiled block.
+func mProf_Malloc(p unsafe.Pointer, size uintptr) {
+	var stk [maxStack]uintptr
+	nstk := callers(4, stk[:])
+
+	index := (mProfCycle.read() + 2) % uint32(len(memRecord{}.future))
+
+	b := stkbucket(memProfile, size, stk[:nstk], true)
+	mp := b.mp()
+	mpc := &mp.future[index]
+
+	lock(&profMemFutureLock[index])
+	mpc.allocs++
+	mpc.alloc_bytes += size
+	unlock(&profMemFutureLock[index])
+
+	// Setprofilebucket locks a bunch of other mutexes, so we call it outside of
+	// the profiler locks. This reduces potential contention and chances of
+	// deadlocks. Since the object must be alive during the call to
+	// mProf_Malloc, it's fine to do this non-atomically.
+	systemstack(func() {
+		setprofilebucket(p, b)
+	})
+}
+
+// Called when freeing a profiled block.
+func mProf_Free(b *bucket, size uintptr) {
+	index := (mProfCycle.read() + 1) % uint32(len(memRecord{}.future))
+
+	mp := b.mp()
+	mpc := &mp.future[index]
+
+	lock(&profMemFutureLock[index])
+	mpc.frees++
+	mpc.free_bytes += size
+	unlock(&profMemFutureLock[index])
+}
+
+var blockprofilerate uint64 // in CPU ticks
+
+// SetBlockProfileRate controls the fraction of goroutine blocking events
+// that are reported in the blocking profile. The profiler aims to sample
+// an average of one blocking event per rate nanoseconds spent blocked.
+//
+// To include every blocking event in the profile, pass rate = 1.
+// To turn off profiling entirely, pass rate <= 0.
+func SetBlockProfileRate(rate int) {
+	var r int64
+	if rate <= 0 {
+		r = 0 // disable profiling
+	} else if rate == 1 {
+		r = 1 // profile everything
+	} else {
+		// convert ns to cycles, use float64 to prevent overflow during multiplication
+		r = int64(float64(rate) * float64(tickspersecond()) / (1000 * 1000 * 1000))
+		if r == 0 {
+			r = 1
+		}
+	}
+
+	atomic.Store64(&blockprofilerate, uint64(r))
+}
+
+func blockevent(cycles int64, skip int) {
+	if cycles <= 0 {
+		cycles = 1
+	}
+
+	rate := int64(atomic.Load64(&blockprofilerate))
+	if blocksampled(cycles, rate) {
+		saveblockevent(cycles, rate, skip+1, blockProfile)
+	}
+}
+
+// blocksampled returns true for all events where cycles >= rate. Shorter
+// events have a cycles/rate random chance of returning true.
+func blocksampled(cycles, rate int64) bool {
+	if rate <= 0 || (rate > cycles && int64(fastrand())%rate > cycles) {
+		return false
+	}
+	return true
+}
+
+func saveblockevent(cycles, rate int64, skip int, which bucketType) {
+	gp := getg()
+	var nstk int
+	var stk [maxStack]uintptr
+	if gp.m.curg == nil || gp.m.curg == gp {
+		nstk = callers(skip, stk[:])
+	} else {
+		nstk = gcallers(gp.m.curg, skip, stk[:])
+	}
+	b := stkbucket(which, 0, stk[:nstk], true)
+	bp := b.bp()
+
+	lock(&profBlockLock)
+	// We want to up-scale the count and cycles according to the
+	// probability that the event was sampled. For block profile events,
+	// the sample probability is 1 if cycles >= rate, and cycles / rate
+	// otherwise. For mutex profile events, the sample probability is 1 / rate.
+	// We scale the events by 1 / (probability the event was sampled).
+	if which == blockProfile && cycles < rate {
+		// Remove sampling bias, see discussion on http://golang.org/cl/299991.
+		bp.count += float64(rate) / float64(cycles)
+		bp.cycles += rate
+	} else if which == mutexProfile {
+		bp.count += float64(rate)
+		bp.cycles += rate * cycles
+	} else {
+		bp.count++
+		bp.cycles += cycles
+	}
+	unlock(&profBlockLock)
+}
+
+var mutexprofilerate uint64 // fraction sampled
+
+// SetMutexProfileFraction controls the fraction of mutex contention events
+// that are reported in the mutex profile. On average 1/rate events are
+// reported. The previous rate is returned.
+//
+// To turn off profiling entirely, pass rate 0.
+// To just read the current rate, pass rate < 0.
+// (For n>1 the details of sampling may change.)
+func SetMutexProfileFraction(rate int) int {
+	if rate < 0 {
+		return int(mutexprofilerate)
+	}
+	old := mutexprofilerate
+	atomic.Store64(&mutexprofilerate, uint64(rate))
+	return int(old)
+}
+
+//go:linkname mutexevent sync.event
+func mutexevent(cycles int64, skip int) {
+	if cycles < 0 {
+		cycles = 0
+	}
+	rate := int64(atomic.Load64(&mutexprofilerate))
+	// TODO(pjw): measure impact of always calling fastrand vs using something
+	// like malloc.go:nextSample()
+	if rate > 0 && int64(fastrand())%rate == 0 {
+		saveblockevent(cycles, rate, skip+1, mutexProfile)
+	}
+}
+
+// Go interface to profile data.
+
+// A StackRecord describes a single execution stack.
+type StackRecord struct {
+	Stack0 [32]uintptr // stack trace for this record; ends at first 0 entry
+}
+
+// Stack returns the stack trace associated with the record,
+// a prefix of r.Stack0.
+func (r *StackRecord) Stack() []uintptr {
+	for i, v := range r.Stack0 {
+		if v == 0 {
+			return r.Stack0[0:i]
+		}
+	}
+	return r.Stack0[0:]
+}
+
+// MemProfileRate controls the fraction of memory allocations
+// that are recorded and reported in the memory profile.
+// The profiler aims to sample an average of
+// one allocation per MemProfileRate bytes allocated.
+//
+// To include every allocated block in the profile, set MemProfileRate to 1.
+// To turn off profiling entirely, set MemProfileRate to 0.
+//
+// The tools that process the memory profiles assume that the
+// profile rate is constant across the lifetime of the program
+// and equal to the current value. Programs that change the
+// memory profiling rate should do so just once, as early as
+// possible in the execution of the program (for example,
+// at the beginning of main).
+var MemProfileRate int = 512 * 1024
+
+// disableMemoryProfiling is set by the linker if runtime.MemProfile
+// is not used and the link type guarantees nobody else could use it
+// elsewhere.
+var disableMemoryProfiling bool
+
+// A MemProfileRecord describes the live objects allocated
+// by a particular call sequence (stack trace).
+type MemProfileRecord struct {
+	AllocBytes, FreeBytes     int64       // number of bytes allocated, freed
+	AllocObjects, FreeObjects int64       // number of objects allocated, freed
+	Stack0                    [32]uintptr // stack trace for this record; ends at first 0 entry
+}
+
+// InUseBytes returns the number of bytes in use (AllocBytes - FreeBytes).
+func (r *MemProfileRecord) InUseBytes() int64 { return r.AllocBytes - r.FreeBytes }
+
+// InUseObjects returns the number of objects in use (AllocObjects - FreeObjects).
+func (r *MemProfileRecord) InUseObjects() int64 {
+	return r.AllocObjects - r.FreeObjects
+}
+
+// Stack returns the stack trace associated with the record,
+// a prefix of r.Stack0.
+func (r *MemProfileRecord) Stack() []uintptr {
+	for i, v := range r.Stack0 {
+		if v == 0 {
+			return r.Stack0[0:i]
+		}
+	}
+	return r.Stack0[0:]
+}
+
+// MemProfile returns a profile of memory allocated and freed per allocation
+// site.
+//
+// MemProfile returns n, the number of records in the current memory profile.
+// If len(p) >= n, MemProfile copies the profile into p and returns n, true.
+// If len(p) < n, MemProfile does not change p and returns n, false.
+//
+// If inuseZero is true, the profile includes allocation records
+// where r.AllocBytes > 0 but r.AllocBytes == r.FreeBytes.
+// These are sites where memory was allocated, but it has all
+// been released back to the runtime.
+//
+// The returned profile may be up to two garbage collection cycles old.
+// This is to avoid skewing the profile toward allocations; because
+// allocations happen in real time but frees are delayed until the garbage
+// collector performs sweeping, the profile only accounts for allocations
+// that have had a chance to be freed by the garbage collector.
+//
+// Most clients should use the runtime/pprof package or
+// the testing package's -test.memprofile flag instead
+// of calling MemProfile directly.
+func MemProfile(p []MemProfileRecord, inuseZero bool) (n int, ok bool) {
+	cycle := mProfCycle.read()
+	// If we're between mProf_NextCycle and mProf_Flush, take care
+	// of flushing to the active profile so we only have to look
+	// at the active profile below.
+	index := cycle % uint32(len(memRecord{}.future))
+	lock(&profMemActiveLock)
+	lock(&profMemFutureLock[index])
+	mProf_FlushLocked(index)
+	unlock(&profMemFutureLock[index])
+	clear := true
+	head := (*bucket)(mbuckets.Load())
+	for b := head; b != nil; b = b.allnext {
+		mp := b.mp()
+		if inuseZero || mp.active.alloc_bytes != mp.active.free_bytes {
+			n++
+		}
+		if mp.active.allocs != 0 || mp.active.frees != 0 {
+			clear = false
+		}
+	}
+	if clear {
+		// Absolutely no data, suggesting that a garbage collection
+		// has not yet happened. In order to allow profiling when
+		// garbage collection is disabled from the beginning of execution,
+		// accumulate all of the cycles, and recount buckets.
+		n = 0
+		for b := head; b != nil; b = b.allnext {
+			mp := b.mp()
+			for c := range mp.future {
+				lock(&profMemFutureLock[c])
+				mp.active.add(&mp.future[c])
+				mp.future[c] = memRecordCycle{}
+				unlock(&profMemFutureLock[c])
+			}
+			if inuseZero || mp.active.alloc_bytes != mp.active.free_bytes {
+				n++
+			}
+		}
+	}
+	if n <= len(p) {
+		ok = true
+		idx := 0
+		for b := head; b != nil; b = b.allnext {
+			mp := b.mp()
+			if inuseZero || mp.active.alloc_bytes != mp.active.free_bytes {
+				record(&p[idx], b)
+				idx++
+			}
+		}
+	}
+	unlock(&profMemActiveLock)
+	return
+}
+
+// Write b's data to r.
+func record(r *MemProfileRecord, b *bucket) {
+	mp := b.mp()
+	r.AllocBytes = int64(mp.active.alloc_bytes)
+	r.FreeBytes = int64(mp.active.free_bytes)
+	r.AllocObjects = int64(mp.active.allocs)
+	r.FreeObjects = int64(mp.active.frees)
+	if raceenabled {
+		racewriterangepc(unsafe.Pointer(&r.Stack0[0]), unsafe.Sizeof(r.Stack0), getcallerpc(), abi.FuncPCABIInternal(MemProfile))
+	}
+	if msanenabled {
+		msanwrite(unsafe.Pointer(&r.Stack0[0]), unsafe.Sizeof(r.Stack0))
+	}
+	if asanenabled {
+		asanwrite(unsafe.Pointer(&r.Stack0[0]), unsafe.Sizeof(r.Stack0))
+	}
+	copy(r.Stack0[:], b.stk())
+	for i := int(b.nstk); i < len(r.Stack0); i++ {
+		r.Stack0[i] = 0
+	}
+}
+
+func iterate_memprof(fn func(*bucket, uintptr, *uintptr, uintptr, uintptr, uintptr)) {
+	lock(&profMemActiveLock)
+	head := (*bucket)(mbuckets.Load())
+	for b := head; b != nil; b = b.allnext {
+		mp := b.mp()
+		fn(b, b.nstk, &b.stk()[0], b.size, mp.active.allocs, mp.active.frees)
+	}
+	unlock(&profMemActiveLock)
+}
+
+// BlockProfileRecord describes blocking events originated
+// at a particular call sequence (stack trace).
+type BlockProfileRecord struct {
+	Count  int64
+	Cycles int64
+	StackRecord
+}
+
+// BlockProfile returns n, the number of records in the current blocking profile.
+// If len(p) >= n, BlockProfile copies the profile into p and returns n, true.
+// If len(p) < n, BlockProfile does not change p and returns n, false.
+//
+// Most clients should use the runtime/pprof package or
+// the testing package's -test.blockprofile flag instead
+// of calling BlockProfile directly.
+func BlockProfile(p []BlockProfileRecord) (n int, ok bool) {
+	lock(&profBlockLock)
+	head := (*bucket)(bbuckets.Load())
+	for b := head; b != nil; b = b.allnext {
+		n++
+	}
+	if n <= len(p) {
+		ok = true
+		for b := head; b != nil; b = b.allnext {
+			bp := b.bp()
+			r := &p[0]
+			r.Count = int64(bp.count)
+			// Prevent callers from having to worry about division by zero errors.
+			// See discussion on http://golang.org/cl/299991.
+			if r.Count == 0 {
+				r.Count = 1
+			}
+			r.Cycles = bp.cycles
+			if raceenabled {
+				racewriterangepc(unsafe.Pointer(&r.Stack0[0]), unsafe.Sizeof(r.Stack0), getcallerpc(), abi.FuncPCABIInternal(BlockProfile))
+			}
+			if msanenabled {
+				msanwrite(unsafe.Pointer(&r.Stack0[0]), unsafe.Sizeof(r.Stack0))
+			}
+			if asanenabled {
+				asanwrite(unsafe.Pointer(&r.Stack0[0]), unsafe.Sizeof(r.Stack0))
+			}
+			i := copy(r.Stack0[:], b.stk())
+			for ; i < len(r.Stack0); i++ {
+				r.Stack0[i] = 0
+			}
+			p = p[1:]
+		}
+	}
+	unlock(&profBlockLock)
+	return
+}
+
+// MutexProfile returns n, the number of records in the current mutex profile.
+// If len(p) >= n, MutexProfile copies the profile into p and returns n, true.
+// Otherwise, MutexProfile does not change p, and returns n, false.
+//
+// Most clients should use the runtime/pprof package
+// instead of calling MutexProfile directly.
+func MutexProfile(p []BlockProfileRecord) (n int, ok bool) {
+	lock(&profBlockLock)
+	head := (*bucket)(xbuckets.Load())
+	for b := head; b != nil; b = b.allnext {
+		n++
+	}
+	if n <= len(p) {
+		ok = true
+		for b := head; b != nil; b = b.allnext {
+			bp := b.bp()
+			r := &p[0]
+			r.Count = int64(bp.count)
+			r.Cycles = bp.cycles
+			i := copy(r.Stack0[:], b.stk())
+			for ; i < len(r.Stack0); i++ {
+				r.Stack0[i] = 0
+			}
+			p = p[1:]
+		}
+	}
+	unlock(&profBlockLock)
+	return
+}
+
+// ThreadCreateProfile returns n, the number of records in the thread creation profile.
+// If len(p) >= n, ThreadCreateProfile copies the profile into p and returns n, true.
+// If len(p) < n, ThreadCreateProfile does not change p and returns n, false.
+//
+// Most clients should use the runtime/pprof package instead
+// of calling ThreadCreateProfile directly.
+func ThreadCreateProfile(p []StackRecord) (n int, ok bool) {
+	first := (*m)(atomic.Loadp(unsafe.Pointer(&allm)))
+	for mp := first; mp != nil; mp = mp.alllink {
+		n++
+	}
+	if n <= len(p) {
+		ok = true
+		i := 0
+		for mp := first; mp != nil; mp = mp.alllink {
+			p[i].Stack0 = mp.createstack
+			i++
+		}
+	}
+	return
+}
+
+//go:linkname runtime_goroutineProfileWithLabels runtime/pprof.runtime_goroutineProfileWithLabels
+func runtime_goroutineProfileWithLabels(p []StackRecord, labels []unsafe.Pointer) (n int, ok bool) {
+	return goroutineProfileWithLabels(p, labels)
+}
+
+// labels may be nil. If labels is non-nil, it must have the same length as p.
+func goroutineProfileWithLabels(p []StackRecord, labels []unsafe.Pointer) (n int, ok bool) {
+	if labels != nil && len(labels) != len(p) {
+		labels = nil
+	}
+
+	return goroutineProfileWithLabelsConcurrent(p, labels)
+}
+
+var goroutineProfile = struct {
+	sema    uint32
+	active  bool
+	offset  atomic.Int64
+	records []StackRecord
+	labels  []unsafe.Pointer
+}{
+	sema: 1,
+}
+
+// goroutineProfileState indicates the status of a goroutine's stack for the
+// current in-progress goroutine profile. Goroutines' stacks are initially
+// "Absent" from the profile, and end up "Satisfied" by the time the profile is
+// complete. While a goroutine's stack is being captured, its
+// goroutineProfileState will be "InProgress" and it will not be able to run
+// until the capture completes and the state moves to "Satisfied".
+//
+// Some goroutines (the finalizer goroutine, which at various times can be
+// either a "system" or a "user" goroutine, and the goroutine that is
+// coordinating the profile, any goroutines created during the profile) move
+// directly to the "Satisfied" state.
+type goroutineProfileState uint32
+
+const (
+	goroutineProfileAbsent goroutineProfileState = iota
+	goroutineProfileInProgress
+	goroutineProfileSatisfied
+)
+
+type goroutineProfileStateHolder atomic.Uint32
+
+func (p *goroutineProfileStateHolder) Load() goroutineProfileState {
+	return goroutineProfileState((*atomic.Uint32)(p).Load())
+}
+
+func (p *goroutineProfileStateHolder) Store(value goroutineProfileState) {
+	(*atomic.Uint32)(p).Store(uint32(value))
+}
+
+func (p *goroutineProfileStateHolder) CompareAndSwap(old, new goroutineProfileState) bool {
+	return (*atomic.Uint32)(p).CompareAndSwap(uint32(old), uint32(new))
+}
+
+func goroutineProfileWithLabelsConcurrent(p []StackRecord, labels []unsafe.Pointer) (n int, ok bool) {
+	semacquire(&goroutineProfile.sema)
+
+	ourg := getg()
+
+	stopTheWorld(stwGoroutineProfile)
+	// Using gcount while the world is stopped should give us a consistent view
+	// of the number of live goroutines, minus the number of goroutines that are
+	// alive and permanently marked as "system". But to make this count agree
+	// with what we'd get from isSystemGoroutine, we need special handling for
+	// goroutines that can vary between user and system to ensure that the count
+	// doesn't change during the collection. So, check the finalizer goroutine
+	// in particular.
+	n = int(gcount())
+	if fingStatus.Load()&fingRunningFinalizer != 0 {
+		n++
+	}
+
+	if n > len(p) {
+		// There's not enough space in p to store the whole profile, so (per the
+		// contract of runtime.GoroutineProfile) we're not allowed to write to p
+		// at all and must return n, false.
+		startTheWorld()
+		semrelease(&goroutineProfile.sema)
+		return n, false
+	}
+
+	// Save current goroutine.
+	sp := getcallersp()
+	pc := getcallerpc()
+	systemstack(func() {
+		saveg(pc, sp, ourg, &p[0])
+	})
+	ourg.goroutineProfiled.Store(goroutineProfileSatisfied)
+	goroutineProfile.offset.Store(1)
+
+	// Prepare for all other goroutines to enter the profile. Aside from ourg,
+	// every goroutine struct in the allgs list has its goroutineProfiled field
+	// cleared. Any goroutine created from this point on (while
+	// goroutineProfile.active is set) will start with its goroutineProfiled
+	// field set to goroutineProfileSatisfied.
+	goroutineProfile.active = true
+	goroutineProfile.records = p
+	goroutineProfile.labels = labels
+	// The finalizer goroutine needs special handling because it can vary over
+	// time between being a user goroutine (eligible for this profile) and a
+	// system goroutine (to be excluded). Pick one before restarting the world.
+	if fing != nil {
+		fing.goroutineProfiled.Store(goroutineProfileSatisfied)
+		if readgstatus(fing) != _Gdead && !isSystemGoroutine(fing, false) {
+			doRecordGoroutineProfile(fing)
+		}
+	}
+	startTheWorld()
+
+	// Visit each goroutine that existed as of the startTheWorld call above.
+	//
+	// New goroutines may not be in this list, but we didn't want to know about
+	// them anyway. If they do appear in this list (via reusing a dead goroutine
+	// struct, or racing to launch between the world restarting and us getting
+	// the list), they will already have their goroutineProfiled field set to
+	// goroutineProfileSatisfied before their state transitions out of _Gdead.
+	//
+	// Any goroutine that the scheduler tries to execute concurrently with this
+	// call will start by adding itself to the profile (before the act of
+	// executing can cause any changes in its stack).
+	forEachGRace(func(gp1 *g) {
+		tryRecordGoroutineProfile(gp1, Gosched)
+	})
+
+	stopTheWorld(stwGoroutineProfileCleanup)
+	endOffset := goroutineProfile.offset.Swap(0)
+	goroutineProfile.active = false
+	goroutineProfile.records = nil
+	goroutineProfile.labels = nil
+	startTheWorld()
+
+	// Restore the invariant that every goroutine struct in allgs has its
+	// goroutineProfiled field cleared.
+	forEachGRace(func(gp1 *g) {
+		gp1.goroutineProfiled.Store(goroutineProfileAbsent)
+	})
+
+	if raceenabled {
+		raceacquire(unsafe.Pointer(&labelSync))
+	}
+
+	if n != int(endOffset) {
+		// It's a big surprise that the number of goroutines changed while we
+		// were collecting the profile. But probably better to return a
+		// truncated profile than to crash the whole process.
+		//
+		// For instance, needm moves a goroutine out of the _Gdead state and so
+		// might be able to change the goroutine count without interacting with
+		// the scheduler. For code like that, the race windows are small and the
+		// combination of features is uncommon, so it's hard to be (and remain)
+		// sure we've caught them all.
+	}
+
+	semrelease(&goroutineProfile.sema)
+	return n, true
+}
+
+// tryRecordGoroutineProfileWB asserts that write barriers are allowed and calls
+// tryRecordGoroutineProfile.
+//
+//go:yeswritebarrierrec
+func tryRecordGoroutineProfileWB(gp1 *g) {
+	if getg().m.p.ptr() == nil {
+		throw("no P available, write barriers are forbidden")
+	}
+	tryRecordGoroutineProfile(gp1, osyield)
+}
+
+// tryRecordGoroutineProfile ensures that gp1 has the appropriate representation
+// in the current goroutine profile: either that it should not be profiled, or
+// that a snapshot of its call stack and labels are now in the profile.
+func tryRecordGoroutineProfile(gp1 *g, yield func()) {
+	if readgstatus(gp1) == _Gdead {
+		// Dead goroutines should not appear in the profile. Goroutines that
+		// start while profile collection is active will get goroutineProfiled
+		// set to goroutineProfileSatisfied before transitioning out of _Gdead,
+		// so here we check _Gdead first.
+		return
+	}
+	if isSystemGoroutine(gp1, true) {
+		// System goroutines should not appear in the profile. (The finalizer
+		// goroutine is marked as "already profiled".)
+		return
+	}
+
+	for {
+		prev := gp1.goroutineProfiled.Load()
+		if prev == goroutineProfileSatisfied {
+			// This goroutine is already in the profile (or is new since the
+			// start of collection, so shouldn't appear in the profile).
+			break
+		}
+		if prev == goroutineProfileInProgress {
+			// Something else is adding gp1 to the goroutine profile right now.
+			// Give that a moment to finish.
+			yield()
+			continue
+		}
+
+		// While we have gp1.goroutineProfiled set to
+		// goroutineProfileInProgress, gp1 may appear _Grunnable but will not
+		// actually be able to run. Disable preemption for ourselves, to make
+		// sure we finish profiling gp1 right away instead of leaving it stuck
+		// in this limbo.
+		mp := acquirem()
+		if gp1.goroutineProfiled.CompareAndSwap(goroutineProfileAbsent, goroutineProfileInProgress) {
+			doRecordGoroutineProfile(gp1)
+			gp1.goroutineProfiled.Store(goroutineProfileSatisfied)
+		}
+		releasem(mp)
+	}
+}
+
+// doRecordGoroutineProfile writes gp1's call stack and labels to an in-progress
+// goroutine profile. Preemption is disabled.
+//
+// This may be called via tryRecordGoroutineProfile in two ways: by the
+// goroutine that is coordinating the goroutine profile (running on its own
+// stack), or from the scheduler in preparation to execute gp1 (running on the
+// system stack).
+func doRecordGoroutineProfile(gp1 *g) {
+	if readgstatus(gp1) == _Grunning {
+		print("doRecordGoroutineProfile gp1=", gp1.goid, "\n")
+		throw("cannot read stack of running goroutine")
+	}
+
+	offset := int(goroutineProfile.offset.Add(1)) - 1
+
+	if offset >= len(goroutineProfile.records) {
+		// Should be impossible, but better to return a truncated profile than
+		// to crash the entire process at this point. Instead, deal with it in
+		// goroutineProfileWithLabelsConcurrent where we have more context.
+		return
+	}
+
+	// saveg calls gentraceback, which may call cgo traceback functions. When
+	// called from the scheduler, this is on the system stack already so
+	// traceback.go:cgoContextPCs will avoid calling back into the scheduler.
+	//
+	// When called from the goroutine coordinating the profile, we still have
+	// set gp1.goroutineProfiled to goroutineProfileInProgress and so are still
+	// preventing it from being truly _Grunnable. So we'll use the system stack
+	// to avoid schedule delays.
+	systemstack(func() { saveg(^uintptr(0), ^uintptr(0), gp1, &goroutineProfile.records[offset]) })
+
+	if goroutineProfile.labels != nil {
+		goroutineProfile.labels[offset] = gp1.labels
+	}
+}
+
+func goroutineProfileWithLabelsSync(p []StackRecord, labels []unsafe.Pointer) (n int, ok bool) {
+	gp := getg()
+
+	isOK := func(gp1 *g) bool {
+		// Checking isSystemGoroutine here makes GoroutineProfile
+		// consistent with both NumGoroutine and Stack.
+		return gp1 != gp && readgstatus(gp1) != _Gdead && !isSystemGoroutine(gp1, false)
+	}
+
+	stopTheWorld(stwGoroutineProfile)
+
+	// World is stopped, no locking required.
+	n = 1
+	forEachGRace(func(gp1 *g) {
+		if isOK(gp1) {
+			n++
+		}
+	})
+
+	if n <= len(p) {
+		ok = true
+		r, lbl := p, labels
+
+		// Save current goroutine.
+		sp := getcallersp()
+		pc := getcallerpc()
+		systemstack(func() {
+			saveg(pc, sp, gp, &r[0])
+		})
+		r = r[1:]
+
+		// If we have a place to put our goroutine labelmap, insert it there.
+		if labels != nil {
+			lbl[0] = gp.labels
+			lbl = lbl[1:]
+		}
+
+		// Save other goroutines.
+		forEachGRace(func(gp1 *g) {
+			if !isOK(gp1) {
+				return
+			}
+
+			if len(r) == 0 {
+				// Should be impossible, but better to return a
+				// truncated profile than to crash the entire process.
+				return
+			}
+			// saveg calls gentraceback, which may call cgo traceback functions.
+			// The world is stopped, so it cannot use cgocall (which will be
+			// blocked at exitsyscall). Do it on the system stack so it won't
+			// call into the schedular (see traceback.go:cgoContextPCs).
+			systemstack(func() { saveg(^uintptr(0), ^uintptr(0), gp1, &r[0]) })
+			if labels != nil {
+				lbl[0] = gp1.labels
+				lbl = lbl[1:]
+			}
+			r = r[1:]
+		})
+	}
+
+	if raceenabled {
+		raceacquire(unsafe.Pointer(&labelSync))
+	}
+
+	startTheWorld()
+	return n, ok
+}
+
+// GoroutineProfile returns n, the number of records in the active goroutine stack profile.
+// If len(p) >= n, GoroutineProfile copies the profile into p and returns n, true.
+// If len(p) < n, GoroutineProfile does not change p and returns n, false.
+//
+// Most clients should use the runtime/pprof package instead
+// of calling GoroutineProfile directly.
+func GoroutineProfile(p []StackRecord) (n int, ok bool) {
+
+	return goroutineProfileWithLabels(p, nil)
+}
+
+func saveg(pc, sp uintptr, gp *g, r *StackRecord) {
+	var u unwinder
+	u.initAt(pc, sp, 0, gp, unwindSilentErrors)
+	n := tracebackPCs(&u, 0, r.Stack0[:])
+	if n < len(r.Stack0) {
+		r.Stack0[n] = 0
+	}
+}
+
+// Stack formats a stack trace of the calling goroutine into buf
+// and returns the number of bytes written to buf.
+// If all is true, Stack formats stack traces of all other goroutines
+// into buf after the trace for the current goroutine.
+func Stack(buf []byte, all bool) int {
+	if all {
+		stopTheWorld(stwAllGoroutinesStack)
+	}
+
+	n := 0
+	if len(buf) > 0 {
+		gp := getg()
+		sp := getcallersp()
+		pc := getcallerpc()
+		systemstack(func() {
+			g0 := getg()
+			// Force traceback=1 to override GOTRACEBACK setting,
+			// so that Stack's results are consistent.
+			// GOTRACEBACK is only about crash dumps.
+			g0.m.traceback = 1
+			g0.writebuf = buf[0:0:len(buf)]
+			goroutineheader(gp)
+			traceback(pc, sp, 0, gp)
+			if all {
+				tracebackothers(gp)
+			}
+			g0.m.traceback = 0
+			n = len(g0.writebuf)
+			g0.writebuf = nil
+		})
+	}
+
+	if all {
+		startTheWorld()
+	}
+	return n
+}
+
+// Tracing of alloc/free/gc.
+
+var tracelock mutex
+
+func tracealloc(p unsafe.Pointer, size uintptr, typ *_type) {
+	lock(&tracelock)
+	gp := getg()
+	gp.m.traceback = 2
+	if typ == nil {
+		print("tracealloc(", p, ", ", hex(size), ")\n")
+	} else {
+		print("tracealloc(", p, ", ", hex(size), ", ", toRType(typ).string(), ")\n")
+	}
+	if gp.m.curg == nil || gp == gp.m.curg {
+		goroutineheader(gp)
+		pc := getcallerpc()
+		sp := getcallersp()
+		systemstack(func() {
+			traceback(pc, sp, 0, gp)
+		})
+	} else {
+		goroutineheader(gp.m.curg)
+		traceback(^uintptr(0), ^uintptr(0), 0, gp.m.curg)
+	}
+	print("\n")
+	gp.m.traceback = 0
+	unlock(&tracelock)
+}
+
+func tracefree(p unsafe.Pointer, size uintptr) {
+	lock(&tracelock)
+	gp := getg()
+	gp.m.traceback = 2
+	print("tracefree(", p, ", ", hex(size), ")\n")
+	goroutineheader(gp)
+	pc := getcallerpc()
+	sp := getcallersp()
+	systemstack(func() {
+		traceback(pc, sp, 0, gp)
+	})
+	print("\n")
+	gp.m.traceback = 0
+	unlock(&tracelock)
+}
+
+func tracegc() {
+	lock(&tracelock)
+	gp := getg()
+	gp.m.traceback = 2
+	print("tracegc()\n")
+	// running on m->g0 stack; show all non-g0 goroutines
+	tracebackothers(gp)
+	print("end tracegc\n")
+	print("\n")
+	gp.m.traceback = 0
+	unlock(&tracelock)
+}