1 files changed, 0 insertions, 176 deletions
diff --git a/libgo/go/runtime/mgcsweepbuf.go b/libgo/go/runtime/mgcsweepbuf.go
deleted file mode 100644
index 1f722c3..0000000
--- a/libgo/go/runtime/mgcsweepbuf.go
+++ /dev/null
@@ -1,176 +0,0 @@
-// Copyright 2016 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package runtime
-
-import (
-	"internal/cpu"
-	"runtime/internal/atomic"
-	"runtime/internal/sys"
-	"unsafe"
-)
-
-// A gcSweepBuf is a set of *mspans.
-//
-// gcSweepBuf is safe for concurrent push operations *or* concurrent
-// pop operations, but not both simultaneously.
-type gcSweepBuf struct {
-	// A gcSweepBuf is a two-level data structure consisting of a
-	// growable spine that points to fixed-sized blocks. The spine
-	// can be accessed without locks, but adding a block or
-	// growing it requires taking the spine lock.
-	//
-	// Because each mspan covers at least 8K of heap and takes at
-	// most 8 bytes in the gcSweepBuf, the growth of the spine is
-	// quite limited.
-	//
-	// The spine and all blocks are allocated off-heap, which
-	// allows this to be used in the memory manager and avoids the
-	// need for write barriers on all of these. We never release
-	// this memory because there could be concurrent lock-free
-	// access and we're likely to reuse it anyway. (In principle,
-	// we could do this during STW.)
-
-	spineLock mutex
-	spine     unsafe.Pointer // *[N]*gcSweepBlock, accessed atomically
-	spineLen  uintptr        // Spine array length, accessed atomically
-	spineCap  uintptr        // Spine array cap, accessed under lock
-
-	// index is the first unused slot in the logical concatenation
-	// of all blocks. It is accessed atomically.
-	index uint32
-}
-
-const (
-	gcSweepBlockEntries    = 512 // 4KB on 64-bit
-	gcSweepBufInitSpineCap = 256 // Enough for 1GB heap on 64-bit
-)
-
-type gcSweepBlock struct {
-	spans [gcSweepBlockEntries]*mspan
-}
-
-// push adds span s to buffer b. push is safe to call concurrently
-// with other push operations, but NOT to call concurrently with pop.
-func (b *gcSweepBuf) push(s *mspan) {
-	// Obtain our slot.
-	cursor := uintptr(atomic.Xadd(&b.index, +1) - 1)
-	top, bottom := cursor/gcSweepBlockEntries, cursor%gcSweepBlockEntries
-
-	// Do we need to add a block?
-	spineLen := atomic.Loaduintptr(&b.spineLen)
-	var block *gcSweepBlock
-retry:
-	if top < spineLen {
-		spine := atomic.Loadp(unsafe.Pointer(&b.spine))
-		blockp := add(spine, sys.PtrSize*top)
-		block = (*gcSweepBlock)(atomic.Loadp(blockp))
-	} else {
-		// Add a new block to the spine, potentially growing
-		// the spine.
-		lock(&b.spineLock)
-		// spineLen cannot change until we release the lock,
-		// but may have changed while we were waiting.
-		spineLen = atomic.Loaduintptr(&b.spineLen)
-		if top < spineLen {
-			unlock(&b.spineLock)
-			goto retry
-		}
-
-		if spineLen == b.spineCap {
-			// Grow the spine.
-			newCap := b.spineCap * 2
-			if newCap == 0 {
-				newCap = gcSweepBufInitSpineCap
-			}
-			newSpine := persistentalloc(newCap*sys.PtrSize, cpu.CacheLineSize, &memstats.gc_sys)
-			if b.spineCap != 0 {
-				// Blocks are allocated off-heap, so
-				// no write barriers.
-				memmove(newSpine, b.spine, b.spineCap*sys.PtrSize)
-			}
-			// Spine is allocated off-heap, so no write barrier.
-			atomic.StorepNoWB(unsafe.Pointer(&b.spine), newSpine)
-			b.spineCap = newCap
-			// We can't immediately free the old spine
-			// since a concurrent push with a lower index
-			// could still be reading from it. We let it
-			// leak because even a 1TB heap would waste
-			// less than 2MB of memory on old spines. If
-			// this is a problem, we could free old spines
-			// during STW.
-		}
-
-		// Allocate a new block and add it to the spine.
-		block = (*gcSweepBlock)(persistentalloc(unsafe.Sizeof(gcSweepBlock{}), cpu.CacheLineSize, &memstats.gc_sys))
-		blockp := add(b.spine, sys.PtrSize*top)
-		// Blocks are allocated off-heap, so no write barrier.
-		atomic.StorepNoWB(blockp, unsafe.Pointer(block))
-		atomic.Storeuintptr(&b.spineLen, spineLen+1)
-		unlock(&b.spineLock)
-	}
-
-	// We have a block. Insert the span atomically, since there may be
-	// concurrent readers via the block API.
-	atomic.StorepNoWB(unsafe.Pointer(&block.spans[bottom]), unsafe.Pointer(s))
-}
-
-// pop removes and returns a span from buffer b, or nil if b is empty.
-// pop is safe to call concurrently with other pop operations, but NOT
-// to call concurrently with push.
-func (b *gcSweepBuf) pop() *mspan {
-	cursor := atomic.Xadd(&b.index, -1)
-	if int32(cursor) < 0 {
-		atomic.Xadd(&b.index, +1)
-		return nil
-	}
-
-	// There are no concurrent spine or block modifications during
-	// pop, so we can omit the atomics.
-	top, bottom := cursor/gcSweepBlockEntries, cursor%gcSweepBlockEntries
-	blockp := (**gcSweepBlock)(add(b.spine, sys.PtrSize*uintptr(top)))
-	block := *blockp
-	s := block.spans[bottom]
-	// Clear the pointer for block(i).
-	block.spans[bottom] = nil
-	return s
-}
-
-// numBlocks returns the number of blocks in buffer b. numBlocks is
-// safe to call concurrently with any other operation. Spans that have
-// been pushed prior to the call to numBlocks are guaranteed to appear
-// in some block in the range [0, numBlocks()), assuming there are no
-// intervening pops. Spans that are pushed after the call may also
-// appear in these blocks.
-func (b *gcSweepBuf) numBlocks() int {
-	return int(divRoundUp(uintptr(atomic.Load(&b.index)), gcSweepBlockEntries))
-}
-
-// block returns the spans in the i'th block of buffer b. block is
-// safe to call concurrently with push. The block may contain nil
-// pointers that must be ignored, and each entry in the block must be
-// loaded atomically.
-func (b *gcSweepBuf) block(i int) []*mspan {
-	// Perform bounds check before loading spine address since
-	// push ensures the allocated length is at least spineLen.
-	if i < 0 || uintptr(i) >= atomic.Loaduintptr(&b.spineLen) {
-		throw("block index out of range")
-	}
-
-	// Get block i.
-	spine := atomic.Loadp(unsafe.Pointer(&b.spine))
-	blockp := add(spine, sys.PtrSize*uintptr(i))
-	block := (*gcSweepBlock)(atomic.Loadp(blockp))
-
-	// Slice the block if necessary.
-	cursor := uintptr(atomic.Load(&b.index))
-	top, bottom := cursor/gcSweepBlockEntries, cursor%gcSweepBlockEntries
-	var spans []*mspan
-	if uintptr(i) < top {
-		spans = block.spans[:]
-	} else {
-		spans = block.spans[:bottom]
-	}
-	return spans
-}