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atomic operation

pull/3530/head
chrislu 2 years ago
parent
commit
301b49b63f
  1. 17
      weed/mount/page_writer_pattern.go

17
weed/mount/page_writer_pattern.go

@ -1,5 +1,7 @@
package mount package mount
import "sync/atomic"
type WriterPattern struct { type WriterPattern struct {
isSequentialCounter int64 isSequentialCounter int64
lastWriteStopOffset int64 lastWriteStopOffset int64
@ -20,18 +22,19 @@ func NewWriterPattern(chunkSize int64) *WriterPattern {
} }
func (rp *WriterPattern) MonitorWriteAt(offset int64, size int) { func (rp *WriterPattern) MonitorWriteAt(offset int64, size int) {
if rp.lastWriteStopOffset == offset {
if rp.isSequentialCounter < ModeChangeLimit {
rp.isSequentialCounter++
lastOffset := atomic.SwapInt64(&rp.lastWriteStopOffset, offset+int64(size))
counter := atomic.LoadInt64(&rp.isSequentialCounter)
if lastOffset == offset {
if counter < ModeChangeLimit {
atomic.AddInt64(&rp.isSequentialCounter, 1)
} }
} else { } else {
if rp.isSequentialCounter > -ModeChangeLimit {
rp.isSequentialCounter--
if counter > -ModeChangeLimit {
atomic.AddInt64(&rp.isSequentialCounter, -1)
} }
} }
rp.lastWriteStopOffset = offset + int64(size)
} }
func (rp *WriterPattern) IsSequentialMode() bool { func (rp *WriterPattern) IsSequentialMode() bool {
return rp.isSequentialCounter >= 0
return atomic.LoadInt64(&rp.isSequentialCounter) >= 0
} }
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