func (c *CacheMap) create_get_submsg(msg *message.Message,
address uint64, logblock uint32,
buffer []byte) *message.Message {
m := message.NewMsgGet()
msg.Add(m)
// Set IoPkt
mio := m.IoPkt()
mio.Address = address
mio.Buffer = buffer
mio.LogBlock = logblock
return m
}
func (c *CacheMap) Put(msg *message.Message) error {
err := msg.Check()
if err != nil {
return err
}
c.lock.Lock()
defer c.lock.Unlock()
io := msg.IoPkt()
if io.Blocks > 1 {
// Have parent message wait for its children
defer msg.Done()
//
// It does not matter that we send small blocks to the Log, since
// it will buffer them before sending them out to the cache device
//
// We do need to send each one sperately now so that the cache
// policy hopefully aligns them one after the other.
//
for block := uint32(0); block < io.Blocks; block++ {
child := message.NewMsgPut()
msg.Add(child)
child_io := child.IoPkt()
child_io.Address = io.Address + uint64(block)
child_io.Buffer = SubBlockBuffer(io.Buffer, c.blocksize, block, 1)
child_io.LogBlock = c.put(child_io.Address)
child_io.Blocks = 1
// Send to next one in line
c.pipeline <- child
}
} else {
io.LogBlock = c.put(io.Address)
c.pipeline <- msg
}
return nil
}
func (c *Log) get(msg *message.Message) error {
var n int
var err error
defer msg.Done()
iopkt := msg.IoPkt()
var readmsg *message.Message
var readmsg_block uint32
for block := uint32(0); block < iopkt.Blocks; block++ {
ramhit := false
index := iopkt.LogBlock + block
offset := c.offset(index)
// Check if the data is in RAM. Go through each buffered segment
for i := 0; i < c.segmentbuffers; i++ {
c.segments[i].lock.RLock()
if c.inRange(index, &c.segments[i]) {
ramhit = true
n, err = c.segments[i].data.ReadAt(SubBlockBuffer(iopkt.Buffer, c.blocksize, block, 1),
offset-c.segments[i].offset)
godbc.Check(err == nil, err, block, offset, i)
godbc.Check(uint32(n) == c.blocksize)
c.stats.RamHit()
}
c.segments[i].lock.RUnlock()
}
// We did not find it in ram, let's start making a message
if !ramhit {
if readmsg == nil {
readmsg = message.NewMsgGet()
msg.Add(readmsg)
io := readmsg.IoPkt()
io.LogBlock = index
io.Blocks = 1
readmsg_block = block
} else {
readmsg.IoPkt().Blocks++
}
io := readmsg.IoPkt()
io.Buffer = SubBlockBuffer(iopkt.Buffer,
c.blocksize,
readmsg_block,
io.Blocks)
} else if readmsg != nil {
// We have a pending message, but the
// buffer block was not contiguous.
c.logreaders <- readmsg
readmsg = nil
}
}
// Send pending read
if readmsg != nil {
c.logreaders <- readmsg
}
return nil
}
