/// <summary>
/// insert this segment into cache, kick out other if needed
/// </summary>
/// <param name="seg"></param>
/// <precondition>seg is a new page brought in memory</precondition>
/// <postcondition>seg is insert into the cache, and the front of the LRU list, kick out one page if needed.</postcondition>
internal void _put_in_cache(Segment seg)
{
//if the cache is full, kick least recently used one out
if (m_cache.Count > m_cacheLimit)
{
//pick least recently used one
Segment victim = m_LRU.Prev;
Debug.Assert(victim != m_LRU);
if (victim.Dirty)
{
//write it out to the disk
byte[] content = victim.Serialize();
Debug.Assert(content.Length <= m_pageSize);
m_diskFile.SynWrite(content, 0, victim.SegmentID * m_pageSize, content.Length);
}
victim.BreakLinks();
bool t = m_cache.Delete(victim.SegmentID); //removed this one out of the cache
Debug.Assert(t);
}
if (m_cache.Insert(seg) == false)
{
throw new OOD.Exception.ProgramLogicError(
this,
"Trying to insert a existing key into CacheHashtable.");
}
seg.BuildLinks(m_LRU, m_LRU.Next); //move it the front of the LRU list
}
/// <summary>
/// insert this segment into cache, kick out other if needed
/// </summary>
/// <param name="seg"></param>
/// <precondition>seg is a new page brought in memory</precondition>
/// <postcondition>seg is insert into the cache, and the front of the LRU list, kick out one page if needed.</postcondition>
internal void _put_in_cache(Segment seg)
{
//if the cache is full, kick least recently used one out
if (m_cache.Count > m_cacheLimit)
{
//pick least recently used one
Segment victim = m_LRU.Prev;
Debug.Assert(victim != m_LRU);
if (victim.Dirty)
{
_write_back(victim);
}
victim.BreakLinks();
bool t = m_cache.Delete(victim.SegmentID); //removed this one out of the cache
Debug.Assert(t);
}
if (m_cache.Insert(seg) == false)
{
throw new OOD.Exception.ProgramLogicError(
this,
"Trying to insert an existing key into CacheHashtable");
}
seg.BuildLinks(m_LRU, m_LRU.Next); //move it the front of the LRU list
}