RoundRobinCoreAllocator.cc

/*
 * Copyright (c) 2008-2014, Pedigree Developers
 *
 * Please see the CONTRIB file in the root of the source tree for a full
 * list of contributors.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
 
#include "pedigree/kernel/LockGuard.h"
#include "pedigree/kernel/Log.h"
#include "pedigree/kernel/process/PerProcessorScheduler.h"
#include "pedigree/kernel/process/RoundRobinCoreAllocator.h"
#include "pedigree/kernel/process/Thread.h"
#include "pedigree/kernel/utilities/Iterator.h"
#include "pedigree/kernel/utilities/utility.h"
 
class PerProcessorScheduler;
class Thread;
 
RoundRobinCoreAllocator::RoundRobinCoreAllocator() : m_ProcMap(), m_pNext(0) {}
 
RoundRobinCoreAllocator::~RoundRobinCoreAllocator() {}
 
bool RoundRobinCoreAllocator::initialise(List<PerProcessorScheduler*>& procList) {
  List<PerProcessorScheduler*>::Iterator it = procList.begin();
  PerProcessorScheduler* pFirst = m_pNext = *it;
  it++;
 
  // 1 CPU?
  if (it == procList.end()) {
    NOTICE("RoundRobinCoreAllocator: quitting, only one CPU was present.");
    m_ProcMap.insert(pFirst, pFirst);
    return true;
  }
 
  for (; it != procList.end(); it++) {
    m_ProcMap.insert(pFirst, *it);
    pFirst = *it;
  }
 
  // Loop.
  m_ProcMap.insert(pFirst, m_pNext);
 
  return true;
}
 
PerProcessorScheduler* RoundRobinCoreAllocator::allocateThread(Thread* pThread) {
  ThreadPlacement placement;
  pThread->snapshotPlacementLocked(placement);
  LockGuard<Spinlock> guard(m_Lock);
  PerProcessorScheduler* first = m_pNext;
  do {
    m_pNext = m_ProcMap.lookup(m_pNext);
    if (placement.allowed.empty() || placement.allowed.contains(m_pNext->logicalCpu()))
      return m_pNext;
  } while (m_pNext != first);
  FATAL("Thread allocator found no allowed online processor.");
}