/*

 * Copyright (c) 2020 Red Hat, Inc.

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version 2

 * of the License, or (at your option) any later version.

 * 

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 * 

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

 * 02110-1301, USA. 

 *

 * $Id: //eng/vdo-releases/aluminum/src/c++/vdo/base/allocationSelector.c#1 $

 */

#include "allocationSelector.h"

#include "allocationSelectorInternals.h"

#include "memoryAlloc.h"

#include "types.h"

enum {

  ALLOCATIONS_PER_ZONE = 128,

};

/**********************************************************************/

int makeAllocationSelector(ZoneCount            physicalZoneCount,

                           ThreadID             threadID,

                           AllocationSelector **selectorPtr)

{

  AllocationSelector *selector;

  int result = ALLOCATE(1, AllocationSelector, __func__, &selector);

  if (result != VDO_SUCCESS) {

    return result;

  }

  *selector = (AllocationSelector) {

    .nextAllocationZone = threadID % physicalZoneCount,

    .lastPhysicalZone   = physicalZoneCount - 1,

  };

  *selectorPtr = selector;

  return VDO_SUCCESS;

}

/**********************************************************************/

void freeAllocationSelector(AllocationSelector **selectorPtr)

{

  AllocationSelector *selector = *selectorPtr;

  if (selector == NULL) {

    return;

  }

  FREE(selector);

  *selectorPtr = NULL;

}

/**********************************************************************/

ZoneCount getNextAllocationZone(AllocationSelector *selector)

{

  if (selector->lastPhysicalZone > 0) {

    if (selector->allocationCount < ALLOCATIONS_PER_ZONE) {

      selector->allocationCount++;

    } else {

      selector->allocationCount = 1;

      if (selector->nextAllocationZone < selector->lastPhysicalZone) {

        selector->nextAllocationZone++;

      } else {

        selector->nextAllocationZone = 0;

      }

    }

  }

  return selector->nextAllocationZone;

}