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libs/ck-libs/fem/fem_lock.C

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/* File: fem_lock.C
 * Authors: Nilesh Choudhury
 *
 */

#include "fem_lock.h"
#include "fem_mesh_modify.h"

FEM_lock::FEM_lock(int i, femMeshModify *m) {
  idx = i;
  owner = -1;
  isOwner = false;
  isLocked = false;
  hasLocks = false;
  isLocking = false;
  isUnlocking = false;
  lockedChunks.removeAll();
  mmod = m;
}

FEM_lock::~FEM_lock() {
  //before deleting it, ensure that it is not holding any locks
  if(hasLocks) {
    unlock();
  }
  delete &lockedChunks;
}

bool FEM_lock::existsChunk(int index) {
  for(int i=0; i<lockedChunks.size(); i++) {
    if(lockedChunks[i] == index) return true;
  }
  return false;
}

//will only return if it gets the locks
//the set of nodes or elems that a chunk can ask to be locked can either be 
//shared, ghosts or local nodes/elements.
int FEM_lock::lock(int numNodes, int *nodes, int numElems, int* elems, int elemType) {
  bool done = false;
  int ret = 0;
  CkAssert(!hasLocks && (lockedChunks.size()==0) && !isLocking && !isUnlocking); //should not try to lock while it has locks
  while(!done) {
    if((!isLocked || (isLocked && isOwner)) && !isUnlocking && !isLocking) {
      isLocking = true; //I've started modifying locked chunks, so I should be sure
      for(int i=0; i<numNodes; i++) {
    if(i==0) { //lock myself, just once
      if(!existsChunk(idx)) {
        lockedChunks.push_back(idx);
      }
    }
    //which chunk does this belong to
    //add that chunk to the lock list, if it does not exist already.
    if(nodes[i] != -1) {
      if(nodes[i] < -1) {
        if(!mmod->fmMesh->node.ghost->is_valid(FEM_To_ghost_index(nodes[i]))) {
          //clean up whatever has been done
          lockedChunks.removeAll();
          isLocking = false;
          return 0;
        }
      } 
      else if(!mmod->fmMesh->node.is_valid(nodes[i])) {
        //clean up whatever has been done
        lockedChunks.removeAll();
        isLocking = false;
        return 0;
      }
      int numchunks;
      IDXL_Share **chunks1;
      mmod->fmUtil->getChunkNos(0,nodes[i],&numchunks,&chunks1);
      for(int j=0; j<numchunks; j++) {
        if(!existsChunk(chunks1[j]->chk)) {
          lockedChunks.push_back(chunks1[j]->chk);
        }
      }
      for(int j=0; j<numchunks; j++) {
        delete chunks1[j];
      }
      if(numchunks!=0) free(chunks1);
    }
      }
      for(int i=0; i<numElems; i++) {
    //which chunk does this belong to
    //add that chunk to the lock list, if not already in it.
    if(elems[i] != -1) {
      if(elems[i] < -1) {
        if(!mmod->fmMesh->elem[elemType].ghost->is_valid(FEM_To_ghost_index(elems[i]))) {
          //clean up whatever has been done
          lockedChunks.removeAll();
          isLocking = false;
          return 0;
        }
      } 
      else if(!mmod->fmMesh->elem[elemType].is_valid(elems[i])) {
        //clean up whatever has been done
        lockedChunks.removeAll();
        isLocking = false;
        return 0;
      }
      int numchunks;
      IDXL_Share **chunks1;
      mmod->fmUtil->getChunkNos(1,elems[i],&numchunks,&chunks1,elemType);
      for(int j=0; j<numchunks; j++) {
        if(!existsChunk(chunks1[j]->chk)) {
          lockedChunks.push_back(chunks1[j]->chk);
        }
      }
      for(int j=0; j<numchunks; j++) {
        delete chunks1[j];
      }
      if(numchunks!=0) free(chunks1);
    }
      }

      //sort the elements in ascending order
      int tmp;
      int numLocks = lockedChunks.size();
      for(int i=0; i<numLocks; i++) {
    for(int j=i+1; j<numLocks; j++) {
      if(lockedChunks[i] > lockedChunks[j]) {
        tmp = lockedChunks[i];
        lockedChunks[i] = lockedChunks[j];
        lockedChunks[j] = tmp;
      }
    }
      }

      //lock them
      for(int i=0; i<numLocks; i++) {
    ret = lock(lockedChunks[i],idx);
    CkAssert(ret == 1);
    if(ret != 1) {
      return -1;
    } else {
      hasLocks = true;
    }
      }
      done = true;
      isLocking = false;
    }
    else {
      CthYield();
      //block
    }
  }
  CkAssert(!isLocking && !isUnlocking && hasLocks && lockedChunks.size()>0);
  return 1;
}

int FEM_lock::unlock() {
  bool done = false;
  int ret = 0;
  if(!hasLocks && lockedChunks.size()==0) {
    return 0;
  }
  CkAssert(hasLocks && (lockedChunks.size()>0) && !isUnlocking && !isLocking); //should not try to unlock if it does not have locks
  while(!done) {
    if((!isLocked || (isLocked && isOwner)) && !isLocking && !isUnlocking) {
      //get rid of the locks
      isUnlocking = true;
      if(hasLocks) {
    for(int i=0; i<lockedChunks.size(); i++) {
      ret = unlock(lockedChunks[i],idx);
      CkAssert(ret == 1);
      if(ret != 1) return -1;
    }
      }
      hasLocks = false;
      lockedChunks.removeAll(); //free up the list.. the next lock will build it again
      done = true;
      isUnlocking = false;
    }
    else {
      CthYield();
      //block
    }
  }
  CkAssert(!isUnlocking && !isLocking && !hasLocks && (lockedChunks.size()==0));
  return 1;
}

int FEM_lock::lock(int chunkNo, int own) {
  intMsg *ret = new intMsg(0);
  CkAssert(!(isLocked && (own==owner) && (chunkNo==idx))); //should not try to lock me, if it has already locked me
  while(true) {
    if((!isLocked || (chunkNo != idx)) && !isUnlocking) {
      if(chunkNo == idx) {
    isLocked = true;
    owner = own;
    if(owner == idx) {
      isOwner = true;
      hasLocks = true;
    }
    else {
      isOwner = false;
    }
    CkPrintf("Chunk %d locked by chunk %d\n",chunkNo, own);
      }
      else {
    int2Msg *imsg = new int2Msg(chunkNo,own);
    ret = meshMod[chunkNo].lockRemoteChunk(imsg);
    CkAssert(ret->i == 1);
    if(ret->i != 1) return -1;
    else {
      hasLocks = true;
    }
      }
      break;
    }
    else {
      CthYield();
    }
  }
  return 1;
}

//for sanity, only the owner should unlock it
int FEM_lock::unlock(int chunkNo, int own) {
  intMsg *ret = new intMsg(0);
  CkAssert(!(!isLocked && (chunkNo==idx))); //noone should try to unlock me, if I am not locked
  CkAssert(!(isLocked && (chunkNo==idx) && (owner!=own))); //if I am locked by someone else, only he should try to unlock me
  while(true) {
    if(isLocked || (chunkNo != idx) && !isLocking) {
      if(chunkNo == idx) {
    isLocked = false;
    owner = -1;
    isOwner = false;
    CkPrintf("Chunk %d unlocked by chunk %d\n",chunkNo, own);
      }
      else {
    int2Msg *imsg = new int2Msg(chunkNo,own);
    ret = meshMod[chunkNo].unlockRemoteChunk(imsg);
    CkAssert(ret->i == 1);
    if(ret->i != 1) return -1;
      }
      break;
    }
    else {
      CthYield();
    }
  }
  return 1;
}

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