1.1 --- a/vmalloc.c	Thu Oct 06 16:24:17 2011 +0200
     1.2 +++ b/vmalloc.c	Wed Jan 04 16:10:11 2012 -0800
     1.3 @@ -1,495 +1,495 @@
     1.4 -/*
     1.5 - *  Copyright 2009 OpenSourceCodeStewardshipFoundation.org
     1.6 - *  Licensed under GNU General Public License version 2
     1.7 - *
     1.8 - * Author: seanhalle@yahoo.com
     1.9 - *
    1.10 - * Created on November 14, 2009, 9:07 PM
    1.11 - */
    1.12 -
    1.13 -#include <malloc.h>
    1.14 -#include <inttypes.h>
    1.15 -#include <stdlib.h>
    1.16 -#include <stdio.h>
    1.17 -
    1.18 -#include "VMS.h"
    1.19 -#include "Histogram/Histogram.h"
    1.20 -
    1.21 -/*Helper function
    1.22 - *Insert a newly generated free chunk into the first spot on the free list.
    1.23 - * The chunk is cast as a MallocProlog, so the various pointers in it are
    1.24 - * accessed with C's help -- and the size of the prolog is easily added to
    1.25 - * the pointer when a chunk is returned to the app -- so C handles changes
    1.26 - * in pointer sizes among machines.
    1.27 - *
    1.28 - *The list head is a normal MallocProlog struct -- identified by its
    1.29 - * prevChunkInFreeList being NULL -- the only one.
    1.30 - *
    1.31 - *The end of the list is identified by next chunk being NULL, as usual.
    1.32 - */
    1.33 -void inline
    1.34 -add_chunk_to_free_list( MallocProlog *chunk, MallocProlog *listHead )
    1.35 - { 
    1.36 -   chunk->nextChunkInFreeList     = listHead->nextChunkInFreeList;
    1.37 -   if( chunk->nextChunkInFreeList != NULL ) //if not last in free list
    1.38 -      chunk->nextChunkInFreeList->prevChunkInFreeList = chunk;
    1.39 -   chunk->prevChunkInFreeList     = listHead;
    1.40 -   listHead->nextChunkInFreeList  = chunk;
    1.41 - }
    1.42 -
    1.43 -
    1.44 -/*This is sequential code, meant to only be called from the Master, not from
    1.45 - * any slave VPs.
    1.46 - *Search down list, checking size by the nextHigherInMem pointer, to find
    1.47 - * first chunk bigger than size needed.
    1.48 - *Shave off the extra and make it into a new free-list element, hook it in
    1.49 - * then return the address of the found element plus size of prolog.
    1.50 - *
    1.51 - *Will find a
    1.52 - */
    1.53 -void *VMS__malloc( size_t sizeRequested )
    1.54 - { MallocProlog *foundElem = NULL, *currElem, *newElem;
    1.55 -   ssize_t        amountExtra, sizeConsumed,sizeOfFound;
    1.56 -   uint32        foundElemIsTopOfHeap;
    1.57 -
    1.58 -   //============================= MEASUREMENT STUFF ========================
    1.59 -   #ifdef MEAS__TIME_MALLOC
    1.60 -   int32 startStamp, endStamp;
    1.61 -   saveLowTimeStampCountInto( startStamp );
    1.62 -   #endif
    1.63 -   //========================================================================
    1.64 -   
    1.65 -      //step up the size to be aligned at 16-byte boundary, prob better ways
    1.66 -   sizeRequested = (sizeRequested + 16) & ~15;
    1.67 -   currElem = (_VMSMasterEnv->freeListHead)->nextChunkInFreeList;
    1.68 -
    1.69 -   while( currElem != NULL )
    1.70 -    {    //check if size of currElem is big enough
    1.71 -      sizeOfFound=(size_t)((uintptr_t)currElem->nextHigherInMem -(uintptr_t)currElem);
    1.72 -      amountExtra = sizeOfFound - sizeRequested - sizeof(MallocProlog);
    1.73 -      if( amountExtra > 0 )
    1.74 -       {    //found it, get out of loop
    1.75 -         foundElem = currElem;
    1.76 -         currElem = NULL;
    1.77 -       }
    1.78 -      else
    1.79 -         currElem = currElem->nextChunkInFreeList;
    1.80 -    }
    1.81 -   
    1.82 -   if( foundElem == NULL )
    1.83 -    { ERROR("\nmalloc failed\n")
    1.84 -      return (void *)NULL;  //indicates malloc failed
    1.85 -    }
    1.86 -      //Using a kludge to identify the element that is the top chunk in the
    1.87 -      // heap -- saving top-of-heap addr in head's nextHigherInMem -- and
    1.88 -      // save addr of start of heap in head's nextLowerInMem
    1.89 -      //Will handle top of Heap specially
    1.90 -   foundElemIsTopOfHeap = foundElem->nextHigherInMem ==
    1.91 -                          _VMSMasterEnv->freeListHead->nextHigherInMem;
    1.92 -   
    1.93 -      //before shave off and try to insert new elem, remove found elem
    1.94 -      //note, foundElem will never be the head, so always has valid prevChunk
    1.95 -   foundElem->prevChunkInFreeList->nextChunkInFreeList =
    1.96 -                                              foundElem->nextChunkInFreeList;
    1.97 -   if( foundElem->nextChunkInFreeList != NULL )
    1.98 -    { foundElem->nextChunkInFreeList->prevChunkInFreeList =
    1.99 -                                              foundElem->prevChunkInFreeList;
   1.100 -    }
   1.101 -   foundElem->prevChunkInFreeList = NULL;//indicates elem currently allocated
   1.102 -   
   1.103 -      //if enough, turn extra into new elem & insert it
   1.104 -   if( amountExtra > 64 )
   1.105 -    {   //make new elem by adding to addr of curr elem then casting
   1.106 -        sizeConsumed = sizeof(MallocProlog) + sizeRequested; 
   1.107 -        newElem = (MallocProlog *)( (uintptr_t)foundElem + sizeConsumed );
   1.108 -        newElem->nextLowerInMem    = foundElem; //This is evil (but why?) 
   1.109 -        newElem->nextHigherInMem   = foundElem->nextHigherInMem; //This is evil (but why?)
   1.110 -        foundElem->nextHigherInMem = newElem;
   1.111 -        if( ! foundElemIsTopOfHeap )
   1.112 -        {  //there is no next higher for top of heap, so can't write to it
   1.113 -           newElem->nextHigherInMem->nextLowerInMem = newElem;
   1.114 -        }
   1.115 -        add_chunk_to_free_list( newElem, _VMSMasterEnv->freeListHead );
   1.116 -    }
   1.117 -   else
   1.118 -    {
   1.119 -      sizeConsumed = sizeOfFound;
   1.120 -    }
   1.121 -  _VMSMasterEnv->amtOfOutstandingMem += sizeConsumed;
   1.122 -
   1.123 -   //============================= MEASUREMENT STUFF ========================
   1.124 -   #ifdef MEAS__TIME_MALLOC
   1.125 -   saveLowTimeStampCountInto( endStamp );
   1.126 -   addIntervalToHist( startStamp, endStamp, _VMSMasterEnv->mallocTimeHist );
   1.127 -   #endif
   1.128 -   //========================================================================
   1.129 -
   1.130 -      //skip over the prolog by adding its size to the pointer return
   1.131 -   return (void*)((uintptr_t)foundElem + sizeof(MallocProlog));
   1.132 - }
   1.133 -
   1.134 -/*This is sequential code, meant to only be called from the Master, not from
   1.135 - * any slave VPs.
   1.136 - *Search down list, checking size by the nextHigherInMem pointer, to find
   1.137 - * first chunk bigger than size needed.
   1.138 - *Shave off the extra and make it into a new free-list element, hook it in
   1.139 - * then return the address of the found element plus size of prolog.
   1.140 - *
   1.141 - * The difference to the regular malloc is, that all the allocated chunks are
   1.142 - * aligned and padded to the size of a CACHE_LINE. Thus creating a new chunk
   1.143 - * before the aligned chunk.
   1.144 - */
   1.145 -void *VMS__malloc_aligned( size_t sizeRequested )
   1.146 - { MallocProlog *foundElem = NULL, *currElem, *newElem;
   1.147 -   ssize_t        amountExtra, sizeConsumed,sizeOfFound,prevAmount;
   1.148 -   uint32        foundElemIsTopOfHeap;
   1.149 -
   1.150 -   //============================= MEASUREMENT STUFF ========================
   1.151 -   #ifdef MEAS__TIME_MALLOC
   1.152 -   uint32 startStamp, endStamp;
   1.153 -   saveLowTimeStampCountInto( startStamp );
   1.154 -   #endif
   1.155 -   //========================================================================
   1.156 -   
   1.157 -      //step up the size to be multiple of the cache line size
   1.158 -   sizeRequested = (sizeRequested + CACHE_LINE) & ~(CACHE_LINE-1);
   1.159 -   currElem = (_VMSMasterEnv->freeListHead)->nextChunkInFreeList;
   1.160 -
   1.161 -   while( currElem != NULL )
   1.162 -    {    //check if size of currElem is big enough
   1.163 -      sizeOfFound=(size_t)((uintptr_t)currElem->nextHigherInMem -(uintptr_t)currElem);
   1.164 -      amountExtra = sizeOfFound - sizeRequested - sizeof(MallocProlog);
   1.165 -      if( amountExtra > 0 )
   1.166 -       {    
   1.167 -         //look if the found element is already aligned
   1.168 -         if((((uintptr_t)currElem+sizeof(MallocProlog)) & (uintptr_t)(CACHE_LINE-1)) == 0){
   1.169 -             //found it, get out of loop
   1.170 -             foundElem = currElem;
   1.171 -             break;
   1.172 -         }else{
   1.173 -             //find first aligned address and check if it's still big enough
   1.174 -             //check also if the space before the aligned address is big enough
   1.175 -             //for a new element
   1.176 -             void *firstAlignedAddr = (void*)(((uintptr_t)currElem + 2*CACHE_LINE) & ~((uintptr_t)(CACHE_LINE-1)));
   1.177 -             prevAmount = (uintptr_t)firstAlignedAddr - (uintptr_t)currElem;
   1.178 -             sizeOfFound=(uintptr_t)currElem->nextHigherInMem -(uintptr_t)firstAlignedAddr + sizeof(MallocProlog);
   1.179 -             amountExtra= sizeOfFound - sizeRequested - sizeof(MallocProlog);
   1.180 -             if(prevAmount > 2*sizeof(MallocProlog) && amountExtra > 0 ){
   1.181 -                 //found suitable element
   1.182 -                 //create new previous element and exit loop
   1.183 -                 MallocProlog *newAlignedElem = (MallocProlog*)firstAlignedAddr - 1;
   1.184 -                 
   1.185 -                 //insert new element into free list
   1.186 -                 if(currElem->nextChunkInFreeList != NULL)
   1.187 -                     currElem->nextChunkInFreeList->prevChunkInFreeList = newAlignedElem;                     
   1.188 -                 newAlignedElem->prevChunkInFreeList = currElem;
   1.189 -                 newAlignedElem->nextChunkInFreeList = currElem->nextChunkInFreeList;
   1.190 -                 currElem->nextChunkInFreeList = newAlignedElem;
   1.191 -                 
   1.192 -                 //set higherInMem and lowerInMem
   1.193 -                 newAlignedElem->nextHigherInMem = currElem->nextHigherInMem;
   1.194 -                 foundElemIsTopOfHeap = currElem->nextHigherInMem ==
   1.195 -                          _VMSMasterEnv->freeListHead->nextHigherInMem;
   1.196 -                 if(!foundElemIsTopOfHeap)
   1.197 -                     currElem->nextHigherInMem->nextLowerInMem = newAlignedElem;
   1.198 -                 currElem->nextHigherInMem = newAlignedElem;
   1.199 -                 newAlignedElem->nextLowerInMem = currElem;
   1.200 -                 
   1.201 -                 //Found new element leaving loop
   1.202 -                 foundElem = newAlignedElem;
   1.203 -                 break;
   1.204 -             }
   1.205 -         }
   1.206 -         
   1.207 -       }
   1.208 -       currElem = currElem->nextChunkInFreeList;
   1.209 -    }
   1.210 -
   1.211 -   if( foundElem == NULL )
   1.212 -    { ERROR("\nmalloc failed\n")
   1.213 -      return (void *)NULL;  //indicates malloc failed
   1.214 -    }
   1.215 -      //Using a kludge to identify the element that is the top chunk in the
   1.216 -      // heap -- saving top-of-heap addr in head's nextHigherInMem -- and
   1.217 -      // save addr of start of heap in head's nextLowerInMem
   1.218 -      //Will handle top of Heap specially
   1.219 -   foundElemIsTopOfHeap = foundElem->nextHigherInMem ==
   1.220 -                          _VMSMasterEnv->freeListHead->nextHigherInMem;
   1.221 -
   1.222 -      //before shave off and try to insert new elem, remove found elem
   1.223 -      //note, foundElem will never be the head, so always has valid prevChunk
   1.224 -   foundElem->prevChunkInFreeList->nextChunkInFreeList =
   1.225 -                                              foundElem->nextChunkInFreeList;
   1.226 -   if( foundElem->nextChunkInFreeList != NULL )
   1.227 -    { foundElem->nextChunkInFreeList->prevChunkInFreeList =
   1.228 -                                              foundElem->prevChunkInFreeList;
   1.229 -    }
   1.230 -   foundElem->prevChunkInFreeList = NULL;//indicates elem currently allocated
   1.231 -   
   1.232 -      //if enough, turn extra into new elem & insert it
   1.233 -   if( amountExtra > 64 )
   1.234 -    {    //make new elem by adding to addr of curr elem then casting
   1.235 -      sizeConsumed = sizeof(MallocProlog) + sizeRequested;
   1.236 -      newElem = (MallocProlog *)( (uintptr_t)foundElem + sizeConsumed );
   1.237 -      newElem->nextHigherInMem   = foundElem->nextHigherInMem;
   1.238 -      newElem->nextLowerInMem    = foundElem;
   1.239 -      foundElem->nextHigherInMem = newElem;
   1.240 -      
   1.241 -      if( ! foundElemIsTopOfHeap )
   1.242 -       {    //there is no next higher for top of heap, so can't write to it
   1.243 -         newElem->nextHigherInMem->nextLowerInMem = newElem;
   1.244 -       }
   1.245 -      add_chunk_to_free_list( newElem, _VMSMasterEnv->freeListHead );
   1.246 -    }
   1.247 -   else
   1.248 -    {
   1.249 -      sizeConsumed = sizeOfFound;
   1.250 -    }
   1.251 -  _VMSMasterEnv->amtOfOutstandingMem += sizeConsumed;
   1.252 -
   1.253 -   //============================= MEASUREMENT STUFF ========================
   1.254 -   #ifdef MEAS__TIME_MALLOC
   1.255 -   saveLowTimeStampCountInto( endStamp );
   1.256 -   addIntervalToHist( startStamp, endStamp, _VMSMasterEnv->mallocTimeHist );
   1.257 -   #endif
   1.258 -   //========================================================================
   1.259 -
   1.260 -      //skip over the prolog by adding its size to the pointer return
   1.261 -   return (void*)((uintptr_t)foundElem + sizeof(MallocProlog));
   1.262 - }
   1.263 -
   1.264 -
   1.265 -/*This is sequential code -- only to be called from the Master
   1.266 - * When free, subtract the size of prolog from pointer, then cast it to a
   1.267 - * MallocProlog.  Then check the nextLower and nextHigher chunks to see if
   1.268 - * one or both are also free, and coalesce if so, and if neither free, then
   1.269 - * add this one to free-list.
   1.270 - */
   1.271 -void
   1.272 -VMS__free( void *ptrToFree )
   1.273 - { MallocProlog *elemToFree, *nextLowerElem, *nextHigherElem;
   1.274 -   size_t         sizeOfElem;
   1.275 -   uint32         lowerExistsAndIsFree, higherExistsAndIsFree;
   1.276 -
   1.277 -   //============================= MEASUREMENT STUFF ========================
   1.278 -   #ifdef MEAS__TIME_MALLOC
   1.279 -   int32 startStamp, endStamp;
   1.280 -   saveLowTimeStampCountInto( startStamp );
   1.281 -   #endif
   1.282 -   //========================================================================
   1.283 -
   1.284 -   if( ptrToFree < (void*)_VMSMasterEnv->freeListHead->nextLowerInMem ||
   1.285 -       ptrToFree > (void*)_VMSMasterEnv->freeListHead->nextHigherInMem )
   1.286 -    {    //outside the range of data owned by VMS's malloc, so do nothing
   1.287 -      return;
   1.288 -    }
   1.289 -      //subtract size of prolog to get pointer to prolog, then cast
   1.290 -   elemToFree = (MallocProlog *)((uintptr_t)ptrToFree - sizeof(MallocProlog));
   1.291 -   sizeOfElem =(size_t)((uintptr_t)elemToFree->nextHigherInMem-(uintptr_t)elemToFree);
   1.292 -
   1.293 -   if( elemToFree->prevChunkInFreeList != NULL )
   1.294 -    { printf( "error: freeing same element twice!" ); exit(1);
   1.295 -    }
   1.296 -
   1.297 -   _VMSMasterEnv->amtOfOutstandingMem -= sizeOfElem;
   1.298 -
   1.299 -   nextLowerElem  = elemToFree->nextLowerInMem;
   1.300 -   nextHigherElem = elemToFree->nextHigherInMem;
   1.301 -
   1.302 -   if( nextHigherElem == NULL )
   1.303 -      higherExistsAndIsFree = FALSE;
   1.304 -   else //okay exists, now check if in the free-list by checking back ptr
   1.305 -      higherExistsAndIsFree = (nextHigherElem->prevChunkInFreeList != NULL);
   1.306 -    
   1.307 -   if( nextLowerElem == NULL )
   1.308 -      lowerExistsAndIsFree = FALSE;
   1.309 -   else //okay, it exists, now check if it's free
   1.310 -      lowerExistsAndIsFree = (nextLowerElem->prevChunkInFreeList != NULL);
   1.311 -    
   1.312 -
   1.313 -      //now, know what exists and what's free
   1.314 -   if( lowerExistsAndIsFree )
   1.315 -    { if( higherExistsAndIsFree )
   1.316 -       {    //both exist and are free, so coalesce all three
   1.317 -            //First, remove higher from free-list
   1.318 -         nextHigherElem->prevChunkInFreeList->nextChunkInFreeList =
   1.319 -                                         nextHigherElem->nextChunkInFreeList;
   1.320 -         if( nextHigherElem->nextChunkInFreeList != NULL ) //end-of-list?
   1.321 -            nextHigherElem->nextChunkInFreeList->prevChunkInFreeList =
   1.322 -                                         nextHigherElem->prevChunkInFreeList;
   1.323 -            //Now, fix-up sequence-in-mem list -- by side-effect, this also
   1.324 -            // changes size of the lower elem, which is still in free-list
   1.325 -         nextLowerElem->nextHigherInMem = nextHigherElem->nextHigherInMem;
   1.326 -         if( nextHigherElem->nextHigherInMem !=
   1.327 -             _VMSMasterEnv->freeListHead->nextHigherInMem )
   1.328 -            nextHigherElem->nextHigherInMem->nextLowerInMem = nextLowerElem;
   1.329 -            //notice didn't do anything to elemToFree -- it simply is no
   1.330 -            // longer reachable from any of the lists.  Wonder if could be a
   1.331 -            // security leak because left valid addresses in it,
   1.332 -            // but don't care for now.
   1.333 -       }
   1.334 -      else
   1.335 -       {    //lower is the only of the two that exists and is free,
   1.336 -            //In this case, no adjustment to free-list, just change mem-list.
   1.337 -            // By side-effect, changes size of the lower elem
   1.338 -         nextLowerElem->nextHigherInMem = elemToFree->nextHigherInMem;
   1.339 -         if( elemToFree->nextHigherInMem !=
   1.340 -             _VMSMasterEnv->freeListHead->nextHigherInMem )
   1.341 -            elemToFree->nextHigherInMem->nextLowerInMem = nextLowerElem;
   1.342 -       }
   1.343 -    }
   1.344 -   else
   1.345 -    {    //lower either doesn't exist or isn't free, so check higher
   1.346 -      if( higherExistsAndIsFree )
   1.347 -       {    //higher exists and is the only of the two free
   1.348 -            //First, in free-list, replace higher elem with the one to free
   1.349 -         elemToFree->nextChunkInFreeList=nextHigherElem->nextChunkInFreeList;
   1.350 -         elemToFree->prevChunkInFreeList=nextHigherElem->prevChunkInFreeList;
   1.351 -         elemToFree->prevChunkInFreeList->nextChunkInFreeList = elemToFree;
   1.352 -         if( elemToFree->nextChunkInFreeList != NULL ) // end-of-list?
   1.353 -            elemToFree->nextChunkInFreeList->prevChunkInFreeList =elemToFree;
   1.354 -            //Now chg mem-list. By side-effect, changes size of elemToFree
   1.355 -         elemToFree->nextHigherInMem = nextHigherElem->nextHigherInMem;
   1.356 -         if( elemToFree->nextHigherInMem !=
   1.357 -             _VMSMasterEnv->freeListHead->nextHigherInMem )
   1.358 -            elemToFree->nextHigherInMem->nextLowerInMem = elemToFree;
   1.359 -       }
   1.360 -      else
   1.361 -       {    //neither lower nor higher is availabe to coalesce so add to list
   1.362 -            // this makes prev chunk ptr non-null, which indicates it's free
   1.363 -         elemToFree->nextChunkInFreeList =
   1.364 -                            _VMSMasterEnv->freeListHead->nextChunkInFreeList;
   1.365 -         _VMSMasterEnv->freeListHead->nextChunkInFreeList = elemToFree;
   1.366 -         if( elemToFree->nextChunkInFreeList != NULL ) // end-of-list?
   1.367 -            elemToFree->nextChunkInFreeList->prevChunkInFreeList =elemToFree;
   1.368 -         elemToFree->prevChunkInFreeList = _VMSMasterEnv->freeListHead;
   1.369 -       }
   1.370 -    }
   1.371 -   //============================= MEASUREMENT STUFF ========================
   1.372 -   #ifdef MEAS__TIME_MALLOC
   1.373 -   saveLowTimeStampCountInto( endStamp );
   1.374 -   addIntervalToHist( startStamp, endStamp, _VMSMasterEnv->freeTimeHist );
   1.375 -   #endif
   1.376 -   //========================================================================
   1.377 -
   1.378 - }
   1.379 -
   1.380 -
   1.381 -/*Allocates memory from the external system -- higher overhead
   1.382 - *
   1.383 - *Because of Linux's malloc throwing bizarre random faults when malloc is
   1.384 - * used inside a VMS virtual processor, have to pass this as a request and
   1.385 - * have the core loop do it when it gets around to it -- will look for these
   1.386 - * chores leftover from the previous animation of masterVP the next time it
   1.387 - * goes to animate the masterVP -- so it takes two separate masterVP
   1.388 - * animations, separated by work, to complete an external malloc or
   1.389 - * external free request.
   1.390 - *
   1.391 - *Thinking core loop accepts signals -- just looks if signal-location is
   1.392 - * empty or not --
   1.393 - */
   1.394 -void *
   1.395 -VMS__malloc_in_ext( size_t sizeRequested )
   1.396 - {
   1.397 - /*
   1.398 -      //This is running in the master, so no chance for multiple cores to be
   1.399 -      // competing for the core's flag.
   1.400 -   if(  *(_VMSMasterEnv->coreLoopSignalAddr[ 0 ]) != 0 )
   1.401 -    {    //something has already signalled to core loop, so save the signal
   1.402 -         // and look, next time master animated, to see if can send it.
   1.403 -         //Note, the addr to put a signal is in the coreloop's frame, so just
   1.404 -         // checks it each time through -- make it volatile to avoid GCC
   1.405 -         // optimizations -- it's a coreloop local var that only changes
   1.406 -         // after jumping away.  The signal includes the addr to send the
   1.407 -         //return to -- even if just empty return completion-signal
   1.408 -         //
   1.409 -         //save the signal in some queue that the master looks at each time
   1.410 -         // it starts up -- one loc says if empty for fast common case --
   1.411 -         //something like that -- want to hide this inside this call -- but
   1.412 -         // think this has to come as a request -- req handler gives procr
   1.413 -         // back to master loop, which gives it back to req handler at point
   1.414 -         // it sees that core loop has sent return signal.  Something like
   1.415 -         // that.
   1.416 -      saveTheSignal
   1.417 -
   1.418 -    }
   1.419 -  coreSigData->type = malloc;
   1.420 -  coreSigData->sizeToMalloc = sizeRequested;
   1.421 -  coreSigData->locToSignalCompletion = &figureOut;
   1.422 -   _VMSMasterEnv->coreLoopSignals[ 0 ] = coreSigData;
   1.423 -  */
   1.424 -      //just risk system-stack faults until get this figured out
   1.425 -   return malloc( sizeRequested );
   1.426 - }
   1.427 -
   1.428 -
   1.429 -/*Frees memory that was allocated in the external system -- higher overhead
   1.430 - *
   1.431 - *As noted in external malloc comment, this is clunky 'cause the free has
   1.432 - * to be called in the core loop.
   1.433 - */
   1.434 -void
   1.435 -VMS__free_in_ext( void *ptrToFree )
   1.436 - {
   1.437 -      //just risk system-stack faults until get this figured out
   1.438 -   free( ptrToFree );
   1.439 -
   1.440 -      //TODO: fix this -- so 
   1.441 - }
   1.442 -
   1.443 -
   1.444 -/*Designed to be called from the main thread outside of VMS, during init
   1.445 - */
   1.446 -MallocProlog *
   1.447 -VMS_ext__create_free_list()
   1.448 - { MallocProlog *freeListHead, *firstChunk;
   1.449 -
   1.450 -      //Note, this is running in the main thread -- all increases in malloc
   1.451 -      // mem and all frees of it must be done in this thread, with the
   1.452 -      // thread's original stack available
   1.453 -   freeListHead = malloc( sizeof(MallocProlog) );
   1.454 -   firstChunk   = malloc( MALLOC_ADDITIONAL_MEM_FROM_OS_SIZE );
   1.455 -   if( firstChunk == NULL ) {printf("malloc error\n"); exit(1);}
   1.456 -   
   1.457 -   //Touch memory to avoid page faults
   1.458 -   void *ptr,*endPtr; 
   1.459 -   endPtr = (void*)firstChunk+MALLOC_ADDITIONAL_MEM_FROM_OS_SIZE;
   1.460 -   for(ptr = firstChunk; ptr < endPtr; ptr+=PAGE_SIZE)
   1.461 -   {
   1.462 -       *(char*)ptr = 0;
   1.463 -   }
   1.464 -
   1.465 -   freeListHead->prevChunkInFreeList = NULL;
   1.466 -      //Use this addr to free the heap when cleanup
   1.467 -   freeListHead->nextLowerInMem      = firstChunk;
   1.468 -      //to identify top-of-heap elem, compare this addr to elem's next higher
   1.469 -   freeListHead->nextHigherInMem     = (void*)( (uintptr_t)firstChunk +
   1.470 -                                         MALLOC_ADDITIONAL_MEM_FROM_OS_SIZE);
   1.471 -   freeListHead->nextChunkInFreeList = firstChunk;
   1.472 -
   1.473 -   firstChunk->nextChunkInFreeList   = NULL;
   1.474 -   firstChunk->prevChunkInFreeList   = freeListHead;
   1.475 -      //next Higher has to be set to top of chunk, so can calc size in malloc
   1.476 -   firstChunk->nextHigherInMem       = (void*)( (uintptr_t)firstChunk +
   1.477 -                                         MALLOC_ADDITIONAL_MEM_FROM_OS_SIZE);
   1.478 -   firstChunk->nextLowerInMem        = NULL; //identifies as bott of heap
   1.479 -   
   1.480 -   _VMSMasterEnv->amtOfOutstandingMem = 0; //none allocated yet
   1.481 -
   1.482 -   return freeListHead;
   1.483 - }
   1.484 -
   1.485 -
   1.486 -/*Designed to be called from the main thread outside of VMS, during cleanup
   1.487 - */
   1.488 -void
   1.489 -VMS_ext__free_free_list( MallocProlog *freeListHead )
   1.490 - {    
   1.491 -      //stashed a ptr to the one and only bug chunk malloc'd from OS in the
   1.492 -      // free list head's next lower in mem pointer
   1.493 -   free( freeListHead->nextLowerInMem );
   1.494 -
   1.495 -   //don't free the head -- it'll be in an array eventually -- free whole
   1.496 -   // array when all the free lists linked from it have already been freed
   1.497 - }
   1.498 -
   1.499 +/*
   1.500 + *  Copyright 2009 OpenSourceCodeStewardshipFoundation.org
   1.501 + *  Licensed under GNU General Public License version 2
   1.502 + *
   1.503 + * Author: seanhalle@yahoo.com
   1.504 + *
   1.505 + * Created on November 14, 2009, 9:07 PM
   1.506 + */
   1.507 +
   1.508 +#include <malloc.h>
   1.509 +#include <inttypes.h>
   1.510 +#include <stdlib.h>
   1.511 +#include <stdio.h>
   1.512 +
   1.513 +#include "VMS.h"
   1.514 +#include "Histogram/Histogram.h"
   1.515 +
   1.516 +/*Helper function
   1.517 + *Insert a newly generated free chunk into the first spot on the free list.
   1.518 + * The chunk is cast as a MallocProlog, so the various pointers in it are
   1.519 + * accessed with C's help -- and the size of the prolog is easily added to
   1.520 + * the pointer when a chunk is returned to the app -- so C handles changes
   1.521 + * in pointer sizes among machines.
   1.522 + *
   1.523 + *The list head is a normal MallocProlog struct -- identified by its
   1.524 + * prevChunkInFreeList being NULL -- the only one.
   1.525 + *
   1.526 + *The end of the list is identified by next chunk being NULL, as usual.
   1.527 + */
   1.528 +void inline
   1.529 +add_chunk_to_free_list( MallocProlog *chunk, MallocProlog *listHead )
   1.530 + { 
   1.531 +   chunk->nextChunkInFreeList     = listHead->nextChunkInFreeList;
   1.532 +   if( chunk->nextChunkInFreeList != NULL ) //if not last in free list
   1.533 +      chunk->nextChunkInFreeList->prevChunkInFreeList = chunk;
   1.534 +   chunk->prevChunkInFreeList     = listHead;
   1.535 +   listHead->nextChunkInFreeList  = chunk;
   1.536 + }
   1.537 +
   1.538 +
   1.539 +/*This is sequential code, meant to only be called from the Master, not from
   1.540 + * any slave VPs.
   1.541 + *Search down list, checking size by the nextHigherInMem pointer, to find
   1.542 + * first chunk bigger than size needed.
   1.543 + *Shave off the extra and make it into a new free-list element, hook it in
   1.544 + * then return the address of the found element plus size of prolog.
   1.545 + *
   1.546 + *Will find a
   1.547 + */
   1.548 +void *VMS__malloc( size_t sizeRequested )
   1.549 + { MallocProlog *foundElem = NULL, *currElem, *newElem;
   1.550 +   ssize_t        amountExtra, sizeConsumed,sizeOfFound;
   1.551 +   uint32        foundElemIsTopOfHeap;
   1.552 +
   1.553 +   //============================= MEASUREMENT STUFF ========================
   1.554 +   #ifdef MEAS__TIME_MALLOC
   1.555 +   int32 startStamp, endStamp;
   1.556 +   saveLowTimeStampCountInto( startStamp );
   1.557 +   #endif
   1.558 +   //========================================================================
   1.559 +   
   1.560 +      //step up the size to be aligned at 16-byte boundary, prob better ways
   1.561 +   sizeRequested = (sizeRequested + 16) & ~15;
   1.562 +   currElem = (_VMSMasterEnv->freeListHead)->nextChunkInFreeList;
   1.563 +
   1.564 +   while( currElem != NULL )
   1.565 +    {    //check if size of currElem is big enough
   1.566 +      sizeOfFound=(size_t)((uintptr_t)currElem->nextHigherInMem -(uintptr_t)currElem);
   1.567 +      amountExtra = sizeOfFound - sizeRequested - sizeof(MallocProlog);
   1.568 +      if( amountExtra > 0 )
   1.569 +       {    //found it, get out of loop
   1.570 +         foundElem = currElem;
   1.571 +         currElem = NULL;
   1.572 +       }
   1.573 +      else
   1.574 +         currElem = currElem->nextChunkInFreeList;
   1.575 +    }
   1.576 +   
   1.577 +   if( foundElem == NULL )
   1.578 +    { ERROR("\nmalloc failed\n")
   1.579 +      return (void *)NULL;  //indicates malloc failed
   1.580 +    }
   1.581 +      //Using a kludge to identify the element that is the top chunk in the
   1.582 +      // heap -- saving top-of-heap addr in head's nextHigherInMem -- and
   1.583 +      // save addr of start of heap in head's nextLowerInMem
   1.584 +      //Will handle top of Heap specially
   1.585 +   foundElemIsTopOfHeap = foundElem->nextHigherInMem ==
   1.586 +                          _VMSMasterEnv->freeListHead->nextHigherInMem;
   1.587 +   
   1.588 +      //before shave off and try to insert new elem, remove found elem
   1.589 +      //note, foundElem will never be the head, so always has valid prevChunk
   1.590 +   foundElem->prevChunkInFreeList->nextChunkInFreeList =
   1.591 +                                              foundElem->nextChunkInFreeList;
   1.592 +   if( foundElem->nextChunkInFreeList != NULL )
   1.593 +    { foundElem->nextChunkInFreeList->prevChunkInFreeList =
   1.594 +                                              foundElem->prevChunkInFreeList;
   1.595 +    }
   1.596 +   foundElem->prevChunkInFreeList = NULL;//indicates elem currently allocated
   1.597 +   
   1.598 +      //if enough, turn extra into new elem & insert it
   1.599 +   if( amountExtra > 64 )
   1.600 +    {   //make new elem by adding to addr of curr elem then casting
   1.601 +        sizeConsumed = sizeof(MallocProlog) + sizeRequested; 
   1.602 +        newElem = (MallocProlog *)( (uintptr_t)foundElem + sizeConsumed );
   1.603 +        newElem->nextLowerInMem    = foundElem; //This is evil (but why?) 
   1.604 +        newElem->nextHigherInMem   = foundElem->nextHigherInMem; //This is evil (but why?)
   1.605 +        foundElem->nextHigherInMem = newElem;
   1.606 +        if( ! foundElemIsTopOfHeap )
   1.607 +        {  //there is no next higher for top of heap, so can't write to it
   1.608 +           newElem->nextHigherInMem->nextLowerInMem = newElem;
   1.609 +        }
   1.610 +        add_chunk_to_free_list( newElem, _VMSMasterEnv->freeListHead );
   1.611 +    }
   1.612 +   else
   1.613 +    {
   1.614 +      sizeConsumed = sizeOfFound;
   1.615 +    }
   1.616 +  _VMSMasterEnv->amtOfOutstandingMem += sizeConsumed;
   1.617 +
   1.618 +   //============================= MEASUREMENT STUFF ========================
   1.619 +   #ifdef MEAS__TIME_MALLOC
   1.620 +   saveLowTimeStampCountInto( endStamp );
   1.621 +   addIntervalToHist( startStamp, endStamp, _VMSMasterEnv->mallocTimeHist );
   1.622 +   #endif
   1.623 +   //========================================================================
   1.624 +
   1.625 +      //skip over the prolog by adding its size to the pointer return
   1.626 +   return (void*)((uintptr_t)foundElem + sizeof(MallocProlog));
   1.627 + }
   1.628 +
   1.629 +/*This is sequential code, meant to only be called from the Master, not from
   1.630 + * any slave VPs.
   1.631 + *Search down list, checking size by the nextHigherInMem pointer, to find
   1.632 + * first chunk bigger than size needed.
   1.633 + *Shave off the extra and make it into a new free-list element, hook it in
   1.634 + * then return the address of the found element plus size of prolog.
   1.635 + *
   1.636 + * The difference to the regular malloc is, that all the allocated chunks are
   1.637 + * aligned and padded to the size of a CACHE_LINE. Thus creating a new chunk
   1.638 + * before the aligned chunk.
   1.639 + */
   1.640 +void *VMS__malloc_aligned( size_t sizeRequested )
   1.641 + { MallocProlog *foundElem = NULL, *currElem, *newElem;
   1.642 +   ssize_t        amountExtra, sizeConsumed,sizeOfFound,prevAmount;
   1.643 +   uint32        foundElemIsTopOfHeap;
   1.644 +
   1.645 +   //============================= MEASUREMENT STUFF ========================
   1.646 +   #ifdef MEAS__TIME_MALLOC
   1.647 +   uint32 startStamp, endStamp;
   1.648 +   saveLowTimeStampCountInto( startStamp );
   1.649 +   #endif
   1.650 +   //========================================================================
   1.651 +   
   1.652 +      //step up the size to be multiple of the cache line size
   1.653 +   sizeRequested = (sizeRequested + CACHE_LINE) & ~(CACHE_LINE-1);
   1.654 +   currElem = (_VMSMasterEnv->freeListHead)->nextChunkInFreeList;
   1.655 +
   1.656 +   while( currElem != NULL )
   1.657 +    {    //check if size of currElem is big enough
   1.658 +      sizeOfFound=(size_t)((uintptr_t)currElem->nextHigherInMem -(uintptr_t)currElem);
   1.659 +      amountExtra = sizeOfFound - sizeRequested - sizeof(MallocProlog);
   1.660 +      if( amountExtra > 0 )
   1.661 +       {    
   1.662 +         //look if the found element is already aligned
   1.663 +         if((((uintptr_t)currElem+sizeof(MallocProlog)) & (uintptr_t)(CACHE_LINE-1)) == 0){
   1.664 +             //found it, get out of loop
   1.665 +             foundElem = currElem;
   1.666 +             break;
   1.667 +         }else{
   1.668 +             //find first aligned address and check if it's still big enough
   1.669 +             //check also if the space before the aligned address is big enough
   1.670 +             //for a new element
   1.671 +             void *firstAlignedAddr = (void*)(((uintptr_t)currElem + 2*CACHE_LINE) & ~((uintptr_t)(CACHE_LINE-1)));
   1.672 +             prevAmount = (uintptr_t)firstAlignedAddr - (uintptr_t)currElem;
   1.673 +             sizeOfFound=(uintptr_t)currElem->nextHigherInMem -(uintptr_t)firstAlignedAddr + sizeof(MallocProlog);
   1.674 +             amountExtra= sizeOfFound - sizeRequested - sizeof(MallocProlog);
   1.675 +             if(prevAmount > 2*sizeof(MallocProlog) && amountExtra > 0 ){
   1.676 +                 //found suitable element
   1.677 +                 //create new previous element and exit loop
   1.678 +                 MallocProlog *newAlignedElem = (MallocProlog*)firstAlignedAddr - 1;
   1.679 +                 
   1.680 +                 //insert new element into free list
   1.681 +                 if(currElem->nextChunkInFreeList != NULL)
   1.682 +                     currElem->nextChunkInFreeList->prevChunkInFreeList = newAlignedElem;                     
   1.683 +                 newAlignedElem->prevChunkInFreeList = currElem;
   1.684 +                 newAlignedElem->nextChunkInFreeList = currElem->nextChunkInFreeList;
   1.685 +                 currElem->nextChunkInFreeList = newAlignedElem;
   1.686 +                 
   1.687 +                 //set higherInMem and lowerInMem
   1.688 +                 newAlignedElem->nextHigherInMem = currElem->nextHigherInMem;
   1.689 +                 foundElemIsTopOfHeap = currElem->nextHigherInMem ==
   1.690 +                          _VMSMasterEnv->freeListHead->nextHigherInMem;
   1.691 +                 if(!foundElemIsTopOfHeap)
   1.692 +                     currElem->nextHigherInMem->nextLowerInMem = newAlignedElem;
   1.693 +                 currElem->nextHigherInMem = newAlignedElem;
   1.694 +                 newAlignedElem->nextLowerInMem = currElem;
   1.695 +                 
   1.696 +                 //Found new element leaving loop
   1.697 +                 foundElem = newAlignedElem;
   1.698 +                 break;
   1.699 +             }
   1.700 +         }
   1.701 +         
   1.702 +       }
   1.703 +       currElem = currElem->nextChunkInFreeList;
   1.704 +    }
   1.705 +
   1.706 +   if( foundElem == NULL )
   1.707 +    { ERROR("\nmalloc failed\n")
   1.708 +      return (void *)NULL;  //indicates malloc failed
   1.709 +    }
   1.710 +      //Using a kludge to identify the element that is the top chunk in the
   1.711 +      // heap -- saving top-of-heap addr in head's nextHigherInMem -- and
   1.712 +      // save addr of start of heap in head's nextLowerInMem
   1.713 +      //Will handle top of Heap specially
   1.714 +   foundElemIsTopOfHeap = foundElem->nextHigherInMem ==
   1.715 +                          _VMSMasterEnv->freeListHead->nextHigherInMem;
   1.716 +
   1.717 +      //before shave off and try to insert new elem, remove found elem
   1.718 +      //note, foundElem will never be the head, so always has valid prevChunk
   1.719 +   foundElem->prevChunkInFreeList->nextChunkInFreeList =
   1.720 +                                              foundElem->nextChunkInFreeList;
   1.721 +   if( foundElem->nextChunkInFreeList != NULL )
   1.722 +    { foundElem->nextChunkInFreeList->prevChunkInFreeList =
   1.723 +                                              foundElem->prevChunkInFreeList;
   1.724 +    }
   1.725 +   foundElem->prevChunkInFreeList = NULL;//indicates elem currently allocated
   1.726 +   
   1.727 +      //if enough, turn extra into new elem & insert it
   1.728 +   if( amountExtra > 64 )
   1.729 +    {    //make new elem by adding to addr of curr elem then casting
   1.730 +      sizeConsumed = sizeof(MallocProlog) + sizeRequested;
   1.731 +      newElem = (MallocProlog *)( (uintptr_t)foundElem + sizeConsumed );
   1.732 +      newElem->nextHigherInMem   = foundElem->nextHigherInMem;
   1.733 +      newElem->nextLowerInMem    = foundElem;
   1.734 +      foundElem->nextHigherInMem = newElem;
   1.735 +      
   1.736 +      if( ! foundElemIsTopOfHeap )
   1.737 +       {    //there is no next higher for top of heap, so can't write to it
   1.738 +         newElem->nextHigherInMem->nextLowerInMem = newElem;
   1.739 +       }
   1.740 +      add_chunk_to_free_list( newElem, _VMSMasterEnv->freeListHead );
   1.741 +    }
   1.742 +   else
   1.743 +    {
   1.744 +      sizeConsumed = sizeOfFound;
   1.745 +    }
   1.746 +  _VMSMasterEnv->amtOfOutstandingMem += sizeConsumed;
   1.747 +
   1.748 +   //============================= MEASUREMENT STUFF ========================
   1.749 +   #ifdef MEAS__TIME_MALLOC
   1.750 +   saveLowTimeStampCountInto( endStamp );
   1.751 +   addIntervalToHist( startStamp, endStamp, _VMSMasterEnv->mallocTimeHist );
   1.752 +   #endif
   1.753 +   //========================================================================
   1.754 +
   1.755 +      //skip over the prolog by adding its size to the pointer return
   1.756 +   return (void*)((uintptr_t)foundElem + sizeof(MallocProlog));
   1.757 + }
   1.758 +
   1.759 +
   1.760 +/*This is sequential code -- only to be called from the Master
   1.761 + * When free, subtract the size of prolog from pointer, then cast it to a
   1.762 + * MallocProlog.  Then check the nextLower and nextHigher chunks to see if
   1.763 + * one or both are also free, and coalesce if so, and if neither free, then
   1.764 + * add this one to free-list.
   1.765 + */
   1.766 +void
   1.767 +VMS__free( void *ptrToFree )
   1.768 + { MallocProlog *elemToFree, *nextLowerElem, *nextHigherElem;
   1.769 +   size_t         sizeOfElem;
   1.770 +   uint32         lowerExistsAndIsFree, higherExistsAndIsFree;
   1.771 +
   1.772 +   //============================= MEASUREMENT STUFF ========================
   1.773 +   #ifdef MEAS__TIME_MALLOC
   1.774 +   int32 startStamp, endStamp;
   1.775 +   saveLowTimeStampCountInto( startStamp );
   1.776 +   #endif
   1.777 +   //========================================================================
   1.778 +
   1.779 +   if( ptrToFree < (void*)_VMSMasterEnv->freeListHead->nextLowerInMem ||
   1.780 +       ptrToFree > (void*)_VMSMasterEnv->freeListHead->nextHigherInMem )
   1.781 +    {    //outside the range of data owned by VMS's malloc, so do nothing
   1.782 +      return;
   1.783 +    }
   1.784 +      //subtract size of prolog to get pointer to prolog, then cast
   1.785 +   elemToFree = (MallocProlog *)((uintptr_t)ptrToFree - sizeof(MallocProlog));
   1.786 +   sizeOfElem =(size_t)((uintptr_t)elemToFree->nextHigherInMem-(uintptr_t)elemToFree);
   1.787 +
   1.788 +   if( elemToFree->prevChunkInFreeList != NULL )
   1.789 +    { printf( "error: freeing same element twice!" ); exit(1);
   1.790 +    }
   1.791 +
   1.792 +   _VMSMasterEnv->amtOfOutstandingMem -= sizeOfElem;
   1.793 +
   1.794 +   nextLowerElem  = elemToFree->nextLowerInMem;
   1.795 +   nextHigherElem = elemToFree->nextHigherInMem;
   1.796 +
   1.797 +   if( nextHigherElem == NULL )
   1.798 +      higherExistsAndIsFree = FALSE;
   1.799 +   else //okay exists, now check if in the free-list by checking back ptr
   1.800 +      higherExistsAndIsFree = (nextHigherElem->prevChunkInFreeList != NULL);
   1.801 +    
   1.802 +   if( nextLowerElem == NULL )
   1.803 +      lowerExistsAndIsFree = FALSE;
   1.804 +   else //okay, it exists, now check if it's free
   1.805 +      lowerExistsAndIsFree = (nextLowerElem->prevChunkInFreeList != NULL);
   1.806 +    
   1.807 +
   1.808 +      //now, know what exists and what's free
   1.809 +   if( lowerExistsAndIsFree )
   1.810 +    { if( higherExistsAndIsFree )
   1.811 +       {    //both exist and are free, so coalesce all three
   1.812 +            //First, remove higher from free-list
   1.813 +         nextHigherElem->prevChunkInFreeList->nextChunkInFreeList =
   1.814 +                                         nextHigherElem->nextChunkInFreeList;
   1.815 +         if( nextHigherElem->nextChunkInFreeList != NULL ) //end-of-list?
   1.816 +            nextHigherElem->nextChunkInFreeList->prevChunkInFreeList =
   1.817 +                                         nextHigherElem->prevChunkInFreeList;
   1.818 +            //Now, fix-up sequence-in-mem list -- by side-effect, this also
   1.819 +            // changes size of the lower elem, which is still in free-list
   1.820 +         nextLowerElem->nextHigherInMem = nextHigherElem->nextHigherInMem;
   1.821 +         if( nextHigherElem->nextHigherInMem !=
   1.822 +             _VMSMasterEnv->freeListHead->nextHigherInMem )
   1.823 +            nextHigherElem->nextHigherInMem->nextLowerInMem = nextLowerElem;
   1.824 +            //notice didn't do anything to elemToFree -- it simply is no
   1.825 +            // longer reachable from any of the lists.  Wonder if could be a
   1.826 +            // security leak because left valid addresses in it,
   1.827 +            // but don't care for now.
   1.828 +       }
   1.829 +      else
   1.830 +       {    //lower is the only of the two that exists and is free,
   1.831 +            //In this case, no adjustment to free-list, just change mem-list.
   1.832 +            // By side-effect, changes size of the lower elem
   1.833 +         nextLowerElem->nextHigherInMem = elemToFree->nextHigherInMem;
   1.834 +         if( elemToFree->nextHigherInMem !=
   1.835 +             _VMSMasterEnv->freeListHead->nextHigherInMem )
   1.836 +            elemToFree->nextHigherInMem->nextLowerInMem = nextLowerElem;
   1.837 +       }
   1.838 +    }
   1.839 +   else
   1.840 +    {    //lower either doesn't exist or isn't free, so check higher
   1.841 +      if( higherExistsAndIsFree )
   1.842 +       {    //higher exists and is the only of the two free
   1.843 +            //First, in free-list, replace higher elem with the one to free
   1.844 +         elemToFree->nextChunkInFreeList=nextHigherElem->nextChunkInFreeList;
   1.845 +         elemToFree->prevChunkInFreeList=nextHigherElem->prevChunkInFreeList;
   1.846 +         elemToFree->prevChunkInFreeList->nextChunkInFreeList = elemToFree;
   1.847 +         if( elemToFree->nextChunkInFreeList != NULL ) // end-of-list?
   1.848 +            elemToFree->nextChunkInFreeList->prevChunkInFreeList =elemToFree;
   1.849 +            //Now chg mem-list. By side-effect, changes size of elemToFree
   1.850 +         elemToFree->nextHigherInMem = nextHigherElem->nextHigherInMem;
   1.851 +         if( elemToFree->nextHigherInMem !=
   1.852 +             _VMSMasterEnv->freeListHead->nextHigherInMem )
   1.853 +            elemToFree->nextHigherInMem->nextLowerInMem = elemToFree;
   1.854 +       }
   1.855 +      else
   1.856 +       {    //neither lower nor higher is availabe to coalesce so add to list
   1.857 +            // this makes prev chunk ptr non-null, which indicates it's free
   1.858 +         elemToFree->nextChunkInFreeList =
   1.859 +                            _VMSMasterEnv->freeListHead->nextChunkInFreeList;
   1.860 +         _VMSMasterEnv->freeListHead->nextChunkInFreeList = elemToFree;
   1.861 +         if( elemToFree->nextChunkInFreeList != NULL ) // end-of-list?
   1.862 +            elemToFree->nextChunkInFreeList->prevChunkInFreeList =elemToFree;
   1.863 +         elemToFree->prevChunkInFreeList = _VMSMasterEnv->freeListHead;
   1.864 +       }
   1.865 +    }
   1.866 +   //============================= MEASUREMENT STUFF ========================
   1.867 +   #ifdef MEAS__TIME_MALLOC
   1.868 +   saveLowTimeStampCountInto( endStamp );
   1.869 +   addIntervalToHist( startStamp, endStamp, _VMSMasterEnv->freeTimeHist );
   1.870 +   #endif
   1.871 +   //========================================================================
   1.872 +
   1.873 + }
   1.874 +
   1.875 +
   1.876 +/*Allocates memory from the external system -- higher overhead
   1.877 + *
   1.878 + *Because of Linux's malloc throwing bizarre random faults when malloc is
   1.879 + * used inside a VMS virtual processor, have to pass this as a request and
   1.880 + * have the core loop do it when it gets around to it -- will look for these
   1.881 + * chores leftover from the previous animation of masterVP the next time it
   1.882 + * goes to animate the masterVP -- so it takes two separate masterVP
   1.883 + * animations, separated by work, to complete an external malloc or
   1.884 + * external free request.
   1.885 + *
   1.886 + *Thinking core loop accepts signals -- just looks if signal-location is
   1.887 + * empty or not --
   1.888 + */
   1.889 +void *
   1.890 +VMS__malloc_in_ext( size_t sizeRequested )
   1.891 + {
   1.892 + /*
   1.893 +      //This is running in the master, so no chance for multiple cores to be
   1.894 +      // competing for the core's flag.
   1.895 +   if(  *(_VMSMasterEnv->coreLoopSignalAddr[ 0 ]) != 0 )
   1.896 +    {    //something has already signalled to core loop, so save the signal
   1.897 +         // and look, next time master animated, to see if can send it.
   1.898 +         //Note, the addr to put a signal is in the coreloop's frame, so just
   1.899 +         // checks it each time through -- make it volatile to avoid GCC
   1.900 +         // optimizations -- it's a coreloop local var that only changes
   1.901 +         // after jumping away.  The signal includes the addr to send the
   1.902 +         //return to -- even if just empty return completion-signal
   1.903 +         //
   1.904 +         //save the signal in some queue that the master looks at each time
   1.905 +         // it starts up -- one loc says if empty for fast common case --
   1.906 +         //something like that -- want to hide this inside this call -- but
   1.907 +         // think this has to come as a request -- req handler gives procr
   1.908 +         // back to master loop, which gives it back to req handler at point
   1.909 +         // it sees that core loop has sent return signal.  Something like
   1.910 +         // that.
   1.911 +      saveTheSignal
   1.912 +
   1.913 +    }
   1.914 +  coreSigData->type = malloc;
   1.915 +  coreSigData->sizeToMalloc = sizeRequested;
   1.916 +  coreSigData->locToSignalCompletion = &figureOut;
   1.917 +   _VMSMasterEnv->coreLoopSignals[ 0 ] = coreSigData;
   1.918 +  */
   1.919 +      //just risk system-stack faults until get this figured out
   1.920 +   return malloc( sizeRequested );
   1.921 + }
   1.922 +
   1.923 +
   1.924 +/*Frees memory that was allocated in the external system -- higher overhead
   1.925 + *
   1.926 + *As noted in external malloc comment, this is clunky 'cause the free has
   1.927 + * to be called in the core loop.
   1.928 + */
   1.929 +void
   1.930 +VMS__free_in_ext( void *ptrToFree )
   1.931 + {
   1.932 +      //just risk system-stack faults until get this figured out
   1.933 +   free( ptrToFree );
   1.934 +
   1.935 +      //TODO: fix this -- so 
   1.936 + }
   1.937 +
   1.938 +
   1.939 +/*Designed to be called from the main thread outside of VMS, during init
   1.940 + */
   1.941 +MallocProlog *
   1.942 +VMS_ext__create_free_list()
   1.943 + { MallocProlog *freeListHead, *firstChunk;
   1.944 +
   1.945 +      //Note, this is running in the main thread -- all increases in malloc
   1.946 +      // mem and all frees of it must be done in this thread, with the
   1.947 +      // thread's original stack available
   1.948 +   freeListHead = malloc( sizeof(MallocProlog) );
   1.949 +   firstChunk   = malloc( MALLOC_ADDITIONAL_MEM_FROM_OS_SIZE );
   1.950 +   if( firstChunk == NULL ) {printf("malloc error\n"); exit(1);}
   1.951 +   
   1.952 +   //Touch memory to avoid page faults
   1.953 +   void *ptr,*endPtr; 
   1.954 +   endPtr = (void*)firstChunk+MALLOC_ADDITIONAL_MEM_FROM_OS_SIZE;
   1.955 +   for(ptr = firstChunk; ptr < endPtr; ptr+=PAGE_SIZE)
   1.956 +   {
   1.957 +       *(char*)ptr = 0;
   1.958 +   }
   1.959 +
   1.960 +   freeListHead->prevChunkInFreeList = NULL;
   1.961 +      //Use this addr to free the heap when cleanup
   1.962 +   freeListHead->nextLowerInMem      = firstChunk;
   1.963 +      //to identify top-of-heap elem, compare this addr to elem's next higher
   1.964 +   freeListHead->nextHigherInMem     = (void*)( (uintptr_t)firstChunk +
   1.965 +                                         MALLOC_ADDITIONAL_MEM_FROM_OS_SIZE);
   1.966 +   freeListHead->nextChunkInFreeList = firstChunk;
   1.967 +
   1.968 +   firstChunk->nextChunkInFreeList   = NULL;
   1.969 +   firstChunk->prevChunkInFreeList   = freeListHead;
   1.970 +      //next Higher has to be set to top of chunk, so can calc size in malloc
   1.971 +   firstChunk->nextHigherInMem       = (void*)( (uintptr_t)firstChunk +
   1.972 +                                         MALLOC_ADDITIONAL_MEM_FROM_OS_SIZE);
   1.973 +   firstChunk->nextLowerInMem        = NULL; //identifies as bott of heap
   1.974 +   
   1.975 +   _VMSMasterEnv->amtOfOutstandingMem = 0; //none allocated yet
   1.976 +
   1.977 +   return freeListHead;
   1.978 + }
   1.979 +
   1.980 +
   1.981 +/*Designed to be called from the main thread outside of VMS, during cleanup
   1.982 + */
   1.983 +void
   1.984 +VMS_ext__free_free_list( MallocProlog *freeListHead )
   1.985 + {    
   1.986 +      //stashed a ptr to the one and only bug chunk malloc'd from OS in the
   1.987 +      // free list head's next lower in mem pointer
   1.988 +   free( freeListHead->nextLowerInMem );
   1.989 +
   1.990 +   //don't free the head -- it'll be in an array eventually -- free whole
   1.991 +   // array when all the free lists linked from it have already been freed
   1.992 + }
   1.993 +