+ if (!prioritisedExists) /* None found, so we can clear this */
+ dev->hasPendingPrioritisedGCs = 0;
+ }
+
+ /* If we're doing aggressive GC then we are happy to take a less-dirty block, and
+ * search harder.
+ * else (we're doing a leasurely gc), then we only bother to do this if the
+ * block has only a few pages in use.
+ */
+
+ if (!selected){
+ int pagesUsed;
+ int nBlocks = dev->internalEndBlock - dev->internalStartBlock + 1;
+ if (aggressive){
+ threshold = dev->param.nChunksPerBlock;
+ iterations = nBlocks;
+ } else {
+ int maxThreshold = dev->param.nChunksPerBlock/2;
+ threshold = background ?
+ (dev->gcNotDone + 2) * 2 : 0;
+ if(threshold <YAFFS_GC_PASSIVE_THRESHOLD)
+ threshold = YAFFS_GC_PASSIVE_THRESHOLD;
+ if(threshold > maxThreshold)
+ threshold = maxThreshold;
+
+ iterations = nBlocks / 16 + 1;
+ if (iterations > 100)
+ iterations = 100;
+ }
+
+ for (i = 0;
+ i < iterations &&
+ (dev->gcDirtiest < 1 ||
+ dev->gcPagesInUse > YAFFS_GC_GOOD_ENOUGH);
+ i++) {
+ dev->gcBlockFinder++;
+ if (dev->gcBlockFinder < dev->internalStartBlock ||
+ dev->gcBlockFinder > dev->internalEndBlock)
+ dev->gcBlockFinder = dev->internalStartBlock;
+
+ bi = yaffs_GetBlockInfo(dev, dev->gcBlockFinder);
+
+ pagesUsed = bi->pagesInUse - bi->softDeletions;
+
+ if (bi->blockState == YAFFS_BLOCK_STATE_FULL &&
+ pagesUsed < dev->param.nChunksPerBlock &&
+ (dev->gcDirtiest < 1 || pagesUsed < dev->gcPagesInUse) &&
+ yaffs_BlockNotDisqualifiedFromGC(dev, bi)) {
+ dev->gcDirtiest = dev->gcBlockFinder;
+ dev->gcPagesInUse = pagesUsed;
+ }
+ }
+
+ if(dev->gcDirtiest > 0 && dev->gcPagesInUse <= threshold)
+ selected = dev->gcDirtiest;
+ }
+
+ /*
+ * If nothing has been selected for a while, try selecting the oldest dirty
+ * because that's gumming up the works.
+ */
+
+ if(!selected && dev->param.isYaffs2 &&
+ dev->gcNotDone >= ( background ? 10 : 20)){
+ yaffs_FindOldestDirtySequence(dev);
+ if(dev->oldestDirtyBlock > 0) {
+ selected = dev->oldestDirtyBlock;
+ dev->gcDirtiest = selected;
+ dev->oldestDirtyGCs++;
+ bi = yaffs_GetBlockInfo(dev, selected);
+ dev->gcPagesInUse = bi->pagesInUse - bi->softDeletions;
+ } else
+ dev->gcNotDone = 0;
+ }
+
+ if(selected){
+ T(YAFFS_TRACE_GC,
+ (TSTR("GC Selected block %d with %d free, prioritised:%d" TENDSTR),
+ selected,
+ dev->param.nChunksPerBlock - dev->gcPagesInUse,
+ prioritised));
+
+ if(background)
+ dev->backgroundGCs++;
+ dev->gcDirtiest = 0;
+ dev->gcPagesInUse = 0;
+ dev->gcNotDone = 0;
+ if(dev->refreshSkip > 0)
+ dev->refreshSkip--;
+ } else{
+ dev->gcNotDone++;
+ T(YAFFS_TRACE_GC,
+ (TSTR("GC none: finder %d skip %d threshold %d dirtiest %d using %d oldest %d%s" TENDSTR),
+ dev->gcBlockFinder, dev->gcNotDone,
+ threshold,
+ dev->gcDirtiest, dev->gcPagesInUse,
+ dev->oldestDirtyBlock,
+ background ? " bg" : ""));
+ }
+
+ return selected;
+}
+
+/* New garbage collector
+ * If we're very low on erased blocks then we do aggressive garbage collection
+ * otherwise we do "leasurely" garbage collection.
+ * Aggressive gc looks further (whole array) and will accept less dirty blocks.
+ * Passive gc only inspects smaller areas and will only accept more dirty blocks.
+ *
+ * The idea is to help clear out space in a more spread-out manner.
+ * Dunno if it really does anything useful.
+ */
+static int yaffs_CheckGarbageCollection(yaffs_Device *dev, int background)
+{
+ int aggressive = 0;
+ int gcOk = YAFFS_OK;
+ int maxTries = 0;
+
+ int minErased;
+ int erasedChunks;
+
+ int checkpointBlockAdjust;
+
+ if(dev->param.gcControl &&
+ (dev->param.gcControl(dev) & 1) == 0)
+ return YAFFS_OK;
+
+ if (dev->gcDisable) {
+ /* Bail out so we don't get recursive gc */
+ return YAFFS_OK;
+ }
+
+ /* This loop should pass the first time.
+ * We'll only see looping here if the collection does not increase space.
+ */
+
+ do {
+ maxTries++;
+
+ checkpointBlockAdjust = yaffs_CalcCheckpointBlocksRequired(dev) - dev->blocksInCheckpoint;
+ if (checkpointBlockAdjust < 0)
+ checkpointBlockAdjust = 0;
+
+ minErased = dev->param.nReservedBlocks + checkpointBlockAdjust + 1;
+ erasedChunks = dev->nErasedBlocks * dev->param.nChunksPerBlock;
+
+ /* If we need a block soon then do aggressive gc.*/
+ if (dev->nErasedBlocks < minErased)
+ aggressive = 1;
+ else {
+ if(dev->gcSkip > 20)
+ dev->gcSkip = 20;
+ if(erasedChunks < dev->nFreeChunks/2 ||
+ dev->gcSkip < 1 ||
+ background)
+ aggressive = 0;
+ else {
+ dev->gcSkip--;
+ break;
+ }
+ }
+
+ dev->gcSkip = 5;
+
+ /* If we don't already have a block being gc'd then see if we should start another */
+
+ if (dev->gcBlock < 1 && !aggressive) {
+ dev->gcBlock = yaffs_FindRefreshBlock(dev);
+ dev->gcChunk = 0;
+ }
+ if (dev->gcBlock < 1) {
+ dev->gcBlock = yaffs_FindBlockForGarbageCollection(dev, aggressive, background);
+ dev->gcChunk = 0;
+ }
+
+ if (dev->gcBlock > 0) {
+ dev->allGCs++;
+ if (!aggressive)
+ dev->passiveGCs++;
+
+ T(YAFFS_TRACE_GC,
+ (TSTR