Don't run the GC too often

Some test cases were badly trashing the GC, running it
way too often. Fix this by only running the GC after
we allocated more than 50% of the amount of available
items.

Change-Id: Icfe6d0730552ef2298963de706213ebc9e3e342c
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>

1 files changed, 13 insertions, 8 deletions

diff --git a/src/qml/jsruntime/qv4mm.cpp b/src/qml/jsruntime/qv4mm.cpp
index 057a583dc3..c2d0c3a5ed 100644
--- a/src/qml/jsruntime/qv4mm.cpp
+++ b/src/qml/jsruntime/qv4mm.cpp
@@ -146,6 +146,8 @@ struct MemoryManager::Data
     uint nChunks[MaxItemSize/16];
     uint availableItems[MaxItemSize/16];
     uint allocCount[MaxItemSize/16];
+    int totalItems;
+    int totalAlloc;
     struct Chunk {
         PageAllocation memory;
         int chunkSize;
@@ -249,21 +251,20 @@ Managed *MemoryManager::alloc(std::size_t size)
     willAllocate(size);
 #endif // DETAILED_MM_STATS
 
-    assert(size >= 16);
-    assert(size % 16 == 0);
+    Q_ASSERT(size >= 16);
+    Q_ASSERT(size % 16 == 0);
 
     size_t pos = size >> 4;
-    ++m_d->allocCount[pos];
 
     // fits into a small bucket
-    assert(size < MemoryManager::Data::MaxItemSize);
+    Q_ASSERT(size < MemoryManager::Data::MaxItemSize);
 
     Managed *m = m_d->smallItems[pos];
     if (m)
         goto found;
 
     // try to free up space, otherwise allocate
-    if (m_d->allocCount[pos] > (m_d->availableItems[pos] >> 1) && !m_d->aggressiveGC) {
+    if (m_d->allocCount[pos] > (m_d->availableItems[pos] >> 1) && m_d->totalAlloc > (m_d->totalItems >> 1) && !m_d->aggressiveGC) {
         runGC();
         m = m_d->smallItems[pos];
         if (m)
@@ -299,6 +300,7 @@ Managed *MemoryManager::alloc(std::size_t size)
         *last = 0;
         m = m_d->smallItems[pos];
         m_d->availableItems[pos] += allocation.memory.size()/size - 1;
+        m_d->totalItems += allocation.memory.size()/size - 1;
 #ifdef V4_USE_VALGRIND
         VALGRIND_MAKE_MEM_NOACCESS(allocation.memory, allocation.chunkSize);
 #endif
@@ -309,6 +311,8 @@ Managed *MemoryManager::alloc(std::size_t size)
     VALGRIND_MEMPOOL_ALLOC(this, m, size);
 #endif
 
+    ++m_d->allocCount[pos];
+    ++m_d->totalAlloc;
     m_d->smallItems[pos] = m->nextFree();
     return m;
 }
@@ -477,7 +481,7 @@ void MemoryManager::sweep(char *chunkStart, std::size_t chunkSize, size_t size,
 //        qDebug("chunk @ %p, size = %lu, in use: %s, mark bit: %s",
 //               chunk, m->size, (m->inUse ? "yes" : "no"), (m->markBit ? "true" : "false"));
 
-        assert((qintptr) chunk % 16 == 0);
+        Q_ASSERT((qintptr) chunk % 16 == 0);
 
         if (m->inUse) {
             if (m->markBit) {
@@ -538,6 +542,7 @@ void MemoryManager::runGC()
 //              << " objects in " << t.elapsed()
 //              << "ms" << std::endl;
     memset(m_d->allocCount, 0, sizeof(m_d->allocCount));
+    m_d->totalAlloc = 0;
 }
 
 void MemoryManager::setEnableGC(bool enableGC)
@@ -621,7 +626,7 @@ void MemoryManager::collectFromStack() const
         heapChunkBoundaries[i++] = reinterpret_cast<char*>(it->memory.base()) - 1;
         heapChunkBoundaries[i++] = reinterpret_cast<char*>(it->memory.base()) + it->memory.size() - it->chunkSize;
     }
-    assert(i == m_d->heapChunks.count() * 2);
+    Q_ASSERT(i == m_d->heapChunks.count() * 2);
 
     for (; current < m_d->stackTop; ++current) {
         char* genericPtr = reinterpret_cast<char *>(*current);
@@ -630,7 +635,7 @@ void MemoryManager::collectFromStack() const
             continue;
         int index = std::lower_bound(heapChunkBoundaries, heapChunkBoundariesEnd, genericPtr) - heapChunkBoundaries;
         // An odd index means the pointer is _before_ the end of a heap chunk and therefore valid.
-        assert(index >= 0 && index < m_d->heapChunks.count() * 2);
+        Q_ASSERT(index >= 0 && index < m_d->heapChunks.count() * 2);
         if (index & 1) {
             int size = m_d->heapChunks.at(index >> 1).chunkSize;
             Managed *m = reinterpret_cast<Managed *>(genericPtr);