* Added ObjectCache::alignment, the object alignment and used the alignment for

incrementing the cache color cycle. Using the fixed value (8) would
  potentially misalign the object again.
* Don't use CACHE_ALIGN_ON_SIZE for object caches any longer -- we have the
  alignment parameter anyway (the flag is still used for the MemoryManager,
  though).
* ObjectCache::InitSlab(): Slab coloring *was* done when CACHE_ALIGN_ON_SIZE
  was given, i.e. exactly the wrong way around. Also the cache_color_cycle
  computation was weird -- color 0 was used twice in a row.
* The "slabs" and "slab_cache" KDL commands also print the alignment, now.



git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@37534 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/system/kernel/slab/ObjectCache.cpp

@@ -17,9 +17,6 @@
 #include "slab_private.h"
 
 
-static const size_t kCacheColorPeriod = 8;
-
-
 static void
 object_cache_return_object_wrapper(object_depot* depot, void* cookie,
 	void* object, uint32 flags)
@@ -52,6 +49,9 @@ ObjectCache::Init(const char* name, size_t objectSize, size_t alignment,
 	if (objectSize < sizeof(object_link))
 		objectSize = sizeof(object_link);
 
+	if (alignment < kMinObjectAlignment)
+		alignment = kMinObjectAlignment;
+
 	if (alignment > 0 && (objectSize & (alignment - 1)))
 		object_size = objectSize + alignment - (objectSize & (alignment - 1));
 	else
@@ -60,6 +60,7 @@ ObjectCache::Init(const char* name, size_t objectSize, size_t alignment,
 	TRACE_CACHE(this, "init %lu, %lu -> %lu", objectSize, alignment,
 		object_size);
 
+	this->alignment = alignment;
 	cache_color_cycle = 0;
 	total_objects = 0;
 	used_count = 0;
@@ -123,15 +124,11 @@ ObjectCache::InitSlab(slab* slab, void* pages, size_t byteCount, uint32 flags)
 
 	size_t spareBytes = byteCount - (slab->size * object_size);
 
-	if ((this->flags & CACHE_ALIGN_ON_SIZE) != 0) {
-		slab->offset = cache_color_cycle;
+	slab->offset = cache_color_cycle;
 
-		if (slab->offset > spareBytes)
-			cache_color_cycle = slab->offset = 0;
-		else
-			cache_color_cycle += kCacheColorPeriod;
-	} else
-		slab->offset = 0;
+	cache_color_cycle += alignment;
+	if (cache_color_cycle > spareBytes)
+		cache_color_cycle = 0;
 
 	TRACE_CACHE(this, "  %lu objects, %lu spare bytes, offset %lu",
 		slab->size, spareBytes, slab->offset);

src/system/kernel/slab/ObjectCache.h

@@ -41,6 +41,7 @@ struct ObjectCache : DoublyLinkedListLinkImpl<ObjectCache> {
 			char				name[32];
 			mutex				lock;
 			size_t				object_size;
+			size_t				alignment;
 			size_t				cache_color_cycle;
 			SlabList			empty;
 			SlabList			partial;

src/system/kernel/slab/Slab.cpp

@@ -208,17 +208,18 @@ dump_slab(::slab* slab)
 static int
 dump_slabs(int argc, char* argv[])
 {
-	kprintf("%10s %22s %8s %8s %6s %8s %8s %8s\n", "address", "name",
-		"objsize", "usage", "empty", "usedobj", "total", "flags");
+	kprintf("%10s %22s %8s %8s %8s %6s %8s %8s %8s\n", "address", "name",
+		"objsize", "align", "usage", "empty", "usedobj", "total", "flags");
 
 	ObjectCacheList::Iterator it = sObjectCaches.GetIterator();
 
 	while (it.HasNext()) {
 		ObjectCache* cache = it.Next();
 
-		kprintf("%p %22s %8lu %8lu %6lu %8lu %8lu %8lx\n", cache, cache->name,
-			cache->object_size, cache->usage, cache->empty_count,
-			cache->used_count, cache->total_objects, cache->flags);
+		kprintf("%p %22s %8lu %8" B_PRIuSIZE " %8lu %6lu %8lu %8lu %8lx\n",
+			cache, cache->name, cache->object_size, cache->alignment,
+			cache->usage, cache->empty_count, cache->used_count,
+			cache->total_objects, cache->flags);
 	}
 
 	return 0;
@@ -238,6 +239,7 @@ dump_cache_info(int argc, char* argv[])
 	kprintf("name:              %s\n", cache->name);
 	kprintf("lock:              %p\n", &cache->lock);
 	kprintf("object_size:       %lu\n", cache->object_size);
+	kprintf("alignment:         %" B_PRIuSIZE "\n", cache->alignment);
 	kprintf("cache_color_cycle: %lu\n", cache->cache_color_cycle);
 	kprintf("total_objects:     %lu\n", cache->total_objects);
 	kprintf("used_count:        %lu\n", cache->used_count);

src/system/kernel/slab/allocator.cpp

@@ -74,7 +74,7 @@ size_to_index(size_t size)
 void*
 block_alloc(size_t size, size_t alignment, uint32 flags)
 {
-	if (alignment > 8) {
+	if (alignment > kMinObjectAlignment) {
 		// Make size >= alignment and a power of two. This is sufficient, since
 		// all of our object caches with power of two sizes are aligned. We may
 		// waste quite a bit of memory, but memalign() is very rarely used
@@ -173,16 +173,15 @@ block_allocator_init_boot()
 		size_t size = kBlockSizes[index];
 
 		// align the power of two objects to their size
-		if ((size & (size - 1)) == 0)
-			flags |= CACHE_ALIGN_ON_SIZE;
+		size_t alignment = (size & (size - 1)) == 0 ? size : 0;
 
 		// For the larger allocation sizes disable the object depot, so we don't
 		// keep lot's of unused objects around.
 		if (size > 2048)
 			flags |= CACHE_NO_DEPOT;
 
-		sBlockCaches[index] = create_object_cache_etc(name, size, 0, 0, 0, 0,
-			flags, NULL, NULL, NULL, NULL);
+		sBlockCaches[index] = create_object_cache_etc(name, size, alignment, 0,
+			0, 0, flags, NULL, NULL, NULL, NULL);
 		if (sBlockCaches[index] == NULL)
 			panic("allocator: failed to init block cache");
 	}

src/system/kernel/slab/slab_private.h

@@ -26,6 +26,11 @@
 #define COMPONENT_PARANOIA_LEVEL	OBJECT_CACHE_PARANOIA
 #include <debug_paranoia.h>
 
+
+
+static const size_t kMinObjectAlignment = 8;
+
+
 struct ObjectCache;
 struct object_depot;