BBlockCache: Use a pthread_mutex instead of BLocker.

The lighter "struct mutex" is in a private header, so we can't
inline it in a public one, so just use pthread_mutex here.

By adjusting padding, the class size stays the same (72 bytes
on 32-bit, 96 bytes on 64-bit; confirmed via static_assert.)

A quick benchmark running "new/delete BMessage" in a loop on 4
threads at once goes from 30-36 seconds before this commit
to around 13-17 seconds, sometimes as low as 3 seconds, afterwards,
so clearly this is a significant improvement.

This also eliminates another BLocker allocated on application startup.

headers/os/support/BlockCache.h

@@ -6,7 +6,7 @@
 #define _BLOCK_CACHE_H
 
 
-#include <Locker.h>
+#include <SupportDefs.h>
 
 
 enum {
@@ -31,16 +31,18 @@ private:
 						BBlockCache	&operator=(const BBlockCache &);
 
 private:
-		struct _FreeBlock;
+	struct _FreeBlock;
 
-		_FreeBlock*	fFreeList;
-		size_t		fBlockSize;
-		int32		fFreeBlocks;
-		int32		fBlockCount;
-		BLocker		fLocker;
-		void*		(*fAlloc)(size_t size);
-		void		(*fFree)(void *pointer);
-		uint32		_reserved[2];
+	_FreeBlock*		fFreeList;
+	const size_t	fBlockSize;
+	void*			(*fAlloc)(size_t size);
+	void			(*fFree)(void *pointer);
+
+	pthread_mutex_t fLock;
+	int32			fFreeBlocks;
+	int32			fBlockCount;
+
+	uint32 _reserved[6];
 };
 
 

src/kits/support/BlockCache.cpp

@@ -9,6 +9,7 @@
 #include <string.h>
 #include <stdlib.h>
 #include <new>
+#include <pthread.h>
 
 
 #ifdef __HAIKU__
@@ -39,11 +40,10 @@ BBlockCache::BBlockCache(uint32 blockCount, size_t blockSize,
 	:
 	fFreeList(0),
 	fBlockSize(blockSize),
+	fAlloc(NULL),
+	fFree(NULL),
 	fFreeBlocks(0),
-	fBlockCount(blockCount),
-	fLocker("some BBlockCache lock"),
-	fAlloc(0),
-	fFree(0)
+	fBlockCount(blockCount)
 {
 	switch (allocationType) {
 		case B_OBJECT_CACHE:
@@ -61,6 +61,8 @@ BBlockCache::BBlockCache(uint32 blockCount, size_t blockSize,
 	if (heap_debug_get_allocation_info != NULL)
 		return;
 
+	pthread_mutex_init(&fLock, NULL);
+
 	// To properly maintain a list of free buffers, a buffer must be
 	// large enough to contain the _FreeBlock struct that is used.
 	if (blockSize < sizeof(_FreeBlock))
@@ -87,7 +89,7 @@ BBlockCache::BBlockCache(uint32 blockCount, size_t blockSize,
 BBlockCache::~BBlockCache()
 {
 	// walk the free list and deallocate all blocks
-	fLocker.Lock();
+	pthread_mutex_lock(&fLock);
 	while (fFreeList) {
 		ASSERT(fFreeList->magic1 == MAGIC1);
 		ASSERT(fFreeList->magic2 == MAGIC2 + (uint32)(addr_t)fFreeList->next);
@@ -96,7 +98,8 @@ BBlockCache::~BBlockCache()
 		DEBUG_ONLY(memset(pointer, 0xCC, sizeof(_FreeBlock)));
 		fFree(pointer);
 	}
-	fLocker.Unlock();
+
+	pthread_mutex_destroy(&fLock);
 }
 
 
@@ -106,8 +109,7 @@ BBlockCache::Get(size_t blockSize)
 	if (heap_debug_get_allocation_info != NULL)
 		return fAlloc(blockSize);
 
-	if (!fLocker.Lock())
-		return 0;
+	pthread_mutex_lock(&fLock);
 	void *pointer;
 	if (blockSize == fBlockSize && fFreeList != 0) {
 		// we can take a block from the list
@@ -117,14 +119,16 @@ BBlockCache::Get(size_t blockSize)
 		fFreeList = fFreeList->next;
 		fFreeBlocks--;
 		DEBUG_ONLY(memset(pointer, 0xCC, sizeof(_FreeBlock)));
+		pthread_mutex_unlock(&fLock);
+		return pointer;
 	} else {
+		pthread_mutex_unlock(&fLock);
 		if (blockSize < sizeof(_FreeBlock))
 			blockSize = sizeof(_FreeBlock);
 		pointer = fAlloc(blockSize);
 		DEBUG_ONLY(if (pointer) memset(pointer, 0xCC, sizeof(_FreeBlock)));
+		return pointer;
 	}
-	fLocker.Unlock();
-	return pointer;
 }
 
 
@@ -136,8 +140,7 @@ BBlockCache::Save(void *pointer, size_t blockSize)
 		return;
 	}
 
-	if (!fLocker.Lock())
-		return;
+	pthread_mutex_lock(&fLock);
 	if (blockSize == fBlockSize && fFreeBlocks < fBlockCount) {
 		// the block needs to be returned to the cache
 		_FreeBlock *block = reinterpret_cast<_FreeBlock *>(pointer);
@@ -146,11 +149,13 @@ BBlockCache::Save(void *pointer, size_t blockSize)
 		fFreeBlocks++;
 		DEBUG_ONLY(block->magic1 = MAGIC1);
 		DEBUG_ONLY(block->magic2 = MAGIC2 + (uint32)(addr_t)block->next);
+		pthread_mutex_unlock(&fLock);
 	} else {
+		pthread_mutex_unlock(&fLock);
 		DEBUG_ONLY(memset(pointer, 0xCC, sizeof(_FreeBlock)));
 		fFree(pointer);
+		return;
 	}
-	fLocker.Unlock();
 }