6 files changed, 202 insertions, 105 deletions

diff --git a/src/gallium/auxiliary/pipebuffer/pb_buffer_fenced.c b/src/gallium/auxiliary/pipebuffer/pb_buffer_fenced.c
index 410d336fef..17b2781052 100644
--- a/src/gallium/auxiliary/pipebuffer/pb_buffer_fenced.c
+++ b/src/gallium/auxiliary/pipebuffer/pb_buffer_fenced.c
@@ -69,7 +69,7 @@
 
 struct fenced_buffer_list
 {
-   _glthread_Mutex mutex;
+   pipe_mutex mutex;
    
    struct pipe_winsys *winsys;
    
@@ -240,7 +240,7 @@ fenced_buffer_destroy(struct pb_buffer *buf)
    struct fenced_buffer *fenced_buf = fenced_buffer(buf);   
    struct fenced_buffer_list *fenced_list = fenced_buf->list;
 
-   _glthread_LOCK_MUTEX(fenced_list->mutex);
+   pipe_mutex_lock(fenced_list->mutex);
    assert(fenced_buf->base.base.refcount == 0);
    if (fenced_buf->fence) {
       struct pipe_winsys *winsys = fenced_list->winsys;
@@ -263,7 +263,7 @@ fenced_buffer_destroy(struct pb_buffer *buf)
    else {
       _fenced_buffer_destroy(fenced_buf);
    }
-   _glthread_UNLOCK_MUTEX(fenced_list->mutex);
+   pipe_mutex_unlock(fenced_list->mutex);
 }
 
 
@@ -396,7 +396,7 @@ buffer_fence(struct pb_buffer *buf,
       return;
    }
    
-   _glthread_LOCK_MUTEX(fenced_list->mutex);
+   pipe_mutex_lock(fenced_list->mutex);
    if (fenced_buf->fence)
       _fenced_buffer_remove(fenced_list, fenced_buf);
    if (fence) {
@@ -404,7 +404,7 @@ buffer_fence(struct pb_buffer *buf,
       fenced_buf->flags |= flags & PIPE_BUFFER_USAGE_GPU_READ_WRITE;
       _fenced_buffer_add(fenced_buf);
    }
-   _glthread_UNLOCK_MUTEX(fenced_list->mutex);
+   pipe_mutex_unlock(fenced_list->mutex);
 }
 
 
@@ -423,7 +423,7 @@ fenced_buffer_list_create(struct pipe_winsys *winsys)
 
    fenced_list->numDelayed = 0;
    
-   _glthread_INIT_MUTEX(fenced_list->mutex);
+   pipe_mutex_init(fenced_list->mutex);
 
    return fenced_list;
 }
@@ -433,28 +433,28 @@ void
 fenced_buffer_list_check_free(struct fenced_buffer_list *fenced_list, 
                               int wait)
 {
-   _glthread_LOCK_MUTEX(fenced_list->mutex);
+   pipe_mutex_lock(fenced_list->mutex);
    _fenced_buffer_list_check_free(fenced_list, wait);
-   _glthread_UNLOCK_MUTEX(fenced_list->mutex);
+   pipe_mutex_unlock(fenced_list->mutex);
 }
 
 
 void
 fenced_buffer_list_destroy(struct fenced_buffer_list *fenced_list)
 {
-   _glthread_LOCK_MUTEX(fenced_list->mutex);
+   pipe_mutex_lock(fenced_list->mutex);
 
    /* Wait on outstanding fences */
    while (fenced_list->numDelayed) {
-      _glthread_UNLOCK_MUTEX(fenced_list->mutex);
+      pipe_mutex_unlock(fenced_list->mutex);
 #if defined(PIPE_OS_LINUX)
       sched_yield();
 #endif
       _fenced_buffer_list_check_free(fenced_list, 1);
-      _glthread_LOCK_MUTEX(fenced_list->mutex);
+      pipe_mutex_lock(fenced_list->mutex);
    }
 
-   _glthread_UNLOCK_MUTEX(fenced_list->mutex);
+   pipe_mutex_unlock(fenced_list->mutex);
    
    FREE(fenced_list);
 }
diff --git a/src/gallium/auxiliary/pipebuffer/pb_bufmgr_cache.c b/src/gallium/auxiliary/pipebuffer/pb_bufmgr_cache.c
index b914c2d0fe..1ec422fb19 100644
--- a/src/gallium/auxiliary/pipebuffer/pb_bufmgr_cache.c
+++ b/src/gallium/auxiliary/pipebuffer/pb_bufmgr_cache.c
@@ -79,7 +79,7 @@ struct pb_cache_manager
    struct pb_manager *provider;
    unsigned usecs;
    
-   _glthread_Mutex mutex;
+   pipe_mutex mutex;
    
    struct list_head delayed;
    size_t numDelayed;
@@ -153,7 +153,7 @@ pb_cache_buffer_destroy(struct pb_buffer *_buf)
    struct pb_cache_buffer *buf = pb_cache_buffer(_buf);   
    struct pb_cache_manager *mgr = buf->mgr;
 
-   _glthread_LOCK_MUTEX(mgr->mutex);
+   pipe_mutex_lock(mgr->mutex);
    assert(buf->base.base.refcount == 0);
    
    _pb_cache_buffer_list_check_free(mgr);
@@ -162,7 +162,7 @@ pb_cache_buffer_destroy(struct pb_buffer *_buf)
    util_time_add(&buf->start, mgr->usecs, &buf->end);
    LIST_ADDTAIL(&buf->head, &mgr->delayed);
    ++mgr->numDelayed;
-   _glthread_UNLOCK_MUTEX(mgr->mutex);
+   pipe_mutex_unlock(mgr->mutex);
 }
 
 
@@ -235,7 +235,7 @@ pb_cache_manager_create_buffer(struct pb_manager *_mgr,
    struct list_head *curr, *next;
    struct util_time now;
    
-   _glthread_LOCK_MUTEX(mgr->mutex);
+   pipe_mutex_lock(mgr->mutex);
 
    buf = NULL;
    curr = mgr->delayed.next;
@@ -249,27 +249,35 @@ pb_cache_manager_create_buffer(struct pb_manager *_mgr,
 	 buf = curr_buf;
       else if(util_time_timeout(&curr_buf->start, &curr_buf->end, &now))
 	 _pb_cache_buffer_destroy(curr_buf);
+      else
+         /* This buffer (and all hereafter) are still hot in cache */
+         break;
       curr = next; 
       next = curr->next;
    }
 
    /* keep searching in the hot buffers */
-   while(!buf && curr != &mgr->delayed) {
-      curr_buf = LIST_ENTRY(struct pb_cache_buffer, curr, head);
-      if(pb_cache_is_buffer_compat(curr_buf, size, desc))
-	 buf = curr_buf;
-      curr = next; 
-      next = curr->next;
+   if(!buf) {
+      while(curr != &mgr->delayed) {
+         curr_buf = LIST_ENTRY(struct pb_cache_buffer, curr, head);
+         if(pb_cache_is_buffer_compat(curr_buf, size, desc)) {
+            buf = curr_buf;
+            break;
+         }
+         /* no need to check the timeout here */
+         curr = next;
+         next = curr->next;
+      }
    }
    
    if(buf) {
       LIST_DEL(&buf->head);
-      _glthread_UNLOCK_MUTEX(mgr->mutex);
+      pipe_mutex_unlock(mgr->mutex);
       ++buf->base.base.refcount;
       return &buf->base;
    }
    
-   _glthread_UNLOCK_MUTEX(mgr->mutex);
+   pipe_mutex_unlock(mgr->mutex);
 
    buf = CALLOC_STRUCT(pb_cache_buffer);
    if(!buf)
@@ -305,7 +313,7 @@ pb_cache_flush(struct pb_manager *_mgr)
    struct list_head *curr, *next;
    struct pb_cache_buffer *buf;
 
-   _glthread_LOCK_MUTEX(mgr->mutex);
+   pipe_mutex_lock(mgr->mutex);
    curr = mgr->delayed.next;
    next = curr->next;
    while(curr != &mgr->delayed) {
@@ -314,7 +322,7 @@ pb_cache_flush(struct pb_manager *_mgr)
       curr = next; 
       next = curr->next;
    }
-   _glthread_UNLOCK_MUTEX(mgr->mutex);
+   pipe_mutex_unlock(mgr->mutex);
 }
 
 
@@ -345,7 +353,7 @@ pb_cache_manager_create(struct pb_manager *provider,
    mgr->usecs = usecs;
    LIST_INITHEAD(&mgr->delayed);
    mgr->numDelayed = 0;
-   _glthread_INIT_MUTEX(mgr->mutex);
+   pipe_mutex_init(mgr->mutex);
       
    return &mgr->base;
 }
diff --git a/src/gallium/auxiliary/pipebuffer/pb_bufmgr_debug.c b/src/gallium/auxiliary/pipebuffer/pb_bufmgr_debug.c
index 4cb8c3bb55..5f1ed3e5a8 100644
--- a/src/gallium/auxiliary/pipebuffer/pb_bufmgr_debug.c
+++ b/src/gallium/auxiliary/pipebuffer/pb_bufmgr_debug.c
@@ -129,7 +129,7 @@ check_random_pattern(const uint8_t *dst, size_t size,
    for(i = 0; i < size; ++i) {
       if(*dst++ != random_pattern[i % sizeof(random_pattern)]) {
          *min_ofs = MIN2(*min_ofs, i);
-         *max_ofs = MIN2(*max_ofs, i);
+         *max_ofs = MAX2(*max_ofs, i);
 	 result = FALSE;
       }
    }
@@ -138,12 +138,30 @@ check_random_pattern(const uint8_t *dst, size_t size,
 
 
 static void
-pb_debug_buffer_destroy(struct pb_buffer *_buf)
+pb_debug_buffer_fill(struct pb_debug_buffer *buf)
 {
-   struct pb_debug_buffer *buf = pb_debug_buffer(_buf);  
    uint8_t *map;
    
-   assert(!buf->base.base.refcount);
+   map = pb_map(buf->buffer, PIPE_BUFFER_USAGE_CPU_WRITE);
+   assert(map);
+   if(map) {
+      fill_random_pattern(map, buf->underflow_size);
+      fill_random_pattern(map + buf->underflow_size + buf->base.base.size, 
+                          buf->overflow_size);
+      pb_unmap(buf->buffer);
+   }
+}
+
+
+/**
+ * Check for under/over flows.
+ * 
+ * Should be called with the buffer unmaped.
+ */
+static void
+pb_debug_buffer_check(struct pb_debug_buffer *buf)
+{
+   uint8_t *map;
    
    map = pb_map(buf->buffer, PIPE_BUFFER_USAGE_CPU_READ);
    assert(map);
@@ -154,24 +172,45 @@ pb_debug_buffer_destroy(struct pb_buffer *_buf)
       underflow = !check_random_pattern(map, buf->underflow_size, 
                                         &min_ofs, &max_ofs);
       if(underflow) {
-	 debug_printf("buffer underflow (%u of %u bytes) detected\n",
-	              buf->underflow_size - min_ofs,
-	              buf->underflow_size);
+         debug_printf("buffer underflow (offset -%u%s to -%u bytes) detected\n",
+                      buf->underflow_size - min_ofs,
+                      min_ofs == 0 ? "+" : "",
+                      buf->underflow_size - max_ofs);
       }
       
       overflow = !check_random_pattern(map + buf->underflow_size + buf->base.base.size, 
                                        buf->overflow_size, 
                                        &min_ofs, &max_ofs);
       if(overflow) {
-         debug_printf("buffer overflow (%u of %u bytes) detected\n",
+         debug_printf("buffer overflow (size %u plus offset %u to %u%s bytes) detected\n",
+                      buf->base.base.size,
+                      min_ofs,
                       max_ofs,
-                      buf->overflow_size);
+                      max_ofs == buf->overflow_size - 1 ? "+" : "");
       }
       
       debug_assert(!underflow && !overflow);
-      
+
+      /* re-fill if not aborted */
+      if(underflow)
+         fill_random_pattern(map, buf->underflow_size);
+      if(overflow)
+         fill_random_pattern(map + buf->underflow_size + buf->base.base.size, 
+                             buf->overflow_size);
+
       pb_unmap(buf->buffer);
    }
+}
+
+
+static void
+pb_debug_buffer_destroy(struct pb_buffer *_buf)
+{
+   struct pb_debug_buffer *buf = pb_debug_buffer(_buf);  
+   
+   assert(!buf->base.base.refcount);
+   
+   pb_debug_buffer_check(buf);
 
    pb_reference(&buf->buffer, NULL);
    FREE(buf);
@@ -183,9 +222,14 @@ pb_debug_buffer_map(struct pb_buffer *_buf,
                     unsigned flags)
 {
    struct pb_debug_buffer *buf = pb_debug_buffer(_buf);
-   void *map = pb_map(buf->buffer, flags);
+   void *map;
+   
+   pb_debug_buffer_check(buf);
+
+   map = pb_map(buf->buffer, flags);
    if(!map)
       return NULL;
+   
    return (uint8_t *)map + buf->underflow_size;
 }
 
@@ -195,6 +239,8 @@ pb_debug_buffer_unmap(struct pb_buffer *_buf)
 {
    struct pb_debug_buffer *buf = pb_debug_buffer(_buf);   
    pb_unmap(buf->buffer);
+   
+   pb_debug_buffer_check(buf);
 }
 
 
@@ -227,7 +273,6 @@ pb_debug_manager_create_buffer(struct pb_manager *_mgr,
    struct pb_debug_buffer *buf;
    struct pb_desc real_desc;
    size_t real_size;
-   uint8_t *map;
    
    buf = CALLOC_STRUCT(pb_debug_buffer);
    if(!buf)
@@ -262,13 +307,7 @@ pb_debug_manager_create_buffer(struct pb_manager *_mgr,
    buf->underflow_size = mgr->band_size;
    buf->overflow_size = buf->buffer->base.size - buf->underflow_size - size;
    
-   map = pb_map(buf->buffer, PIPE_BUFFER_USAGE_CPU_WRITE);
-   assert(map);
-   if(map) {
-      fill_random_pattern(map, buf->underflow_size);
-      fill_random_pattern(map + buf->underflow_size + size, buf->overflow_size);
-      pb_unmap(buf->buffer);
-   }
+   pb_debug_buffer_fill(buf);
    
    return &buf->base;
 }
diff --git a/src/gallium/auxiliary/pipebuffer/pb_bufmgr_mm.c b/src/gallium/auxiliary/pipebuffer/pb_bufmgr_mm.c
index b40eb6cc90..e8c7f8e1f8 100644
--- a/src/gallium/auxiliary/pipebuffer/pb_bufmgr_mm.c
+++ b/src/gallium/auxiliary/pipebuffer/pb_bufmgr_mm.c
@@ -53,7 +53,7 @@ struct mm_pb_manager
 {
    struct pb_manager base;
    
-   _glthread_Mutex mutex;
+   pipe_mutex mutex;
    
    size_t size;
    struct mem_block *heap;
@@ -99,10 +99,10 @@ mm_buffer_destroy(struct pb_buffer *buf)
    
    assert(buf->base.refcount == 0);
    
-   _glthread_LOCK_MUTEX(mm->mutex);
+   pipe_mutex_lock(mm->mutex);
    mmFreeMem(mm_buf->block);
    FREE(buf);
-   _glthread_UNLOCK_MUTEX(mm->mutex);
+   pipe_mutex_unlock(mm->mutex);
 }
 
 
@@ -158,11 +158,11 @@ mm_bufmgr_create_buffer(struct pb_manager *mgr,
    if(desc->alignment % (1 << mm->align2))
       return NULL;
    
-   _glthread_LOCK_MUTEX(mm->mutex);
+   pipe_mutex_lock(mm->mutex);
 
    mm_buf = CALLOC_STRUCT(mm_buffer);
    if (!mm_buf) {
-      _glthread_UNLOCK_MUTEX(mm->mutex);
+      pipe_mutex_unlock(mm->mutex);
       return NULL;
    }
 
@@ -185,7 +185,7 @@ mm_bufmgr_create_buffer(struct pb_manager *mgr,
       mm_buf->block = mmAllocMem(mm->heap, size, mm->align2, 0);
       if(!mm_buf->block) {
          FREE(mm_buf);
-         _glthread_UNLOCK_MUTEX(mm->mutex);
+         pipe_mutex_unlock(mm->mutex);
          return NULL;
       }
    }
@@ -194,7 +194,7 @@ mm_bufmgr_create_buffer(struct pb_manager *mgr,
    assert(0 <= (unsigned)mm_buf->block->ofs && (unsigned)mm_buf->block->ofs < mm->size);
    assert(size <= (unsigned)mm_buf->block->size && (unsigned)mm_buf->block->ofs + (unsigned)mm_buf->block->size <= mm->size);
    
-   _glthread_UNLOCK_MUTEX(mm->mutex);
+   pipe_mutex_unlock(mm->mutex);
    return SUPER(mm_buf);
 }
 
@@ -204,14 +204,14 @@ mm_bufmgr_destroy(struct pb_manager *mgr)
 {
    struct mm_pb_manager *mm = mm_pb_manager(mgr);
    
-   _glthread_LOCK_MUTEX(mm->mutex);
+   pipe_mutex_lock(mm->mutex);
 
    mmDestroy(mm->heap);
    
    pb_unmap(mm->buffer);
    pb_reference(&mm->buffer, NULL);
    
-   _glthread_UNLOCK_MUTEX(mm->mutex);
+   pipe_mutex_unlock(mm->mutex);
    
    FREE(mgr);
 }
@@ -236,7 +236,7 @@ mm_bufmgr_create_from_buffer(struct pb_buffer *buffer,
    mm->size = size;
    mm->align2 = align2; /* 64-byte alignment */
 
-   _glthread_INIT_MUTEX(mm->mutex);
+   pipe_mutex_init(mm->mutex);
 
    mm->buffer = buffer; 
 
diff --git a/src/gallium/auxiliary/pipebuffer/pb_bufmgr_pool.c b/src/gallium/auxiliary/pipebuffer/pb_bufmgr_pool.c
index 93d2cc9635..3ef72c5bbb 100644
--- a/src/gallium/auxiliary/pipebuffer/pb_bufmgr_pool.c
+++ b/src/gallium/auxiliary/pipebuffer/pb_bufmgr_pool.c
@@ -56,7 +56,7 @@ struct pool_pb_manager
 {
    struct pb_manager base;
    
-   _glthread_Mutex mutex;
+   pipe_mutex mutex;
    
    size_t bufSize;
    size_t bufAlign;
@@ -110,10 +110,10 @@ pool_buffer_destroy(struct pb_buffer *buf)
    
    assert(pool_buf->base.base.refcount == 0);
 
-   _glthread_LOCK_MUTEX(pool->mutex);
+   pipe_mutex_lock(pool->mutex);
    LIST_ADD(&pool_buf->head, &pool->free);
    pool->numFree++;
-   _glthread_UNLOCK_MUTEX(pool->mutex);
+   pipe_mutex_unlock(pool->mutex);
 }
 
 
@@ -124,9 +124,9 @@ pool_buffer_map(struct pb_buffer *buf, unsigned flags)
    struct pool_pb_manager *pool = pool_buf->mgr;
    void *map;
 
-   _glthread_LOCK_MUTEX(pool->mutex);
+   pipe_mutex_lock(pool->mutex);
    map = (unsigned char *) pool->map + pool_buf->start;
-   _glthread_UNLOCK_MUTEX(pool->mutex);
+   pipe_mutex_unlock(pool->mutex);
    return map;
 }
 
@@ -171,10 +171,10 @@ pool_bufmgr_create_buffer(struct pb_manager *mgr,
    assert(size == pool->bufSize);
    assert(pool->bufAlign % desc->alignment == 0);
    
-   _glthread_LOCK_MUTEX(pool->mutex);
+   pipe_mutex_lock(pool->mutex);
 
    if (pool->numFree == 0) {
-      _glthread_UNLOCK_MUTEX(pool->mutex);
+      pipe_mutex_unlock(pool->mutex);
       debug_printf("warning: out of fixed size buffer objects\n");
       return NULL;
    }
@@ -182,7 +182,7 @@ pool_bufmgr_create_buffer(struct pb_manager *mgr,
    item = pool->free.next;
 
    if (item == &pool->free) {
-      _glthread_UNLOCK_MUTEX(pool->mutex);
+      pipe_mutex_unlock(pool->mutex);
       debug_printf("error: fixed size buffer pool corruption\n");
       return NULL;
    }
@@ -190,7 +190,7 @@ pool_bufmgr_create_buffer(struct pb_manager *mgr,
    LIST_DEL(item);
    --pool->numFree;
 
-   _glthread_UNLOCK_MUTEX(pool->mutex);
+   pipe_mutex_unlock(pool->mutex);
    
    pool_buf = LIST_ENTRY(struct pool_buffer, item, head);
    assert(pool_buf->base.base.refcount == 0);
@@ -206,14 +206,14 @@ static void
 pool_bufmgr_destroy(struct pb_manager *mgr)
 {
    struct pool_pb_manager *pool = pool_pb_manager(mgr);
-   _glthread_LOCK_MUTEX(pool->mutex);
+   pipe_mutex_lock(pool->mutex);
 
    FREE(pool->bufs);
    
    pb_unmap(pool->buffer);
    pb_reference(&pool->buffer, NULL);
    
-   _glthread_UNLOCK_MUTEX(pool->mutex);
+   pipe_mutex_unlock(pool->mutex);
    
    FREE(mgr);
 }
@@ -246,7 +246,7 @@ pool_bufmgr_create(struct pb_manager *provider,
    pool->bufSize = bufSize;
    pool->bufAlign = desc->alignment; 
    
-   _glthread_INIT_MUTEX(pool->mutex);
+   pipe_mutex_init(pool->mutex);
 
    pool->buffer = provider->create_buffer(provider, numBufs*bufSize, desc); 
    if (!pool->buffer)
diff --git a/src/gallium/auxiliary/pipebuffer/pb_bufmgr_slab.c b/src/gallium/auxiliary/pipebuffer/pb_bufmgr_slab.c
index af307e265a..8698c4cff6 100644
--- a/src/gallium/auxiliary/pipebuffer/pb_bufmgr_slab.c
+++ b/src/gallium/auxiliary/pipebuffer/pb_bufmgr_slab.c
@@ -30,6 +30,8 @@
  * @file
  * S-lab pool implementation.
  * 
+ * @sa http://en.wikipedia.org/wiki/Slab_allocation
+ * 
  * @author Thomas Hellstrom <thomas-at-tungstengraphics-dot-com>
  * @author Jose Fonseca <jrfonseca@tungstengraphics.com>
  */
@@ -49,46 +51,96 @@
 
 struct pb_slab;
 
+
+/**
+ * Buffer in a slab.
+ * 
+ * Sub-allocation of a contiguous buffer.
+ */
 struct pb_slab_buffer
 {
    struct pb_buffer base;
    
    struct pb_slab *slab;
+   
    struct list_head head;
+   
    unsigned mapCount;
+   
+   /** Offset relative to the start of the slab buffer. */
    size_t start;
-   _glthread_Cond event;
+   
+   /** Use when validating, to signal that all mappings are finished */
+   /* TODO: Actually validation does not reach this stage yet */
+   pipe_condvar event;
 };
 
+
+/**
+ * Slab -- a contiguous piece of memory. 
+ */
 struct pb_slab
 {
    struct list_head head;
    struct list_head freeBuffers;
    size_t numBuffers;
    size_t numFree;
+   
    struct pb_slab_buffer *buffers;
    struct pb_slab_manager *mgr;
    
+   /** Buffer from the provider */
    struct pb_buffer *bo;
+   
    void *virtual;   
 };
 
+
+/**
+ * It adds/removes slabs as needed in order to meet the allocation/destruction 
+ * of individual buffers.
+ */
 struct pb_slab_manager 
 {
    struct pb_manager base;
    
+   /** From where we get our buffers */
    struct pb_manager *provider;
+   
+   /** Size of the buffers we hand on downstream */
    size_t bufSize;
+   
+   /** Size of the buffers we request upstream */
    size_t slabSize;
+   
+   /** 
+    * Alignment, usage to be used to allocate the slab buffers.
+    * 
+    * We can only provide buffers which are consistent (in alignment, usage) 
+    * with this description.   
+    */
    struct pb_desc desc;
 
+   /** 
+    * Partial slabs
+    * 
+    * Full slabs are not stored in any list. Empty slabs are destroyed 
+    * immediatly.
+    */
    struct list_head slabs;
-   struct list_head freeSlabs;
    
-   _glthread_Mutex mutex;
+   pipe_mutex mutex;
 };
 
+
 /**
+ * Wrapper around several slabs, therefore capable of handling buffers of 
+ * multiple sizes. 
+ * 
+ * This buffer manager just dispatches buffer allocations to the appropriate slab
+ * manager, according to the requested buffer size, or by passes the slab 
+ * managers altogether for even greater sizes.
+ * 
  * The data of this structure remains constant after
  * initialization and thus needs no mutex protection.
  */
@@ -97,12 +149,17 @@ struct pb_slab_range_manager
    struct pb_manager base;
 
    struct pb_manager *provider;
+   
    size_t minBufSize;
    size_t maxBufSize;
+   
+   /** @sa pb_slab_manager::desc */ 
    struct pb_desc desc;
    
    unsigned numBuckets;
    size_t *bucketSizes;
+   
+   /** Array of pb_slab_manager, one for each bucket size */
    struct pb_manager **buckets;
 };
 
@@ -143,7 +200,7 @@ pb_slab_buffer_destroy(struct pb_buffer *_buf)
    struct pb_slab_manager *mgr = slab->mgr;
    struct list_head *list = &buf->head;
 
-   _glthread_LOCK_MUTEX(mgr->mutex);
+   pipe_mutex_lock(mgr->mutex);
    
    assert(buf->base.base.refcount == 0);
    
@@ -156,30 +213,16 @@ pb_slab_buffer_destroy(struct pb_buffer *_buf)
    if (slab->head.next == &slab->head)
       LIST_ADDTAIL(&slab->head, &mgr->slabs);
 
+   /* If the slab becomes totally empty, free it */
    if (slab->numFree == slab->numBuffers) {
       list = &slab->head;
-      LIST_DEL(list);
-      LIST_ADDTAIL(list, &mgr->freeSlabs);
+      LIST_DELINIT(list);
+      pb_reference(&slab->bo, NULL);
+      FREE(slab->buffers);
+      FREE(slab);
    }
 
-   if (mgr->slabs.next == &mgr->slabs || slab->numFree
-	 != slab->numBuffers) {
-
-      struct list_head *next;
-
-      for (list = mgr->freeSlabs.next, next = list->next; list
-	    != &mgr->freeSlabs; list = next, next = list->next) {
-
-	 slab = LIST_ENTRY(struct pb_slab, list, head);
-
-	 LIST_DELINIT(list);
-	 pb_reference(&slab->bo, NULL);
-	 FREE(slab->buffers);
-	 FREE(slab);
-      }
-   }
-   
-   _glthread_UNLOCK_MUTEX(mgr->mutex);
+   pipe_mutex_unlock(mgr->mutex);
 }
 
 
@@ -201,7 +244,7 @@ pb_slab_buffer_unmap(struct pb_buffer *_buf)
 
    --buf->mapCount;
    if (buf->mapCount == 0) 
-       _glthread_COND_BROADCAST(buf->event);
+       pipe_condvar_broadcast(buf->event);
 }
 
 
@@ -225,6 +268,11 @@ pb_slab_buffer_vtbl = {
 };
 
 
+/**
+ * Create a new slab.
+ * 
+ * Called when we ran out of free slabs.
+ */
 static enum pipe_error
 pb_slab_create(struct pb_slab_manager *mgr)
 {
@@ -238,17 +286,14 @@ pb_slab_create(struct pb_slab_manager *mgr)
    if (!slab)
       return PIPE_ERROR_OUT_OF_MEMORY;
 
-   /*
-    * FIXME: We should perhaps allow some variation in slabsize in order
-    * to efficiently reuse slabs.
-    */
-
    slab->bo = mgr->provider->create_buffer(mgr->provider, mgr->slabSize, &mgr->desc);
    if(!slab->bo) {
       ret = PIPE_ERROR_OUT_OF_MEMORY;
       goto out_err0;
    }
 
+   /* Note down the slab virtual address. All mappings are accessed directly 
+    * through this address so it is required that the buffer is pinned. */
    slab->virtual = pb_map(slab->bo, 
                           PIPE_BUFFER_USAGE_CPU_READ |
                           PIPE_BUFFER_USAGE_CPU_WRITE);
@@ -256,7 +301,6 @@ pb_slab_create(struct pb_slab_manager *mgr)
       ret = PIPE_ERROR_OUT_OF_MEMORY;
       goto out_err1;
    }
-
    pb_unmap(slab->bo);
 
    numBuffers = slab->bo->base.size / mgr->bufSize;
@@ -283,12 +327,13 @@ pb_slab_create(struct pb_slab_manager *mgr)
       buf->slab = slab;
       buf->start = i* mgr->bufSize;
       buf->mapCount = 0;
-      _glthread_INIT_COND(buf->event);
+      pipe_condvar_init(buf->event);
       LIST_ADDTAIL(&buf->head, &slab->freeBuffers);
       slab->numFree++;
       buf++;
    }
 
+   /* Add this slab to the list of partial slabs */
    LIST_ADDTAIL(&slab->head, &mgr->slabs);
 
    return PIPE_OK;
@@ -328,23 +373,29 @@ pb_slab_manager_create_buffer(struct pb_manager *_mgr,
    if(!pb_check_usage(desc->usage, mgr->desc.usage))
       return NULL;
 
-   _glthread_LOCK_MUTEX(mgr->mutex);
+   pipe_mutex_lock(mgr->mutex);
+   
+   /* Create a new slab, if we run out of partial slabs */
    if (mgr->slabs.next == &mgr->slabs) {
       (void) pb_slab_create(mgr);
       if (mgr->slabs.next == &mgr->slabs) {
-	 _glthread_UNLOCK_MUTEX(mgr->mutex);
+	 pipe_mutex_unlock(mgr->mutex);
 	 return NULL;
       }
    }
+   
+   /* Allocate the buffer from a partial (or just created) slab */
    list = mgr->slabs.next;
    slab = LIST_ENTRY(struct pb_slab, list, head);
+   
+   /* If totally full remove from the partial slab list */
    if (--slab->numFree == 0)
       LIST_DELINIT(list);
 
    list = slab->freeBuffers.next;
    LIST_DELINIT(list);
 
-   _glthread_UNLOCK_MUTEX(mgr->mutex);
+   pipe_mutex_unlock(mgr->mutex);
    buf = LIST_ENTRY(struct pb_slab_buffer, list, head);
    
    ++buf->base.base.refcount;
@@ -386,9 +437,8 @@ pb_slab_manager_create(struct pb_manager *provider,
    mgr->desc = *desc;
 
    LIST_INITHEAD(&mgr->slabs);
-   LIST_INITHEAD(&mgr->freeSlabs);
    
-   _glthread_INIT_MUTEX(mgr->mutex);
+   pipe_mutex_init(mgr->mutex);
 
    return &mgr->base;
 }