Changeset 0773396 in mainline for kernel/generic/src/mm/frame.c

Timestamp:

2013-12-25T13:05:25Z (10 years ago)

Author:

Martin Decky <martin@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

bc54126c

Parents:

f4a47e52 (diff), 6946f23 (diff)
Note: this is a merge changeset, the changes displayed below correspond to the merge itself.
Use the (diff) links above to see all the changes relative to each parent.

Message:

merge mainline changes

File:

• kernel/generic/src/mm/frame.c (modified) (57 diffs)

kernel/generic/src/mm/frame.c

@@ -38 +38 @@
  *
  * This file contains the physical frame allocator and memory zone management.
- * The frame allocator is built on top of the buddy allocator.
- *
- * @see buddy.c
+ * The frame allocator is built on top of the two-level bitmap structure.
+ *
  */
 
@@ -92 +91 @@
 }
 
-NO_TRACE static inline size_t make_frame_index(zone_t *zone, frame_t *frame)
-{
-        return (frame - zone->frames);
-}
-
 /** Initialize frame structure.
  *
@@ -104 +98 @@
 NO_TRACE static void frame_initialize(frame_t *frame)
 {
-        frame->refcount = 1;
-        frame->buddy_order = 0;
+        frame->refcount = 0;
+        frame->parent = NULL;
 }
 
@@ -161 +155 @@
         
         /* Move other zones up */
-        size_t j;
-        for (j = zones.count; j > i; j--) {
+        for (size_t j = zones.count; j > i; j--)
                 zones.info[j] = zones.info[j - 1];
-                if (zones.info[j].buddy_system != NULL)
-                        zones.info[j].buddy_system->data =
-                            (void *) &zones.info[j];
-        }
         
         zones.count++;
@@ -237 +226 @@
 }
 
-/** @return True if zone can allocate specified order */
-NO_TRACE static bool zone_can_alloc(zone_t *zone, uint8_t order)
-{
+/** @return True if zone can allocate specified number of frames */
+NO_TRACE static bool zone_can_alloc(zone_t *zone, size_t count,
+    pfn_t constraint)
+{
+        /*
+         * The function bitmap_allocate_range() does not modify
+         * the bitmap if the last argument is NULL.
+         */
+        
         return ((zone->flags & ZONE_AVAILABLE) &&
-            buddy_system_can_alloc(zone->buddy_system, order));
-}
-
-/** Find a zone that can allocate order frames.
+            bitmap_allocate_range(&zone->bitmap, count, zone->base,
+            FRAME_LOWPRIO, constraint, NULL));
+}
+
+/** Find a zone that can allocate specified number of frames
+ *
+ * This function searches among all zones. Assume interrupts are
+ * disabled and zones lock is locked.
+ *
+ * @param count      Number of free frames we are trying to find.
+ * @param flags      Required flags of the zone.
+ * @param constraint Indication of bits that cannot be set in the
+ *                   physical frame number of the first allocated frame.
+ * @param hint       Preferred zone.
+ *
+ * @return Zone that can allocate specified number of frames.
+ * @return -1 if no zone can satisfy the request.
+ *
+ */
+NO_TRACE static size_t find_free_zone_all(size_t count, zone_flags_t flags,
+    pfn_t constraint, size_t hint)
+{
+        for (size_t pos = 0; pos < zones.count; pos++) {
+                size_t i = (pos + hint) % zones.count;
+                
+                /* Check whether the zone meets the search criteria. */
+                if (!ZONE_FLAGS_MATCH(zones.info[i].flags, flags))
+                        continue;
+                
+                /* Check if the zone can satisfy the allocation request. */
+                if (zone_can_alloc(&zones.info[i], count, constraint))
+                        return i;
+        }
+        
+        return (size_t) -1;
+}
+
+/** Check if frame range  priority memory
+ *
+ * @param pfn   Starting frame.
+ * @param count Number of frames.
+ *
+ * @return True if the range contains only priority memory.
+ *
+ */
+NO_TRACE static bool is_high_priority(pfn_t base, size_t count)
+{
+        return (base + count <= FRAME_LOWPRIO);
+}
+
+/** Find a zone that can allocate specified number of frames
+ *
+ * This function ignores zones that contain only high-priority
+ * memory. Assume interrupts are disabled and zones lock is locked.
+ *
+ * @param count      Number of free frames we are trying to find.
+ * @param flags      Required flags of the zone.
+ * @param constraint Indication of bits that cannot be set in the
+ *                   physical frame number of the first allocated frame.
+ * @param hint       Preferred zone.
+ *
+ * @return Zone that can allocate specified number of frames.
+ * @return -1 if no low-priority zone can satisfy the request.
+ *
+ */
+NO_TRACE static size_t find_free_zone_lowprio(size_t count, zone_flags_t flags,
+    pfn_t constraint, size_t hint)
+{       
+        for (size_t pos = 0; pos < zones.count; pos++) {
+                size_t i = (pos + hint) % zones.count;
+                
+                /* Skip zones containing only high-priority memory. */
+                if (is_high_priority(zones.info[i].base, zones.info[i].count))
+                        continue;
+                
+                /* Check whether the zone meets the search criteria. */
+                if (!ZONE_FLAGS_MATCH(zones.info[i].flags, flags))
+                        continue;
+                
+                /* Check if the zone can satisfy the allocation request. */
+                if (zone_can_alloc(&zones.info[i], count, constraint))
+                        return i;
+        }
+        
+        return (size_t) -1;
+}
+
+/** Find a zone that can allocate specified number of frames
  *
  * Assume interrupts are disabled and zones lock is
  * locked.
  *
- * @param order Size (2^order) of free space we are trying to find.
- * @param flags Required flags of the target zone.
- * @param hind  Preferred zone.
- *
- */
-NO_TRACE static size_t find_free_zone(uint8_t order, zone_flags_t flags,
-    size_t hint)
+ * @param count      Number of free frames we are trying to find.
+ * @param flags      Required flags of the target zone.
+ * @param constraint Indication of bits that cannot be set in the
+ *                   physical frame number of the first allocated frame.
+ * @param hint       Preferred zone.
+ *
+ * @return Zone that can allocate specified number of frames.
+ * @return -1 if no zone can satisfy the request.
+ *
+ */
+NO_TRACE static size_t find_free_zone(size_t count, zone_flags_t flags,
+    pfn_t constraint, size_t hint)
 {
         if (hint >= zones.count)
                 hint = 0;
         
-        size_t i = hint;
-        do {
-                /*
-                 * Check whether the zone meets the search criteria.
-                 */
-                if (ZONE_FLAGS_MATCH(zones.info[i].flags, flags)) {
-                        /*
-                         * Check if the zone has 2^order frames area available.
-                         */
-                        if (zone_can_alloc(&zones.info[i], order))
-                                return i;
-                }
-                
-                i++;
-                if (i >= zones.count)
-                        i = 0;
-                
-        } while (i != hint);
-        
-        return (size_t) -1;
-}
-
-/**************************/
-/* Buddy system functions */
-/**************************/
-
-/** Buddy system find_block implementation.
- *
- * Find block that is parent of current list.
- * That means go to lower addresses, until such block is found
- *
- * @param order Order of parent must be different then this
- *              parameter!!
- *
- */
-NO_TRACE static link_t *zone_buddy_find_block(buddy_system_t *buddy,
-    link_t *child, uint8_t order)
-{
-        frame_t *frame = list_get_instance(child, frame_t, buddy_link);
-        zone_t *zone = (zone_t *) buddy->data;
-        
-        size_t index = frame_index(zone, frame);
-        do {
-                if (zone->frames[index].buddy_order != order)
-                        return &zone->frames[index].buddy_link;
-        } while (index-- > 0);
-        
-        return NULL;
-}
-
-/** Buddy system find_buddy implementation.
- *
- * @param buddy Buddy system.
- * @param block Block for which buddy should be found.
- *
- * @return Buddy for given block if found.
- *
- */
-NO_TRACE static link_t *zone_buddy_find_buddy(buddy_system_t *buddy,
-    link_t *block)
-{
-        frame_t *frame = list_get_instance(block, frame_t, buddy_link);
-        zone_t *zone = (zone_t *) buddy->data;
-        ASSERT(IS_BUDDY_ORDER_OK(frame_index_abs(zone, frame),
-            frame->buddy_order));
-        
-        bool is_left = IS_BUDDY_LEFT_BLOCK_ABS(zone, frame);
-        
-        size_t index;
-        if (is_left) {
-                index = (frame_index(zone, frame)) +
-                    (1 << frame->buddy_order);
-        } else {  /* is_right */
-                index = (frame_index(zone, frame)) -
-                    (1 << frame->buddy_order);
-        }
-        
-        if (frame_index_valid(zone, index)) {
-                if ((zone->frames[index].buddy_order == frame->buddy_order) &&
-                    (zone->frames[index].refcount == 0)) {
-                        return &zone->frames[index].buddy_link;
-                }
-        }
-        
-        return NULL;
-}
-
-/** Buddy system bisect implementation.
- *
- * @param buddy Buddy system.
- * @param block Block to bisect.
- *
- * @return Right block.
- *
- */
-NO_TRACE static link_t *zone_buddy_bisect(buddy_system_t *buddy, link_t *block)
-{
-        frame_t *frame_l = list_get_instance(block, frame_t, buddy_link);
-        frame_t *frame_r = (frame_l + (1 << (frame_l->buddy_order - 1)));
-        
-        return &frame_r->buddy_link;
-}
-
-/** Buddy system coalesce implementation.
- *
- * @param buddy   Buddy system.
- * @param block_1 First block.
- * @param block_2 First block's buddy.
- *
- * @return Coalesced block (actually block that represents lower
- *         address).
- *
- */
-NO_TRACE static link_t *zone_buddy_coalesce(buddy_system_t *buddy,
-    link_t *block_1, link_t *block_2)
-{
-        frame_t *frame1 = list_get_instance(block_1, frame_t, buddy_link);
-        frame_t *frame2 = list_get_instance(block_2, frame_t, buddy_link);
-        
-        return ((frame1 < frame2) ? block_1 : block_2);
-}
-
-/** Buddy system set_order implementation.
- *
- * @param buddy Buddy system.
- * @param block Buddy system block.
- * @param order Order to set.
- *
- */
-NO_TRACE static void zone_buddy_set_order(buddy_system_t *buddy, link_t *block,
-    uint8_t order)
-{
-        list_get_instance(block, frame_t, buddy_link)->buddy_order = order;
-}
-
-/** Buddy system get_order implementation.
- *
- * @param buddy Buddy system.
- * @param block Buddy system block.
- *
- * @return Order of block.
- *
- */
-NO_TRACE static uint8_t zone_buddy_get_order(buddy_system_t *buddy,
-    link_t *block)
-{
-        return list_get_instance(block, frame_t, buddy_link)->buddy_order;
-}
-
-/** Buddy system mark_busy implementation.
- *
- * @param buddy Buddy system.
- * @param block Buddy system block.
- *
- */
-NO_TRACE static void zone_buddy_mark_busy(buddy_system_t *buddy, link_t *block)
-{
-        list_get_instance(block, frame_t, buddy_link)->refcount = 1;
-}
-
-/** Buddy system mark_available implementation.
- *
- * @param buddy Buddy system.
- * @param block Buddy system block.
- *
- */
-NO_TRACE static void zone_buddy_mark_available(buddy_system_t *buddy,
-    link_t *block)
-{
-        list_get_instance(block, frame_t, buddy_link)->refcount = 0;
-}
-
-static buddy_system_operations_t zone_buddy_system_operations = {
-        .find_buddy = zone_buddy_find_buddy,
-        .bisect = zone_buddy_bisect,
-        .coalesce = zone_buddy_coalesce,
-        .set_order = zone_buddy_set_order,
-        .get_order = zone_buddy_get_order,
-        .mark_busy = zone_buddy_mark_busy,
-        .mark_available = zone_buddy_mark_available,
-        .find_block = zone_buddy_find_block
-};
+        /*
+         * Prefer zones with low-priority memory over
+         * zones with high-priority memory.
+         */
+        
+        size_t znum = find_free_zone_lowprio(count, flags, constraint, hint);
+        if (znum != (size_t) -1)
+                return znum;
+        
+        /* Take all zones into account */
+        return find_free_zone_all(count, flags, constraint, hint);
+}
 
 /******************/
@@ -447 +361 @@
 /******************/
 
+/** Return frame from zone. */
+NO_TRACE static frame_t *zone_get_frame(zone_t *zone, size_t index)
+{
+        ASSERT(index < zone->count);
+        
+        return &zone->frames[index];
+}
+
 /** Allocate frame in particular zone.
  *
@@ -452 +374 @@
  * Panics if allocation is impossible.
  *
- * @param zone  Zone to allocate from.
- * @param order Allocate exactly 2^order frames.
+ * @param zone       Zone to allocate from.
+ * @param count      Number of frames to allocate
+ * @param constraint Indication of bits that cannot be set in the
+ *                   physical frame number of the first allocated frame.
  *
  * @return Frame index in zone.
  *
  */
-NO_TRACE static pfn_t zone_frame_alloc(zone_t *zone, uint8_t order)
+NO_TRACE static size_t zone_frame_alloc(zone_t *zone, size_t count,
+    pfn_t constraint)
 {
         ASSERT(zone->flags & ZONE_AVAILABLE);
         
-        /* Allocate frames from zone buddy system */
-        link_t *link = buddy_system_alloc(zone->buddy_system, order);
-        
-        ASSERT(link);
+        /* Allocate frames from zone */
+        size_t index;
+        int avail = bitmap_allocate_range(&zone->bitmap, count, zone->base,
+            FRAME_LOWPRIO, constraint, &index);
+        
+        ASSERT(avail);
+        
+        /* Update frame reference count */
+        for (size_t i = 0; i < count; i++) {
+                frame_t *frame = zone_get_frame(zone, index + i);
+                
+                ASSERT(frame->refcount == 0);
+                frame->refcount = 1;
+        }
         
         /* Update zone information. */
-        zone->free_count -= (1 << order);
-        zone->busy_count += (1 << order);
-        
-        /* Frame will be actually a first frame of the block. */
-        frame_t *frame = list_get_instance(link, frame_t, buddy_link);
-        
-        /* Get frame address */
-        return make_frame_index(zone, frame);
+        zone->free_count -= count;
+        zone->busy_count += count;
+        
+        return index;
 }
 
@@ -482 +413 @@
  * Assume zone is locked and is available for deallocation.
  *
- * @param zone      Pointer to zone from which the frame is to be freed.
- * @param frame_idx Frame index relative to zone.
- *
- * @return          Number of freed frames.
- *
- */
-NO_TRACE static size_t zone_frame_free(zone_t *zone, size_t frame_idx)
+ * @param zone  Pointer to zone from which the frame is to be freed.
+ * @param index Frame index relative to zone.
+ *
+ * @return Number of freed frames.
+ *
+ */
+NO_TRACE static size_t zone_frame_free(zone_t *zone, size_t index)
 {
         ASSERT(zone->flags & ZONE_AVAILABLE);
         
-        frame_t *frame = &zone->frames[frame_idx];
-        size_t size = 0;
-        
-        ASSERT(frame->refcount);
+        frame_t *frame = zone_get_frame(zone, index);
+        
+        ASSERT(frame->refcount > 0);
         
         if (!--frame->refcount) {
-                size = 1 << frame->buddy_order;
-                buddy_system_free(zone->buddy_system, &frame->buddy_link);              
+                bitmap_set(&zone->bitmap, index, 0);
+                
                 /* Update zone information. */
-                zone->free_count += size;
-                zone->busy_count -= size;
-        }
-        
-        return size;
-}
-
-/** Return frame from zone. */
-NO_TRACE static frame_t *zone_get_frame(zone_t *zone, size_t frame_idx)
-{
-        ASSERT(frame_idx < zone->count);
-        return &zone->frames[frame_idx];
+                zone->free_count++;
+                zone->busy_count--;
+                
+                return 1;
+        }
+        
+        return 0;
 }
 
 /** Mark frame in zone unavailable to allocation. */
-NO_TRACE static void zone_mark_unavailable(zone_t *zone, size_t frame_idx)
-{
-        if (!(zone->flags & ZONE_AVAILABLE))
+NO_TRACE static void zone_mark_unavailable(zone_t *zone, size_t index)
+{
+        ASSERT(zone->flags & ZONE_AVAILABLE);
+        
+        frame_t *frame = zone_get_frame(zone, index);
+        if (frame->refcount > 0)
                 return;
-//      ASSERT(zone->flags & ZONE_AVAILABLE);
-        
-        frame_t *frame = zone_get_frame(zone, frame_idx);
-        if (frame->refcount)
-                return;
-        
-        link_t *link __attribute__ ((unused));
-        
-        link = buddy_system_alloc_block(zone->buddy_system,
-            &frame->buddy_link);
-        
-        ASSERT(link);
+        
+        frame->refcount = 1;
+        bitmap_set_range(&zone->bitmap, index, 1);
+        
         zone->free_count--;
         reserve_force_alloc(1);
@@ -538 +458 @@
 /** Merge two zones.
  *
- * Expect buddy to point to space at least zone_conf_size large.
  * Assume z1 & z2 are locked and compatible and zones lock is
  * locked.
  *
- * @param z1     First zone to merge.
- * @param z2     Second zone to merge.
- * @param old_z1 Original date of the first zone.
- * @param buddy  Merged zone buddy.
+ * @param z1       First zone to merge.
+ * @param z2       Second zone to merge.
+ * @param old_z1   Original data of the first zone.
+ * @param confdata Merged zone configuration data.
  *
  */
 NO_TRACE static void zone_merge_internal(size_t z1, size_t z2, zone_t *old_z1,
-    buddy_system_t *buddy)
+    void *confdata)
 {
         ASSERT(zones.info[z1].flags & ZONE_AVAILABLE);
@@ -564 +483 @@
         zones.info[z1].free_count += zones.info[z2].free_count;
         zones.info[z1].busy_count += zones.info[z2].busy_count;
-        zones.info[z1].buddy_system = buddy;
-        
-        uint8_t order = fnzb(zones.info[z1].count);
-        buddy_system_create(zones.info[z1].buddy_system, order,
-            &zone_buddy_system_operations, (void *) &zones.info[z1]);
-        
-        zones.info[z1].frames =
-            (frame_t *) ((uint8_t *) zones.info[z1].buddy_system
-            + buddy_conf_size(order));
-        
-        /* This marks all frames busy */
-        size_t i;
-        for (i = 0; i < zones.info[z1].count; i++)
-                frame_initialize(&zones.info[z1].frames[i]);
-        
-        /* Copy frames from both zones to preserve full frame orders,
-         * parents etc. Set all free frames with refcount = 0 to 1, because
-         * we add all free frames to buddy allocator later again, clearing
-         * order to 0. Don't set busy frames with refcount = 0, as they
-         * will not be reallocated during merge and it would make later
-         * problems with allocation/free.
+        
+        bitmap_initialize(&zones.info[z1].bitmap, zones.info[z1].count,
+            confdata + (sizeof(frame_t) * zones.info[z1].count));
+        bitmap_clear_range(&zones.info[z1].bitmap, 0, zones.info[z1].count);
+        
+        zones.info[z1].frames = (frame_t *) confdata;
+        
+        /*
+         * Copy frames and bits from both zones to preserve parents, etc.
          */
-        for (i = 0; i < old_z1->count; i++)
+        
+        for (size_t i = 0; i < old_z1->count; i++) {
+                bitmap_set(&zones.info[z1].bitmap, i,
+                    bitmap_get(&old_z1->bitmap, i));
                 zones.info[z1].frames[i] = old_z1->frames[i];
-        
-        for (i = 0; i < zones.info[z2].count; i++)
-                zones.info[z1].frames[base_diff + i]
-                    = zones.info[z2].frames[i];
-        
-        i = 0;
-        while (i < zones.info[z1].count) {
-                if (zones.info[z1].frames[i].refcount) {
-                        /* Skip busy frames */
-                        i += 1 << zones.info[z1].frames[i].buddy_order;
-                } else {
-                        /* Free frames, set refcount = 1
-                         * (all free frames have refcount == 0, we need not
-                         * to check the order)
-                         */
-                        zones.info[z1].frames[i].refcount = 1;
-                        zones.info[z1].frames[i].buddy_order = 0;
-                        i++;
-                }
-        }
-        
-        /* Add free blocks from the original zone z1 */
-        while (zone_can_alloc(old_z1, 0)) {
-                /* Allocate from the original zone */
-                pfn_t frame_idx = zone_frame_alloc(old_z1, 0);
-                
-                /* Free the frame from the merged zone */
-                frame_t *frame = &zones.info[z1].frames[frame_idx];
-                frame->refcount = 0;
-                buddy_system_free(zones.info[z1].buddy_system, &frame->buddy_link);
-        }
-        
-        /* Add free blocks from the original zone z2 */
-        while (zone_can_alloc(&zones.info[z2], 0)) {
-                /* Allocate from the original zone */
-                pfn_t frame_idx = zone_frame_alloc(&zones.info[z2], 0);
-                
-                /* Free the frame from the merged zone */
-                frame_t *frame = &zones.info[z1].frames[base_diff + frame_idx];
-                frame->refcount = 0;
-                buddy_system_free(zones.info[z1].buddy_system, &frame->buddy_link);
+        }
+        
+        for (size_t i = 0; i < zones.info[z2].count; i++) {
+                bitmap_set(&zones.info[z1].bitmap, base_diff + i,
+                    bitmap_get(&zones.info[z2].bitmap, i));
+                zones.info[z1].frames[base_diff + i] =
+                    zones.info[z2].frames[i];
         }
 }
@@ -651 +527 @@
         size_t cframes = SIZE2FRAMES(zone_conf_size(count));
         
-        if ((pfn < zones.info[znum].base)
-            || (pfn >= zones.info[znum].base + zones.info[znum].count))
+        if ((pfn < zones.info[znum].base) ||
+            (pfn >= zones.info[znum].base + zones.info[znum].count))
                 return;
         
-        frame_t *frame __attribute__ ((unused));
-
-        frame = &zones.info[znum].frames[pfn - zones.info[znum].base];
-        ASSERT(!frame->buddy_order);
-        
-        size_t i;
-        for (i = 0; i < cframes; i++) {
-                zones.info[znum].busy_count++;
+        for (size_t i = 0; i < cframes; i++)
                 (void) zone_frame_free(&zones.info[znum],
                     pfn - zones.info[znum].base + i);
-        }
-}
-
-/** Reduce allocated block to count of order 0 frames.
- *
- * The allocated block needs 2^order frames. Reduce all frames
- * in the block to order 0 and free the unneeded frames. This means that
- * when freeing the previously allocated block starting with frame_idx,
- * you have to free every frame.
- *
- * @param znum      Zone.
- * @param frame_idx Index the first frame of the block.
- * @param count     Allocated frames in block.
- *
- */
-NO_TRACE static void zone_reduce_region(size_t znum, pfn_t frame_idx,
-    size_t count)
-{
-        ASSERT(zones.info[znum].flags & ZONE_AVAILABLE);
-        ASSERT(frame_idx + count < zones.info[znum].count);
-        
-        uint8_t order = zones.info[znum].frames[frame_idx].buddy_order;
-        ASSERT((size_t) (1 << order) >= count);
-        
-        /* Reduce all blocks to order 0 */
-        size_t i;
-        for (i = 0; i < (size_t) (1 << order); i++) {
-                frame_t *frame = &zones.info[znum].frames[i + frame_idx];
-                frame->buddy_order = 0;
-                if (!frame->refcount)
-                        frame->refcount = 1;
-                ASSERT(frame->refcount == 1);
-        }
-        
-        /* Free unneeded frames */
-        for (i = count; i < (size_t) (1 << order); i++)
-                (void) zone_frame_free(&zones.info[znum], i + frame_idx);
 }
 
@@ -721 +553 @@
         bool ret = true;
         
-        /* We can join only 2 zones with none existing inbetween,
+        /*
+         * We can join only 2 zones with none existing inbetween,
          * the zones have to be available and with the same
          * set of flags
@@ -735 +568 @@
             + zones.info[z2].count));
         
-        uint8_t order;
-        if (cframes == 1)
-                order = 0;
-        else
-                order = fnzb(cframes - 1) + 1;
-        
         /* Allocate merged zone data inside one of the zones */
         pfn_t pfn;
-        if (zone_can_alloc(&zones.info[z1], order)) {
-                pfn = zones.info[z1].base + zone_frame_alloc(&zones.info[z1], order);
-        } else if (zone_can_alloc(&zones.info[z2], order)) {
-                pfn = zones.info[z2].base + zone_frame_alloc(&zones.info[z2], order);
+        if (zone_can_alloc(&zones.info[z1], cframes, 0)) {
+                pfn = zones.info[z1].base +
+                    zone_frame_alloc(&zones.info[z1], cframes, 0);
+        } else if (zone_can_alloc(&zones.info[z2], cframes, 0)) {
+                pfn = zones.info[z2].base +
+                    zone_frame_alloc(&zones.info[z2], cframes, 0);
         } else {
                 ret = false;
@@ -754 +583 @@
         /* Preserve original data from z1 */
         zone_t old_z1 = zones.info[z1];
-        old_z1.buddy_system->data = (void *) &old_z1;
         
         /* Do zone merging */
-        buddy_system_t *buddy = (buddy_system_t *) PA2KA(PFN2ADDR(pfn));
-        zone_merge_internal(z1, z2, &old_z1, buddy);
-        
-        /* Free unneeded config frames */
-        zone_reduce_region(z1, pfn - zones.info[z1].base, cframes);
+        zone_merge_internal(z1, z2, &old_z1, (void *) PA2KA(PFN2ADDR(pfn)));
         
         /* Subtract zone information from busy frames */
@@ -774 +598 @@
         
         /* Move zones down */
-        size_t i;
-        for (i = z2 + 1; i < zones.count; i++) {
+        for (size_t i = z2 + 1; i < zones.count; i++)
                 zones.info[i - 1] = zones.info[i];
-                if (zones.info[i - 1].buddy_system != NULL)
-                        zones.info[i - 1].buddy_system->data =
-                            (void *) &zones.info[i - 1];
-        }
         
         zones.count--;
@@ -799 +618 @@
 void zone_merge_all(void)
 {
-        size_t i = 0;
+        size_t i = 1;
+        
         while (i < zones.count) {
-                if (!zone_merge(i, i + 1))
+                if (!zone_merge(i - 1, i))
                         i++;
         }
@@ -808 +628 @@
 /** Create new frame zone.
  *
- * @param zone  Zone to construct.
- * @param buddy Address of buddy system configuration information.
- * @param start Physical address of the first frame within the zone.
- * @param count Count of frames in zone.
- * @param flags Zone flags.
+ * @param zone     Zone to construct.
+ * @param start    Physical address of the first frame within the zone.
+ * @param count    Count of frames in zone.
+ * @param flags    Zone flags.
+ * @param confdata Configuration data of the zone.
  *
  * @return Initialized zone.
  *
  */
-NO_TRACE static void zone_construct(zone_t *zone, buddy_system_t *buddy,
-    pfn_t start, size_t count, zone_flags_t flags)
+NO_TRACE static void zone_construct(zone_t *zone, pfn_t start, size_t count,
+    zone_flags_t flags, void *confdata)
 {
         zone->base = start;
@@ -825 +645 @@
         zone->free_count = count;
         zone->busy_count = 0;
-        zone->buddy_system = buddy;
         
         if (flags & ZONE_AVAILABLE) {
                 /*
-                 * Compute order for buddy system and initialize
+                 * Initialize frame bitmap (located after the array of
+                 * frame_t structures in the configuration space).
                  */
-                uint8_t order = fnzb(count);
-                buddy_system_create(zone->buddy_system, order,
-                    &zone_buddy_system_operations, (void *) zone);
-                
-                /* Allocate frames _after_ the confframe */
-                
-                /* Check sizes */
-                zone->frames = (frame_t *) ((uint8_t *) zone->buddy_system +
-                    buddy_conf_size(order));
-                
-                size_t i;
-                for (i = 0; i < count; i++)
+                
+                bitmap_initialize(&zone->bitmap, count, confdata +
+                    (sizeof(frame_t) * count));
+                bitmap_clear_range(&zone->bitmap, 0, count);
+                
+                /*
+                 * Initialize the array of frame_t structures.
+                 */
+                
+                zone->frames = (frame_t *) confdata;
+                
+                for (size_t i = 0; i < count; i++)
                         frame_initialize(&zone->frames[i]);
-                
-                /* Stuffing frames */
-                for (i = 0; i < count; i++) {
-                        zone->frames[i].refcount = 0;
-                        buddy_system_free(zone->buddy_system, &zone->frames[i].buddy_link);
-                }
-        } else
+        } else {
+                bitmap_initialize(&zone->bitmap, 0, NULL);
                 zone->frames = NULL;
+        }
 }
 
@@ -863 +679 @@
 size_t zone_conf_size(size_t count)
 {
-        return (count * sizeof(frame_t) + buddy_conf_size(fnzb(count)));
+        return (count * sizeof(frame_t) + bitmap_size(count));
 }
 
@@ -869 +685 @@
 pfn_t zone_external_conf_alloc(size_t count)
 {
-        size_t size = zone_conf_size(count);
-        size_t order = ispwr2(size) ? fnzb(size) : (fnzb(size) + 1);
-
-        return ADDR2PFN((uintptr_t) frame_alloc(order - FRAME_WIDTH,
-            FRAME_LOWMEM | FRAME_ATOMIC));
+        size_t frames = SIZE2FRAMES(zone_conf_size(count));
+        
+        return ADDR2PFN((uintptr_t)
+            frame_alloc(frames, FRAME_LOWMEM | FRAME_ATOMIC, 0));
 }
 
@@ -881 +696 @@
  * @param count     Size of zone in frames.
  * @param confframe Where configuration frames are supposed to be.
- *                  Automatically checks, that we will not disturb the
+ *                  Automatically checks that we will not disturb the
  *                  kernel and possibly init. If confframe is given
  *                  _outside_ this zone, it is expected, that the area is
@@ -898 +713 @@
         
         if (flags & ZONE_AVAILABLE) {  /* Create available zone */
-                /* Theoretically we could have NULL here, practically make sure
+                /*
+                 * Theoretically we could have NULL here, practically make sure
                  * nobody tries to do that. If some platform requires, remove
                  * the assert
                  */
                 ASSERT(confframe != ADDR2PFN((uintptr_t ) NULL));
-
+                
                 /* Update the known end of physical memory. */
                 config.physmem_end = max(config.physmem_end, PFN2ADDR(start + count));
                 
-                /* If confframe is supposed to be inside our zone, then make sure
+                /*
+                 * If confframe is supposed to be inside our zone, then make sure
                  * it does not span kernel & init
                  */
                 size_t confcount = SIZE2FRAMES(zone_conf_size(count));
+                
                 if ((confframe >= start) && (confframe < start + count)) {
                         for (; confframe < start + count; confframe++) {
@@ -923 +741 @@
                                 
                                 bool overlap = false;
-                                size_t i;
-                                for (i = 0; i < init.cnt; i++)
+                                for (size_t i = 0; i < init.cnt; i++) {
                                         if (overlaps(addr, PFN2ADDR(confcount),
                                             init.tasks[i].paddr,
@@ -931 +748 @@
                                                 break;
                                         }
+                                }
+                                
                                 if (overlap)
                                         continue;
@@ -937 +756 @@
                         }
                         
-                        if (confframe >= start + count) {
-                                flags &= ~ZONE_AVAILABLE;
-                                goto nonavail;
-//                              panic("Cannot find configuration data for zone.");
-                        }
+                        if (confframe >= start + count)
+                                panic("Cannot find configuration data for zone.");
                 }
                 
@@ -950 +766 @@
                 }
                 
-                buddy_system_t *buddy = (buddy_system_t *) PA2KA(PFN2ADDR(confframe));
-                zone_construct(&zones.info[znum], buddy, start, count, flags);
+                void *confdata = (void *) PA2KA(PFN2ADDR(confframe));
+                zone_construct(&zones.info[znum], start, count, flags, confdata);
                 
                 /* If confdata in zone, mark as unavailable */
                 if ((confframe >= start) && (confframe < start + count)) {
-                        size_t i;
-                        for (i = confframe; i < confframe + confcount; i++)
+                        for (size_t i = confframe; i < confframe + confcount; i++)
                                 zone_mark_unavailable(&zones.info[znum],
                                     i - zones.info[znum].base);
@@ -965 +780 @@
                 return znum;
         }
-nonavail:
-        (void)0; // label trick
+        
         /* Non-available zone */
         size_t znum = zones_insert_zone(start, count, flags);
@@ -973 +787 @@
                 return (size_t) -1;
         }
-        zone_construct(&zones.info[znum], NULL, start, count, flags);
+        
+        zone_construct(&zones.info[znum], start, count, flags, NULL);
         
         irq_spinlock_unlock(&zones.lock, true);
@@ -1015 +830 @@
 }
 
-/** Allocate power-of-two frames of physical memory.
- *
- * @param order Allocate exactly 2^order frames.
- * @param flags Flags for host zone selection and address processing.
- * @param pzone Preferred zone.
+/** Allocate frames of physical memory.
+ *
+ * @param count      Number of continuous frames to allocate.
+ * @param flags      Flags for host zone selection and address processing.
+ * @param constraint Indication of physical address bits that cannot be
+ *                   set in the address of the first allocated frame.
+ * @param pzone      Preferred zone.
  *
  * @return Physical address of the allocated frame.
  *
  */
-void *frame_alloc_generic(uint8_t order, frame_flags_t flags, size_t *pzone)
-{
-        size_t size = ((size_t) 1) << order;
+uintptr_t frame_alloc_generic(size_t count, frame_flags_t flags,
+    uintptr_t constraint, size_t *pzone)
+{
+        ASSERT(count > 0);
+        
         size_t hint = pzone ? (*pzone) : 0;
+        pfn_t frame_constraint = ADDR2PFN(constraint);
         
         /*
          * If not told otherwise, we must first reserve the memory.
          */
-        if (!(flags & FRAME_NO_RESERVE)) 
-                reserve_force_alloc(size);
-
+        if (!(flags & FRAME_NO_RESERVE))
+                reserve_force_alloc(count);
+        
 loop:
         irq_spinlock_lock(&zones.lock, true);
@@ -1041 +861 @@
          * First, find suitable frame zone.
          */
-        size_t znum = find_free_zone(order,
-            FRAME_TO_ZONE_FLAGS(flags), hint);
-        
-        /* If no memory, reclaim some slab memory,
-           if it does not help, reclaim all */
+        size_t znum = find_free_zone(count, FRAME_TO_ZONE_FLAGS(flags),
+            frame_constraint, hint);
+        
+        /*
+         * If no memory, reclaim some slab memory,
+         * if it does not help, reclaim all.
+         */
         if ((znum == (size_t) -1) && (!(flags & FRAME_NO_RECLAIM))) {
                 irq_spinlock_unlock(&zones.lock, true);
@@ -1052 +874 @@
                 
                 if (freed > 0)
-                        znum = find_free_zone(order,
-                            FRAME_TO_ZONE_FLAGS(flags), hint);
+                        znum = find_free_zone(count, FRAME_TO_ZONE_FLAGS(flags),
+                            frame_constraint, hint);
                 
                 if (znum == (size_t) -1) {
@@ -1061 +883 @@
                         
                         if (freed > 0)
-                                znum = find_free_zone(order,
-                                    FRAME_TO_ZONE_FLAGS(flags), hint);
+                                znum = find_free_zone(count, FRAME_TO_ZONE_FLAGS(flags),
+                                    frame_constraint, hint);
                 }
         }
@@ -1069 +891 @@
                 if (flags & FRAME_ATOMIC) {
                         irq_spinlock_unlock(&zones.lock, true);
+                        
                         if (!(flags & FRAME_NO_RESERVE))
-                                reserve_free(size);
-                        return NULL;
+                                reserve_free(count);
+                        
+                        return 0;
                 }
                 
@@ -1081 +905 @@
                 
                 if (!THREAD)
-                        panic("Cannot wait for memory to become available.");
+                        panic("Cannot wait for %zu frames to become available "
+                            "(%zu available).", count, avail);
                 
                 /*
@@ -1088 +913 @@
                 
 #ifdef CONFIG_DEBUG
-                printf("Thread %" PRIu64 " waiting for %zu frames, "
-                    "%zu available.\n", THREAD->tid, size, avail);
+                printf("Thread %" PRIu64 " waiting for %zu frames "
+                    "(%zu available).\n", THREAD->tid, count, avail);
 #endif
                 
                 /*
-                 * Since the mem_avail_mtx is an active mutex, we need to disable interrupts
-                 * to prevent deadlock with TLB shootdown.
+                 * Since the mem_avail_mtx is an active mutex, we need to
+                 * disable interrupts to prevent deadlock with TLB shootdown.
                  */
                 ipl_t ipl = interrupts_disable();
@@ -1100 +925 @@
                 
                 if (mem_avail_req > 0)
-                        mem_avail_req = min(mem_avail_req, size);
+                        mem_avail_req = min(mem_avail_req, count);
                 else
-                        mem_avail_req = size;
+                        mem_avail_req = count;
+                
                 size_t gen = mem_avail_gen;
                 
@@ -1118 +944 @@
         }
         
-        pfn_t pfn = zone_frame_alloc(&zones.info[znum], order)
-            + zones.info[znum].base;
+        pfn_t pfn = zone_frame_alloc(&zones.info[znum], count,
+            frame_constraint) + zones.info[znum].base;
         
         irq_spinlock_unlock(&zones.lock, true);
@@ -1126 +952 @@
                 *pzone = znum;
         
-        if (flags & FRAME_KA)
-                return (void *) PA2KA(PFN2ADDR(pfn));
-        
-        return (void *) PFN2ADDR(pfn);
-}
-
-void *frame_alloc(uint8_t order, frame_flags_t flags)
-{
-        return frame_alloc_generic(order, flags, NULL);
-}
-
-void *frame_alloc_noreserve(uint8_t order, frame_flags_t flags)
-{
-        return frame_alloc_generic(order, flags | FRAME_NO_RESERVE, NULL);
-}
-
-/** Free a frame.
- *
- * Find respective frame structure for supplied physical frame address.
- * Decrement frame reference count. If it drops to zero, move the frame
- * structure to free list.
- *
- * @param frame Physical Address of of the frame to be freed.
+        return PFN2ADDR(pfn);
+}
+
+uintptr_t frame_alloc(size_t count, frame_flags_t flags, uintptr_t constraint)
+{
+        return frame_alloc_generic(count, flags, constraint, NULL);
+}
+
+/** Free frames of physical memory.
+ *
+ * Find respective frame structures for supplied physical frames.
+ * Decrement each frame reference count. If it drops to zero, mark
+ * the frames as available.
+ *
+ * @param start Physical Address of the first frame to be freed.
+ * @param count Number of frames to free.
  * @param flags Flags to control memory reservation.
  *
  */
-void frame_free_generic(uintptr_t frame, frame_flags_t flags)
-{
-        size_t size;
+void frame_free_generic(uintptr_t start, size_t count, frame_flags_t flags)
+{
+        size_t freed = 0;
         
         irq_spinlock_lock(&zones.lock, true);
         
-        /*
-         * First, find host frame zone for addr.
-         */
-        pfn_t pfn = ADDR2PFN(frame);
-        size_t znum = find_zone(pfn, 1, 0);
-
-        ASSERT(znum != (size_t) -1);
-        
-        size = zone_frame_free(&zones.info[znum], pfn - zones.info[znum].base);
+        for (size_t i = 0; i < count; i++) {
+                /*
+                 * First, find host frame zone for addr.
+                 */
+                pfn_t pfn = ADDR2PFN(start) + i;
+                size_t znum = find_zone(pfn, 1, 0);
+                
+                ASSERT(znum != (size_t) -1);
+                
+                freed += zone_frame_free(&zones.info[znum],
+                    pfn - zones.info[znum].base);
+        }
         
         irq_spinlock_unlock(&zones.lock, true);
@@ -1172 +994 @@
         /*
          * Signal that some memory has been freed.
+         * Since the mem_avail_mtx is an active mutex,
+         * we need to disable interruptsto prevent deadlock
+         * with TLB shootdown.
          */
-
-        
-        /*
-         * Since the mem_avail_mtx is an active mutex, we need to disable interrupts
-         * to prevent deadlock with TLB shootdown.
-         */
+        
         ipl_t ipl = interrupts_disable();
         mutex_lock(&mem_avail_mtx);
+        
         if (mem_avail_req > 0)
-                mem_avail_req -= min(mem_avail_req, size);
+                mem_avail_req -= min(mem_avail_req, freed);
         
         if (mem_avail_req == 0) {
@@ -1188 +1009 @@
                 condvar_broadcast(&mem_avail_cv);
         }
+        
         mutex_unlock(&mem_avail_mtx);
         interrupts_restore(ipl);
         
         if (!(flags & FRAME_NO_RESERVE))
-                reserve_free(size);
-}
-
-void frame_free(uintptr_t frame)
-{
-        frame_free_generic(frame, 0);
-}
-
-void frame_free_noreserve(uintptr_t frame)
-{
-        frame_free_generic(frame, FRAME_NO_RESERVE);
+                reserve_free(freed);
+}
+
+void frame_free(uintptr_t frame, size_t count)
+{
+        frame_free_generic(frame, count, 0);
+}
+
+void frame_free_noreserve(uintptr_t frame, size_t count)
+{
+        frame_free_generic(frame, count, FRAME_NO_RESERVE);
 }
 
@@ -1236 +1058 @@
         irq_spinlock_lock(&zones.lock, true);
         
-        size_t i;
-        for (i = 0; i < count; i++) {
+        for (size_t i = 0; i < count; i++) {
                 size_t znum = find_zone(start + i, 1, 0);
+                
                 if (znum == (size_t) -1)  /* PFN not found */
                         continue;
@@ -1263 +1085 @@
         /* Tell the architecture to create some memory */
         frame_low_arch_init();
+        
         if (config.cpu_active == 1) {
                 frame_mark_unavailable(ADDR2PFN(KA2PA(config.base)),
@@ -1269 +1092 @@
                     SIZE2FRAMES(config.stack_size));
                 
-                size_t i;
-                for (i = 0; i < init.cnt; i++) {
-                        pfn_t pfn = ADDR2PFN(init.tasks[i].paddr);
-                        frame_mark_unavailable(pfn,
+                for (size_t i = 0; i < init.cnt; i++)
+                        frame_mark_unavailable(ADDR2PFN(init.tasks[i].paddr),
                             SIZE2FRAMES(init.tasks[i].size));
-                }
                 
                 if (ballocs.size)
@@ -1280 +1100 @@
                             SIZE2FRAMES(ballocs.size));
                 
-                /* Black list first frame, as allocating NULL would
+                /*
+                 * Blacklist first frame, as allocating NULL would
                  * fail in some places
                  */
                 frame_mark_unavailable(0, 1);
         }
+        
         frame_high_arch_init();
 }
@@ -1290 +1112 @@
 /** Adjust bounds of physical memory region according to low/high memory split.
  *
- * @param low[in]       If true, the adjustment is performed to make the region
- *                      fit in the low memory. Otherwise the adjustment is
- *                      performed to make the region fit in the high memory.
- * @param basep[inout]  Pointer to a variable which contains the region's base
- *                      address and which may receive the adjusted base address.
- * @param sizep[inout]  Pointer to a variable which contains the region's size
- *                      and which may receive the adjusted size.
- * @retun               True if the region still exists even after the
- *                      adjustment, false otherwise.
+ * @param low[in]      If true, the adjustment is performed to make the region
+ *                     fit in the low memory. Otherwise the adjustment is
+ *                     performed to make the region fit in the high memory.
+ * @param basep[inout] Pointer to a variable which contains the region's base
+ *                     address and which may receive the adjusted base address.
+ * @param sizep[inout] Pointer to a variable which contains the region's size
+ *                     and which may receive the adjusted size.
+ *
+ * @return True if the region still exists even after the adjustment.
+ * @return False otherwise.
+ *
  */
 bool frame_adjust_zone_bounds(bool low, uintptr_t *basep, size_t *sizep)
 {
         uintptr_t limit = KA2PA(config.identity_base) + config.identity_size;
-
+        
         if (low) {
                 if (*basep > limit)
                         return false;
+                
                 if (*basep + *sizep > limit)
                         *sizep = limit - *basep;
@@ -1312 +1137 @@
                 if (*basep + *sizep <= limit)
                         return false;
+                
                 if (*basep <= limit) {
                         *sizep -= limit - *basep;
@@ -1317 +1143 @@
                 }
         }
+        
         return true;
 }
@@ -1328 +1155 @@
         
         uint64_t total = 0;
-        size_t i;
-        for (i = 0; i < zones.count; i++)
+        
+        for (size_t i = 0; i < zones.count; i++)
                 total += (uint64_t) FRAMES2SIZE(zones.info[i].count);
         
@@ -1352 +1179 @@
         *free = 0;
         
-        size_t i;
-        for (i = 0; i < zones.count; i++) {
+        for (size_t i = 0; i < zones.count; i++) {
                 *total += (uint64_t) FRAMES2SIZE(zones.info[i].count);
                 
@@ -1381 +1207 @@
         /*
          * Because printing may require allocation of memory, we may not hold
-         * the frame allocator locks when printing zone statistics.  Therefore,
+         * the frame allocator locks when printing zone statistics. Therefore,
          * we simply gather the statistics under the protection of the locks and
          * print the statistics when the locks have been released.
@@ -1390 +1216 @@
          */
         
-        size_t i;
-        for (i = 0;; i++) {
+        size_t free_lowmem = 0;
+        size_t free_highmem = 0;
+        size_t free_highprio = 0;
+        
+        for (size_t i = 0;; i++) {
                 irq_spinlock_lock(&zones.lock, true);
                 
@@ -1399 +1228 @@
                 }
                 
-                uintptr_t base = PFN2ADDR(zones.info[i].base);
+                pfn_t fbase = zones.info[i].base;
+                uintptr_t base = PFN2ADDR(fbase);
                 size_t count = zones.info[i].count;
                 zone_flags_t flags = zones.info[i].flags;
@@ -1405 +1235 @@
                 size_t busy_count = zones.info[i].busy_count;
                 
+                bool available = ((flags & ZONE_AVAILABLE) != 0);
+                bool lowmem = ((flags & ZONE_LOWMEM) != 0);
+                bool highmem = ((flags & ZONE_HIGHMEM) != 0);
+                bool highprio = is_high_priority(fbase, count);
+                
+                if (available) {
+                        if (lowmem)
+                                free_lowmem += free_count;
+                        
+                        if (highmem)
+                                free_highmem += free_count;
+                        
+                        if (highprio) {
+                                free_highprio += free_count;
+                        } else {
+                                /*
+                                 * Walk all frames of the zone and examine
+                                 * all high priority memory to get accurate
+                                 * statistics.
+                                 */
+                                
+                                for (size_t index = 0; index < count; index++) {
+                                        if (is_high_priority(fbase + index, 0)) {
+                                                if (!bitmap_get(&zones.info[i].bitmap, index))
+                                                        free_highprio++;
+                                        } else
+                                                break;
+                                }
+                        }
+                }
+                
                 irq_spinlock_unlock(&zones.lock, true);
-                
-                bool available = ((flags & ZONE_AVAILABLE) != 0);
                 
                 printf("%-4zu", i);
@@ -1432 +1291 @@
                 printf("\n");
         }
+        
+        printf("\n");
+        
+        uint64_t size;
+        const char *size_suffix;
+        
+        bin_order_suffix(FRAMES2SIZE(free_lowmem), &size, &size_suffix,
+            false);
+        printf("Available low memory:    %zu frames (%" PRIu64 " %s)\n",
+            free_lowmem, size, size_suffix);
+        
+        bin_order_suffix(FRAMES2SIZE(free_highmem), &size, &size_suffix,
+            false);
+        printf("Available high memory:   %zu frames (%" PRIu64 " %s)\n",
+            free_highmem, size, size_suffix);
+        
+        bin_order_suffix(FRAMES2SIZE(free_highprio), &size, &size_suffix,
+            false);
+        printf("Available high priority: %zu frames (%" PRIu64 " %s)\n",
+            free_highprio, size, size_suffix);
 }
 
@@ -1444 +1323 @@
         size_t znum = (size_t) -1;
         
-        size_t i;
-        for (i = 0; i < zones.count; i++) {
+        for (size_t i = 0; i < zones.count; i++) {
                 if ((i == num) || (PFN2ADDR(zones.info[i].base) == num)) {
                         znum = i;
@@ -1458 +1336 @@
         }
         
-        uintptr_t base = PFN2ADDR(zones.info[i].base);
-        zone_flags_t flags = zones.info[i].flags;
-        size_t count = zones.info[i].count;
-        size_t free_count = zones.info[i].free_count;
-        size_t busy_count = zones.info[i].busy_count;
+        size_t free_lowmem = 0;
+        size_t free_highmem = 0;
+        size_t free_highprio = 0;
+        
+        pfn_t fbase = zones.info[znum].base;
+        uintptr_t base = PFN2ADDR(fbase);
+        zone_flags_t flags = zones.info[znum].flags;
+        size_t count = zones.info[znum].count;
+        size_t free_count = zones.info[znum].free_count;
+        size_t busy_count = zones.info[znum].busy_count;
+        
+        bool available = ((flags & ZONE_AVAILABLE) != 0);
+        bool lowmem = ((flags & ZONE_LOWMEM) != 0);
+        bool highmem = ((flags & ZONE_HIGHMEM) != 0);
+        bool highprio = is_high_priority(fbase, count);
+        
+        if (available) {
+                if (lowmem)
+                        free_lowmem = free_count;
+                
+                if (highmem)
+                        free_highmem = free_count;
+                
+                if (highprio) {
+                        free_highprio = free_count;
+                } else {
+                        /*
+                         * Walk all frames of the zone and examine
+                         * all high priority memory to get accurate
+                         * statistics.
+                         */
+                        
+                        for (size_t index = 0; index < count; index++) {
+                                if (is_high_priority(fbase + index, 0)) {
+                                        if (!bitmap_get(&zones.info[znum].bitmap, index))
+                                                free_highprio++;
+                                } else
+                                        break;
+                        }
+                }
+        }
         
         irq_spinlock_unlock(&zones.lock, true);
-        
-        bool available = ((flags & ZONE_AVAILABLE) != 0);
         
         uint64_t size;
         const char *size_suffix;
+        
         bin_order_suffix(FRAMES2SIZE(count), &size, &size_suffix, false);
         
-        printf("Zone number:       %zu\n", znum);
-        printf("Zone base address: %p\n", (void *) base);
-        printf("Zone size:         %zu frames (%" PRIu64 " %s)\n", count,
+        printf("Zone number:             %zu\n", znum);
+        printf("Zone base address:       %p\n", (void *) base);
+        printf("Zone size:               %zu frames (%" PRIu64 " %s)\n", count,
             size, size_suffix);
-        printf("Zone flags:        %c%c%c%c%c\n",
+        printf("Zone flags:              %c%c%c%c%c\n",
             available ? 'A' : '-',
             (flags & ZONE_RESERVED) ? 'R' : '-',
@@ -1486 +1399 @@
                 bin_order_suffix(FRAMES2SIZE(busy_count), &size, &size_suffix,
                     false);
-                printf("Allocated space:   %zu frames (%" PRIu64 " %s)\n",
+                printf("Allocated space:         %zu frames (%" PRIu64 " %s)\n",
                     busy_count, size, size_suffix);
+                
                 bin_order_suffix(FRAMES2SIZE(free_count), &size, &size_suffix,
                     false);
-                printf("Available space:   %zu frames (%" PRIu64 " %s)\n",
+                printf("Available space:         %zu frames (%" PRIu64 " %s)\n",
                     free_count, size, size_suffix);
+                
+                bin_order_suffix(FRAMES2SIZE(free_lowmem), &size, &size_suffix,
+                    false);
+                printf("Available low memory:    %zu frames (%" PRIu64 " %s)\n",
+                    free_lowmem, size, size_suffix);
+                
+                bin_order_suffix(FRAMES2SIZE(free_highmem), &size, &size_suffix,
+                    false);
+                printf("Available high memory:   %zu frames (%" PRIu64 " %s)\n",
+                    free_highmem, size, size_suffix);
+                
+                bin_order_suffix(FRAMES2SIZE(free_highprio), &size, &size_suffix,
+                    false);
+                printf("Available high priority: %zu frames (%" PRIu64 " %s)\n",
+                    free_highprio, size, size_suffix);
         }
 }