WebSVN – HelenOS – Diff – /branches/tracing/kernel/generic/src/mm/buddy.c

 /*
  * Copyright (c) 2005 Jakub Jermar
  * All rights reserved.
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
+ *
  * - Redistributions of source code must retain the above copyright
  *   notice, this list of conditions and the following disclaimer.
  * - Redistributions in binary form must reproduce the above copyright
  *   notice, this list of conditions and the following disclaimer in the
  *   documentation and/or other materials provided with the distribution.
  * - The name of the author may not be used to endorse or promote products
  *   derived from this software without specific prior written permission.
+ *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 /** @addtogroup genericmm
  * @{
  */
 /**
  * @file
  * @brief   Buddy allocator framework.
+ *
  * This file contains buddy system allocator framework.
- * Specialized functions are needed for this abstract framework
+ * Specialized functions are needed for this abstract framework to be useful.
- * to be useful.
  */
 #include <mm/buddy.h>
 #include <mm/frame.h>
 #include <arch/types.h>
 #include <debug.h>
 #include <print.h>
 #include <macros.h>
-/** Return size needed for the buddy configuration data */
+/** Return size needed for the buddy configuration data. */
 size_t buddy_conf_size(int max_order)
+{
     return sizeof(buddy_system_t) + (max_order + 1) * sizeof(link_t);
+}
-/** Create buddy system
+/** Create buddy system.
+ *
  * Allocate memory for and initialize new buddy system.
+ *
- * @param b Preallocated buddy system control data.
+ * @param b     Preallocated buddy system control data.
  * @param max_order The biggest allocable size will be 2^max_order.
- * @param op Operations for new buddy system.
+ * @param op        Operations for new buddy system.
- * @param data Pointer to be used by implementation.
+ * @param data      Pointer to be used by implementation.
  *
- * @return New buddy system.
+ * @return      New buddy system.
  */
+void
-void buddy_system_create(buddy_system_t *b,
+buddy_system_create(buddy_system_t *b, uint8_t max_order,
-             uint8_t max_order,
-             buddy_system_operations_t *op,
+    buddy_system_operations_t *op, void *data)
-             void *data)
+{
     int i;
     ASSERT(max_order < BUDDY_SYSTEM_INNER_BLOCK);
     ASSERT(op->find_buddy);
     ASSERT(op->set_order);
     ASSERT(op->get_order);
     ASSERT(op->bisect);
     ASSERT(op->coalesce);
     ASSERT(op->mark_busy);
     /*
-     * Use memory after our own structure
+     * Use memory after our own structure.
      */
     b->order = (link_t *) (&b[1]);
     for (i = 0; i <= max_order; i++)
         list_initialize(&b->order[i]);
     b->max_order = max_order;
     b->op = op;
     b->data = data;
+}
-/** Check if buddy system can allocate block
+/** Check if buddy system can allocate block.
+ *
- * @param b Buddy system pointer
+ * @param b     Buddy system pointer.
- * @param i Size of the block (2^i)
+ * @param i     Size of the block (2^i).
+ *
- * @return True if block can be allocated
+ * @return      True if block can be allocated.
  */
-bool buddy_system_can_alloc(buddy_system_t *b, uint8_t i) {
+bool buddy_system_can_alloc(buddy_system_t *b, uint8_t i)
+{
     uint8_t k;
     /*
      * If requested block is greater then maximal block
      * we know immediatly that we cannot satisfy the request.
      */
-    if (i > b->max_order) return false;
+    if (i > b->max_order)
+        return false;
     /*
      * Check if any bigger or equal order has free elements
      */
-    for (k=i; k <= b->max_order; k++) {
+    for (k = i; k <= b->max_order; k++) {
         if (!list_empty(&b->order[k])) {
             return true;
+        }
+    }
     return false;
+}
-/** Allocate PARTICULAR block from buddy system
+/** Allocate PARTICULAR block from buddy system.
+ *
- * @ return Block of data or NULL if no such block was found
+ * @return      Block of data or NULL if no such block was found.
  */
 link_t *buddy_system_alloc_block(buddy_system_t *b, link_t *block)
+{
     link_t *left,*right, *tmp;
     uint8_t order;
     left = b->op->find_block(b, block, BUDDY_SYSTEM_INNER_BLOCK);
     ASSERT(left);
     list_remove(left);
     while (1) {
-        if (! b->op->get_order(b,left)) {
+        if (!b->op->get_order(b, left)) {
             b->op->mark_busy(b, left);
             return left;
+        }
         order = b->op->get_order(b, left);
         right = b->op->bisect(b, left);
-        b->op->set_order(b, left, order-1);
+        b->op->set_order(b, left, order - 1);
-        b->op->set_order(b, right, order-1);
+        b->op->set_order(b, right, order - 1);
         tmp = b->op->find_block(b, block, BUDDY_SYSTEM_INNER_BLOCK);
         if (tmp == right) {
             right = left;
             left = tmp;
+        }
         ASSERT(tmp == left);
         b->op->mark_busy(b, left);
         buddy_system_free(b, right);
         b->op->mark_available(b, left);
+    }
+}
 /** Allocate block from buddy system.
+ *
- * @param b Buddy system pointer.
+ * @param b     Buddy system pointer.
- * @param i Returned block will be 2^i big.
+ * @param i     Returned block will be 2^i big.
+ *
- * @return Block of data represented by link_t.
+ * @return      Block of data represented by link_t.
  */
 link_t *buddy_system_alloc(buddy_system_t *b, uint8_t i)
+{
     link_t *res, *hlp;
     ASSERT(i <= b->max_order);
     /*
      * If the list of order i is not empty,
      * the request can be immediatelly satisfied.
      */
     if (!list_empty(&b->order[i])) {
         res = b->order[i].next;
         list_remove(res);
         b->op->mark_busy(b, res);
         return res;
+    }
     /*
      * If order i is already the maximal order,
      * the request cannot be satisfied.
      */
     if (i == b->max_order)
         return NULL;
     /*
      * Try to recursively satisfy the request from higher order lists.
      */
     hlp = buddy_system_alloc(b, i + 1);
     /*
      * The request could not be satisfied
      * from higher order lists.
      */
     if (!hlp)
         return NULL;
     res = hlp;
     /*
      * Bisect the block and set order of both of its parts to i.
      */
     hlp = b->op->bisect(b, res);
     b->op->set_order(b, res, i);
     b->op->set_order(b, hlp, i);
     /*
      * Return the other half to buddy system. Mark the first part
      * full, so that it won't coalesce again.
      */
     b->op->mark_busy(b, res);
     buddy_system_free(b, hlp);
     return res;
+}
 /** Return block to buddy system.
+ *
- * @param b Buddy system pointer.
+ * @param b     Buddy system pointer.
- * @param block Block to return.
+ * @param block     Block to return.
  */
 void buddy_system_free(buddy_system_t *b, link_t *block)
+{
     link_t *buddy, *hlp;
     uint8_t i;
     /*
      * Determine block's order.
      */
     i = b->op->get_order(b, block);
     ASSERT(i <= b->max_order);
     if (i != b->max_order) {
         /*
          * See if there is any buddy in the list of order i.
          */
         buddy = b->op->find_buddy(b, block);
         if (buddy) {
             ASSERT(b->op->get_order(b, buddy) == i);
             /*
              * Remove buddy from the list of order i.
              */
             list_remove(buddy);
             /*
              * Invalidate order of both block and buddy.
              */
             b->op->set_order(b, block, BUDDY_SYSTEM_INNER_BLOCK);
             b->op->set_order(b, buddy, BUDDY_SYSTEM_INNER_BLOCK);
             /*
              * Coalesce block and buddy into one block.
              */
             hlp = b->op->coalesce(b, block, buddy);
             /*
              * Set order of the coalesced block to i + 1.
              */
             b->op->set_order(b, hlp, i + 1);
             /*
-             * Recursively add the coalesced block to the list of order i + 1.
+             * Recursively add the coalesced block to the list of
+             * order i + 1.
              */
             buddy_system_free(b, hlp);
             return;
+        }
+    }
     /*
      * Insert block into the list of order i.
      */
     list_append(block, &b->order[i]);
-}
-/** Prints out structure of buddy system
- *
- * @param b Pointer to buddy system
- * @param elem_size Element size
- */
-void buddy_system_structure_print(buddy_system_t *b, size_t elem_size) {
-    index_t i;
-    count_t cnt, elem_count = 0, block_count = 0;
-    link_t *cur;
-    printf("Order\tBlocks\tSize    \tBlock size\tElems per block\n");
-    printf("-----\t------\t--------\t----------\t---------------\n");
-    for (i = 0;i <= b->max_order; i++) {
-        cnt = 0;
-        if (!list_empty(&b->order[i])) {
-            for (cur = b->order[i].next; cur != &b->order[i]; cur = cur->next)
-                cnt++;
-        }
-        printf("#%" PRIi "\t%5" PRIc "\t%7" PRIc "K\t%8" PRIi "K\t%6u\t",
-            i, cnt, SIZE2KB(cnt * (1 << i) * elem_size), SIZE2KB((1 << i) * elem_size), 1 << i);
-        if (!list_empty(&b->order[i])) {
-            for (cur = b->order[i].next; cur != &b->order[i]; cur = cur->next) {
-                b->op->print_id(b, cur);
-                printf(" ");
-            }
-        }
-        printf("\n");
-        block_count += cnt;
-        elem_count += (1 << i) * cnt;
-    }
-    printf("-----\t------\t--------\t----------\t---------------\n");
-    printf("Buddy system contains %" PRIc " free elements (%" PRIc " blocks)\n" , elem_count, block_count);
+}
 /** @}
  */

Subversion Repositories HelenOS

(root)/branches/tracing/kernel/generic/src/mm/buddy.c – Rev 3424 → 3425