Changeset 70e2b2d in mainline for kernel/generic/src/sysinfo/sysinfo.c

Timestamp:

2010-04-18T10:23:15Z (15 years ago)

Author:

Martin Decky <martin@…>

Branches:

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

Children:

c3d4bb45

Parents:

da98918

Message:

avoid costly allocation and generation of data when it is actually not necessary

File:

• kernel/generic/src/sysinfo/sysinfo.c (modified) (12 diffs)

kernel/generic/src/sysinfo/sysinfo.c

@@ -496 +496 @@
                 
                 unative_t val;
-                void *data;
                 size_t size;
                 
@@ -518 +517 @@
                         break;
                 case SYSINFO_VAL_FUNCTION_DATA:
-                        data = cur->val.fn_data(cur, &size);
-                        
-                        /* N.B.: The generated binary data should be freed */
-                        if (data != NULL)
-                                free(data);
-                        
+                        /* N.B.: No data was actually returned (only a dry run) */
+                        (void) cur->val.fn_data(cur, &size, true);
                         printf("+ %s (%" PRIs" bytes) [generated]\n", cur->name,
                             size);
@@ -579 +574 @@
  * and sysinfo_lock held.
  *
- * @param name Sysinfo path.
- * @param root Root item of the sysinfo (sub)tree.
- *             If it is NULL then consider the global
- *             sysinfo tree.
+ * @param name    Sysinfo path.
+ * @param root    Root item of the sysinfo (sub)tree.
+ *                If it is NULL then consider the global
+ *                sysinfo tree.
+ * @param dry_run Do not actually get any generated
+ *                binary data, just calculate the size.
  *
  * @return Item value (constant or generated).
  *
  */
-static sysinfo_return_t sysinfo_get_item(const char *name, sysinfo_item_t **root)
+static sysinfo_return_t sysinfo_get_item(const char *name,
+    sysinfo_item_t **root, bool dry_run)
 {
         if (root == NULL)
@@ -614 +612 @@
                         break;
                 case SYSINFO_VAL_FUNCTION_DATA:
-                        ret.data.data = item->val.fn_data(item, &ret.data.size);
+                        ret.data.data = item->val.fn_data(item, &ret.data.size,
+                            dry_run);
                         break;
                 }
@@ -635 +634 @@
  * (the last passed character must be null).
  *
- * @param ptr  Sysinfo path in the user address space.
- * @param size Size of the path string.
- *
- */
-static sysinfo_return_t sysinfo_get_item_uspace(void *ptr, size_t size)
+ * @param ptr     Sysinfo path in the user address space.
+ * @param size    Size of the path string.
+ * @param dry_run Do not actually get any generated
+ *                binary data, just calculate the size.
+ *
+ */
+static sysinfo_return_t sysinfo_get_item_uspace(void *ptr, size_t size,
+    bool dry_run)
 {
         sysinfo_return_t ret;
@@ -652 +654 @@
         if ((copy_from_uspace(path, ptr, size + 1) == 0)
             && (path[size] == 0))
-                ret = sysinfo_get_item(path, NULL);
+                ret = sysinfo_get_item(path, NULL, dry_run);
         
         free(path);
@@ -677 +679 @@
         spinlock_lock(&sysinfo_lock);
         
-        /* Get the item */
-        sysinfo_return_t ret = sysinfo_get_item_uspace(path_ptr, path_size);
-        
-        /* N.B.: The generated binary data should be freed */
-        if ((ret.tag == SYSINFO_VAL_FUNCTION_DATA) && (ret.data.data != NULL))
-                free(ret.data.data);
+        /* Get the item.
+        
+           N.B.: There is no need to free any potential generated
+           binary data since we request a dry run */
+        sysinfo_return_t ret = sysinfo_get_item_uspace(path_ptr, path_size, true);
         
         /* Map generated value types to constant types
@@ -720 +721 @@
         spinlock_lock(&sysinfo_lock);
         
-        /* Get the item */
-        sysinfo_return_t ret = sysinfo_get_item_uspace(path_ptr, path_size);
+        /* Get the item.
+        
+           N.B.: There is no need to free any potential generated
+           binary data since we request a dry run */
+        sysinfo_return_t ret = sysinfo_get_item_uspace(path_ptr, path_size, true);
         int rc;
         
@@ -730 +734 @@
                 rc = EINVAL;
         
-        /* N.B.: The generated binary data should be freed */
-        if ((ret.tag == SYSINFO_VAL_FUNCTION_DATA) && (ret.data.data != NULL))
-                free(ret.data.data);
-        
         spinlock_unlock(&sysinfo_lock);
         interrupts_restore(ipl);
@@ -762 +762 @@
         spinlock_lock(&sysinfo_lock);
         
-        /* Get the item */
-        sysinfo_return_t ret = sysinfo_get_item_uspace(path_ptr, path_size);
+        /* Get the item.
+        
+           N.B.: There is no need to free any potential generated
+           binary data since we request a dry run */
+        sysinfo_return_t ret = sysinfo_get_item_uspace(path_ptr, path_size, true);
         int rc;
         
@@ -773 +776 @@
                 rc = EINVAL;
         
-        /* N.B.: The generated binary data should be freed */
-        if ((ret.tag == SYSINFO_VAL_FUNCTION_DATA) && (ret.data.data != NULL))
-                free(ret.data.data);
-        
         spinlock_unlock(&sysinfo_lock);
         interrupts_restore(ipl);
@@ -811 +810 @@
         
         /* Get the item */
-        sysinfo_return_t ret = sysinfo_get_item_uspace(path_ptr, path_size);
+        sysinfo_return_t ret = sysinfo_get_item_uspace(path_ptr, path_size, false);
         int rc;