Changeset fdc190f in mainline

Timestamp:

2018-11-13T16:48:08Z (6 years ago)

Author:

Jiří Zárevúcky <zarevucky.jiri@…>

Branches:

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

Children:

bcd4dd4

Parents:

71fb5ac

git-author:

Jiří Zárevúcky <zarevucky.jiri@…> (2018-11-13 16:44:03)

git-committer:

Jiří Zárevúcky <zarevucky.jiri@…> (2018-11-13 16:48:08)

Message:

Split realloc()

File:

• kernel/generic/src/mm/malloc.c (modified) (4 diffs)

kernel/generic/src/mm/malloc.c

@@ -82 +82 @@
 }
 
+static inline bool _is_pow2(size_t x)
+{
+        return (x & (x - 1)) == 0;
+}
+
 static void _check_sizes(size_t *alignment, size_t *size)
 {
@@ -87 +92 @@
         assert(alignment);
 
-        assert(*size > 0);
+        /* Force size to be nonzero. */
+        if (*size == 0)
+                *size = 1;
 
         /* Alignment must be a power of 2. */
-        assert(__builtin_popcountl(*alignment) <= 1);
+        assert(_is_pow2(*alignment));
         assert(*alignment <= PAGE_SIZE);
 
@@ -132 +139 @@
         /* We assume that slab objects are aligned naturally */
         return slab_alloc(cache_for_size(size), FRAME_ATOMIC);
+}
+
+static void *mem_realloc(void *old_ptr, size_t alignment, size_t old_size,
+    size_t new_size)
+{
+        assert(old_ptr);
+        _check_sizes(&alignment, &old_size);
+        _check_sizes(&alignment, &new_size);
+
+        // TODO: handle big objects
+        assert(new_size <= (1 << SLAB_MAX_MALLOC_W));
+
+        slab_cache_t *old_cache = cache_for_size(old_size);
+        slab_cache_t *new_cache = cache_for_size(new_size);
+        if (old_cache == new_cache)
+                return old_ptr;
+
+        void *new_ptr = slab_alloc(new_cache, FRAME_ATOMIC);
+        if (!new_ptr)
+                return NULL;
+
+        memcpy(new_ptr, old_ptr, min(old_size, new_size));
+        slab_free(old_cache, old_ptr);
+        return new_ptr;
 }
 
@@ -186 +217 @@
         size_t old_size = ((size_t *) old_obj)[-1];
 
-        if (cache_for_size(old_size + _offset) ==
-            cache_for_size(new_size + _offset))
-                return old_obj;
-
-        void *new_obj = malloc(new_size);
+        void *new_obj = mem_realloc(old_obj - _offset, alignof(max_align_t),
+            old_size + _offset, new_size + _offset) + _offset;
         if (!new_obj)
                 return NULL;
 
-        memcpy(new_obj, old_obj, min(old_size, new_size));
-        free(old_obj);
+        ((size_t *) new_obj)[-1] = new_size;
         return new_obj;
 }